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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/kernel/events/core.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Performance events core code:
*
* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
* Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
* Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*/
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/idr.h>
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/hash.h>
#include <linux/tick.h>
#include <linux/sysfs.h>
#include <linux/dcache.h>
#include <linux/percpu.h>
#include <linux/ptrace.h>
#include <linux/reboot.h>
#include <linux/vmstat.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/vmalloc.h>
#include <linux/hardirq.h>
#include <linux/hugetlb.h>
#include <linux/rculist.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/anon_inodes.h>
#include <linux/kernel_stat.h>
#include <linux/cgroup.h>
#include <linux/perf_event.h>
#include <linux/trace_events.h>
#include <linux/hw_breakpoint.h>
#include <linux/mm_types.h>
#include <linux/module.h>
#include <linux/mman.h>
#include <linux/compat.h>
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/namei.h>
#include <linux/parser.h>
#include <linux/sched/clock.h>
#include <linux/sched/mm.h>
#include <linux/proc_ns.h>
#include <linux/mount.h>
#include <linux/min_heap.h>
#include <linux/highmem.h>
#include <linux/pgtable.h>
#include <linux/buildid.h>
#include "internal.h"
#include <asm/irq_regs.h>
typedef int (*remote_function_f)(void *);
struct remote_function_call {
struct task_struct *p;
remote_function_f func;
void *info;
int ret;
};
static void remote_function(void *data)
{
struct remote_function_call *tfc = data;
struct task_struct *p = tfc->p;
if (p) {
/* -EAGAIN */
if (task_cpu(p) != smp_processor_id())
return;
/*
* Now that we're on right CPU with IRQs disabled, we can test
* if we hit the right task without races.
*/
tfc->ret = -ESRCH; /* No such (running) process */
if (p != current)
return;
}
tfc->ret = tfc->func(tfc->info);
}
/**
* task_function_call - call a function on the cpu on which a task runs
* @p: the task to evaluate
* @func: the function to be called
* @info: the function call argument
*
* Calls the function @func when the task is currently running. This might
* be on the current CPU, which just calls the function directly. This will
* retry due to any failures in smp_call_function_single(), such as if the
* task_cpu() goes offline concurrently.
*
* returns @func return value or -ESRCH or -ENXIO when the process isn't running
*/
static int
task_function_call(struct task_struct *p, remote_function_f func, void *info)
{
struct remote_function_call data = {
.p = p,
.func = func,
.info = info,
.ret = -EAGAIN,
};
int ret;
for (;;) {
ret = smp_call_function_single(task_cpu(p), remote_function,
&data, 1);
if (!ret)
ret = data.ret;
if (ret != -EAGAIN)
break;
cond_resched();
}
return ret;
}
/**
* cpu_function_call - call a function on the cpu
* @cpu: target cpu to queue this function
* @func: the function to be called
* @info: the function call argument
*
* Calls the function @func on the remote cpu.
*
* returns: @func return value or -ENXIO when the cpu is offline
*/
static int cpu_function_call(int cpu, remote_function_f func, void *info)
{
struct remote_function_call data = {
.p = NULL,
.func = func,
.info = info,
.ret = -ENXIO, /* No such CPU */
};
smp_call_function_single(cpu, remote_function, &data, 1);
return data.ret;
}
static inline struct perf_cpu_context *
__get_cpu_context(struct perf_event_context *ctx)
{
return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
}
static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
raw_spin_lock(&cpuctx->ctx.lock);
if (ctx)
raw_spin_lock(&ctx->lock);
}
static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
if (ctx)
raw_spin_unlock(&ctx->lock);
raw_spin_unlock(&cpuctx->ctx.lock);
}
#define TASK_TOMBSTONE ((void *)-1L)
static bool is_kernel_event(struct perf_event *event)
{
return READ_ONCE(event->owner) == TASK_TOMBSTONE;
}
/*
* On task ctx scheduling...
*
* When !ctx->nr_events a task context will not be scheduled. This means
* we can disable the scheduler hooks (for performance) without leaving
* pending task ctx state.
*
* This however results in two special cases:
*
* - removing the last event from a task ctx; this is relatively straight
* forward and is done in __perf_remove_from_context.
*
* - adding the first event to a task ctx; this is tricky because we cannot
* rely on ctx->is_active and therefore cannot use event_function_call().
* See perf_install_in_context().
*
* If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
*/
typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
struct perf_event_context *, void *);
struct event_function_struct {
struct perf_event *event;
event_f func;
void *data;
};
static int event_function(void *info)
{
struct event_function_struct *efs = info;
struct perf_event *event = efs->event;
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct perf_event_context *task_ctx = cpuctx->task_ctx;
int ret = 0;
lockdep_assert_irqs_disabled();
perf_ctx_lock(cpuctx, task_ctx);
/*
* Since we do the IPI call without holding ctx->lock things can have
* changed, double check we hit the task we set out to hit.
*/
if (ctx->task) {
if (ctx->task != current) {
ret = -ESRCH;
goto unlock;
}
/*
* We only use event_function_call() on established contexts,
* and event_function() is only ever called when active (or
* rather, we'll have bailed in task_function_call() or the
* above ctx->task != current test), therefore we must have
* ctx->is_active here.
*/
WARN_ON_ONCE(!ctx->is_active);
/*
* And since we have ctx->is_active, cpuctx->task_ctx must
* match.
*/
WARN_ON_ONCE(task_ctx != ctx);
} else {
WARN_ON_ONCE(&cpuctx->ctx != ctx);
}
efs->func(event, cpuctx, ctx, efs->data);
unlock:
perf_ctx_unlock(cpuctx, task_ctx);
return ret;
}
static void event_function_call(struct perf_event *event, event_f func, void *data)
{
struct perf_event_context *ctx = event->ctx;
struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
struct event_function_struct efs = {
.event = event,
.func = func,
.data = data,
};
if (!event->parent) {
/*
* If this is a !child event, we must hold ctx::mutex to
* stabilize the event->ctx relation. See
* perf_event_ctx_lock().
*/
lockdep_assert_held(&ctx->mutex);
}
if (!task) {
cpu_function_call(event->cpu, event_function, &efs);
return;
}
if (task == TASK_TOMBSTONE)
return;
again:
if (!task_function_call(task, event_function, &efs))
return;
raw_spin_lock_irq(&ctx->lock);
/*
* Reload the task pointer, it might have been changed by
* a concurrent perf_event_context_sched_out().
*/
task = ctx->task;
if (task == TASK_TOMBSTONE) {
raw_spin_unlock_irq(&ctx->lock);
return;
}
if (ctx->is_active) {
raw_spin_unlock_irq(&ctx->lock);
goto again;
}
func(event, NULL, ctx, data);
raw_spin_unlock_irq(&ctx->lock);
}
/*
* Similar to event_function_call() + event_function(), but hard assumes IRQs
* are already disabled and we're on the right CPU.
*/
static void event_function_local(struct perf_event *event, event_f func, void *data)
{
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct task_struct *task = READ_ONCE(ctx->task);
struct perf_event_context *task_ctx = NULL;
lockdep_assert_irqs_disabled();
if (task) {
if (task == TASK_TOMBSTONE)
return;
task_ctx = ctx;
}
perf_ctx_lock(cpuctx, task_ctx);
task = ctx->task;
if (task == TASK_TOMBSTONE)
goto unlock;
if (task) {
/*
* We must be either inactive or active and the right task,
* otherwise we're screwed, since we cannot IPI to somewhere
* else.
*/
if (ctx->is_active) {
if (WARN_ON_ONCE(task != current))
goto unlock;
if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
goto unlock;
}
} else {
WARN_ON_ONCE(&cpuctx->ctx != ctx);
}
func(event, cpuctx, ctx, data);
unlock:
perf_ctx_unlock(cpuctx, task_ctx);
}
#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
PERF_FLAG_FD_OUTPUT |\
PERF_FLAG_PID_CGROUP |\
PERF_FLAG_FD_CLOEXEC)
/*
* branch priv levels that need permission checks
*/
#define PERF_SAMPLE_BRANCH_PERM_PLM \
(PERF_SAMPLE_BRANCH_KERNEL |\
PERF_SAMPLE_BRANCH_HV)
enum event_type_t {
EVENT_FLEXIBLE = 0x1,
EVENT_PINNED = 0x2,
EVENT_TIME = 0x4,
/* see ctx_resched() for details */
EVENT_CPU = 0x8,
EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
};
/*
* perf_sched_events : >0 events exist
* perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
*/
static void perf_sched_delayed(struct work_struct *work);
DEFINE_STATIC_KEY_FALSE(perf_sched_events);
static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
static DEFINE_MUTEX(perf_sched_mutex);
static atomic_t perf_sched_count;
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
static DEFINE_PER_CPU(int, perf_sched_cb_usages);
static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
static atomic_t nr_namespaces_events __read_mostly;
static atomic_t nr_task_events __read_mostly;
static atomic_t nr_freq_events __read_mostly;
static atomic_t nr_switch_events __read_mostly;
static atomic_t nr_ksymbol_events __read_mostly;
static atomic_t nr_bpf_events __read_mostly;
static atomic_t nr_cgroup_events __read_mostly;
static atomic_t nr_text_poke_events __read_mostly;
static atomic_t nr_build_id_events __read_mostly;
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;
static cpumask_var_t perf_online_mask;
static struct kmem_cache *perf_event_cache;
/*
* perf event paranoia level:
* -1 - not paranoid at all
* 0 - disallow raw tracepoint access for unpriv
* 1 - disallow cpu events for unpriv
* 2 - disallow kernel profiling for unpriv
*/
int sysctl_perf_event_paranoid __read_mostly = 2;
/* Minimum for 512 kiB + 1 user control page */
int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
/*
* max perf event sample rate
*/
#define DEFAULT_MAX_SAMPLE_RATE 100000
#define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
#define DEFAULT_CPU_TIME_MAX_PERCENT 25
int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
static int perf_sample_allowed_ns __read_mostly =
DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
static void update_perf_cpu_limits(void)
{
u64 tmp = perf_sample_period_ns;
tmp *= sysctl_perf_cpu_time_max_percent;
tmp = div_u64(tmp, 100);
if (!tmp)
tmp = 1;
WRITE_ONCE(perf_sample_allowed_ns, tmp);
}
static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
int perf_proc_update_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
int perf_cpu = sysctl_perf_cpu_time_max_percent;
/*
* If throttling is disabled don't allow the write:
*/
if (write && (perf_cpu == 100 || perf_cpu == 0))
return -EINVAL;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write)
return ret;
max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
update_perf_cpu_limits();
return 0;
}
int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write)
return ret;
if (sysctl_perf_cpu_time_max_percent == 100 ||
sysctl_perf_cpu_time_max_percent == 0) {
printk(KERN_WARNING
"perf: Dynamic interrupt throttling disabled, can hang your system!\n");
WRITE_ONCE(perf_sample_allowed_ns, 0);
} else {
update_perf_cpu_limits();
}
return 0;
}
/*
* perf samples are done in some very critical code paths (NMIs).
* If they take too much CPU time, the system can lock up and not
* get any real work done. This will drop the sample rate when
* we detect that events are taking too long.
*/
#define NR_ACCUMULATED_SAMPLES 128
static DEFINE_PER_CPU(u64, running_sample_length);
static u64 __report_avg;
static u64 __report_allowed;
static void perf_duration_warn(struct irq_work *w)
{
printk_ratelimited(KERN_INFO
"perf: interrupt took too long (%lld > %lld), lowering "
"kernel.perf_event_max_sample_rate to %d\n",
__report_avg, __report_allowed,
sysctl_perf_event_sample_rate);
}
static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
void perf_sample_event_took(u64 sample_len_ns)
{
u64 max_len = READ_ONCE(perf_sample_allowed_ns);
u64 running_len;
u64 avg_len;
u32 max;
if (max_len == 0)
return;
/* Decay the counter by 1 average sample. */
running_len = __this_cpu_read(running_sample_length);
running_len -= running_len/NR_ACCUMULATED_SAMPLES;
running_len += sample_len_ns;
__this_cpu_write(running_sample_length, running_len);
/*
* Note: this will be biased artifically low until we have
* seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
* from having to maintain a count.
*/
avg_len = running_len/NR_ACCUMULATED_SAMPLES;
if (avg_len <= max_len)
return;
__report_avg = avg_len;
__report_allowed = max_len;
/*
* Compute a throttle threshold 25% below the current duration.
*/
avg_len += avg_len / 4;
max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
if (avg_len < max)
max /= (u32)avg_len;
else
max = 1;
WRITE_ONCE(perf_sample_allowed_ns, avg_len);
WRITE_ONCE(max_samples_per_tick, max);
sysctl_perf_event_sample_rate = max * HZ;
perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
if (!irq_work_queue(&perf_duration_work)) {
early_printk("perf: interrupt took too long (%lld > %lld), lowering "
"kernel.perf_event_max_sample_rate to %d\n",
__report_avg, __report_allowed,
sysctl_perf_event_sample_rate);
}
}
static atomic64_t perf_event_id;
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
enum event_type_t event_type);
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
enum event_type_t event_type,
struct task_struct *task);
static void update_context_time(struct perf_event_context *ctx);
static u64 perf_event_time(struct perf_event *event);
void __weak perf_event_print_debug(void) { }
static inline u64 perf_clock(void)
{
return local_clock();
}
static inline u64 perf_event_clock(struct perf_event *event)
{
return event->clock();
}
/*
* State based event timekeeping...
*
* The basic idea is to use event->state to determine which (if any) time
* fields to increment with the current delta. This means we only need to
* update timestamps when we change state or when they are explicitly requested
* (read).
*
* Event groups make things a little more complicated, but not terribly so. The
* rules for a group are that if the group leader is OFF the entire group is
* OFF, irrespecive of what the group member states are. This results in
* __perf_effective_state().
*
* A futher ramification is that when a group leader flips between OFF and
* !OFF, we need to update all group member times.
*
*
* NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
* need to make sure the relevant context time is updated before we try and
* update our timestamps.
*/
static __always_inline enum perf_event_state
__perf_effective_state(struct perf_event *event)
{
struct perf_event *leader = event->group_leader;
if (leader->state <= PERF_EVENT_STATE_OFF)
return leader->state;
return event->state;
}
static __always_inline void
__perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
{
enum perf_event_state state = __perf_effective_state(event);
u64 delta = now - event->tstamp;
*enabled = event->total_time_enabled;
if (state >= PERF_EVENT_STATE_INACTIVE)
*enabled += delta;
*running = event->total_time_running;
if (state >= PERF_EVENT_STATE_ACTIVE)
*running += delta;
}
static void perf_event_update_time(struct perf_event *event)
{
u64 now = perf_event_time(event);
__perf_update_times(event, now, &event->total_time_enabled,
&event->total_time_running);
event->tstamp = now;
}
static void perf_event_update_sibling_time(struct perf_event *leader)
{
struct perf_event *sibling;
for_each_sibling_event(sibling, leader)
perf_event_update_time(sibling);
}
static void
perf_event_set_state(struct perf_event *event, enum perf_event_state state)
{
if (event->state == state)
return;
perf_event_update_time(event);
/*
* If a group leader gets enabled/disabled all its siblings
* are affected too.
*/
if ((event->state < 0) ^ (state < 0))
perf_event_update_sibling_time(event);
WRITE_ONCE(event->state, state);
}
/*
* UP store-release, load-acquire
*/
#define __store_release(ptr, val) \
do { \
barrier(); \
WRITE_ONCE(*(ptr), (val)); \
} while (0)
#define __load_acquire(ptr) \
({ \
__unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \
barrier(); \
___p; \
})
#ifdef CONFIG_CGROUP_PERF
static inline bool
perf_cgroup_match(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
/* @event doesn't care about cgroup */
if (!event->cgrp)
return true;
/* wants specific cgroup scope but @cpuctx isn't associated with any */
if (!cpuctx->cgrp)
return false;
/*
* Cgroup scoping is recursive. An event enabled for a cgroup is
* also enabled for all its descendant cgroups. If @cpuctx's
* cgroup is a descendant of @event's (the test covers identity
* case), it's a match.
*/
return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
event->cgrp->css.cgroup);
}
static inline void perf_detach_cgroup(struct perf_event *event)
{
css_put(&event->cgrp->css);
event->cgrp = NULL;
}
static inline int is_cgroup_event(struct perf_event *event)
{
return event->cgrp != NULL;
}
static inline u64 perf_cgroup_event_time(struct perf_event *event)
{
struct perf_cgroup_info *t;
t = per_cpu_ptr(event->cgrp->info, event->cpu);
return t->time;
}
static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
{
struct perf_cgroup_info *t;
t = per_cpu_ptr(event->cgrp->info, event->cpu);
if (!__load_acquire(&t->active))
return t->time;
now += READ_ONCE(t->timeoffset);
return now;
}
static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
{
if (adv)
info->time += now - info->timestamp;
info->timestamp = now;
/*
* see update_context_time()
*/
WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
}
static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
{
struct perf_cgroup *cgrp = cpuctx->cgrp;
struct cgroup_subsys_state *css;
struct perf_cgroup_info *info;
if (cgrp) {
u64 now = perf_clock();
for (css = &cgrp->css; css; css = css->parent) {
cgrp = container_of(css, struct perf_cgroup, css);
info = this_cpu_ptr(cgrp->info);
__update_cgrp_time(info, now, true);
if (final)
__store_release(&info->active, 0);
}
}
}
static inline void update_cgrp_time_from_event(struct perf_event *event)
{
struct perf_cgroup_info *info;
struct perf_cgroup *cgrp;
/*
* ensure we access cgroup data only when needed and
* when we know the cgroup is pinned (css_get)
*/
if (!is_cgroup_event(event))
return;
cgrp = perf_cgroup_from_task(current, event->ctx);
/*
* Do not update time when cgroup is not active
*/
if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) {
info = this_cpu_ptr(event->cgrp->info);
__update_cgrp_time(info, perf_clock(), true);
}
}
static inline void
perf_cgroup_set_timestamp(struct task_struct *task,
struct perf_event_context *ctx)
{
struct perf_cgroup *cgrp;
struct perf_cgroup_info *info;
struct cgroup_subsys_state *css;
/*
* ctx->lock held by caller
* ensure we do not access cgroup data
* unless we have the cgroup pinned (css_get)
*/
if (!task || !ctx->nr_cgroups)
return;
cgrp = perf_cgroup_from_task(task, ctx);
for (css = &cgrp->css; css; css = css->parent) {
cgrp = container_of(css, struct perf_cgroup, css);
info = this_cpu_ptr(cgrp->info);
__update_cgrp_time(info, ctx->timestamp, false);
__store_release(&info->active, 1);
}
}
static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
/*
* reschedule events based on the cgroup constraint of task.
*
* mode SWOUT : schedule out everything
* mode SWIN : schedule in based on cgroup for next
*/
static void perf_cgroup_switch(struct task_struct *task, int mode)
{
struct perf_cpu_context *cpuctx, *tmp;
struct list_head *list;
unsigned long flags;
/*
* Disable interrupts and preemption to avoid this CPU's
* cgrp_cpuctx_entry to change under us.
*/
local_irq_save(flags);
list = this_cpu_ptr(&cgrp_cpuctx_list);
list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
perf_ctx_lock(cpuctx, cpuctx->task_ctx);
perf_pmu_disable(cpuctx->ctx.pmu);
if (mode & PERF_CGROUP_SWOUT) {
cpu_ctx_sched_out(cpuctx, EVENT_ALL);
/*
* must not be done before ctxswout due
* to event_filter_match() in event_sched_out()
*/
cpuctx->cgrp = NULL;
}
if (mode & PERF_CGROUP_SWIN) {
WARN_ON_ONCE(cpuctx->cgrp);
/*
* set cgrp before ctxsw in to allow
* event_filter_match() to not have to pass
* task around
* we pass the cpuctx->ctx to perf_cgroup_from_task()
* because cgorup events are only per-cpu
*/
cpuctx->cgrp = perf_cgroup_from_task(task,
&cpuctx->ctx);
cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
}
perf_pmu_enable(cpuctx->ctx.pmu);
perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
}
local_irq_restore(flags);
}
static inline void perf_cgroup_sched_out(struct task_struct *task,
struct task_struct *next)
{
struct perf_cgroup *cgrp1;
struct perf_cgroup *cgrp2 = NULL;
rcu_read_lock();
/*
* we come here when we know perf_cgroup_events > 0
* we do not need to pass the ctx here because we know
* we are holding the rcu lock
*/
cgrp1 = perf_cgroup_from_task(task, NULL);
cgrp2 = perf_cgroup_from_task(next, NULL);
/*
* only schedule out current cgroup events if we know
* that we are switching to a different cgroup. Otherwise,
* do no touch the cgroup events.
*/
if (cgrp1 != cgrp2)
perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
rcu_read_unlock();
}
static inline void perf_cgroup_sched_in(struct task_struct *prev,
struct task_struct *task)
{
struct perf_cgroup *cgrp1;
struct perf_cgroup *cgrp2 = NULL;
rcu_read_lock();
/*
* we come here when we know perf_cgroup_events > 0
* we do not need to pass the ctx here because we know
* we are holding the rcu lock
*/
cgrp1 = perf_cgroup_from_task(task, NULL);
cgrp2 = perf_cgroup_from_task(prev, NULL);
/*
* only need to schedule in cgroup events if we are changing
* cgroup during ctxsw. Cgroup events were not scheduled
* out of ctxsw out if that was not the case.
*/
if (cgrp1 != cgrp2)
perf_cgroup_switch(task, PERF_CGROUP_SWIN);
rcu_read_unlock();
}
static int perf_cgroup_ensure_storage(struct perf_event *event,
struct cgroup_subsys_state *css)
{
struct perf_cpu_context *cpuctx;
struct perf_event **storage;
int cpu, heap_size, ret = 0;
/*
* Allow storage to have sufficent space for an iterator for each
* possibly nested cgroup plus an iterator for events with no cgroup.
*/
for (heap_size = 1; css; css = css->parent)
heap_size++;
for_each_possible_cpu(cpu) {
cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
if (heap_size <= cpuctx->heap_size)
continue;
storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
GFP_KERNEL, cpu_to_node(cpu));
if (!storage) {
ret = -ENOMEM;
break;
}
raw_spin_lock_irq(&cpuctx->ctx.lock);
if (cpuctx->heap_size < heap_size) {
swap(cpuctx->heap, storage);
if (storage == cpuctx->heap_default)
storage = NULL;
cpuctx->heap_size = heap_size;
}
raw_spin_unlock_irq(&cpuctx->ctx.lock);
kfree(storage);
}
return ret;
}
static inline int perf_cgroup_connect(int fd, struct perf_event *event,
struct perf_event_attr *attr,
struct perf_event *group_leader)
{
struct perf_cgroup *cgrp;
struct cgroup_subsys_state *css;
struct fd f = fdget(fd);
int ret = 0;
if (!f.file)
return -EBADF;
css = css_tryget_online_from_dir(f.file->f_path.dentry,
&perf_event_cgrp_subsys);
if (IS_ERR(css)) {
ret = PTR_ERR(css);
goto out;
}
ret = perf_cgroup_ensure_storage(event, css);
if (ret)
goto out;
cgrp = container_of(css, struct perf_cgroup, css);
event->cgrp = cgrp;
/*
* all events in a group must monitor
* the same cgroup because a task belongs
* to only one perf cgroup at a time
*/
if (group_leader && group_leader->cgrp != cgrp) {
perf_detach_cgroup(event);
ret = -EINVAL;
}
out:
fdput(f);
return ret;
}
static inline void
perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_cpu_context *cpuctx;
if (!is_cgroup_event(event))
return;
/*
* Because cgroup events are always per-cpu events,
* @ctx == &cpuctx->ctx.
*/
cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
/*
* Since setting cpuctx->cgrp is conditional on the current @cgrp
* matching the event's cgroup, we must do this for every new event,
* because if the first would mismatch, the second would not try again
* and we would leave cpuctx->cgrp unset.
*/
if (ctx->is_active && !cpuctx->cgrp) {
struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
cpuctx->cgrp = cgrp;
}
if (ctx->nr_cgroups++)
return;
list_add(&cpuctx->cgrp_cpuctx_entry,
per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
}
static inline void
perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_cpu_context *cpuctx;
if (!is_cgroup_event(event))
return;
/*
* Because cgroup events are always per-cpu events,
* @ctx == &cpuctx->ctx.
*/
cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
if (--ctx->nr_cgroups)
return;
if (ctx->is_active && cpuctx->cgrp)
cpuctx->cgrp = NULL;
list_del(&cpuctx->cgrp_cpuctx_entry);
}
#else /* !CONFIG_CGROUP_PERF */
static inline bool
perf_cgroup_match(struct perf_event *event)
{
return true;
}
static inline void perf_detach_cgroup(struct perf_event *event)
{}
static inline int is_cgroup_event(struct perf_event *event)
{
return 0;
}
static inline void update_cgrp_time_from_event(struct perf_event *event)
{
}
static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
bool final)
{
}
static inline void perf_cgroup_sched_out(struct task_struct *task,
struct task_struct *next)
{
}
static inline void perf_cgroup_sched_in(struct task_struct *prev,
struct task_struct *task)
{
}
static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
struct perf_event_attr *attr,
struct perf_event *group_leader)
{
return -EINVAL;
}
static inline void
perf_cgroup_set_timestamp(struct task_struct *task,
struct perf_event_context *ctx)
{
}
static inline void
perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
{
}
static inline u64 perf_cgroup_event_time(struct perf_event *event)
{
return 0;
}
static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
{
return 0;
}
static inline void
perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
{
}
static inline void
perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
{
}
#endif
/*
* set default to be dependent on timer tick just
* like original code
*/
#define PERF_CPU_HRTIMER (1000 / HZ)
/*
* function must be called with interrupts disabled
*/
static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
{
struct perf_cpu_context *cpuctx;
bool rotations;
lockdep_assert_irqs_disabled();
cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
rotations = perf_rotate_context(cpuctx);
raw_spin_lock(&cpuctx->hrtimer_lock);
if (rotations)
hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
else
cpuctx->hrtimer_active = 0;
raw_spin_unlock(&cpuctx->hrtimer_lock);
return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
}
static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
{
struct hrtimer *timer = &cpuctx->hrtimer;
struct pmu *pmu = cpuctx->ctx.pmu;
u64 interval;
/* no multiplexing needed for SW PMU */
if (pmu->task_ctx_nr == perf_sw_context)
return;
/*
* check default is sane, if not set then force to
* default interval (1/tick)
*/
interval = pmu->hrtimer_interval_ms;
if (interval < 1)
interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
raw_spin_lock_init(&cpuctx->hrtimer_lock);
hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
timer->function = perf_mux_hrtimer_handler;
}
static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
{
struct hrtimer *timer = &cpuctx->hrtimer;
struct pmu *pmu = cpuctx->ctx.pmu;
unsigned long flags;
/* not for SW PMU */
if (pmu->task_ctx_nr == perf_sw_context)
return 0;
raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
if (!cpuctx->hrtimer_active) {
cpuctx->hrtimer_active = 1;
hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
}
raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
return 0;
}
void perf_pmu_disable(struct pmu *pmu)
{
int *count = this_cpu_ptr(pmu->pmu_disable_count);
if (!(*count)++)
pmu->pmu_disable(pmu);
}
void perf_pmu_enable(struct pmu *pmu)
{
int *count = this_cpu_ptr(pmu->pmu_disable_count);
if (!--(*count))
pmu->pmu_enable(pmu);
}
static DEFINE_PER_CPU(struct list_head, active_ctx_list);
/*
* perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
* perf_event_task_tick() are fully serialized because they're strictly cpu
* affine and perf_event_ctx{activate,deactivate} are called with IRQs
* disabled, while perf_event_task_tick is called from IRQ context.
*/
static void perf_event_ctx_activate(struct perf_event_context *ctx)
{
struct list_head *head = this_cpu_ptr(&active_ctx_list);
lockdep_assert_irqs_disabled();
WARN_ON(!list_empty(&ctx->active_ctx_list));
list_add(&ctx->active_ctx_list, head);
}
static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
{
lockdep_assert_irqs_disabled();
WARN_ON(list_empty(&ctx->active_ctx_list));
list_del_init(&ctx->active_ctx_list);
}
static void get_ctx(struct perf_event_context *ctx)
{
refcount_inc(&ctx->refcount);
}
static void *alloc_task_ctx_data(struct pmu *pmu)
{
if (pmu->task_ctx_cache)
return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
return NULL;
}
static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
{
if (pmu->task_ctx_cache && task_ctx_data)
kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
}
static void free_ctx(struct rcu_head *head)
{
struct perf_event_context *ctx;
ctx = container_of(head, struct perf_event_context, rcu_head);
free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
kfree(ctx);
}
static void put_ctx(struct perf_event_context *ctx)
{
if (refcount_dec_and_test(&ctx->refcount)) {
if (ctx->parent_ctx)
put_ctx(ctx->parent_ctx);
if (ctx->task && ctx->task != TASK_TOMBSTONE)
put_task_struct(ctx->task);
call_rcu(&ctx->rcu_head, free_ctx);
}
}
/*
* Because of perf_event::ctx migration in sys_perf_event_open::move_group and
* perf_pmu_migrate_context() we need some magic.
*
* Those places that change perf_event::ctx will hold both
* perf_event_ctx::mutex of the 'old' and 'new' ctx value.
*
* Lock ordering is by mutex address. There are two other sites where
* perf_event_context::mutex nests and those are:
*
* - perf_event_exit_task_context() [ child , 0 ]
* perf_event_exit_event()
* put_event() [ parent, 1 ]
*
* - perf_event_init_context() [ parent, 0 ]
* inherit_task_group()
* inherit_group()
* inherit_event()
* perf_event_alloc()
* perf_init_event()
* perf_try_init_event() [ child , 1 ]
*
* While it appears there is an obvious deadlock here -- the parent and child
* nesting levels are inverted between the two. This is in fact safe because
* life-time rules separate them. That is an exiting task cannot fork, and a
* spawning task cannot (yet) exit.
*
* But remember that these are parent<->child context relations, and
* migration does not affect children, therefore these two orderings should not
* interact.
*
* The change in perf_event::ctx does not affect children (as claimed above)
* because the sys_perf_event_open() case will install a new event and break
* the ctx parent<->child relation, and perf_pmu_migrate_context() is only
* concerned with cpuctx and that doesn't have children.
*
* The places that change perf_event::ctx will issue:
*
* perf_remove_from_context();
* synchronize_rcu();
* perf_install_in_context();
*
* to affect the change. The remove_from_context() + synchronize_rcu() should
* quiesce the event, after which we can install it in the new location. This
* means that only external vectors (perf_fops, prctl) can perturb the event
* while in transit. Therefore all such accessors should also acquire
* perf_event_context::mutex to serialize against this.
*
* However; because event->ctx can change while we're waiting to acquire
* ctx->mutex we must be careful and use the below perf_event_ctx_lock()
* function.
*
* Lock order:
* exec_update_lock
* task_struct::perf_event_mutex
* perf_event_context::mutex
* perf_event::child_mutex;
* perf_event_context::lock
* perf_event::mmap_mutex
* mmap_lock
* perf_addr_filters_head::lock
*
* cpu_hotplug_lock
* pmus_lock
* cpuctx->mutex / perf_event_context::mutex
*/
static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
{
struct perf_event_context *ctx;
again:
rcu_read_lock();
ctx = READ_ONCE(event->ctx);
if (!refcount_inc_not_zero(&ctx->refcount)) {
rcu_read_unlock();
goto again;
}
rcu_read_unlock();
mutex_lock_nested(&ctx->mutex, nesting);
if (event->ctx != ctx) {
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
goto again;
}
return ctx;
}
static inline struct perf_event_context *
perf_event_ctx_lock(struct perf_event *event)
{
return perf_event_ctx_lock_nested(event, 0);
}
static void perf_event_ctx_unlock(struct perf_event *event,
struct perf_event_context *ctx)
{
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
}
/*
* This must be done under the ctx->lock, such as to serialize against
* context_equiv(), therefore we cannot call put_ctx() since that might end up
* calling scheduler related locks and ctx->lock nests inside those.
*/
static __must_check struct perf_event_context *
unclone_ctx(struct perf_event_context *ctx)
{
struct perf_event_context *parent_ctx = ctx->parent_ctx;
lockdep_assert_held(&ctx->lock);
if (parent_ctx)
ctx->parent_ctx = NULL;
ctx->generation++;
return parent_ctx;
}
static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
enum pid_type type)
{
u32 nr;
/*
* only top level events have the pid namespace they were created in
*/
if (event->parent)
event = event->parent;
nr = __task_pid_nr_ns(p, type, event->ns);
/* avoid -1 if it is idle thread or runs in another ns */
if (!nr && !pid_alive(p))
nr = -1;
return nr;
}
static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
return perf_event_pid_type(event, p, PIDTYPE_TGID);
}
static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
{
return perf_event_pid_type(event, p, PIDTYPE_PID);
}
/*
* If we inherit events we want to return the parent event id
* to userspace.
*/
static u64 primary_event_id(struct perf_event *event)
{
u64 id = event->id;
if (event->parent)
id = event->parent->id;
return id;
}
/*
* Get the perf_event_context for a task and lock it.
*
* This has to cope with the fact that until it is locked,
* the context could get moved to another task.
*/
static struct perf_event_context *
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
{
struct perf_event_context *ctx;
retry:
/*
* One of the few rules of preemptible RCU is that one cannot do
* rcu_read_unlock() while holding a scheduler (or nested) lock when
* part of the read side critical section was irqs-enabled -- see
* rcu_read_unlock_special().
*
* Since ctx->lock nests under rq->lock we must ensure the entire read
* side critical section has interrupts disabled.
*/
local_irq_save(*flags);
rcu_read_lock();
ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
if (ctx) {
/*
* If this context is a clone of another, it might
* get swapped for another underneath us by
* perf_event_task_sched_out, though the
* rcu_read_lock() protects us from any context
* getting freed. Lock the context and check if it
* got swapped before we could get the lock, and retry
* if so. If we locked the right context, then it
* can't get swapped on us any more.
*/
raw_spin_lock(&ctx->lock);
if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
raw_spin_unlock(&ctx->lock);
rcu_read_unlock();
local_irq_restore(*flags);
goto retry;
}
if (ctx->task == TASK_TOMBSTONE ||
!refcount_inc_not_zero(&ctx->refcount)) {
raw_spin_unlock(&ctx->lock);
ctx = NULL;
} else {
WARN_ON_ONCE(ctx->task != task);
}
}
rcu_read_unlock();
if (!ctx)
local_irq_restore(*flags);
return ctx;
}
/*
* Get the context for a task and increment its pin_count so it
* can't get swapped to another task. This also increments its
* reference count so that the context can't get freed.
*/
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
{
struct perf_event_context *ctx;
unsigned long flags;
ctx = perf_lock_task_context(task, ctxn, &flags);
if (ctx) {
++ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
return ctx;
}
static void perf_unpin_context(struct perf_event_context *ctx)
{
unsigned long flags;
raw_spin_lock_irqsave(&ctx->lock, flags);
--ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
/*
* Update the record of the current time in a context.
*/
static void __update_context_time(struct perf_event_context *ctx, bool adv)
{
u64 now = perf_clock();
if (adv)
ctx->time += now - ctx->timestamp;
ctx->timestamp = now;
/*
* The above: time' = time + (now - timestamp), can be re-arranged
* into: time` = now + (time - timestamp), which gives a single value
* offset to compute future time without locks on.
*
* See perf_event_time_now(), which can be used from NMI context where
* it's (obviously) not possible to acquire ctx->lock in order to read
* both the above values in a consistent manner.
*/
WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
}
static void update_context_time(struct perf_event_context *ctx)
{
__update_context_time(ctx, true);
}
static u64 perf_event_time(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
if (unlikely(!ctx))
return 0;
if (is_cgroup_event(event))
return perf_cgroup_event_time(event);
return ctx->time;
}
static u64 perf_event_time_now(struct perf_event *event, u64 now)
{
struct perf_event_context *ctx = event->ctx;
if (unlikely(!ctx))
return 0;
if (is_cgroup_event(event))
return perf_cgroup_event_time_now(event, now);
if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
return ctx->time;
now += READ_ONCE(ctx->timeoffset);
return now;
}
static enum event_type_t get_event_type(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
enum event_type_t event_type;
lockdep_assert_held(&ctx->lock);
/*
* It's 'group type', really, because if our group leader is
* pinned, so are we.
*/
if (event->group_leader != event)
event = event->group_leader;
event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
if (!ctx->task)
event_type |= EVENT_CPU;
return event_type;
}
/*
* Helper function to initialize event group nodes.
*/
static void init_event_group(struct perf_event *event)
{
RB_CLEAR_NODE(&event->group_node);
event->group_index = 0;
}
/*
* Extract pinned or flexible groups from the context
* based on event attrs bits.
*/
static struct perf_event_groups *
get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
{
if (event->attr.pinned)
return &ctx->pinned_groups;
else
return &ctx->flexible_groups;
}
/*
* Helper function to initializes perf_event_group trees.
*/
static void perf_event_groups_init(struct perf_event_groups *groups)
{
groups->tree = RB_ROOT;
groups->index = 0;
}
static inline struct cgroup *event_cgroup(const struct perf_event *event)
{
struct cgroup *cgroup = NULL;
#ifdef CONFIG_CGROUP_PERF
if (event->cgrp)
cgroup = event->cgrp->css.cgroup;
#endif
return cgroup;
}
/*
* Compare function for event groups;
*
* Implements complex key that first sorts by CPU and then by virtual index
* which provides ordering when rotating groups for the same CPU.
*/
static __always_inline int
perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
const u64 left_group_index, const struct perf_event *right)
{
if (left_cpu < right->cpu)
return -1;
if (left_cpu > right->cpu)
return 1;
#ifdef CONFIG_CGROUP_PERF
{
const struct cgroup *right_cgroup = event_cgroup(right);
if (left_cgroup != right_cgroup) {
if (!left_cgroup) {
/*
* Left has no cgroup but right does, no
* cgroups come first.
*/
return -1;
}
if (!right_cgroup) {
/*
* Right has no cgroup but left does, no
* cgroups come first.
*/
return 1;
}
/* Two dissimilar cgroups, order by id. */
if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
return -1;
return 1;
}
}
#endif
if (left_group_index < right->group_index)
return -1;
if (left_group_index > right->group_index)
return 1;
return 0;
}
#define __node_2_pe(node) \
rb_entry((node), struct perf_event, group_node)
static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
{
struct perf_event *e = __node_2_pe(a);
return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
__node_2_pe(b)) < 0;
}
struct __group_key {
int cpu;
struct cgroup *cgroup;
};
static inline int __group_cmp(const void *key, const struct rb_node *node)
{
const struct __group_key *a = key;
const struct perf_event *b = __node_2_pe(node);
/* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
}
/*
* Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
* key (see perf_event_groups_less). This places it last inside the CPU
* subtree.
*/
static void
perf_event_groups_insert(struct perf_event_groups *groups,
struct perf_event *event)
{
event->group_index = ++groups->index;
rb_add(&event->group_node, &groups->tree, __group_less);
}
/*
* Helper function to insert event into the pinned or flexible groups.
*/
static void
add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_event_groups *groups;
groups = get_event_groups(event, ctx);
perf_event_groups_insert(groups, event);
}
/*
* Delete a group from a tree.
*/
static void
perf_event_groups_delete(struct perf_event_groups *groups,
struct perf_event *event)
{
WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
RB_EMPTY_ROOT(&groups->tree));
rb_erase(&event->group_node, &groups->tree);
init_event_group(event);
}
/*
* Helper function to delete event from its groups.
*/
static void
del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_event_groups *groups;
groups = get_event_groups(event, ctx);
perf_event_groups_delete(groups, event);
}
/*
* Get the leftmost event in the cpu/cgroup subtree.
*/
static struct perf_event *
perf_event_groups_first(struct perf_event_groups *groups, int cpu,
struct cgroup *cgrp)
{
struct __group_key key = {
.cpu = cpu,
.cgroup = cgrp,
};
struct rb_node *node;
node = rb_find_first(&key, &groups->tree, __group_cmp);
if (node)
return __node_2_pe(node);
return NULL;
}
/*
* Like rb_entry_next_safe() for the @cpu subtree.
*/
static struct perf_event *
perf_event_groups_next(struct perf_event *event)
{
struct __group_key key = {
.cpu = event->cpu,
.cgroup = event_cgroup(event),
};
struct rb_node *next;
next = rb_next_match(&key, &event->group_node, __group_cmp);
if (next)
return __node_2_pe(next);
return NULL;
}
/*
* Iterate through the whole groups tree.
*/
#define perf_event_groups_for_each(event, groups) \
for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
typeof(*event), group_node); event; \
event = rb_entry_safe(rb_next(&event->group_node), \
typeof(*event), group_node))
/*
* Add an event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
*/
static void
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
{
lockdep_assert_held(&ctx->lock);
WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
event->attach_state |= PERF_ATTACH_CONTEXT;
event->tstamp = perf_event_time(event);
/*
* If we're a stand alone event or group leader, we go to the context
* list, group events are kept attached to the group so that
* perf_group_detach can, at all times, locate all siblings.
*/
if (event->group_leader == event) {
event->group_caps = event->event_caps;
add_event_to_groups(event, ctx);
}
list_add_rcu(&event->event_entry, &ctx->event_list);
ctx->nr_events++;
if (event->attr.inherit_stat)
ctx->nr_stat++;
if (event->state > PERF_EVENT_STATE_OFF)
perf_cgroup_event_enable(event, ctx);
ctx->generation++;
}
/*
* Initialize event state based on the perf_event_attr::disabled.
*/
static inline void perf_event__state_init(struct perf_event *event)
{
event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
PERF_EVENT_STATE_INACTIVE;
}
static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
{
int entry = sizeof(u64); /* value */
int size = 0;
int nr = 1;
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
size += sizeof(u64);
if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
size += sizeof(u64);
if (event->attr.read_format & PERF_FORMAT_ID)
entry += sizeof(u64);
if (event->attr.read_format & PERF_FORMAT_GROUP) {
nr += nr_siblings;
size += sizeof(u64);
}
size += entry * nr;
event->read_size = size;
}
static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
{
struct perf_sample_data *data;
u16 size = 0;
if (sample_type & PERF_SAMPLE_IP)
size += sizeof(data->ip);
if (sample_type & PERF_SAMPLE_ADDR)
size += sizeof(data->addr);
if (sample_type & PERF_SAMPLE_PERIOD)
size += sizeof(data->period);
if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
size += sizeof(data->weight.full);
if (sample_type & PERF_SAMPLE_READ)
size += event->read_size;
if (sample_type & PERF_SAMPLE_DATA_SRC)
size += sizeof(data->data_src.val);
if (sample_type & PERF_SAMPLE_TRANSACTION)
size += sizeof(data->txn);
if (sample_type & PERF_SAMPLE_PHYS_ADDR)
size += sizeof(data->phys_addr);
if (sample_type & PERF_SAMPLE_CGROUP)
size += sizeof(data->cgroup);
if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
size += sizeof(data->data_page_size);
if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
size += sizeof(data->code_page_size);
event->header_size = size;
}
/*
* Called at perf_event creation and when events are attached/detached from a
* group.
*/
static void perf_event__header_size(struct perf_event *event)
{
__perf_event_read_size(event,
event->group_leader->nr_siblings);
__perf_event_header_size(event, event->attr.sample_type);
}
static void perf_event__id_header_size(struct perf_event *event)
{
struct perf_sample_data *data;
u64 sample_type = event->attr.sample_type;
u16 size = 0;
if (sample_type & PERF_SAMPLE_TID)
size += sizeof(data->tid_entry);
if (sample_type & PERF_SAMPLE_TIME)
size += sizeof(data->time);
if (sample_type & PERF_SAMPLE_IDENTIFIER)
size += sizeof(data->id);
if (sample_type & PERF_SAMPLE_ID)
size += sizeof(data->id);
if (sample_type & PERF_SAMPLE_STREAM_ID)
size += sizeof(data->stream_id);
if (sample_type & PERF_SAMPLE_CPU)
size += sizeof(data->cpu_entry);
event->id_header_size = size;
}
static bool perf_event_validate_size(struct perf_event *event)
{
/*
* The values computed here will be over-written when we actually
* attach the event.
*/
__perf_event_read_size(event, event->group_leader->nr_siblings + 1);
__perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
perf_event__id_header_size(event);
/*
* Sum the lot; should not exceed the 64k limit we have on records.
* Conservative limit to allow for callchains and other variable fields.
*/
if (event->read_size + event->header_size +
event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
return false;
return true;
}
static void perf_group_attach(struct perf_event *event)
{
struct perf_event *group_leader = event->group_leader, *pos;
lockdep_assert_held(&event->ctx->lock);
/*
* We can have double attach due to group movement in perf_event_open.
*/
if (event->attach_state & PERF_ATTACH_GROUP)
return;
event->attach_state |= PERF_ATTACH_GROUP;
if (group_leader == event)
return;
WARN_ON_ONCE(group_leader->ctx != event->ctx);
group_leader->group_caps &= event->event_caps;
list_add_tail(&event->sibling_list, &group_leader->sibling_list);
group_leader->nr_siblings++;
perf_event__header_size(group_leader);
for_each_sibling_event(pos, group_leader)
perf_event__header_size(pos);
}
/*
* Remove an event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
*/
static void
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
{
WARN_ON_ONCE(event->ctx != ctx);
lockdep_assert_held(&ctx->lock);
/*
* We can have double detach due to exit/hot-unplug + close.
*/
if (!(event->attach_state & PERF_ATTACH_CONTEXT))
return;
event->attach_state &= ~PERF_ATTACH_CONTEXT;
ctx->nr_events--;
if (event->attr.inherit_stat)
ctx->nr_stat--;
list_del_rcu(&event->event_entry);
if (event->group_leader == event)
del_event_from_groups(event, ctx);
/*
* If event was in error state, then keep it
* that way, otherwise bogus counts will be
* returned on read(). The only way to get out
* of error state is by explicit re-enabling
* of the event
*/
if (event->state > PERF_EVENT_STATE_OFF) {
perf_cgroup_event_disable(event, ctx);
perf_event_set_state(event, PERF_EVENT_STATE_OFF);
}
ctx->generation++;
}
static int
perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
{
if (!has_aux(aux_event))
return 0;
if (!event->pmu->aux_output_match)
return 0;
return event->pmu->aux_output_match(aux_event);
}
static void put_event(struct perf_event *event);
static void event_sched_out(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx);
static void perf_put_aux_event(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct perf_event *iter;
/*
* If event uses aux_event tear down the link
*/
if (event->aux_event) {
iter = event->aux_event;
event->aux_event = NULL;
put_event(iter);
return;
}
/*
* If the event is an aux_event, tear down all links to
* it from other events.
*/
for_each_sibling_event(iter, event->group_leader) {
if (iter->aux_event != event)
continue;
iter->aux_event = NULL;
put_event(event);
/*
* If it's ACTIVE, schedule it out and put it into ERROR
* state so that we don't try to schedule it again. Note
* that perf_event_enable() will clear the ERROR status.
*/
event_sched_out(iter, cpuctx, ctx);
perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
}
}
static bool perf_need_aux_event(struct perf_event *event)
{
return !!event->attr.aux_output || !!event->attr.aux_sample_size;
}
static int perf_get_aux_event(struct perf_event *event,
struct perf_event *group_leader)
{
/*
* Our group leader must be an aux event if we want to be
* an aux_output. This way, the aux event will precede its
* aux_output events in the group, and therefore will always
* schedule first.
*/
if (!group_leader)
return 0;
/*
* aux_output and aux_sample_size are mutually exclusive.
*/
if (event->attr.aux_output && event->attr.aux_sample_size)
return 0;
if (event->attr.aux_output &&
!perf_aux_output_match(event, group_leader))
return 0;
if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
return 0;
if (!atomic_long_inc_not_zero(&group_leader->refcount))
return 0;
/*
* Link aux_outputs to their aux event; this is undone in
* perf_group_detach() by perf_put_aux_event(). When the
* group in torn down, the aux_output events loose their
* link to the aux_event and can't schedule any more.
*/
event->aux_event = group_leader;
return 1;
}
static inline struct list_head *get_event_list(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
}
/*
* Events that have PERF_EV_CAP_SIBLING require being part of a group and
* cannot exist on their own, schedule them out and move them into the ERROR
* state. Also see _perf_event_enable(), it will not be able to recover
* this ERROR state.
*/
static inline void perf_remove_sibling_event(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
event_sched_out(event, cpuctx, ctx);
perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
}
static void perf_group_detach(struct perf_event *event)
{
struct perf_event *leader = event->group_leader;
struct perf_event *sibling, *tmp;
struct perf_event_context *ctx = event->ctx;
lockdep_assert_held(&ctx->lock);
/*
* We can have double detach due to exit/hot-unplug + close.
*/
if (!(event->attach_state & PERF_ATTACH_GROUP))
return;
event->attach_state &= ~PERF_ATTACH_GROUP;
perf_put_aux_event(event);
/*
* If this is a sibling, remove it from its group.
*/
if (leader != event) {
list_del_init(&event->sibling_list);
event->group_leader->nr_siblings--;
goto out;
}
/*
* If this was a group event with sibling events then
* upgrade the siblings to singleton events by adding them
* to whatever list we are on.
*/
list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
if (sibling->event_caps & PERF_EV_CAP_SIBLING)
perf_remove_sibling_event(sibling);
sibling->group_leader = sibling;
list_del_init(&sibling->sibling_list);
/* Inherit group flags from the previous leader */
sibling->group_caps = event->group_caps;
if (!RB_EMPTY_NODE(&event->group_node)) {
add_event_to_groups(sibling, event->ctx);
if (sibling->state == PERF_EVENT_STATE_ACTIVE)
list_add_tail(&sibling->active_list, get_event_list(sibling));
}
WARN_ON_ONCE(sibling->ctx != event->ctx);
}
out:
for_each_sibling_event(tmp, leader)
perf_event__header_size(tmp);
perf_event__header_size(leader);
}
static void sync_child_event(struct perf_event *child_event);
static void perf_child_detach(struct perf_event *event)
{
struct perf_event *parent_event = event->parent;
if (!(event->attach_state & PERF_ATTACH_CHILD))
return;
event->attach_state &= ~PERF_ATTACH_CHILD;
if (WARN_ON_ONCE(!parent_event))
return;
lockdep_assert_held(&parent_event->child_mutex);
sync_child_event(event);
list_del_init(&event->child_list);
}
static bool is_orphaned_event(struct perf_event *event)
{
return event->state == PERF_EVENT_STATE_DEAD;
}
static inline int __pmu_filter_match(struct perf_event *event)
{
struct pmu *pmu = event->pmu;
return pmu->filter_match ? pmu->filter_match(event) : 1;
}
/*
* Check whether we should attempt to schedule an event group based on
* PMU-specific filtering. An event group can consist of HW and SW events,
* potentially with a SW leader, so we must check all the filters, to
* determine whether a group is schedulable:
*/
static inline int pmu_filter_match(struct perf_event *event)
{
struct perf_event *sibling;
if (!__pmu_filter_match(event))
return 0;
for_each_sibling_event(sibling, event) {
if (!__pmu_filter_match(sibling))
return 0;
}
return 1;
}
static inline int
event_filter_match(struct perf_event *event)
{
return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
perf_cgroup_match(event) && pmu_filter_match(event);
}
static void
event_sched_out(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
WARN_ON_ONCE(event->ctx != ctx);
lockdep_assert_held(&ctx->lock);
if (event->state != PERF_EVENT_STATE_ACTIVE)
return;
/*
* Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
* we can schedule events _OUT_ individually through things like
* __perf_remove_from_context().
*/
list_del_init(&event->active_list);
perf_pmu_disable(event->pmu);
event->pmu->del(event, 0);
event->oncpu = -1;
if (READ_ONCE(event->pending_disable) >= 0) {
WRITE_ONCE(event->pending_disable, -1);
perf_cgroup_event_disable(event, ctx);
state = PERF_EVENT_STATE_OFF;
}
perf_event_set_state(event, state);
if (!is_software_event(event))
cpuctx->active_oncpu--;
if (!--ctx->nr_active)
perf_event_ctx_deactivate(ctx);
if (event->attr.freq && event->attr.sample_freq)
ctx->nr_freq--;
if (event->attr.exclusive || !cpuctx->active_oncpu)
cpuctx->exclusive = 0;
perf_pmu_enable(event->pmu);
}
static void
group_sched_out(struct perf_event *group_event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
struct perf_event *event;
if (group_event->state != PERF_EVENT_STATE_ACTIVE)
return;
perf_pmu_disable(ctx->pmu);
event_sched_out(group_event, cpuctx, ctx);
/*
* Schedule out siblings (if any):
*/
for_each_sibling_event(event, group_event)
event_sched_out(event, cpuctx, ctx);
perf_pmu_enable(ctx->pmu);
}
#define DETACH_GROUP 0x01UL
#define DETACH_CHILD 0x02UL
/*
* Cross CPU call to remove a performance event
*
* We disable the event on the hardware level first. After that we
* remove it from the context list.
*/
static void
__perf_remove_from_context(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
void *info)
{
unsigned long flags = (unsigned long)info;
if (ctx->is_active & EVENT_TIME) {
update_context_time(ctx);
update_cgrp_time_from_cpuctx(cpuctx, false);
}
event_sched_out(event, cpuctx, ctx);
if (flags & DETACH_GROUP)
perf_group_detach(event);
if (flags & DETACH_CHILD)
perf_child_detach(event);
list_del_event(event, ctx);
if (!ctx->nr_events && ctx->is_active) {
if (ctx == &cpuctx->ctx)
update_cgrp_time_from_cpuctx(cpuctx, true);
ctx->is_active = 0;
ctx->rotate_necessary = 0;
if (ctx->task) {
WARN_ON_ONCE(cpuctx->task_ctx != ctx);
cpuctx->task_ctx = NULL;
}
}
}
/*
* Remove the event from a task's (or a CPU's) list of events.
*
* If event->ctx is a cloned context, callers must make sure that
* every task struct that event->ctx->task could possibly point to
* remains valid. This is OK when called from perf_release since
* that only calls us on the top-level context, which can't be a clone.
* When called from perf_event_exit_task, it's OK because the
* context has been detached from its task.
*/
static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
{
struct perf_event_context *ctx = event->ctx;
lockdep_assert_held(&ctx->mutex);
/*
* Because of perf_event_exit_task(), perf_remove_from_context() ought
* to work in the face of TASK_TOMBSTONE, unlike every other
* event_function_call() user.
*/
raw_spin_lock_irq(&ctx->lock);
/*
* Cgroup events are per-cpu events, and must IPI because of
* cgrp_cpuctx_list.
*/
if (!ctx->is_active && !is_cgroup_event(event)) {
__perf_remove_from_context(event, __get_cpu_context(ctx),
ctx, (void *)flags);
raw_spin_unlock_irq(&ctx->lock);
return;
}
raw_spin_unlock_irq(&ctx->lock);
event_function_call(event, __perf_remove_from_context, (void *)flags);
}
/*
* Cross CPU call to disable a performance event
*/
static void __perf_event_disable(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
void *info)
{
if (event->state < PERF_EVENT_STATE_INACTIVE)
return;
if (ctx->is_active & EVENT_TIME) {
update_context_time(ctx);
update_cgrp_time_from_event(event);
}
if (event == event->group_leader)
group_sched_out(event, cpuctx, ctx);
else
event_sched_out(event, cpuctx, ctx);
perf_event_set_state(event, PERF_EVENT_STATE_OFF);
perf_cgroup_event_disable(event, ctx);
}
/*
* Disable an event.
*
* If event->ctx is a cloned context, callers must make sure that
* every task struct that event->ctx->task could possibly point to
* remains valid. This condition is satisfied when called through
* perf_event_for_each_child or perf_event_for_each because they
* hold the top-level event's child_mutex, so any descendant that
* goes to exit will block in perf_event_exit_event().
*
* When called from perf_pending_event it's OK because event->ctx
* is the current context on this CPU and preemption is disabled,
* hence we can't get into perf_event_task_sched_out for this context.
*/
static void _perf_event_disable(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
raw_spin_lock_irq(&ctx->lock);
if (event->state <= PERF_EVENT_STATE_OFF) {
raw_spin_unlock_irq(&ctx->lock);
return;
}
raw_spin_unlock_irq(&ctx->lock);
event_function_call(event, __perf_event_disable, NULL);
}
void perf_event_disable_local(struct perf_event *event)
{
event_function_local(event, __perf_event_disable, NULL);
}
/*
* Strictly speaking kernel users cannot create groups and therefore this
* interface does not need the perf_event_ctx_lock() magic.
*/
void perf_event_disable(struct perf_event *event)
{
struct perf_event_context *ctx;
ctx = perf_event_ctx_lock(event);
_perf_event_disable(event);
perf_event_ctx_unlock(event, ctx);
}
EXPORT_SYMBOL_GPL(perf_event_disable);
void perf_event_disable_inatomic(struct perf_event *event)
{
WRITE_ONCE(event->pending_disable, smp_processor_id());
/* can fail, see perf_pending_event_disable() */
irq_work_queue(&event->pending);
}
#define MAX_INTERRUPTS (~0ULL)
static void perf_log_throttle(struct perf_event *event, int enable);
static void perf_log_itrace_start(struct perf_event *event);
static int
event_sched_in(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
int ret = 0;
WARN_ON_ONCE(event->ctx != ctx);
lockdep_assert_held(&ctx->lock);
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;
WRITE_ONCE(event->oncpu, smp_processor_id());
/*
* Order event::oncpu write to happen before the ACTIVE state is
* visible. This allows perf_event_{stop,read}() to observe the correct
* ->oncpu if it sees ACTIVE.
*/
smp_wmb();
perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
/*
* Unthrottle events, since we scheduled we might have missed several
* ticks already, also for a heavily scheduling task there is little
* guarantee it'll get a tick in a timely manner.
*/
if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
perf_log_throttle(event, 1);
event->hw.interrupts = 0;
}
perf_pmu_disable(event->pmu);
perf_log_itrace_start(event);
if (event->pmu->add(event, PERF_EF_START)) {
perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
event->oncpu = -1;
ret = -EAGAIN;
goto out;
}
if (!is_software_event(event))
cpuctx->active_oncpu++;
if (!ctx->nr_active++)
perf_event_ctx_activate(ctx);
if (event->attr.freq && event->attr.sample_freq)
ctx->nr_freq++;
if (event->attr.exclusive)
cpuctx->exclusive = 1;
out:
perf_pmu_enable(event->pmu);
return ret;
}
static int
group_sched_in(struct perf_event *group_event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
struct perf_event *event, *partial_group = NULL;
struct pmu *pmu = ctx->pmu;
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
if (event_sched_in(group_event, cpuctx, ctx))
goto error;
/*
* Schedule in siblings as one group (if any):
*/
for_each_sibling_event(event, group_event) {
if (event_sched_in(event, cpuctx, ctx)) {
partial_group = event;
goto group_error;
}
}
if (!pmu->commit_txn(pmu))
return 0;
group_error:
/*
* Groups can be scheduled in as one unit only, so undo any
* partial group before returning:
* The events up to the failed event are scheduled out normally.
*/
for_each_sibling_event(event, group_event) {
if (event == partial_group)
break;
event_sched_out(event, cpuctx, ctx);
}
event_sched_out(group_event, cpuctx, ctx);
error:
pmu->cancel_txn(pmu);
return -EAGAIN;
}
/*
* Work out whether we can put this event group on the CPU now.
*/
static int group_can_go_on(struct perf_event *event,
struct perf_cpu_context *cpuctx,
int can_add_hw)
{
/*
* Groups consisting entirely of software events can always go on.
*/
if (event->group_caps & PERF_EV_CAP_SOFTWARE)
return 1;
/*
* If an exclusive group is already on, no other hardware
* events can go on.
*/
if (cpuctx->exclusive)
return 0;
/*
* If this group is exclusive and there are already
* events on the CPU, it can't go on.
*/
if (event->attr.exclusive && !list_empty(get_event_list(event)))
return 0;
/*
* Otherwise, try to add it if all previous groups were able
* to go on.
*/
return can_add_hw;
}
static void add_event_to_ctx(struct perf_event *event,
struct perf_event_context *ctx)
{
list_add_event(event, ctx);
perf_group_attach(event);
}
static void ctx_sched_out(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx,
enum event_type_t event_type);
static void
ctx_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx,
enum event_type_t event_type,
struct task_struct *task);
static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
enum event_type_t event_type)
{
if (!cpuctx->task_ctx)
return;
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
return;
ctx_sched_out(ctx, cpuctx, event_type);
}
static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
struct task_struct *task)
{
cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
if (ctx)
ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
if (ctx)
ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
}
/*
* We want to maintain the following priority of scheduling:
* - CPU pinned (EVENT_CPU | EVENT_PINNED)
* - task pinned (EVENT_PINNED)
* - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
* - task flexible (EVENT_FLEXIBLE).
*
* In order to avoid unscheduling and scheduling back in everything every
* time an event is added, only do it for the groups of equal priority and
* below.
*
* This can be called after a batch operation on task events, in which case
* event_type is a bit mask of the types of events involved. For CPU events,
* event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
*/
static void ctx_resched(struct perf_cpu_context *cpuctx,
struct perf_event_context *task_ctx,
enum event_type_t event_type)
{
enum event_type_t ctx_event_type;
bool cpu_event = !!(event_type & EVENT_CPU);
/*
* If pinned groups are involved, flexible groups also need to be
* scheduled out.
*/
if (event_type & EVENT_PINNED)
event_type |= EVENT_FLEXIBLE;
ctx_event_type = event_type & EVENT_ALL;
perf_pmu_disable(cpuctx->ctx.pmu);
if (task_ctx)
task_ctx_sched_out(cpuctx, task_ctx, event_type);
/*
* Decide which cpu ctx groups to schedule out based on the types
* of events that caused rescheduling:
* - EVENT_CPU: schedule out corresponding groups;
* - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
* - otherwise, do nothing more.
*/
if (cpu_event)
cpu_ctx_sched_out(cpuctx, ctx_event_type);
else if (ctx_event_type & EVENT_PINNED)
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
perf_event_sched_in(cpuctx, task_ctx, current);
perf_pmu_enable(cpuctx->ctx.pmu);
}
void perf_pmu_resched(struct pmu *pmu)
{
struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
struct perf_event_context *task_ctx = cpuctx->task_ctx;
perf_ctx_lock(cpuctx, task_ctx);
ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
perf_ctx_unlock(cpuctx, task_ctx);
}
/*
* Cross CPU call to install and enable a performance event
*
* Very similar to remote_function() + event_function() but cannot assume that
* things like ctx->is_active and cpuctx->task_ctx are set.
*/
static int __perf_install_in_context(void *info)
{
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct perf_event_context *task_ctx = cpuctx->task_ctx;
bool reprogram = true;
int ret = 0;
raw_spin_lock(&cpuctx->ctx.lock);
if (ctx->task) {
raw_spin_lock(&ctx->lock);
task_ctx = ctx;
reprogram = (ctx->task == current);
/*
* If the task is running, it must be running on this CPU,
* otherwise we cannot reprogram things.
*
* If its not running, we don't care, ctx->lock will
* serialize against it becoming runnable.
*/
if (task_curr(ctx->task) && !reprogram) {
ret = -ESRCH;
goto unlock;
}
WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
} else if (task_ctx) {
raw_spin_lock(&task_ctx->lock);
}
#ifdef CONFIG_CGROUP_PERF
if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
/*
* If the current cgroup doesn't match the event's
* cgroup, we should not try to schedule it.
*/
struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
reprogram = cgroup_is_descendant(cgrp->css.cgroup,
event->cgrp->css.cgroup);
}
#endif
if (reprogram) {
ctx_sched_out(ctx, cpuctx, EVENT_TIME);
add_event_to_ctx(event, ctx);
ctx_resched(cpuctx, task_ctx, get_event_type(event));
} else {
add_event_to_ctx(event, ctx);
}
unlock:
perf_ctx_unlock(cpuctx, task_ctx);
return ret;
}
static bool exclusive_event_installable(struct perf_event *event,
struct perf_event_context *ctx);
/*
* Attach a performance event to a context.
*
* Very similar to event_function_call, see comment there.
*/
static void
perf_install_in_context(struct perf_event_context *ctx,
struct perf_event *event,
int cpu)
{
struct task_struct *task = READ_ONCE(ctx->task);
lockdep_assert_held(&ctx->mutex);
WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
if (event->cpu != -1)
event->cpu = cpu;
/*
* Ensures that if we can observe event->ctx, both the event and ctx
* will be 'complete'. See perf_iterate_sb_cpu().
*/
smp_store_release(&event->ctx, ctx);
/*
* perf_event_attr::disabled events will not run and can be initialized
* without IPI. Except when this is the first event for the context, in
* that case we need the magic of the IPI to set ctx->is_active.
* Similarly, cgroup events for the context also needs the IPI to
* manipulate the cgrp_cpuctx_list.
*
* The IOC_ENABLE that is sure to follow the creation of a disabled
* event will issue the IPI and reprogram the hardware.
*/
if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
ctx->nr_events && !is_cgroup_event(event)) {
raw_spin_lock_irq(&ctx->lock);
if (ctx->task == TASK_TOMBSTONE) {
raw_spin_unlock_irq(&ctx->lock);
return;
}
add_event_to_ctx(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
return;
}
if (!task) {
cpu_function_call(cpu, __perf_install_in_context, event);
return;
}
/*
* Should not happen, we validate the ctx is still alive before calling.
*/
if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
return;
/*
* Installing events is tricky because we cannot rely on ctx->is_active
* to be set in case this is the nr_events 0 -> 1 transition.
*
* Instead we use task_curr(), which tells us if the task is running.
* However, since we use task_curr() outside of rq::lock, we can race
* against the actual state. This means the result can be wrong.
*
* If we get a false positive, we retry, this is harmless.
*
* If we get a false negative, things are complicated. If we are after
* perf_event_context_sched_in() ctx::lock will serialize us, and the
* value must be correct. If we're before, it doesn't matter since
* perf_event_context_sched_in() will program the counter.
*
* However, this hinges on the remote context switch having observed
* our task->perf_event_ctxp[] store, such that it will in fact take
* ctx::lock in perf_event_context_sched_in().
*
* We do this by task_function_call(), if the IPI fails to hit the task
* we know any future context switch of task must see the
* perf_event_ctpx[] store.
*/
/*
* This smp_mb() orders the task->perf_event_ctxp[] store with the
* task_cpu() load, such that if the IPI then does not find the task
* running, a future context switch of that task must observe the
* store.
*/
smp_mb();
again:
if (!task_function_call(task, __perf_install_in_context, event))
return;
raw_spin_lock_irq(&ctx->lock);
task = ctx->task;
if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
/*
* Cannot happen because we already checked above (which also
* cannot happen), and we hold ctx->mutex, which serializes us
* against perf_event_exit_task_context().
*/
raw_spin_unlock_irq(&ctx->lock);
return;
}
/*
* If the task is not running, ctx->lock will avoid it becoming so,
* thus we can safely install the event.
*/
if (task_curr(task)) {
raw_spin_unlock_irq(&ctx->lock);
goto again;
}
add_event_to_ctx(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
}
/*
* Cross CPU call to enable a performance event
*/
static void __perf_event_enable(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
void *info)
{
struct perf_event *leader = event->group_leader;
struct perf_event_context *task_ctx;
if (event->state >= PERF_EVENT_STATE_INACTIVE ||
event->state <= PERF_EVENT_STATE_ERROR)
return;
if (ctx->is_active)
ctx_sched_out(ctx, cpuctx, EVENT_TIME);
perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
perf_cgroup_event_enable(event, ctx);
if (!ctx->is_active)
return;
if (!event_filter_match(event)) {
ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
return;
}
/*
* If the event is in a group and isn't the group leader,
* then don't put it on unless the group is on.
*/
if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
return;
}
task_ctx = cpuctx->task_ctx;
if (ctx->task)
WARN_ON_ONCE(task_ctx != ctx);
ctx_resched(cpuctx, task_ctx, get_event_type(event));
}
/*
* Enable an event.
*
* If event->ctx is a cloned context, callers must make sure that
* every task struct that event->ctx->task could possibly point to
* remains valid. This condition is satisfied when called through
* perf_event_for_each_child or perf_event_for_each as described
* for perf_event_disable.
*/
static void _perf_event_enable(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
raw_spin_lock_irq(&ctx->lock);
if (event->state >= PERF_EVENT_STATE_INACTIVE ||
event->state < PERF_EVENT_STATE_ERROR) {
out:
raw_spin_unlock_irq(&ctx->lock);
return;
}
/*
* If the event is in error state, clear that first.
*
* That way, if we see the event in error state below, we know that it
* has gone back into error state, as distinct from the task having
* been scheduled away before the cross-call arrived.
*/
if (event->state == PERF_EVENT_STATE_ERROR) {
/*
* Detached SIBLING events cannot leave ERROR state.
*/
if (event->event_caps & PERF_EV_CAP_SIBLING &&
event->group_leader == event)
goto out;
event->state = PERF_EVENT_STATE_OFF;
}
raw_spin_unlock_irq(&ctx->lock);
event_function_call(event, __perf_event_enable, NULL);
}
/*
* See perf_event_disable();
*/
void perf_event_enable(struct perf_event *event)
{
struct perf_event_context *ctx;
ctx = perf_event_ctx_lock(event);
_perf_event_enable(event);
perf_event_ctx_unlock(event, ctx);
}
EXPORT_SYMBOL_GPL(perf_event_enable);
struct stop_event_data {
struct perf_event *event;
unsigned int restart;
};
static int __perf_event_stop(void *info)
{
struct stop_event_data *sd = info;
struct perf_event *event = sd->event;
/* if it's already INACTIVE, do nothing */
if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
return 0;
/* matches smp_wmb() in event_sched_in() */
smp_rmb();
/*
* There is a window with interrupts enabled before we get here,
* so we need to check again lest we try to stop another CPU's event.
*/
if (READ_ONCE(event->oncpu) != smp_processor_id())
return -EAGAIN;
event->pmu->stop(event, PERF_EF_UPDATE);
/*
* May race with the actual stop (through perf_pmu_output_stop()),
* but it is only used for events with AUX ring buffer, and such
* events will refuse to restart because of rb::aux_mmap_count==0,
* see comments in perf_aux_output_begin().
*
* Since this is happening on an event-local CPU, no trace is lost
* while restarting.
*/
if (sd->restart)
event->pmu->start(event, 0);
return 0;
}
static int perf_event_stop(struct perf_event *event, int restart)
{
struct stop_event_data sd = {
.event = event,
.restart = restart,
};
int ret = 0;
do {
if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
return 0;
/* matches smp_wmb() in event_sched_in() */
smp_rmb();
/*
* We only want to restart ACTIVE events, so if the event goes
* inactive here (event->oncpu==-1), there's nothing more to do;
* fall through with ret==-ENXIO.
*/
ret = cpu_function_call(READ_ONCE(event->oncpu),
__perf_event_stop, &sd);
} while (ret == -EAGAIN);
return ret;
}
/*
* In order to contain the amount of racy and tricky in the address filter
* configuration management, it is a two part process:
*
* (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
* we update the addresses of corresponding vmas in
* event::addr_filter_ranges array and bump the event::addr_filters_gen;
* (p2) when an event is scheduled in (pmu::add), it calls
* perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
* if the generation has changed since the previous call.
*
* If (p1) happens while the event is active, we restart it to force (p2).
*
* (1) perf_addr_filters_apply(): adjusting filters' offsets based on
* pre-existing mappings, called once when new filters arrive via SET_FILTER
* ioctl;
* (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
* registered mapping, called for every new mmap(), with mm::mmap_lock down
* for reading;
* (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
* of exec.
*/
void perf_event_addr_filters_sync(struct perf_event *event)
{
struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
if (!has_addr_filter(event))
return;
raw_spin_lock(&ifh->lock);
if (event->addr_filters_gen != event->hw.addr_filters_gen) {
event->pmu->addr_filters_sync(event);
event->hw.addr_filters_gen = event->addr_filters_gen;
}
raw_spin_unlock(&ifh->lock);
}
EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
static int _perf_event_refresh(struct perf_event *event, int refresh)
{
/*
* not supported on inherited events
*/
if (event->attr.inherit || !is_sampling_event(event))
return -EINVAL;
atomic_add(refresh, &event->event_limit);
_perf_event_enable(event);
return 0;
}
/*
* See perf_event_disable()
*/
int perf_event_refresh(struct perf_event *event, int refresh)
{
struct perf_event_context *ctx;
int ret;
ctx = perf_event_ctx_lock(event);
ret = _perf_event_refresh(event, refresh);
perf_event_ctx_unlock(event, ctx);
return ret;
}
EXPORT_SYMBOL_GPL(perf_event_refresh);
static int perf_event_modify_breakpoint(struct perf_event *bp,
struct perf_event_attr *attr)
{
int err;
_perf_event_disable(bp);
err = modify_user_hw_breakpoint_check(bp, attr, true);
if (!bp->attr.disabled)
_perf_event_enable(bp);
return err;
}
/*
* Copy event-type-independent attributes that may be modified.
*/
static void perf_event_modify_copy_attr(struct perf_event_attr *to,
const struct perf_event_attr *from)
{
to->sig_data = from->sig_data;
}
static int perf_event_modify_attr(struct perf_event *event,
struct perf_event_attr *attr)
{
int (*func)(struct perf_event *, struct perf_event_attr *);
struct perf_event *child;
int err;
if (event->attr.type != attr->type)
return -EINVAL;
switch (event->attr.type) {
case PERF_TYPE_BREAKPOINT:
func = perf_event_modify_breakpoint;
break;
default:
/* Place holder for future additions. */
return -EOPNOTSUPP;
}
WARN_ON_ONCE(event->ctx->parent_ctx);
mutex_lock(&event->child_mutex);
/*
* Event-type-independent attributes must be copied before event-type
* modification, which will validate that final attributes match the
* source attributes after all relevant attributes have been copied.
*/
perf_event_modify_copy_attr(&event->attr, attr);
err = func(event, attr);
if (err)
goto out;
list_for_each_entry(child, &event->child_list, child_list) {
perf_event_modify_copy_attr(&child->attr, attr);
err = func(child, attr);
if (err)
goto out;
}
out:
mutex_unlock(&event->child_mutex);
return err;
}
static void ctx_sched_out(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx,
enum event_type_t event_type)
{
struct perf_event *event, *tmp;
int is_active = ctx->is_active;
lockdep_assert_held(&ctx->lock);
if (likely(!ctx->nr_events)) {
/*
* See __perf_remove_from_context().
*/
WARN_ON_ONCE(ctx->is_active);
if (ctx->task)
WARN_ON_ONCE(cpuctx->task_ctx);
return;
}
/*
* Always update time if it was set; not only when it changes.
* Otherwise we can 'forget' to update time for any but the last
* context we sched out. For example:
*
* ctx_sched_out(.event_type = EVENT_FLEXIBLE)
* ctx_sched_out(.event_type = EVENT_PINNED)
*
* would only update time for the pinned events.
*/
if (is_active & EVENT_TIME) {
/* update (and stop) ctx time */
update_context_time(ctx);
update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
/*
* CPU-release for the below ->is_active store,
* see __load_acquire() in perf_event_time_now()
*/
barrier();
}
ctx->is_active &= ~event_type;
if (!(ctx->is_active & EVENT_ALL))
ctx->is_active = 0;
if (ctx->task) {
WARN_ON_ONCE(cpuctx->task_ctx != ctx);
if (!ctx->is_active)
cpuctx->task_ctx = NULL;
}
is_active ^= ctx->is_active; /* changed bits */
if (!ctx->nr_active || !(is_active & EVENT_ALL))
return;
perf_pmu_disable(ctx->pmu);
if (is_active & EVENT_PINNED) {
list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
group_sched_out(event, cpuctx, ctx);
}
if (is_active & EVENT_FLEXIBLE) {
list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
group_sched_out(event, cpuctx, ctx);
/*
* Since we cleared EVENT_FLEXIBLE, also clear
* rotate_necessary, is will be reset by
* ctx_flexible_sched_in() when needed.
*/
ctx->rotate_necessary = 0;
}
perf_pmu_enable(ctx->pmu);
}
/*
* Test whether two contexts are equivalent, i.e. whether they have both been
* cloned from the same version of the same context.
*
* Equivalence is measured using a generation number in the context that is
* incremented on each modification to it; see unclone_ctx(), list_add_event()
* and list_del_event().
*/
static int context_equiv(struct perf_event_context *ctx1,
struct perf_event_context *ctx2)
{
lockdep_assert_held(&ctx1->lock);
lockdep_assert_held(&ctx2->lock);
/* Pinning disables the swap optimization */
if (ctx1->pin_count || ctx2->pin_count)
return 0;
/* If ctx1 is the parent of ctx2 */
if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
return 1;
/* If ctx2 is the parent of ctx1 */
if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
return 1;
/*
* If ctx1 and ctx2 have the same parent; we flatten the parent
* hierarchy, see perf_event_init_context().
*/
if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
ctx1->parent_gen == ctx2->parent_gen)
return 1;
/* Unmatched */
return 0;
}
static void __perf_event_sync_stat(struct perf_event *event,
struct perf_event *next_event)
{
u64 value;
if (!event->attr.inherit_stat)
return;
/*
* Update the event value, we cannot use perf_event_read()
* because we're in the middle of a context switch and have IRQs
* disabled, which upsets smp_call_function_single(), however
* we know the event must be on the current CPU, therefore we
* don't need to use it.
*/
if (event->state == PERF_EVENT_STATE_ACTIVE)
event->pmu->read(event);
perf_event_update_time(event);
/*
* In order to keep per-task stats reliable we need to flip the event
* values when we flip the contexts.
*/
value = local64_read(&next_event->count);
value = local64_xchg(&event->count, value);
local64_set(&next_event->count, value);
swap(event->total_time_enabled, next_event->total_time_enabled);
swap(event->total_time_running, next_event->total_time_running);
/*
* Since we swizzled the values, update the user visible data too.
*/
perf_event_update_userpage(event);
perf_event_update_userpage(next_event);
}
static void perf_event_sync_stat(struct perf_event_context *ctx,
struct perf_event_context *next_ctx)
{
struct perf_event *event, *next_event;
if (!ctx->nr_stat)
return;
update_context_time(ctx);
event = list_first_entry(&ctx->event_list,
struct perf_event, event_entry);
next_event = list_first_entry(&next_ctx->event_list,
struct perf_event, event_entry);
while (&event->event_entry != &ctx->event_list &&
&next_event->event_entry != &next_ctx->event_list) {
__perf_event_sync_stat(event, next_event);
event = list_next_entry(event, event_entry);
next_event = list_next_entry(next_event, event_entry);
}
}
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
struct task_struct *next)
{
struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
struct perf_event_context *next_ctx;
struct perf_event_context *parent, *next_parent;
struct perf_cpu_context *cpuctx;
int do_switch = 1;
struct pmu *pmu;
if (likely(!ctx))
return;
pmu = ctx->pmu;
cpuctx = __get_cpu_context(ctx);
if (!cpuctx->task_ctx)
return;
rcu_read_lock();
next_ctx = next->perf_event_ctxp[ctxn];
if (!next_ctx)
goto unlock;
parent = rcu_dereference(ctx->parent_ctx);
next_parent = rcu_dereference(next_ctx->parent_ctx);
/* If neither context have a parent context; they cannot be clones. */
if (!parent && !next_parent)
goto unlock;
if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
/*
* Looks like the two contexts are clones, so we might be
* able to optimize the context switch. We lock both
* contexts and check that they are clones under the
* lock (including re-checking that neither has been
* uncloned in the meantime). It doesn't matter which
* order we take the locks because no other cpu could
* be trying to lock both of these tasks.
*/
raw_spin_lock(&ctx->lock);
raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
if (context_equiv(ctx, next_ctx)) {
WRITE_ONCE(ctx->task, next);
WRITE_ONCE(next_ctx->task, task);
perf_pmu_disable(pmu);
if (cpuctx->sched_cb_usage && pmu->sched_task)
pmu->sched_task(ctx, false);
/*
* PMU specific parts of task perf context can require
* additional synchronization. As an example of such
* synchronization see implementation details of Intel
* LBR call stack data profiling;
*/
if (pmu->swap_task_ctx)
pmu->swap_task_ctx(ctx, next_ctx);
else
swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
perf_pmu_enable(pmu);
/*
* RCU_INIT_POINTER here is safe because we've not
* modified the ctx and the above modification of
* ctx->task and ctx->task_ctx_data are immaterial
* since those values are always verified under
* ctx->lock which we're now holding.
*/
RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
do_switch = 0;
perf_event_sync_stat(ctx, next_ctx);
}
raw_spin_unlock(&next_ctx->lock);
raw_spin_unlock(&ctx->lock);
}
unlock:
rcu_read_unlock();
if (do_switch) {
raw_spin_lock(&ctx->lock);
perf_pmu_disable(pmu);
if (cpuctx->sched_cb_usage && pmu->sched_task)
pmu->sched_task(ctx, false);
task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
perf_pmu_enable(pmu);
raw_spin_unlock(&ctx->lock);
}
}
static DEFINE_PER_CPU(struct list_head, sched_cb_list);
void perf_sched_cb_dec(struct pmu *pmu)
{
struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
this_cpu_dec(perf_sched_cb_usages);
if (!--cpuctx->sched_cb_usage)
list_del(&cpuctx->sched_cb_entry);
}
void perf_sched_cb_inc(struct pmu *pmu)
{
struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
if (!cpuctx->sched_cb_usage++)
list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
this_cpu_inc(perf_sched_cb_usages);
}
/*
* This function provides the context switch callback to the lower code
* layer. It is invoked ONLY when the context switch callback is enabled.
*
* This callback is relevant even to per-cpu events; for example multi event
* PEBS requires this to provide PID/TID information. This requires we flush
* all queued PEBS records before we context switch to a new task.
*/
static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
{
struct pmu *pmu;
pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
if (WARN_ON_ONCE(!pmu->sched_task))
return;
perf_ctx_lock(cpuctx, cpuctx->task_ctx);
perf_pmu_disable(pmu);
pmu->sched_task(cpuctx->task_ctx, sched_in);
perf_pmu_enable(pmu);
perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
}
static void perf_pmu_sched_task(struct task_struct *prev,
struct task_struct *next,
bool sched_in)
{
struct perf_cpu_context *cpuctx;
if (prev == next)
return;
list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
/* will be handled in perf_event_context_sched_in/out */
if (cpuctx->task_ctx)
continue;
__perf_pmu_sched_task(cpuctx, sched_in);
}
}
static void perf_event_switch(struct task_struct *task,
struct task_struct *next_prev, bool sched_in);
#define for_each_task_context_nr(ctxn) \
for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
/*
* Called from scheduler to remove the events of the current task,
* with interrupts disabled.
*
* We stop each event and update the event value in event->count.
*
* This does not protect us against NMI, but disable()
* sets the disabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* not restart the event.
*/
void __perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next)
{
int ctxn;
if (__this_cpu_read(perf_sched_cb_usages))
perf_pmu_sched_task(task, next, false);
if (atomic_read(&nr_switch_events))
perf_event_switch(task, next, false);
for_each_task_context_nr(ctxn)
perf_event_context_sched_out(task, ctxn, next);
/*
* if cgroup events exist on this CPU, then we need
* to check if we have to switch out PMU state.
* cgroup event are system-wide mode only
*/
if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
perf_cgroup_sched_out(task, next);
}
/*
* Called with IRQs disabled
*/
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
enum event_type_t event_type)
{
ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
}
static bool perf_less_group_idx(const void *l, const void *r)
{
const struct perf_event *le = *(const struct perf_event **)l;
const struct perf_event *re = *(const struct perf_event **)r;
return le->group_index < re->group_index;
}
static void swap_ptr(void *l, void *r)
{
void **lp = l, **rp = r;
swap(*lp, *rp);
}
static const struct min_heap_callbacks perf_min_heap = {
.elem_size = sizeof(struct perf_event *),
.less = perf_less_group_idx,
.swp = swap_ptr,
};
static void __heap_add(struct min_heap *heap, struct perf_event *event)
{
struct perf_event **itrs = heap->data;
if (event) {
itrs[heap->nr] = event;
heap->nr++;
}
}
static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
struct perf_event_groups *groups, int cpu,
int (*func)(struct perf_event *, void *),
void *data)
{
#ifdef CONFIG_CGROUP_PERF
struct cgroup_subsys_state *css = NULL;
#endif
/* Space for per CPU and/or any CPU event iterators. */
struct perf_event *itrs[2];
struct min_heap event_heap;
struct perf_event **evt;
int ret;
if (cpuctx) {
event_heap = (struct min_heap){
.data = cpuctx->heap,
.nr = 0,
.size = cpuctx->heap_size,
};
lockdep_assert_held(&cpuctx->ctx.lock);
#ifdef CONFIG_CGROUP_PERF
if (cpuctx->cgrp)
css = &cpuctx->cgrp->css;
#endif
} else {
event_heap = (struct min_heap){
.data = itrs,
.nr = 0,
.size = ARRAY_SIZE(itrs),
};
/* Events not within a CPU context may be on any CPU. */
__heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
}
evt = event_heap.data;
__heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
#ifdef CONFIG_CGROUP_PERF
for (; css; css = css->parent)
__heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
#endif
min_heapify_all(&event_heap, &perf_min_heap);
while (event_heap.nr) {
ret = func(*evt, data);
if (ret)
return ret;
*evt = perf_event_groups_next(*evt);
if (*evt)
min_heapify(&event_heap, 0, &perf_min_heap);
else
min_heap_pop(&event_heap, &perf_min_heap);
}
return 0;
}
/*
* Because the userpage is strictly per-event (there is no concept of context,
* so there cannot be a context indirection), every userpage must be updated
* when context time starts :-(
*
* IOW, we must not miss EVENT_TIME edges.
*/
static inline bool event_update_userpage(struct perf_event *event)
{
if (likely(!atomic_read(&event->mmap_count)))
return false;
perf_event_update_time(event);
perf_event_update_userpage(event);
return true;
}
static inline void group_update_userpage(struct perf_event *group_event)
{
struct perf_event *event;
if (!event_update_userpage(group_event))
return;
for_each_sibling_event(event, group_event)
event_update_userpage(event);
}
static int merge_sched_in(struct perf_event *event, void *data)
{
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
int *can_add_hw = data;
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;
if (!event_filter_match(event))
return 0;
if (group_can_go_on(event, cpuctx, *can_add_hw)) {
if (!group_sched_in(event, cpuctx, ctx))
list_add_tail(&event->active_list, get_event_list(event));
}
if (event->state == PERF_EVENT_STATE_INACTIVE) {
*can_add_hw = 0;
if (event->attr.pinned) {
perf_cgroup_event_disable(event, ctx);
perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
} else {
ctx->rotate_necessary = 1;
perf_mux_hrtimer_restart(cpuctx);
group_update_userpage(event);
}
}
return 0;
}
static void
ctx_pinned_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx)
{
int can_add_hw = 1;
if (ctx != &cpuctx->ctx)
cpuctx = NULL;
visit_groups_merge(cpuctx, &ctx->pinned_groups,
smp_processor_id(),
merge_sched_in, &can_add_hw);
}
static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx)
{
int can_add_hw = 1;
if (ctx != &cpuctx->ctx)
cpuctx = NULL;
visit_groups_merge(cpuctx, &ctx->flexible_groups,
smp_processor_id(),
merge_sched_in, &can_add_hw);
}
static void
ctx_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx,
enum event_type_t event_type,
struct task_struct *task)
{
int is_active = ctx->is_active;
lockdep_assert_held(&ctx->lock);
if (likely(!ctx->nr_events))
return;
if (is_active ^ EVENT_TIME) {
/* start ctx time */
__update_context_time(ctx, false);
perf_cgroup_set_timestamp(task, ctx);
/*
* CPU-release for the below ->is_active store,
* see __load_acquire() in perf_event_time_now()
*/
barrier();
}
ctx->is_active |= (event_type | EVENT_TIME);
if (ctx->task) {
if (!is_active)
cpuctx->task_ctx = ctx;
else
WARN_ON_ONCE(cpuctx->task_ctx != ctx);
}
is_active ^= ctx->is_active; /* changed bits */
/*
* First go through the list and put on any pinned groups
* in order to give them the best chance of going on.
*/
if (is_active & EVENT_PINNED)
ctx_pinned_sched_in(ctx, cpuctx);
/* Then walk through the lower prio flexible groups */
if (is_active & EVENT_FLEXIBLE)
ctx_flexible_sched_in(ctx, cpuctx);
}
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
enum event_type_t event_type,
struct task_struct *task)
{
struct perf_event_context *ctx = &cpuctx->ctx;
ctx_sched_in(ctx, cpuctx, event_type, task);
}
static void perf_event_context_sched_in(struct perf_event_context *ctx,
struct task_struct *task)
{
struct perf_cpu_context *cpuctx;
struct pmu *pmu;
cpuctx = __get_cpu_context(ctx);
/*
* HACK: for HETEROGENEOUS the task context might have switched to a
* different PMU, force (re)set the context,
*/
pmu = ctx->pmu = cpuctx->ctx.pmu;
if (cpuctx->task_ctx == ctx) {
if (cpuctx->sched_cb_usage)
__perf_pmu_sched_task(cpuctx, true);
return;
}
perf_ctx_lock(cpuctx, ctx);
/*
* We must check ctx->nr_events while holding ctx->lock, such
* that we serialize against perf_install_in_context().
*/
if (!ctx->nr_events)
goto unlock;
perf_pmu_disable(pmu);
/*
* We want to keep the following priority order:
* cpu pinned (that don't need to move), task pinned,
* cpu flexible, task flexible.
*
* However, if task's ctx is not carrying any pinned
* events, no need to flip the cpuctx's events around.
*/
if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
perf_event_sched_in(cpuctx, ctx, task);
if (cpuctx->sched_cb_usage && pmu->sched_task)
pmu->sched_task(cpuctx->task_ctx, true);
perf_pmu_enable(pmu);
unlock:
perf_ctx_unlock(cpuctx, ctx);
}
/*
* Called from scheduler to add the events of the current task
* with interrupts disabled.
*
* We restore the event value and then enable it.
*
* This does not protect us against NMI, but enable()
* sets the enabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* keep the event running.
*/
void __perf_event_task_sched_in(struct task_struct *prev,
struct task_struct *task)
{
struct perf_event_context *ctx;
int ctxn;
/*
* If cgroup events exist on this CPU, then we need to check if we have
* to switch in PMU state; cgroup event are system-wide mode only.
*
* Since cgroup events are CPU events, we must schedule these in before
* we schedule in the task events.
*/
if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
perf_cgroup_sched_in(prev, task);
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (likely(!ctx))
continue;
perf_event_context_sched_in(ctx, task);
}
if (atomic_read(&nr_switch_events))
perf_event_switch(task, prev, true);
if (__this_cpu_read(perf_sched_cb_usages))
perf_pmu_sched_task(prev, task, true);
}
static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
{
u64 frequency = event->attr.sample_freq;
u64 sec = NSEC_PER_SEC;
u64 divisor, dividend;
int count_fls, nsec_fls, frequency_fls, sec_fls;
count_fls = fls64(count);
nsec_fls = fls64(nsec);
frequency_fls = fls64(frequency);
sec_fls = 30;
/*
* We got @count in @nsec, with a target of sample_freq HZ
* the target period becomes:
*
* @count * 10^9
* period = -------------------
* @nsec * sample_freq
*
*/
/*
* Reduce accuracy by one bit such that @a and @b converge
* to a similar magnitude.
*/
#define REDUCE_FLS(a, b) \
do { \
if (a##_fls > b##_fls) { \
a >>= 1; \
a##_fls--; \
} else { \
b >>= 1; \
b##_fls--; \
} \
} while (0)
/*
* Reduce accuracy until either term fits in a u64, then proceed with
* the other, so that finally we can do a u64/u64 division.
*/
while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
REDUCE_FLS(nsec, frequency);
REDUCE_FLS(sec, count);
}
if (count_fls + sec_fls > 64) {
divisor = nsec * frequency;
while (count_fls + sec_fls > 64) {
REDUCE_FLS(count, sec);
divisor >>= 1;
}
dividend = count * sec;
} else {
dividend = count * sec;
while (nsec_fls + frequency_fls > 64) {
REDUCE_FLS(nsec, frequency);
dividend >>= 1;
}
divisor = nsec * frequency;
}
if (!divisor)
return dividend;
return div64_u64(dividend, divisor);
}
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
{
struct hw_perf_event *hwc = &event->hw;
s64 period, sample_period;
s64 delta;
period = perf_calculate_period(event, nsec, count);
delta = (s64)(period - hwc->sample_period);
delta = (delta + 7) / 8; /* low pass filter */
sample_period = hwc->sample_period + delta;
if (!sample_period)
sample_period = 1;
hwc->sample_period = sample_period;
if (local64_read(&hwc->period_left) > 8*sample_period) {
if (disable)
event->pmu->stop(event, PERF_EF_UPDATE);
local64_set(&hwc->period_left, 0);
if (disable)
event->pmu->start(event, PERF_EF_RELOAD);
}
}
/*
* combine freq adjustment with unthrottling to avoid two passes over the
* events. At the same time, make sure, having freq events does not change
* the rate of unthrottling as that would introduce bias.
*/
static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
int needs_unthr)
{
struct perf_event *event;
struct hw_perf_event *hwc;
u64 now, period = TICK_NSEC;
s64 delta;
/*
* only need to iterate over all events iff:
* - context have events in frequency mode (needs freq adjust)
* - there are events to unthrottle on this cpu
*/
if (!(ctx->nr_freq || needs_unthr))
return;
raw_spin_lock(&ctx->lock);
perf_pmu_disable(ctx->pmu);
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (event->state != PERF_EVENT_STATE_ACTIVE)
continue;
if (!event_filter_match(event))
continue;
perf_pmu_disable(event->pmu);
hwc = &event->hw;
if (hwc->interrupts == MAX_INTERRUPTS) {
hwc->interrupts = 0;
perf_log_throttle(event, 1);
event->pmu->start(event, 0);
}
if (!event->attr.freq || !event->attr.sample_freq)
goto next;
/*
* stop the event and update event->count
*/
event->pmu->stop(event, PERF_EF_UPDATE);
now = local64_read(&event->count);
delta = now - hwc->freq_count_stamp;
hwc->freq_count_stamp = now;
/*
* restart the event
* reload only if value has changed
* we have stopped the event so tell that
* to perf_adjust_period() to avoid stopping it
* twice.
*/
if (delta > 0)
perf_adjust_period(event, period, delta, false);
event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
next:
perf_pmu_enable(event->pmu);
}
perf_pmu_enable(ctx->pmu);
raw_spin_unlock(&ctx->lock);
}
/*
* Move @event to the tail of the @ctx's elegible events.
*/
static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
{
/*
* Rotate the first entry last of non-pinned groups. Rotation might be
* disabled by the inheritance code.
*/
if (ctx->rotate_disable)
return;
perf_event_groups_delete(&ctx->flexible_groups, event);
perf_event_groups_insert(&ctx->flexible_groups, event);
}
/* pick an event from the flexible_groups to rotate */
static inline struct perf_event *
ctx_event_to_rotate(struct perf_event_context *ctx)
{
struct perf_event *event;
/* pick the first active flexible event */
event = list_first_entry_or_null(&ctx->flexible_active,
struct perf_event, active_list);
/* if no active flexible event, pick the first event */
if (!event) {
event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
typeof(*event), group_node);
}
/*
* Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
* finds there are unschedulable events, it will set it again.
*/
ctx->rotate_necessary = 0;
return event;
}
static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
{
struct perf_event *cpu_event = NULL, *task_event = NULL;
struct perf_event_context *task_ctx = NULL;
int cpu_rotate, task_rotate;
/*
* Since we run this from IRQ context, nobody can install new
* events, thus the event count values are stable.
*/
cpu_rotate = cpuctx->ctx.rotate_necessary;
task_ctx = cpuctx->task_ctx;
task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
if (!(cpu_rotate || task_rotate))
return false;
perf_ctx_lock(cpuctx, cpuctx->task_ctx);
perf_pmu_disable(cpuctx->ctx.pmu);
if (task_rotate)
task_event = ctx_event_to_rotate(task_ctx);
if (cpu_rotate)
cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
/*
* As per the order given at ctx_resched() first 'pop' task flexible
* and then, if needed CPU flexible.
*/
if (task_event || (task_ctx && cpu_event))
ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
if (cpu_event)
cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
if (task_event)
rotate_ctx(task_ctx, task_event);
if (cpu_event)
rotate_ctx(&cpuctx->ctx, cpu_event);
perf_event_sched_in(cpuctx, task_ctx, current);
perf_pmu_enable(cpuctx->ctx.pmu);
perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
return true;
}
void perf_event_task_tick(void)
{
struct list_head *head = this_cpu_ptr(&active_ctx_list);
struct perf_event_context *ctx, *tmp;
int throttled;
lockdep_assert_irqs_disabled();
__this_cpu_inc(perf_throttled_seq);
throttled = __this_cpu_xchg(perf_throttled_count, 0);
tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
perf_adjust_freq_unthr_context(ctx, throttled);
}
static int event_enable_on_exec(struct perf_event *event,
struct perf_event_context *ctx)
{
if (!event->attr.enable_on_exec)
return 0;
event->attr.enable_on_exec = 0;
if (event->state >= PERF_EVENT_STATE_INACTIVE)
return 0;
perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
return 1;
}
/*
* Enable all of a task's events that have been marked enable-on-exec.
* This expects task == current.
*/
static void perf_event_enable_on_exec(int ctxn)
{
struct perf_event_context *ctx, *clone_ctx = NULL;
enum event_type_t event_type = 0;
struct perf_cpu_context *cpuctx;
struct perf_event *event;
unsigned long flags;
int enabled = 0;
local_irq_save(flags);
ctx = current->perf_event_ctxp[ctxn];
if (!ctx || !ctx->nr_events)
goto out;
cpuctx = __get_cpu_context(ctx);
perf_ctx_lock(cpuctx, ctx);
ctx_sched_out(ctx, cpuctx, EVENT_TIME);
list_for_each_entry(event, &ctx->event_list, event_entry) {
enabled |= event_enable_on_exec(event, ctx);
event_type |= get_event_type(event);
}
/*
* Unclone and reschedule this context if we enabled any event.
*/
if (enabled) {
clone_ctx = unclone_ctx(ctx);
ctx_resched(cpuctx, ctx, event_type);
} else {
ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
}
perf_ctx_unlock(cpuctx, ctx);
out:
local_irq_restore(flags);
if (clone_ctx)
put_ctx(clone_ctx);
}
static void perf_remove_from_owner(struct perf_event *event);
static void perf_event_exit_event(struct perf_event *event,
struct perf_event_context *ctx);
/*
* Removes all events from the current task that have been marked
* remove-on-exec, and feeds their values back to parent events.
*/
static void perf_event_remove_on_exec(int ctxn)
{
struct perf_event_context *ctx, *clone_ctx = NULL;
struct perf_event *event, *next;
LIST_HEAD(free_list);
unsigned long flags;
bool modified = false;
ctx = perf_pin_task_context(current, ctxn);
if (!ctx)
return;
mutex_lock(&ctx->mutex);
if (WARN_ON_ONCE(ctx->task != current))
goto unlock;
list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
if (!event->attr.remove_on_exec)
continue;
if (!is_kernel_event(event))
perf_remove_from_owner(event);
modified = true;
perf_event_exit_event(event, ctx);
}
raw_spin_lock_irqsave(&ctx->lock, flags);
if (modified)
clone_ctx = unclone_ctx(ctx);
--ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
unlock:
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
if (clone_ctx)
put_ctx(clone_ctx);
}
struct perf_read_data {
struct perf_event *event;
bool group;
int ret;
};
static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
{
u16 local_pkg, event_pkg;
if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
int local_cpu = smp_processor_id();
event_pkg = topology_physical_package_id(event_cpu);
local_pkg = topology_physical_package_id(local_cpu);
if (event_pkg == local_pkg)
return local_cpu;
}
return event_cpu;
}
/*
* Cross CPU call to read the hardware event
*/
static void __perf_event_read(void *info)
{
struct perf_read_data *data = info;
struct perf_event *sub, *event = data->event;
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct pmu *pmu = event->pmu;
/*
* If this is a task context, we need to check whether it is
* the current task context of this cpu. If not it has been
* scheduled out before the smp call arrived. In that case
* event->count would have been updated to a recent sample
* when the event was scheduled out.
*/
if (ctx->task && cpuctx->task_ctx != ctx)
return;
raw_spin_lock(&ctx->lock);
if (ctx->is_active & EVENT_TIME) {
update_context_time(ctx);
update_cgrp_time_from_event(event);
}
perf_event_update_time(event);
if (data->group)
perf_event_update_sibling_time(event);
if (event->state != PERF_EVENT_STATE_ACTIVE)
goto unlock;
if (!data->group) {
pmu->read(event);
data->ret = 0;
goto unlock;
}
pmu->start_txn(pmu, PERF_PMU_TXN_READ);
pmu->read(event);
for_each_sibling_event(sub, event) {
if (sub->state == PERF_EVENT_STATE_ACTIVE) {
/*
* Use sibling's PMU rather than @event's since
* sibling could be on different (eg: software) PMU.
*/
sub->pmu->read(sub);
}
}
data->ret = pmu->commit_txn(pmu);
unlock:
raw_spin_unlock(&ctx->lock);
}
static inline u64 perf_event_count(struct perf_event *event)
{
return local64_read(&event->count) + atomic64_read(&event->child_count);
}
static void calc_timer_values(struct perf_event *event,
u64 *now,
u64 *enabled,
u64 *running)
{
u64 ctx_time;
*now = perf_clock();
ctx_time = perf_event_time_now(event, *now);
__perf_update_times(event, ctx_time, enabled, running);
}
/*
* NMI-safe method to read a local event, that is an event that
* is:
* - either for the current task, or for this CPU
* - does not have inherit set, for inherited task events
* will not be local and we cannot read them atomically
* - must not have a pmu::count method
*/
int perf_event_read_local(struct perf_event *event, u64 *value,
u64 *enabled, u64 *running)
{
unsigned long flags;
int ret = 0;
/*
* Disabling interrupts avoids all counter scheduling (context
* switches, timer based rotation and IPIs).
*/
local_irq_save(flags);
/*
* It must not be an event with inherit set, we cannot read
* all child counters from atomic context.
*/
if (event->attr.inherit) {
ret = -EOPNOTSUPP;
goto out;
}
/* If this is a per-task event, it must be for current */
if ((event->attach_state & PERF_ATTACH_TASK) &&
event->hw.target != current) {
ret = -EINVAL;
goto out;
}
/* If this is a per-CPU event, it must be for this CPU */
if (!(event->attach_state & PERF_ATTACH_TASK) &&
event->cpu != smp_processor_id()) {
ret = -EINVAL;
goto out;
}
/* If this is a pinned event it must be running on this CPU */
if (event->attr.pinned && event->oncpu != smp_processor_id()) {
ret = -EBUSY;
goto out;
}
/*
* If the event is currently on this CPU, its either a per-task event,
* or local to this CPU. Furthermore it means its ACTIVE (otherwise
* oncpu == -1).
*/
if (event->oncpu == smp_processor_id())
event->pmu->read(event);
*value = local64_read(&event->count);
if (enabled || running) {
u64 __enabled, __running, __now;;
calc_timer_values(event, &__now, &__enabled, &__running);
if (enabled)
*enabled = __enabled;
if (running)
*running = __running;
}
out:
local_irq_restore(flags);
return ret;
}
static int perf_event_read(struct perf_event *event, bool group)
{
enum perf_event_state state = READ_ONCE(event->state);
int event_cpu, ret = 0;
/*
* If event is enabled and currently active on a CPU, update the
* value in the event structure:
*/
again:
if (state == PERF_EVENT_STATE_ACTIVE) {
struct perf_read_data data;
/*
* Orders the ->state and ->oncpu loads such that if we see
* ACTIVE we must also see the right ->oncpu.
*
* Matches the smp_wmb() from event_sched_in().
*/
smp_rmb();
event_cpu = READ_ONCE(event->oncpu);
if ((unsigned)event_cpu >= nr_cpu_ids)
return 0;
data = (struct perf_read_data){
.event = event,
.group = group,
.ret = 0,
};
preempt_disable();
event_cpu = __perf_event_read_cpu(event, event_cpu);
/*
* Purposely ignore the smp_call_function_single() return
* value.
*
* If event_cpu isn't a valid CPU it means the event got
* scheduled out and that will have updated the event count.
*
* Therefore, either way, we'll have an up-to-date event count
* after this.
*/
(void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
preempt_enable();
ret = data.ret;
} else if (state == PERF_EVENT_STATE_INACTIVE) {
struct perf_event_context *ctx = event->ctx;
unsigned long flags;
raw_spin_lock_irqsave(&ctx->lock, flags);
state = event->state;
if (state != PERF_EVENT_STATE_INACTIVE) {
raw_spin_unlock_irqrestore(&ctx->lock, flags);
goto again;
}
/*
* May read while context is not active (e.g., thread is
* blocked), in that case we cannot update context time
*/
if (ctx->is_active & EVENT_TIME) {
update_context_time(ctx);
update_cgrp_time_from_event(event);
}
perf_event_update_time(event);
if (group)
perf_event_update_sibling_time(event);
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
return ret;
}
/*
* Initialize the perf_event context in a task_struct:
*/
static void __perf_event_init_context(struct perf_event_context *ctx)
{
raw_spin_lock_init(&ctx->lock);
mutex_init(&ctx->mutex);
INIT_LIST_HEAD(&ctx->active_ctx_list);
perf_event_groups_init(&ctx->pinned_groups);
perf_event_groups_init(&ctx->flexible_groups);
INIT_LIST_HEAD(&ctx->event_list);
INIT_LIST_HEAD(&ctx->pinned_active);
INIT_LIST_HEAD(&ctx->flexible_active);
refcount_set(&ctx->refcount, 1);
}
static struct perf_event_context *
alloc_perf_context(struct pmu *pmu, struct task_struct *task)
{
struct perf_event_context *ctx;
ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
if (!ctx)
return NULL;
__perf_event_init_context(ctx);
if (task)
ctx->task = get_task_struct(task);
ctx->pmu = pmu;
return ctx;
}
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
struct task_struct *task;
rcu_read_lock();
if (!vpid)
task = current;
else
task = find_task_by_vpid(vpid);
if (task)
get_task_struct(task);
rcu_read_unlock();
if (!task)
return ERR_PTR(-ESRCH);
return task;
}
/*
* Returns a matching context with refcount and pincount.
*/
static struct perf_event_context *
find_get_context(struct pmu *pmu, struct task_struct *task,
struct perf_event *event)
{
struct perf_event_context *ctx, *clone_ctx = NULL;
struct perf_cpu_context *cpuctx;
void *task_ctx_data = NULL;
unsigned long flags;
int ctxn, err;
int cpu = event->cpu;
if (!task) {
/* Must be root to operate on a CPU event: */
err = perf_allow_cpu(&event->attr);
if (err)
return ERR_PTR(err);
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
ctx = &cpuctx->ctx;
get_ctx(ctx);
raw_spin_lock_irqsave(&ctx->lock, flags);
++ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
return ctx;
}
err = -EINVAL;
ctxn = pmu->task_ctx_nr;
if (ctxn < 0)
goto errout;
if (event->attach_state & PERF_ATTACH_TASK_DATA) {
task_ctx_data = alloc_task_ctx_data(pmu);
if (!task_ctx_data) {
err = -ENOMEM;
goto errout;
}
}
retry:
ctx = perf_lock_task_context(task, ctxn, &flags);
if (ctx) {
clone_ctx = unclone_ctx(ctx);
++ctx->pin_count;
if (task_ctx_data && !ctx->task_ctx_data) {
ctx->task_ctx_data = task_ctx_data;
task_ctx_data = NULL;
}
raw_spin_unlock_irqrestore(&ctx->lock, flags);
if (clone_ctx)
put_ctx(clone_ctx);
} else {
ctx = alloc_perf_context(pmu, task);
err = -ENOMEM;
if (!ctx)
goto errout;
if (task_ctx_data) {
ctx->task_ctx_data = task_ctx_data;
task_ctx_data = NULL;
}
err = 0;
mutex_lock(&task->perf_event_mutex);
/*
* If it has already passed perf_event_exit_task().
* we must see PF_EXITING, it takes this mutex too.
*/
if (task->flags & PF_EXITING)
err = -ESRCH;
else if (task->perf_event_ctxp[ctxn])
err = -EAGAIN;
else {
get_ctx(ctx);
++ctx->pin_count;
rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
}
mutex_unlock(&task->perf_event_mutex);
if (unlikely(err)) {
put_ctx(ctx);
if (err == -EAGAIN)
goto retry;
goto errout;
}
}
free_task_ctx_data(pmu, task_ctx_data);
return ctx;
errout:
free_task_ctx_data(pmu, task_ctx_data);
return ERR_PTR(err);
}
static void perf_event_free_filter(struct perf_event *event);
static void free_event_rcu(struct rcu_head *head)
{
struct perf_event *event;
event = container_of(head, struct perf_event, rcu_head);
if (event->ns)
put_pid_ns(event->ns);
perf_event_free_filter(event);
kmem_cache_free(perf_event_cache, event);
}
static void ring_buffer_attach(struct perf_event *event,
struct perf_buffer *rb);
static void detach_sb_event(struct perf_event *event)
{
struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
raw_spin_lock(&pel->lock);
list_del_rcu(&event->sb_list);
raw_spin_unlock(&pel->lock);
}
static bool is_sb_event(struct perf_event *event)
{
struct perf_event_attr *attr = &event->attr;
if (event->parent)
return false;
if (event->attach_state & PERF_ATTACH_TASK)
return false;
if (attr->mmap || attr->mmap_data || attr->mmap2 ||
attr->comm || attr->comm_exec ||
attr->task || attr->ksymbol ||
attr->context_switch || attr->text_poke ||
attr->bpf_event)
return true;
return false;
}
static void unaccount_pmu_sb_event(struct perf_event *event)
{
if (is_sb_event(event))
detach_sb_event(event);
}
static void unaccount_event_cpu(struct perf_event *event, int cpu)
{
if (event->parent)
return;
if (is_cgroup_event(event))
atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
#ifdef CONFIG_NO_HZ_FULL
static DEFINE_SPINLOCK(nr_freq_lock);
#endif
static void unaccount_freq_event_nohz(void)
{
#ifdef CONFIG_NO_HZ_FULL
spin_lock(&nr_freq_lock);
if (atomic_dec_and_test(&nr_freq_events))
tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
spin_unlock(&nr_freq_lock);
#endif
}
static void unaccount_freq_event(void)
{
if (tick_nohz_full_enabled())
unaccount_freq_event_nohz();
else
atomic_dec(&nr_freq_events);
}
static void unaccount_event(struct perf_event *event)
{
bool dec = false;
if (event->parent)
return;
if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
dec = true;
if (event->attr.mmap || event->attr.mmap_data)
atomic_dec(&nr_mmap_events);
if (event->attr.build_id)
atomic_dec(&nr_build_id_events);
if (event->attr.comm)
atomic_dec(&nr_comm_events);
if (event->attr.namespaces)
atomic_dec(&nr_namespaces_events);
if (event->attr.cgroup)
atomic_dec(&nr_cgroup_events);
if (event->attr.task)
atomic_dec(&nr_task_events);
if (event->attr.freq)
unaccount_freq_event();
if (event->attr.context_switch) {
dec = true;
atomic_dec(&nr_switch_events);
}
if (is_cgroup_event(event))
dec = true;
if (has_branch_stack(event))
dec = true;
if (event->attr.ksymbol)
atomic_dec(&nr_ksymbol_events);
if (event->attr.bpf_event)
atomic_dec(&nr_bpf_events);
if (event->attr.text_poke)
atomic_dec(&nr_text_poke_events);
if (dec) {
if (!atomic_add_unless(&perf_sched_count, -1, 1))
schedule_delayed_work(&perf_sched_work, HZ);
}
unaccount_event_cpu(event, event->cpu);
unaccount_pmu_sb_event(event);
}
static void perf_sched_delayed(struct work_struct *work)
{
mutex_lock(&perf_sched_mutex);
if (atomic_dec_and_test(&perf_sched_count))
static_branch_disable(&perf_sched_events);
mutex_unlock(&perf_sched_mutex);
}
/*
* The following implement mutual exclusion of events on "exclusive" pmus
* (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
* at a time, so we disallow creating events that might conflict, namely:
*
* 1) cpu-wide events in the presence of per-task events,
* 2) per-task events in the presence of cpu-wide events,
* 3) two matching events on the same context.
*
* The former two cases are handled in the allocation path (perf_event_alloc(),
* _free_event()), the latter -- before the first perf_install_in_context().
*/
static int exclusive_event_init(struct perf_event *event)
{
struct pmu *pmu = event->pmu;
if (!is_exclusive_pmu(pmu))
return 0;
/*
* Prevent co-existence of per-task and cpu-wide events on the
* same exclusive pmu.
*
* Negative pmu::exclusive_cnt means there are cpu-wide
* events on this "exclusive" pmu, positive means there are
* per-task events.
*
* Since this is called in perf_event_alloc() path, event::ctx
* doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
* to mean "per-task event", because unlike other attach states it
* never gets cleared.
*/
if (event->attach_state & PERF_ATTACH_TASK) {
if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
return -EBUSY;
} else {
if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
return -EBUSY;
}
return 0;
}
static void exclusive_event_destroy(struct perf_event *event)
{
struct pmu *pmu = event->pmu;
if (!is_exclusive_pmu(pmu))
return;
/* see comment in exclusive_event_init() */
if (event->attach_state & PERF_ATTACH_TASK)
atomic_dec(&pmu->exclusive_cnt);
else
atomic_inc(&pmu->exclusive_cnt);
}
static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
{
if ((e1->pmu == e2->pmu) &&
(e1->cpu == e2->cpu ||
e1->cpu == -1 ||
e2->cpu == -1))
return true;
return false;
}
static bool exclusive_event_installable(struct perf_event *event,
struct perf_event_context *ctx)
{
struct perf_event *iter_event;
struct pmu *pmu = event->pmu;
lockdep_assert_held(&ctx->mutex);
if (!is_exclusive_pmu(pmu))
return true;
list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
if (exclusive_event_match(iter_event, event))
return false;
}
return true;
}
static void perf_addr_filters_splice(struct perf_event *event,
struct list_head *head);
static void _free_event(struct perf_event *event)
{
irq_work_sync(&event->pending);
unaccount_event(event);
security_perf_event_free(event);
if (event->rb) {
/*
* Can happen when we close an event with re-directed output.
*
* Since we have a 0 refcount, perf_mmap_close() will skip
* over us; possibly making our ring_buffer_put() the last.
*/
mutex_lock(&event->mmap_mutex);
ring_buffer_attach(event, NULL);
mutex_unlock(&event->mmap_mutex);
}
if (is_cgroup_event(event))
perf_detach_cgroup(event);
if (!event->parent) {
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
put_callchain_buffers();
}
perf_event_free_bpf_prog(event);
perf_addr_filters_splice(event, NULL);
kfree(event->addr_filter_ranges);
if (event->destroy)
event->destroy(event);
/*
* Must be after ->destroy(), due to uprobe_perf_close() using
* hw.target.
*/
if (event->hw.target)
put_task_struct(event->hw.target);
/*
* perf_event_free_task() relies on put_ctx() being 'last', in particular
* all task references must be cleaned up.
*/
if (event->ctx)
put_ctx(event->ctx);
exclusive_event_destroy(event);
module_put(event->pmu->module);
call_rcu(&event->rcu_head, free_event_rcu);
}
/*
* Used to free events which have a known refcount of 1, such as in error paths
* where the event isn't exposed yet and inherited events.
*/
static void free_event(struct perf_event *event)
{
if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
"unexpected event refcount: %ld; ptr=%p\n",
atomic_long_read(&event->refcount), event)) {
/* leak to avoid use-after-free */
return;
}
_free_event(event);
}
/*
* Remove user event from the owner task.
*/
static void perf_remove_from_owner(struct perf_event *event)
{
struct task_struct *owner;
rcu_read_lock();
/*
* Matches the smp_store_release() in perf_event_exit_task(). If we
* observe !owner it means the list deletion is complete and we can
* indeed free this event, otherwise we need to serialize on
* owner->perf_event_mutex.
*/
owner = READ_ONCE(event->owner);
if (owner) {
/*
* Since delayed_put_task_struct() also drops the last
* task reference we can safely take a new reference
* while holding the rcu_read_lock().
*/
get_task_struct(owner);
}
rcu_read_unlock();
if (owner) {
/*
* If we're here through perf_event_exit_task() we're already
* holding ctx->mutex which would be an inversion wrt. the
* normal lock order.
*
* However we can safely take this lock because its the child
* ctx->mutex.
*/
mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
/*
* We have to re-check the event->owner field, if it is cleared
* we raced with perf_event_exit_task(), acquiring the mutex
* ensured they're done, and we can proceed with freeing the
* event.
*/
if (event->owner) {
list_del_init(&event->owner_entry);
smp_store_release(&event->owner, NULL);
}
mutex_unlock(&owner->perf_event_mutex);
put_task_struct(owner);
}
}
static void put_event(struct perf_event *event)
{
if (!atomic_long_dec_and_test(&event->refcount))
return;
_free_event(event);
}
/*
* Kill an event dead; while event:refcount will preserve the event
* object, it will not preserve its functionality. Once the last 'user'
* gives up the object, we'll destroy the thing.
*/
int perf_event_release_kernel(struct perf_event *event)
{
struct perf_event_context *ctx = event->ctx;
struct perf_event *child, *tmp;
LIST_HEAD(free_list);
/*
* If we got here through err_file: fput(event_file); we will not have
* attached to a context yet.
*/
if (!ctx) {
WARN_ON_ONCE(event->attach_state &
(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
goto no_ctx;
}
if (!is_kernel_event(event))
perf_remove_from_owner(event);
ctx = perf_event_ctx_lock(event);
WARN_ON_ONCE(ctx->parent_ctx);
perf_remove_from_context(event, DETACH_GROUP);
raw_spin_lock_irq(&ctx->lock);
/*
* Mark this event as STATE_DEAD, there is no external reference to it
* anymore.
*
* Anybody acquiring event->child_mutex after the below loop _must_
* also see this, most importantly inherit_event() which will avoid
* placing more children on the list.
*
* Thus this guarantees that we will in fact observe and kill _ALL_
* child events.
*/
event->state = PERF_EVENT_STATE_DEAD;
raw_spin_unlock_irq(&ctx->lock);
perf_event_ctx_unlock(event, ctx);
again:
mutex_lock(&event->child_mutex);
list_for_each_entry(child, &event->child_list, child_list) {
/*
* Cannot change, child events are not migrated, see the
* comment with perf_event_ctx_lock_nested().
*/
ctx = READ_ONCE(child->ctx);
/*
* Since child_mutex nests inside ctx::mutex, we must jump
* through hoops. We start by grabbing a reference on the ctx.
*
* Since the event cannot get freed while we hold the
* child_mutex, the context must also exist and have a !0
* reference count.
*/
get_ctx(ctx);
/*
* Now that we have a ctx ref, we can drop child_mutex, and
* acquire ctx::mutex without fear of it going away. Then we
* can re-acquire child_mutex.
*/
mutex_unlock(&event->child_mutex);
mutex_lock(&ctx->mutex);
mutex_lock(&event->child_mutex);
/*
* Now that we hold ctx::mutex and child_mutex, revalidate our
* state, if child is still the first entry, it didn't get freed
* and we can continue doing so.
*/
tmp = list_first_entry_or_null(&event->child_list,
struct perf_event, child_list);
if (tmp == child) {
perf_remove_from_context(child, DETACH_GROUP);
list_move(&child->child_list, &free_list);
/*
* This matches the refcount bump in inherit_event();
* this can't be the last reference.
*/
put_event(event);
}
mutex_unlock(&event->child_mutex);
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
goto again;
}
mutex_unlock(&event->child_mutex);
list_for_each_entry_safe(child, tmp, &free_list, child_list) {
void *var = &child->ctx->refcount;
list_del(&child->child_list);
free_event(child);
/*
* Wake any perf_event_free_task() waiting for this event to be
* freed.
*/
smp_mb(); /* pairs with wait_var_event() */
wake_up_var(var);
}
no_ctx:
put_event(event); /* Must be the 'last' reference */
return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);
/*
* Called when the last reference to the file is gone.
*/
static int perf_release(struct inode *inode, struct file *file)
{
perf_event_release_kernel(file->private_data);
return 0;
}
static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
{
struct perf_event *child;
u64 total = 0;
*enabled = 0;
*running = 0;
mutex_lock(&event->child_mutex);
(void)perf_event_read(event, false);
total += perf_event_count(event);
*enabled += event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
*running += event->total_time_running +
atomic64_read(&event->child_total_time_running);
list_for_each_entry(child, &event->child_list, child_list) {
(void)perf_event_read(child, false);
total += perf_event_count(child);
*enabled += child->total_time_enabled;
*running += child->total_time_running;
}
mutex_unlock(&event->child_mutex);
return total;
}
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
{
struct perf_event_context *ctx;
u64 count;
ctx = perf_event_ctx_lock(event);
count = __perf_event_read_value(event, enabled, running);
perf_event_ctx_unlock(event, ctx);
return count;
}
EXPORT_SYMBOL_GPL(perf_event_read_value);
static int __perf_read_group_add(struct perf_event *leader,
u64 read_format, u64 *values)
{
struct perf_event_context *ctx = leader->ctx;
struct perf_event *sub;
unsigned long flags;
int n = 1; /* skip @nr */
int ret;
ret = perf_event_read(leader, true);
if (ret)
return ret;
raw_spin_lock_irqsave(&ctx->lock, flags);
/*
* Since we co-schedule groups, {enabled,running} times of siblings
* will be identical to those of the leader, so we only publish one
* set.
*/
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
values[n++] += leader->total_time_enabled +
atomic64_read(&leader->child_total_time_enabled);
}
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
values[n++] += leader->total_time_running +
atomic64_read(&leader->child_total_time_running);
}
/*
* Write {count,id} tuples for every sibling.
*/
values[n++] += perf_event_count(leader);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
for_each_sibling_event(sub, leader) {
values[n++] += perf_event_count(sub);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
}
raw_spin_unlock_irqrestore(&ctx->lock, flags);
return 0;
}
static int perf_read_group(struct perf_event *event,
u64 read_format, char __user *buf)
{
struct perf_event *leader = event->group_leader, *child;
struct perf_event_context *ctx = leader->ctx;
int ret;
u64 *values;
lockdep_assert_held(&ctx->mutex);
values = kzalloc(event->read_size, GFP_KERNEL);
if (!values)
return -ENOMEM;
values[0] = 1 + leader->nr_siblings;
/*
* By locking the child_mutex of the leader we effectively
* lock the child list of all siblings.. XXX explain how.
*/
mutex_lock(&leader->child_mutex);
ret = __perf_read_group_add(leader, read_format, values);
if (ret)
goto unlock;
list_for_each_entry(child, &leader->child_list, child_list) {
ret = __perf_read_group_add(child, read_format, values);
if (ret)
goto unlock;
}
mutex_unlock(&leader->child_mutex);
ret = event->read_size;
if (copy_to_user(buf, values, event->read_size))
ret = -EFAULT;
goto out;
unlock:
mutex_unlock(&leader->child_mutex);
out:
kfree(values);
return ret;
}
static int perf_read_one(struct perf_event *event,
u64 read_format, char __user *buf)
{
u64 enabled, running;
u64 values[4];
int n = 0;
values[n++] = __perf_event_read_value(event, &enabled, &running);
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
values[n++] = enabled;
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
values[n++] = running;
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(event);
if (copy_to_user(buf, values, n * sizeof(u64)))
return -EFAULT;
return n * sizeof(u64);
}
static bool is_event_hup(struct perf_event *event)
{
bool no_children;
if (event->state > PERF_EVENT_STATE_EXIT)
return false;
mutex_lock(&event->child_mutex);
no_children = list_empty(&event->child_list);
mutex_unlock(&event->child_mutex);
return no_children;
}
/*
* Read the performance event - simple non blocking version for now
*/
static ssize_t
__perf_read(struct perf_event *event, char __user *buf, size_t count)
{
u64 read_format = event->attr.read_format;
int ret;
/*
* Return end-of-file for a read on an event that is in
* error state (i.e. because it was pinned but it couldn't be
* scheduled on to the CPU at some point).
*/
if (event->state == PERF_EVENT_STATE_ERROR)
return 0;
if (count < event->read_size)
return -ENOSPC;
WARN_ON_ONCE(event->ctx->parent_ctx);
if (read_format & PERF_FORMAT_GROUP)
ret = perf_read_group(event, read_format, buf);
else
ret = perf_read_one(event, read_format, buf);
return ret;
}
static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct perf_event *event = file->private_data;
struct perf_event_context *ctx;
int ret;
ret = security_perf_event_read(event);
if (ret)
return ret;
ctx = perf_event_ctx_lock(event);
ret = __perf_read(event, buf, count);
perf_event_ctx_unlock(event, ctx);
return ret;
}
static __poll_t perf_poll(struct file *file, poll_table *wait)
{
struct perf_event *event = file->private_data;
struct perf_buffer *rb;
__poll_t events = EPOLLHUP;
poll_wait(file, &event->waitq, wait);
if (is_event_hup(event))
return events;
/*
* Pin the event->rb by taking event->mmap_mutex; otherwise
* perf_event_set_output() can swizzle our rb and make us miss wakeups.
*/
mutex_lock(&event->mmap_mutex);
rb = event->rb;
if (rb)
events = atomic_xchg(&rb->poll, 0);
mutex_unlock(&event->mmap_mutex);
return events;
}
static void _perf_event_reset(struct perf_event *event)
{
(void)perf_event_read(event, false);
local64_set(&event->count, 0);
perf_event_update_userpage(event);
}
/* Assume it's not an event with inherit set. */
u64 perf_event_pause(struct perf_event *event, bool reset)
{
struct perf_event_context *ctx;
u64 count;
ctx = perf_event_ctx_lock(event);
WARN_ON_ONCE(event->attr.inherit);
_perf_event_disable(event);
count = local64_read(&event->count);
if (reset)
local64_set(&event->count, 0);
perf_event_ctx_unlock(event, ctx);
return count;
}
EXPORT_SYMBOL_GPL(perf_event_pause);
/*
* Holding the top-level event's child_mutex means that any
* descendant process that has inherited this event will block
* in perf_event_exit_event() if it goes to exit, thus satisfying the
* task existence requirements of perf_event_enable/disable.
*/
static void perf_event_for_each_child(struct perf_event *event,
void (*func)(struct perf_event *))
{
struct perf_event *child;
WARN_ON_ONCE(event->ctx->parent_ctx);
mutex_lock(&event->child_mutex);
func(event);
list_for_each_entry(child, &event->child_list, child_list)
func(child);
mutex_unlock(&event->child_mutex);
}
static void perf_event_for_each(struct perf_event *event,
void (*func)(struct perf_event *))
{
struct perf_event_context *ctx = event->ctx;
struct perf_event *sibling;
lockdep_assert_held(&ctx->mutex);
event = event->group_leader;
perf_event_for_each_child(event, func);
for_each_sibling_event(sibling, event)
perf_event_for_each_child(sibling, func);
}
static void __perf_event_period(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
void *info)
{
u64 value = *((u64 *)info);
bool active;
if (event->attr.freq) {
event->attr.sample_freq = value;
} else {
event->attr.sample_period = value;
event->hw.sample_period = value;
}
active = (event->state == PERF_EVENT_STATE_ACTIVE);
if (active) {
perf_pmu_disable(ctx->pmu);
/*
* We could be throttled; unthrottle now to avoid the tick
* trying to unthrottle while we already re-started the event.
*/
if (event->hw.interrupts == MAX_INTERRUPTS) {
event->hw.interrupts = 0;
perf_log_throttle(event, 1);
}
event->pmu->stop(event, PERF_EF_UPDATE);
}
local64_set(&event->hw.period_left, 0);
if (active) {
event->pmu->start(event, PERF_EF_RELOAD);
perf_pmu_enable(ctx->pmu);
}
}
static int perf_event_check_period(struct perf_event *event, u64 value)
{
return event->pmu->check_period(event, value);
}
static int _perf_event_period(struct perf_event *event, u64 value)
{
if (!is_sampling_event(event))
return -EINVAL;
if (!value)
return -EINVAL;
if (event->attr.freq && value > sysctl_perf_event_sample_rate)
return -EINVAL;
if (perf_event_check_period(event, value))
return -EINVAL;
if (!event->attr.freq && (value & (1ULL << 63)))
return -EINVAL;
event_function_call(event, __perf_event_period, &value);
return 0;
}
int perf_event_period(struct perf_event *event, u64 value)
{
struct perf_event_context *ctx;
int ret;
ctx = perf_event_ctx_lock(event);
ret = _perf_event_period(event, value);
perf_event_ctx_unlock(event, ctx);
return ret;
}
EXPORT_SYMBOL_GPL(perf_event_period);
static const struct file_operations perf_fops;
static inline int perf_fget_light(int fd, struct fd *p)
{
struct fd f = fdget(fd);
if (!f.file)
return -EBADF;
if (f.file->f_op != &perf_fops) {
fdput(f);
return -EBADF;
}
*p = f;
return 0;
}
static int perf_event_set_output(struct perf_event *event,
struct perf_event *output_event);
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
static int perf_copy_attr(struct perf_event_attr __user *uattr,
struct perf_event_attr *attr);
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
{
void (*func)(struct perf_event *);
u32 flags = arg;
switch (cmd) {
case PERF_EVENT_IOC_ENABLE:
func = _perf_event_enable;
break;
case PERF_EVENT_IOC_DISABLE:
func = _perf_event_disable;
break;
case PERF_EVENT_IOC_RESET:
func = _perf_event_reset;
break;
case PERF_EVENT_IOC_REFRESH:
return _perf_event_refresh(event, arg);
case PERF_EVENT_IOC_PERIOD:
{
u64 value;
if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
return -EFAULT;
return _perf_event_period(event, value);
}
case PERF_EVENT_IOC_ID:
{
u64 id = primary_event_id(event);
if (copy_to_user((void __user *)arg, &id, sizeof(id)))
return -EFAULT;
return 0;
}
case PERF_EVENT_IOC_SET_OUTPUT:
{
int ret;
if (arg != -1) {
struct perf_event *output_event;
struct fd output;
ret = perf_fget_light(arg, &output);
if (ret)
return ret;
output_event = output.file->private_data;
ret = perf_event_set_output(event, output_event);
fdput(output);
} else {
ret = perf_event_set_output(event, NULL);
}
return ret;
}
case PERF_EVENT_IOC_SET_FILTER:
return perf_event_set_filter(event, (void __user *)arg);
case PERF_EVENT_IOC_SET_BPF:
{
struct bpf_prog *prog;
int err;
prog = bpf_prog_get(arg);
if (IS_ERR(prog))
return PTR_ERR(prog);
err = perf_event_set_bpf_prog(event, prog, 0);
if (err) {
bpf_prog_put(prog);
return err;
}
return 0;
}
case PERF_EVENT_IOC_PAUSE_OUTPUT: {
struct perf_buffer *rb;
rcu_read_lock();
rb = rcu_dereference(event->rb);
if (!rb || !rb->nr_pages) {
rcu_read_unlock();
return -EINVAL;
}
rb_toggle_paused(rb, !!arg);
rcu_read_unlock();
return 0;
}
case PERF_EVENT_IOC_QUERY_BPF:
return perf_event_query_prog_array(event, (void __user *)arg);
case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
struct perf_event_attr new_attr;
int err = perf_copy_attr((struct perf_event_attr __user *)arg,
&new_attr);
if (err)
return err;
return perf_event_modify_attr(event, &new_attr);
}
default:
return -ENOTTY;
}
if (flags & PERF_IOC_FLAG_GROUP)
perf_event_for_each(event, func);
else
perf_event_for_each_child(event, func);
return 0;
}
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct perf_event *event = file->private_data;
struct perf_event_context *ctx;
long ret;
/* Treat ioctl like writes as it is likely a mutating operation. */
ret = security_perf_event_write(event);
if (ret)
return ret;
ctx = perf_event_ctx_lock(event);
ret = _perf_ioctl(event, cmd, arg);
perf_event_ctx_unlock(event, ctx);
return ret;
}
#ifdef CONFIG_COMPAT
static long perf_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
switch (_IOC_NR(cmd)) {
case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
case _IOC_NR(PERF_EVENT_IOC_ID):
case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
cmd &= ~IOCSIZE_MASK;
cmd |= sizeof(void *) << IOCSIZE_SHIFT;
}
break;
}
return perf_ioctl(file, cmd, arg);
}
#else
# define perf_compat_ioctl NULL
#endif
int perf_event_task_enable(void)
{
struct perf_event_context *ctx;
struct perf_event *event;
mutex_lock(&current->perf_event_mutex);
list_for_each_entry(event, &current->perf_event_list, owner_entry) {
ctx = perf_event_ctx_lock(event);
perf_event_for_each_child(event, _perf_event_enable);
perf_event_ctx_unlock(event, ctx);
}
mutex_unlock(&current->perf_event_mutex);
return 0;
}
int perf_event_task_disable(void)
{
struct perf_event_context *ctx;
struct perf_event *event;
mutex_lock(&current->perf_event_mutex);
list_for_each_entry(event, &current->perf_event_list, owner_entry) {
ctx = perf_event_ctx_lock(event);
perf_event_for_each_child(event, _perf_event_disable);
perf_event_ctx_unlock(event, ctx);
}
mutex_unlock(&current->perf_event_mutex);
return 0;
}
static int perf_event_index(struct perf_event *event)
{
if (event->hw.state & PERF_HES_STOPPED)
return 0;
if (event->state != PERF_EVENT_STATE_ACTIVE)
return 0;
return event->pmu->event_idx(event);
}
static void perf_event_init_userpage(struct perf_event *event)
{
struct perf_event_mmap_page *userpg;
struct perf_buffer *rb;
rcu_read_lock();
rb = rcu_dereference(event->rb);
if (!rb)
goto unlock;
userpg = rb->user_page;
/* Allow new userspace to detect that bit 0 is deprecated */
userpg->cap_bit0_is_deprecated = 1;
userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
userpg->data_offset = PAGE_SIZE;
userpg->data_size = perf_data_size(rb);
unlock:
rcu_read_unlock();
}
void __weak arch_perf_update_userpage(
struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
{
}
/*
* Callers need to ensure there can be no nesting of this function, otherwise
* the seqlock logic goes bad. We can not serialize this because the arch
* code calls this from NMI context.
*/
void perf_event_update_userpage(struct perf_event *event)
{
struct perf_event_mmap_page *userpg;
struct perf_buffer *rb;
u64 enabled, running, now;
rcu_read_lock();
rb = rcu_dereference(event->rb);
if (!rb)
goto unlock;
/*
* compute total_time_enabled, total_time_running
* based on snapshot values taken when the event
* was last scheduled in.
*
* we cannot simply called update_context_time()
* because of locking issue as we can be called in
* NMI context
*/
calc_timer_values(event, &now, &enabled, &running);
userpg = rb->user_page;
/*
* Disable preemption to guarantee consistent time stamps are stored to
* the user page.
*/
preempt_disable();
++userpg->lock;
barrier();
userpg->index = perf_event_index(event);
userpg->offset = perf_event_count(event);
if (userpg->index)
userpg->offset -= local64_read(&event->hw.prev_count);
userpg->time_enabled = enabled +
atomic64_read(&event->child_total_time_enabled);
userpg->time_running = running +
atomic64_read(&event->child_total_time_running);
arch_perf_update_userpage(event, userpg, now);
barrier();
++userpg->lock;
preempt_enable();
unlock:
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(perf_event_update_userpage);
static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
{
struct perf_event *event = vmf->vma->vm_file->private_data;
struct perf_buffer *rb;
vm_fault_t ret = VM_FAULT_SIGBUS;
if (vmf->flags & FAULT_FLAG_MKWRITE) {
if (vmf->pgoff == 0)
ret = 0;
return ret;
}
rcu_read_lock();
rb = rcu_dereference(event->rb);
if (!rb)
goto unlock;
if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
goto unlock;
vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
if (!vmf->page)
goto unlock;
get_page(vmf->page);
vmf->page->mapping = vmf->vma->vm_file->f_mapping;
vmf->page->index = vmf->pgoff;
ret = 0;
unlock:
rcu_read_unlock();
return ret;
}
static void ring_buffer_attach(struct perf_event *event,
struct perf_buffer *rb)
{
struct perf_buffer *old_rb = NULL;
unsigned long flags;
WARN_ON_ONCE(event->parent);
if (event->rb) {
/*
* Should be impossible, we set this when removing
* event->rb_entry and wait/clear when adding event->rb_entry.
*/
WARN_ON_ONCE(event->rcu_pending);
old_rb = event->rb;
spin_lock_irqsave(&old_rb->event_lock, flags);
list_del_rcu(&event->rb_entry);
spin_unlock_irqrestore(&old_rb->event_lock, flags);
event->rcu_batches = get_state_synchronize_rcu();
event->rcu_pending = 1;
}
if (rb) {
if (event->rcu_pending) {
cond_synchronize_rcu(event->rcu_batches);
event->rcu_pending = 0;
}
spin_lock_irqsave(&rb->event_lock, flags);
list_add_rcu(&event->rb_entry, &rb->event_list);
spin_unlock_irqrestore(&rb->event_lock, flags);
}
/*
* Avoid racing with perf_mmap_close(AUX): stop the event
* before swizzling the event::rb pointer; if it's getting
* unmapped, its aux_mmap_count will be 0 and it won't
* restart. See the comment in __perf_pmu_output_stop().
*
* Data will inevitably be lost when set_output is done in
* mid-air, but then again, whoever does it like this is
* not in for the data anyway.
*/
if (has_aux(event))
perf_event_stop(event, 0);
rcu_assign_pointer(event->rb, rb);
if (old_rb) {
ring_buffer_put(old_rb);
/*
* Since we detached before setting the new rb, so that we
* could attach the new rb, we could have missed a wakeup.
* Provide it now.
*/
wake_up_all(&event->waitq);
}
}
static void ring_buffer_wakeup(struct perf_event *event)
{
struct perf_buffer *rb;
if (event->parent)
event = event->parent;
rcu_read_lock();
rb = rcu_dereference(event->rb);
if (rb) {
list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
wake_up_all(&event->waitq);
}
rcu_read_unlock();
}
struct perf_buffer *ring_buffer_get(struct perf_event *event)
{
struct perf_buffer *rb;
if (event->parent)
event = event->parent;
rcu_read_lock();
rb = rcu_dereference(event->rb);
if (rb) {
if (!refcount_inc_not_zero(&rb->refcount))
rb = NULL;
}
rcu_read_unlock();
return rb;
}
void ring_buffer_put(struct perf_buffer *rb)
{
if (!refcount_dec_and_test(&rb->refcount))
return;
WARN_ON_ONCE(!list_empty(&rb->event_list));
call_rcu(&rb->rcu_head, rb_free_rcu);
}
static void perf_mmap_open(struct vm_area_struct *vma)
{
struct perf_event *event = vma->vm_file->private_data;
atomic_inc(&event->mmap_count);
atomic_inc(&event->rb->mmap_count);
if (vma->vm_pgoff)
atomic_inc(&event->rb->aux_mmap_count);
if (event->pmu->event_mapped)
event->pmu->event_mapped(event, vma->vm_mm);
}
static void perf_pmu_output_stop(struct perf_event *event);
/*
* A buffer can be mmap()ed multiple times; either directly through the same
* event, or through other events by use of perf_event_set_output().
*
* In order to undo the VM accounting done by perf_mmap() we need to destroy
* the buffer here, where we still have a VM context. This means we need
* to detach all events redirecting to us.
*/
static void perf_mmap_close(struct vm_area_struct *vma)
{
struct perf_event *event = vma->vm_file->private_data;
struct perf_buffer *rb = ring_buffer_get(event);
struct user_struct *mmap_user = rb->mmap_user;
int mmap_locked = rb->mmap_locked;
unsigned long size = perf_data_size(rb);
bool detach_rest = false;
if (event->pmu->event_unmapped)
event->pmu->event_unmapped(event, vma->vm_mm);
/*
* rb->aux_mmap_count will always drop before rb->mmap_count and
* event->mmap_count, so it is ok to use event->mmap_mutex to
* serialize with perf_mmap here.
*/
if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
/*
* Stop all AUX events that are writing to this buffer,
* so that we can free its AUX pages and corresponding PMU
* data. Note that after rb::aux_mmap_count dropped to zero,
* they won't start any more (see perf_aux_output_begin()).
*/
perf_pmu_output_stop(event);
/* now it's safe to free the pages */
atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
/* this has to be the last one */
rb_free_aux(rb);
WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
mutex_unlock(&event->mmap_mutex);
}
if (atomic_dec_and_test(&rb->mmap_count))
detach_rest = true;
if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
goto out_put;
ring_buffer_attach(event, NULL);
mutex_unlock(&event->mmap_mutex);
/* If there's still other mmap()s of this buffer, we're done. */
if (!detach_rest)
goto out_put;
/*
* No other mmap()s, detach from all other events that might redirect
* into the now unreachable buffer. Somewhat complicated by the
* fact that rb::event_lock otherwise nests inside mmap_mutex.
*/
again:
rcu_read_lock();
list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
if (!atomic_long_inc_not_zero(&event->refcount)) {
/*
* This event is en-route to free_event() which will
* detach it and remove it from the list.
*/
continue;
}
rcu_read_unlock();
mutex_lock(&event->mmap_mutex);
/*
* Check we didn't race with perf_event_set_output() which can
* swizzle the rb from under us while we were waiting to
* acquire mmap_mutex.
*
* If we find a different rb; ignore this event, a next
* iteration will no longer find it on the list. We have to
* still restart the iteration to make sure we're not now
* iterating the wrong list.
*/
if (event->rb == rb)
ring_buffer_attach(event, NULL);
mutex_unlock(&event->mmap_mutex);
put_event(event);
/*
* Restart the iteration; either we're on the wrong list or
* destroyed its integrity by doing a deletion.
*/
goto again;
}
rcu_read_unlock();
/*
* It could be there's still a few 0-ref events on the list; they'll
* get cleaned up by free_event() -- they'll also still have their
* ref on the rb and will free it whenever they are done with it.
*
* Aside from that, this buffer is 'fully' detached and unmapped,
* undo the VM accounting.
*/
atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
&mmap_user->locked_vm);
atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
free_uid(mmap_user);
out_put:
ring_buffer_put(rb); /* could be last */
}
static const struct vm_operations_struct perf_mmap_vmops = {
.open = perf_mmap_open,
.close = perf_mmap_close, /* non mergeable */
.fault = perf_mmap_fault,
.page_mkwrite = perf_mmap_fault,
};
static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
struct perf_event *event = file->private_data;
unsigned long user_locked, user_lock_limit;
struct user_struct *user = current_user();
struct perf_buffer *rb = NULL;
unsigned long locked, lock_limit;
unsigned long vma_size;
unsigned long nr_pages;
long user_extra = 0, extra = 0;
int ret = 0, flags = 0;
/*
* Don't allow mmap() of inherited per-task counters. This would
* create a performance issue due to all children writing to the
* same rb.
*/
if (event->cpu == -1 && event->attr.inherit)
return -EINVAL;
if (!(vma->vm_flags & VM_SHARED))
return -EINVAL;
ret = security_perf_event_read(event);
if (ret)
return ret;
vma_size = vma->vm_end - vma->vm_start;
if (vma->vm_pgoff == 0) {
nr_pages = (vma_size / PAGE_SIZE) - 1;
} else {
/*
* AUX area mapping: if rb->aux_nr_pages != 0, it's already
* mapped, all subsequent mappings should have the same size
* and offset. Must be above the normal perf buffer.
*/
u64 aux_offset, aux_size;
if (!event->rb)
return -EINVAL;
nr_pages = vma_size / PAGE_SIZE;
mutex_lock(&event->mmap_mutex);
ret = -EINVAL;
rb = event->rb;
if (!rb)
goto aux_unlock;
aux_offset = READ_ONCE(rb->user_page->aux_offset);
aux_size = READ_ONCE(rb->user_page->aux_size);
if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
goto aux_unlock;
if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
goto aux_unlock;
/* already mapped with a different offset */
if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
goto aux_unlock;
if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
goto aux_unlock;
/* already mapped with a different size */
if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
goto aux_unlock;
if (!is_power_of_2(nr_pages))
goto aux_unlock;
if (!atomic_inc_not_zero(&rb->mmap_count))
goto aux_unlock;
if (rb_has_aux(rb)) {
atomic_inc(&rb->aux_mmap_count);
ret = 0;
goto unlock;
}
atomic_set(&rb->aux_mmap_count, 1);
user_extra = nr_pages;
goto accounting;
}
/*
* If we have rb pages ensure they're a power-of-two number, so we
* can do bitmasks instead of modulo.
*/
if (nr_pages != 0 && !is_power_of_2(nr_pages))
return -EINVAL;
if (vma_size != PAGE_SIZE * (1 + nr_pages))
return -EINVAL;
WARN_ON_ONCE(event->ctx->parent_ctx);
again:
mutex_lock(&event->mmap_mutex);
if (event->rb) {
if (event->rb->nr_pages != nr_pages) {
ret = -EINVAL;
goto unlock;
}
if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
/*
* Raced against perf_mmap_close() through
* perf_event_set_output(). Try again, hope for better
* luck.
*/
mutex_unlock(&event->mmap_mutex);
goto again;
}
goto unlock;
}
user_extra = nr_pages + 1;
accounting:
user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
/*
* Increase the limit linearly with more CPUs:
*/
user_lock_limit *= num_online_cpus();
user_locked = atomic_long_read(&user->locked_vm);
/*
* sysctl_perf_event_mlock may have changed, so that
* user->locked_vm > user_lock_limit
*/
if (user_locked > user_lock_limit)
user_locked = user_lock_limit;
user_locked += user_extra;
if (user_locked > user_lock_limit) {
/*
* charge locked_vm until it hits user_lock_limit;
* charge the rest from pinned_vm
*/
extra = user_locked - user_lock_limit;
user_extra -= extra;
}
lock_limit = rlimit(RLIMIT_MEMLOCK);
lock_limit >>= PAGE_SHIFT;
locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
if ((locked > lock_limit) && perf_is_paranoid() &&
!capable(CAP_IPC_LOCK)) {
ret = -EPERM;
goto unlock;
}
WARN_ON(!rb && event->rb);
if (vma->vm_flags & VM_WRITE)
flags |= RING_BUFFER_WRITABLE;
if (!rb) {
rb = rb_alloc(nr_pages,
event->attr.watermark ? event->attr.wakeup_watermark : 0,
event->cpu, flags);
if (!rb) {
ret = -ENOMEM;
goto unlock;
}
atomic_set(&rb->mmap_count, 1);
rb->mmap_user = get_current_user();
rb->mmap_locked = extra;
ring_buffer_attach(event, rb);
perf_event_update_time(event);
perf_event_init_userpage(event);
perf_event_update_userpage(event);
} else {
ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
event->attr.aux_watermark, flags);
if (!ret)
rb->aux_mmap_locked = extra;
}
unlock:
if (!ret) {
atomic_long_add(user_extra, &user->locked_vm);
atomic64_add(extra, &vma->vm_mm->pinned_vm);
atomic_inc(&event->mmap_count);
} else if (rb) {
atomic_dec(&rb->mmap_count);
}
aux_unlock:
mutex_unlock(&event->mmap_mutex);
/*
* Since pinned accounting is per vm we cannot allow fork() to copy our
* vma.
*/
vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &perf_mmap_vmops;
if (event->pmu->event_mapped)
event->pmu->event_mapped(event, vma->vm_mm);
return ret;
}
static int perf_fasync(int fd, struct file *filp, int on)
{
struct inode *inode = file_inode(filp);
struct perf_event *event = filp->private_data;
int retval;
inode_lock(inode);
retval = fasync_helper(fd, filp, on, &event->fasync);
inode_unlock(inode);
if (retval < 0)
return retval;
return 0;
}
static const struct file_operations perf_fops = {
.llseek = no_llseek,
.release = perf_release,
.read = perf_read,
.poll = perf_poll,
.unlocked_ioctl = perf_ioctl,
.compat_ioctl = perf_compat_ioctl,
.mmap = perf_mmap,
.fasync = perf_fasync,
};
/*
* Perf event wakeup
*
* If there's data, ensure we set the poll() state and publish everything
* to user-space before waking everybody up.
*/
static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
{
/* only the parent has fasync state */
if (event->parent)
event = event->parent;
return &event->fasync;
}
void perf_event_wakeup(struct perf_event *event)
{
ring_buffer_wakeup(event);
if (event->pending_kill) {
kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
event->pending_kill = 0;
}
}
static void perf_sigtrap(struct perf_event *event)
{
/*
* We'd expect this to only occur if the irq_work is delayed and either
* ctx->task or current has changed in the meantime. This can be the
* case on architectures that do not implement arch_irq_work_raise().
*/
if (WARN_ON_ONCE(event->ctx->task != current))
return;
/*
* perf_pending_event() can race with the task exiting.
*/
if (current->flags & PF_EXITING)
return;
force_sig_perf((void __user *)event->pending_addr,
event->attr.type, event->attr.sig_data);
}
static void perf_pending_event_disable(struct perf_event *event)
{
int cpu = READ_ONCE(event->pending_disable);
if (cpu < 0)
return;
if (cpu == smp_processor_id()) {
WRITE_ONCE(event->pending_disable, -1);
if (event->attr.sigtrap) {
perf_sigtrap(event);
atomic_set_release(&event->event_limit, 1); /* rearm event */
return;
}
perf_event_disable_local(event);
return;
}
/*
* CPU-A CPU-B
*
* perf_event_disable_inatomic()
* @pending_disable = CPU-A;
* irq_work_queue();
*
* sched-out
* @pending_disable = -1;
*
* sched-in
* perf_event_disable_inatomic()
* @pending_disable = CPU-B;
* irq_work_queue(); // FAILS
*
* irq_work_run()
* perf_pending_event()
*
* But the event runs on CPU-B and wants disabling there.
*/
irq_work_queue_on(&event->pending, cpu);
}
static void perf_pending_event(struct irq_work *entry)
{
struct perf_event *event = container_of(entry, struct perf_event, pending);
int rctx;
rctx = perf_swevent_get_recursion_context();
/*
* If we 'fail' here, that's OK, it means recursion is already disabled
* and we won't recurse 'further'.
*/
perf_pending_event_disable(event);
if (event->pending_wakeup) {
event->pending_wakeup = 0;
perf_event_wakeup(event);
}
if (rctx >= 0)
perf_swevent_put_recursion_context(rctx);
}
/*
* We assume there is only KVM supporting the callbacks.
* Later on, we might change it to a list if there is
* another virtualization implementation supporting the callbacks.
*/
struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
return -EBUSY;
rcu_assign_pointer(perf_guest_cbs, cbs);
return 0;
}
EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
return -EINVAL;
rcu_assign_pointer(perf_guest_cbs, NULL);
synchronize_rcu();
return 0;
}
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
static void
perf_output_sample_regs(struct perf_output_handle *handle,
struct pt_regs *regs, u64 mask)
{
int bit;
DECLARE_BITMAP(_mask, 64);
bitmap_from_u64(_mask, mask);
for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
u64 val;
val = perf_reg_value(regs, bit);
perf_output_put(handle, val);
}
}
static void perf_sample_regs_user(struct perf_regs *regs_user,
struct pt_regs *regs)
{
if (user_mode(regs)) {
regs_user->abi = perf_reg_abi(current);
regs_user->regs = regs;
} else if (!(current->flags & PF_KTHREAD)) {
perf_get_regs_user(regs_user, regs);
} else {
regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
regs_user->regs = NULL;
}
}
static void perf_sample_regs_intr(struct perf_regs *regs_intr,
struct pt_regs *regs)
{
regs_intr->regs = regs;
regs_intr->abi = perf_reg_abi(current);
}
/*
* Get remaining task size from user stack pointer.
*
* It'd be better to take stack vma map and limit this more
* precisely, but there's no way to get it safely under interrupt,
* so using TASK_SIZE as limit.
*/
static u64 perf_ustack_task_size(struct pt_regs *regs)
{
unsigned long addr = perf_user_stack_pointer(regs);
if (!addr || addr >= TASK_SIZE)
return 0;
return TASK_SIZE - addr;
}
static u16
perf_sample_ustack_size(u16 stack_size, u16 header_size,
struct pt_regs *regs)
{
u64 task_size;
/* No regs, no stack pointer, no dump. */
if (!regs)
return 0;
/*
* Check if we fit in with the requested stack size into the:
* - TASK_SIZE
* If we don't, we limit the size to the TASK_SIZE.
*
* - remaining sample size
* If we don't, we customize the stack size to
* fit in to the remaining sample size.
*/
task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
stack_size = min(stack_size, (u16) task_size);
/* Current header size plus static size and dynamic size. */
header_size += 2 * sizeof(u64);
/* Do we fit in with the current stack dump size? */
if ((u16) (header_size + stack_size) < header_size) {
/*
* If we overflow the maximum size for the sample,
* we customize the stack dump size to fit in.
*/
stack_size = USHRT_MAX - header_size - sizeof(u64);
stack_size = round_up(stack_size, sizeof(u64));
}
return stack_size;
}
static void
perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
struct pt_regs *regs)
{
/* Case of a kernel thread, nothing to dump */
if (!regs) {
u64 size = 0;
perf_output_put(handle, size);
} else {
unsigned long sp;
unsigned int rem;
u64 dyn_size;
mm_segment_t fs;
/*
* We dump:
* static size
* - the size requested by user or the best one we can fit
* in to the sample max size
* data
* - user stack dump data
* dynamic size
* - the actual dumped size
*/
/* Static size. */
perf_output_put(handle, dump_size);
/* Data. */
sp = perf_user_stack_pointer(regs);
fs = force_uaccess_begin();
rem = __output_copy_user(handle, (void *) sp, dump_size);
force_uaccess_end(fs);
dyn_size = dump_size - rem;
perf_output_skip(handle, rem);
/* Dynamic size. */
perf_output_put(handle, dyn_size);
}
}
static unsigned long perf_prepare_sample_aux(struct perf_event *event,
struct perf_sample_data *data,
size_t size)
{
struct perf_event *sampler = event->aux_event;
struct perf_buffer *rb;
data->aux_size = 0;
if (!sampler)
goto out;
if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
goto out;
if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
goto out;
rb = ring_buffer_get(sampler);
if (!rb)
goto out;
/*
* If this is an NMI hit inside sampling code, don't take
* the sample. See also perf_aux_sample_output().
*/
if (READ_ONCE(rb->aux_in_sampling)) {
data->aux_size = 0;
} else {
size = min_t(size_t, size, perf_aux_size(rb));
data->aux_size = ALIGN(size, sizeof(u64));
}
ring_buffer_put(rb);
out:
return data->aux_size;
}
static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
struct perf_event *event,
struct perf_output_handle *handle,
unsigned long size)
{
unsigned long flags;
long ret;
/*
* Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
* paths. If we start calling them in NMI context, they may race with
* the IRQ ones, that is, for example, re-starting an event that's just
* been stopped, which is why we're using a separate callback that
* doesn't change the event state.
*
* IRQs need to be disabled to prevent IPIs from racing with us.
*/
local_irq_save(flags);
/*
* Guard against NMI hits inside the critical section;
* see also perf_prepare_sample_aux().
*/
WRITE_ONCE(rb->aux_in_sampling, 1);
barrier();
ret = event->pmu->snapshot_aux(event, handle, size);
barrier();
WRITE_ONCE(rb->aux_in_sampling, 0);
local_irq_restore(flags);
return ret;
}
static void perf_aux_sample_output(struct perf_event *event,
struct perf_output_handle *handle,
struct perf_sample_data *data)
{
struct perf_event *sampler = event->aux_event;
struct perf_buffer *rb;
unsigned long pad;
long size;
if (WARN_ON_ONCE(!sampler || !data->aux_size))
return;
rb = ring_buffer_get(sampler);
if (!rb)
return;
size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
/*
* An error here means that perf_output_copy() failed (returned a
* non-zero surplus that it didn't copy), which in its current
* enlightened implementation is not possible. If that changes, we'd
* like to know.
*/
if (WARN_ON_ONCE(size < 0))
goto out_put;
/*
* The pad comes from ALIGN()ing data->aux_size up to u64 in
* perf_prepare_sample_aux(), so should not be more than that.
*/
pad = data->aux_size - size;
if (WARN_ON_ONCE(pad >= sizeof(u64)))
pad = 8;
if (pad) {
u64 zero = 0;
perf_output_copy(handle, &zero, pad);
}
out_put:
ring_buffer_put(rb);
}
static void __perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
{
u64 sample_type = event->attr.sample_type;
data->type = sample_type;
header->size += event->id_header_size;
if (sample_type & PERF_SAMPLE_TID) {
/* namespace issues */
data->tid_entry.pid = perf_event_pid(event, current);
data->tid_entry.tid = perf_event_tid(event, current);
}
if (sample_type & PERF_SAMPLE_TIME)
data->time = perf_event_clock(event);
if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
data->id = primary_event_id(event);
if (sample_type & PERF_SAMPLE_STREAM_ID)
data->stream_id = event->id;
if (sample_type & PERF_SAMPLE_CPU) {
data->cpu_entry.cpu = raw_smp_processor_id();
data->cpu_entry.reserved = 0;
}
}
void perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
{
if (event->attr.sample_id_all)
__perf_event_header__init_id(header, data, event);
}
static void __perf_event__output_id_sample(struct perf_output_handle *handle,
struct perf_sample_data *data)
{
u64 sample_type = data->type;
if (sample_type & PERF_SAMPLE_TID)
perf_output_put(handle, data->tid_entry);
if (sample_type & PERF_SAMPLE_TIME)
perf_output_put(handle, data->time);
if (sample_type & PERF_SAMPLE_ID)
perf_output_put(handle, data->id);
if (sample_type & PERF_SAMPLE_STREAM_ID)
perf_output_put(handle, data->stream_id);
if (sample_type & PERF_SAMPLE_CPU)
perf_output_put(handle, data->cpu_entry);
if (sample_type & PERF_SAMPLE_IDENTIFIER)
perf_output_put(handle, data->id);
}
void perf_event__output_id_sample(struct perf_event *event,
struct perf_output_handle *handle,
struct perf_sample_data *sample)
{
if (event->attr.sample_id_all)
__perf_event__output_id_sample(handle, sample);
}
static void perf_output_read_one(struct perf_output_handle *handle,
struct perf_event *event,
u64 enabled, u64 running)
{
u64 read_format = event->attr.read_format;
u64 values[4];
int n = 0;
values[n++] = perf_event_count(event);
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
values[n++] = enabled +
atomic64_read(&event->child_total_time_enabled);
}
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
values[n++] = running +
atomic64_read(&event->child_total_time_running);
}
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(event);
__output_copy(handle, values, n * sizeof(u64));
}
static void perf_output_read_group(struct perf_output_handle *handle,
struct perf_event *event,
u64 enabled, u64 running)
{
struct perf_event *leader = event->group_leader, *sub;
u64 read_format = event->attr.read_format;
u64 values[5];
int n = 0;
values[n++] = 1 + leader->nr_siblings;
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
values[n++] = enabled;
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
values[n++] = running;
if ((leader != event) &&
(leader->state == PERF_EVENT_STATE_ACTIVE))
leader->pmu->read(leader);
values[n++] = perf_event_count(leader);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(leader);
__output_copy(handle, values, n * sizeof(u64));
for_each_sibling_event(sub, leader) {
n = 0;
if ((sub != event) &&
(sub->state == PERF_EVENT_STATE_ACTIVE))
sub->pmu->read(sub);
values[n++] = perf_event_count(sub);
if (read_format & PERF_FORMAT_ID)
values[n++] = primary_event_id(sub);
__output_copy(handle, values, n * sizeof(u64));
}
}
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
PERF_FORMAT_TOTAL_TIME_RUNNING)
/*
* XXX PERF_SAMPLE_READ vs inherited events seems difficult.
*
* The problem is that its both hard and excessively expensive to iterate the
* child list, not to mention that its impossible to IPI the children running
* on another CPU, from interrupt/NMI context.
*/
static void perf_output_read(struct perf_output_handle *handle,
struct perf_event *event)
{
u64 enabled = 0, running = 0, now;
u64 read_format = event->attr.read_format;
/*
* compute total_time_enabled, total_time_running
* based on snapshot values taken when the event
* was last scheduled in.
*
* we cannot simply called update_context_time()
* because of locking issue as we are called in
* NMI context
*/
if (read_format & PERF_FORMAT_TOTAL_TIMES)
calc_timer_values(event, &now, &enabled, &running);
if (event->attr.read_format & PERF_FORMAT_GROUP)
perf_output_read_group(handle, event, enabled, running);
else
perf_output_read_one(handle, event, enabled, running);
}
static inline bool perf_sample_save_hw_index(struct perf_event *event)
{
return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
}
void perf_output_sample(struct perf_output_handle *handle,
struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
{
u64 sample_type = data->type;
perf_output_put(handle, *header);
if (sample_type & PERF_SAMPLE_IDENTIFIER)
perf_output_put(handle, data->id);
if (sample_type & PERF_SAMPLE_IP)
perf_output_put(handle, data->ip);
if (sample_type & PERF_SAMPLE_TID)
perf_output_put(handle, data->tid_entry);
if (sample_type & PERF_SAMPLE_TIME)
perf_output_put(handle, data->time);
if (sample_type & PERF_SAMPLE_ADDR)
perf_output_put(handle, data->addr);
if (sample_type & PERF_SAMPLE_ID)
perf_output_put(handle, data->id);
if (sample_type & PERF_SAMPLE_STREAM_ID)
perf_output_put(handle, data->stream_id);
if (sample_type & PERF_SAMPLE_CPU)
perf_output_put(handle, data->cpu_entry);
if (sample_type & PERF_SAMPLE_PERIOD)
perf_output_put(handle, data->period);
if (sample_type & PERF_SAMPLE_READ)
perf_output_read(handle, event);
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;
size += data->callchain->nr;
size *= sizeof(u64);
__output_copy(handle, data->callchain, size);
}
if (sample_type & PERF_SAMPLE_RAW) {
struct perf_raw_record *raw = data->raw;
if (raw) {
struct perf_raw_frag *frag = &raw->frag;
perf_output_put(handle, raw->size);
do {
if (frag->copy) {
__output_custom(handle, frag->copy,
frag->data, frag->size);
} else {
__output_copy(handle, frag->data,
frag->size);
}
if (perf_raw_frag_last(frag))
break;
frag = frag->next;
} while (1);
if (frag->pad)
__output_skip(handle, NULL, frag->pad);
} else {
struct {
u32 size;
u32 data;
} raw = {
.size = sizeof(u32),
.data = 0,
};
perf_output_put(handle, raw);
}
}
if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
if (data->br_stack) {
size_t size;
size = data->br_stack->nr
* sizeof(struct perf_branch_entry);
perf_output_put(handle, data->br_stack->nr);
if (perf_sample_save_hw_index(event))
perf_output_put(handle, data->br_stack->hw_idx);
perf_output_copy(handle, data->br_stack->entries, size);
} else {
/*
* we always store at least the value of nr
*/
u64 nr = 0;
perf_output_put(handle, nr);
}
}
if (sample_type & PERF_SAMPLE_REGS_USER) {
u64 abi = data->regs_user.abi;
/*
* If there are no regs to dump, notice it through
* first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
*/
perf_output_put(handle, abi);
if (abi) {
u64 mask = event->attr.sample_regs_user;
perf_output_sample_regs(handle,
data->regs_user.regs,
mask);
}
}
if (sample_type & PERF_SAMPLE_STACK_USER) {
perf_output_sample_ustack(handle,
data->stack_user_size,
data->regs_user.regs);
}
if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
perf_output_put(handle, data->weight.full);
if (sample_type & PERF_SAMPLE_DATA_SRC)
perf_output_put(handle, data->data_src.val);
if (sample_type & PERF_SAMPLE_TRANSACTION)
perf_output_put(handle, data->txn);
if (sample_type & PERF_SAMPLE_REGS_INTR) {
u64 abi = data->regs_intr.abi;
/*
* If there are no regs to dump, notice it through
* first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
*/
perf_output_put(handle, abi);
if (abi) {
u64 mask = event->attr.sample_regs_intr;
perf_output_sample_regs(handle,
data->regs_intr.regs,
mask);
}
}
if (sample_type & PERF_SAMPLE_PHYS_ADDR)
perf_output_put(handle, data->phys_addr);
if (sample_type & PERF_SAMPLE_CGROUP)
perf_output_put(handle, data->cgroup);
if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
perf_output_put(handle, data->data_page_size);
if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
perf_output_put(handle, data->code_page_size);
if (sample_type & PERF_SAMPLE_AUX) {
perf_output_put(handle, data->aux_size);
if (data->aux_size)
perf_aux_sample_output(event, handle, data);
}
if (!event->attr.watermark) {
int wakeup_events = event->attr.wakeup_events;
if (wakeup_events) {
struct perf_buffer *rb = handle->rb;
int events = local_inc_return(&rb->events);
if (events >= wakeup_events) {
local_sub(wakeup_events, &rb->events);
local_inc(&rb->wakeup);
}
}
}
}
static u64 perf_virt_to_phys(u64 virt)
{
u64 phys_addr = 0;
if (!virt)
return 0;
if (virt >= TASK_SIZE) {
/* If it's vmalloc()d memory, leave phys_addr as 0 */
if (virt_addr_valid((void *)(uintptr_t)virt) &&
!(virt >= VMALLOC_START && virt < VMALLOC_END))
phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
} else {
/*
* Walking the pages tables for user address.
* Interrupts are disabled, so it prevents any tear down
* of the page tables.
* Try IRQ-safe get_user_page_fast_only first.
* If failed, leave phys_addr as 0.
*/
if (current->mm != NULL) {
struct page *p;
pagefault_disable();
if (get_user_page_fast_only(virt, 0, &p)) {
phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
put_page(p);
}
pagefault_enable();
}
}
return phys_addr;
}
/*
* Return the pagetable size of a given virtual address.
*/
static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
{
u64 size = 0;
#ifdef CONFIG_HAVE_FAST_GUP
pgd_t *pgdp, pgd;
p4d_t *p4dp, p4d;
pud_t *pudp, pud;
pmd_t *pmdp, pmd;
pte_t *ptep, pte;
pgdp = pgd_offset(mm, addr);
pgd = READ_ONCE(*pgdp);
if (pgd_none(pgd))
return 0;
if (pgd_leaf(pgd))
return pgd_leaf_size(pgd);
p4dp = p4d_offset_lockless(pgdp, pgd, addr);
p4d = READ_ONCE(*p4dp);
if (!p4d_present(p4d))
return 0;
if (p4d_leaf(p4d))
return p4d_leaf_size(p4d);
pudp = pud_offset_lockless(p4dp, p4d, addr);
pud = READ_ONCE(*pudp);
if (!pud_present(pud))
return 0;
if (pud_leaf(pud))
return pud_leaf_size(pud);
pmdp = pmd_offset_lockless(pudp, pud, addr);
pmd = READ_ONCE(*pmdp);
if (!pmd_present(pmd))
return 0;
if (pmd_leaf(pmd))
return pmd_leaf_size(pmd);
ptep = pte_offset_map(&pmd, addr);
pte = ptep_get_lockless(ptep);
if (pte_present(pte))
size = pte_leaf_size(pte);
pte_unmap(ptep);
#endif /* CONFIG_HAVE_FAST_GUP */
return size;
}
static u64 perf_get_page_size(unsigned long addr)
{
struct mm_struct *mm;
unsigned long flags;
u64 size;
if (!addr)
return 0;
/*
* Software page-table walkers must disable IRQs,
* which prevents any tear down of the page tables.
*/
local_irq_save(flags);
mm = current->mm;
if (!mm) {
/*
* For kernel threads and the like, use init_mm so that
* we can find kernel memory.
*/
mm = &init_mm;
}
size = perf_get_pgtable_size(mm, addr);
local_irq_restore(flags);
return size;
}
static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
struct perf_callchain_entry *
perf_callchain(struct perf_event *event, struct pt_regs *regs)
{
bool kernel = !event->attr.exclude_callchain_kernel;
bool user = !event->attr.exclude_callchain_user;
/* Disallow cross-task user callchains. */
bool crosstask = event->ctx->task && event->ctx->task != current;
const u32 max_stack = event->attr.sample_max_stack;
struct perf_callchain_entry *callchain;
if (!kernel && !user)
return &__empty_callchain;
callchain = get_perf_callchain(regs, 0, kernel, user,
max_stack, crosstask, true);
return callchain ?: &__empty_callchain;
}
void perf_prepare_sample(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event,
struct pt_regs *regs)
{
u64 sample_type = event->attr.sample_type;
header->type = PERF_RECORD_SAMPLE;
header->size = sizeof(*header) + event->header_size;
header->misc = 0;
header->misc |= perf_misc_flags(regs);
__perf_event_header__init_id(header, data, event);
if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
data->ip = perf_instruction_pointer(regs);
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;
if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
data->callchain = perf_callchain(event, regs);
size += data->callchain->nr;
header->size += size * sizeof(u64);
}
if (sample_type & PERF_SAMPLE_RAW) {
struct perf_raw_record *raw = data->raw;
int size;
if (raw) {
struct perf_raw_frag *frag = &raw->frag;
u32 sum = 0;
do {
sum += frag->size;
if (perf_raw_frag_last(frag))
break;
frag = frag->next;
} while (1);
size = round_up(sum + sizeof(u32), sizeof(u64));
raw->size = size - sizeof(u32);
frag->pad = raw->size - sum;
} else {
size = sizeof(u64);
}
header->size += size;
}
if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
int size = sizeof(u64); /* nr */
if (data->br_stack) {
if (perf_sample_save_hw_index(event))
size += sizeof(u64);
size += data->br_stack->nr
* sizeof(struct perf_branch_entry);
}
header->size += size;
}
if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
perf_sample_regs_user(&data->regs_user, regs);
if (sample_type & PERF_SAMPLE_REGS_USER) {
/* regs dump ABI info */
int size = sizeof(u64);
if (data->regs_user.regs) {
u64 mask = event->attr.sample_regs_user;
size += hweight64(mask) * sizeof(u64);
}
header->size += size;
}
if (sample_type & PERF_SAMPLE_STACK_USER) {
/*
* Either we need PERF_SAMPLE_STACK_USER bit to be always
* processed as the last one or have additional check added
* in case new sample type is added, because we could eat
* up the rest of the sample size.
*/
u16 stack_size = event->attr.sample_stack_user;
u16 size = sizeof(u64);
stack_size = perf_sample_ustack_size(stack_size, header->size,
data->regs_user.regs);
/*
* If there is something to dump, add space for the dump
* itself and for the field that tells the dynamic size,
* which is how many have been actually dumped.
*/
if (stack_size)
size += sizeof(u64) + stack_size;
data->stack_user_size = stack_size;
header->size += size;
}
if (sample_type & PERF_SAMPLE_REGS_INTR) {
/* regs dump ABI info */
int size = sizeof(u64);
perf_sample_regs_intr(&data->regs_intr, regs);
if (data->regs_intr.regs) {
u64 mask = event->attr.sample_regs_intr;
size += hweight64(mask) * sizeof(u64);
}
header->size += size;
}
if (sample_type & PERF_SAMPLE_PHYS_ADDR)
data->phys_addr = perf_virt_to_phys(data->addr);
#ifdef CONFIG_CGROUP_PERF
if (sample_type & PERF_SAMPLE_CGROUP) {
struct cgroup *cgrp;
/* protected by RCU */
cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
data->cgroup = cgroup_id(cgrp);
}
#endif
/*
* PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
* require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
* but the value will not dump to the userspace.
*/
if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
data->data_page_size = perf_get_page_size(data->addr);
if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
data->code_page_size = perf_get_page_size(data->ip);
if (sample_type & PERF_SAMPLE_AUX) {
u64 size;
header->size += sizeof(u64); /* size */
/*
* Given the 16bit nature of header::size, an AUX sample can
* easily overflow it, what with all the preceding sample bits.
* Make sure this doesn't happen by using up to U16_MAX bytes
* per sample in total (rounded down to 8 byte boundary).
*/
size = min_t(size_t, U16_MAX - header->size,
event->attr.aux_sample_size);
size = rounddown(size, 8);
size = perf_prepare_sample_aux(event, data, size);
WARN_ON_ONCE(size + header->size > U16_MAX);
header->size += size;
}
/*
* If you're adding more sample types here, you likely need to do
* something about the overflowing header::size, like repurpose the
* lowest 3 bits of size, which should be always zero at the moment.
* This raises a more important question, do we really need 512k sized
* samples and why, so good argumentation is in order for whatever you
* do here next.
*/
WARN_ON_ONCE(header->size & 7);
}
static __always_inline int
__perf_event_output(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs,
int (*output_begin)(struct perf_output_handle *,
struct perf_sample_data *,
struct perf_event *,
unsigned int))
{
struct perf_output_handle handle;
struct perf_event_header header;
int err;
/* protect the callchain buffers */
rcu_read_lock();
perf_prepare_sample(&header, data, event, regs);
err = output_begin(&handle, data, event, header.size);
if (err)
goto exit;
perf_output_sample(&handle, &header, data, event);
perf_output_end(&handle);
exit:
rcu_read_unlock();
return err;
}
void
perf_event_output_forward(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
__perf_event_output(event, data, regs, perf_output_begin_forward);
}
void
perf_event_output_backward(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
__perf_event_output(event, data, regs, perf_output_begin_backward);
}
int
perf_event_output(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
return __perf_event_output(event, data, regs, perf_output_begin);
}
/*
* read event_id
*/
struct perf_read_event {
struct perf_event_header header;
u32 pid;
u32 tid;
};
static void
perf_event_read_event(struct perf_event *event,
struct task_struct *task)
{
struct perf_output_handle handle;
struct perf_sample_data sample;
struct perf_read_event read_event = {
.header = {
.type = PERF_RECORD_READ,
.misc = 0,
.size = sizeof(read_event) + event->read_size,
},
.pid = perf_event_pid(event, task),
.tid = perf_event_tid(event, task),
};
int ret;
perf_event_header__init_id(&read_event.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
if (ret)
return;
perf_output_put(&handle, read_event);
perf_output_read(&handle, event);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
typedef void (perf_iterate_f)(struct perf_event *event, void *data);
static void
perf_iterate_ctx(struct perf_event_context *ctx,
perf_iterate_f output,
void *data, bool all)
{
struct perf_event *event;
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (!all) {
if (event->state < PERF_EVENT_STATE_INACTIVE)
continue;
if (!event_filter_match(event))
continue;
}
output(event, data);
}
}
static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
{
struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
struct perf_event *event;
list_for_each_entry_rcu(event, &pel->list, sb_list) {
/*
* Skip events that are not fully formed yet; ensure that
* if we observe event->ctx, both event and ctx will be
* complete enough. See perf_install_in_context().
*/
if (!smp_load_acquire(&event->ctx))
continue;
if (event->state < PERF_EVENT_STATE_INACTIVE)
continue;
if (!event_filter_match(event))
continue;
output(event, data);
}
}
/*
* Iterate all events that need to receive side-band events.
*
* For new callers; ensure that account_pmu_sb_event() includes
* your event, otherwise it might not get delivered.
*/
static void
perf_iterate_sb(perf_iterate_f output, void *data,
struct perf_event_context *task_ctx)
{
struct perf_event_context *ctx;
int ctxn;
rcu_read_lock();
preempt_disable();
/*
* If we have task_ctx != NULL we only notify the task context itself.
* The task_ctx is set only for EXIT events before releasing task
* context.
*/
if (task_ctx) {
perf_iterate_ctx(task_ctx, output, data, false);
goto done;
}
perf_iterate_sb_cpu(output, data);
for_each_task_context_nr(ctxn) {
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
if (ctx)
perf_iterate_ctx(ctx, output, data, false);
}
done:
preempt_enable();
rcu_read_unlock();
}
/*
* Clear all file-based filters at exec, they'll have to be
* re-instated when/if these objects are mmapped again.
*/
static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
{
struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
struct perf_addr_filter *filter;
unsigned int restart = 0, count = 0;
unsigned long flags;
if (!has_addr_filter(event))
return;
raw_spin_lock_irqsave(&ifh->lock, flags);
list_for_each_entry(filter, &ifh->list, entry) {
if (filter->path.dentry) {
event->addr_filter_ranges[count].start = 0;
event->addr_filter_ranges[count].size = 0;
restart++;
}
count++;
}
if (restart)
event->addr_filters_gen++;
raw_spin_unlock_irqrestore(&ifh->lock, flags);
if (restart)
perf_event_stop(event, 1);
}
void perf_event_exec(void)
{
struct perf_event_context *ctx;
int ctxn;
for_each_task_context_nr(ctxn) {
perf_event_enable_on_exec(ctxn);
perf_event_remove_on_exec(ctxn);
rcu_read_lock();
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
if (ctx) {
perf_iterate_ctx(ctx, perf_event_addr_filters_exec,
NULL, true);
}
rcu_read_unlock();
}
}
struct remote_output {
struct perf_buffer *rb;
int err;
};
static void __perf_event_output_stop(struct perf_event *event, void *data)
{
struct perf_event *parent = event->parent;
struct remote_output *ro = data;
struct perf_buffer *rb = ro->rb;
struct stop_event_data sd = {
.event = event,
};
if (!has_aux(event))
return;
if (!parent)
parent = event;
/*
* In case of inheritance, it will be the parent that links to the
* ring-buffer, but it will be the child that's actually using it.
*
* We are using event::rb to determine if the event should be stopped,
* however this may race with ring_buffer_attach() (through set_output),
* which will make us skip the event that actually needs to be stopped.
* So ring_buffer_attach() has to stop an aux event before re-assigning
* its rb pointer.
*/
if (rcu_dereference(parent->rb) == rb)
ro->err = __perf_event_stop(&sd);
}
static int __perf_pmu_output_stop(void *info)
{
struct perf_event *event = info;
struct pmu *pmu = event->ctx->pmu;
struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
struct remote_output ro = {
.rb = event->rb,
};
rcu_read_lock();
perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
if (cpuctx->task_ctx)
perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
&ro, false);
rcu_read_unlock();
return ro.err;
}
static void perf_pmu_output_stop(struct perf_event *event)
{
struct perf_event *iter;
int err, cpu;
restart:
rcu_read_lock();
list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
/*
* For per-CPU events, we need to make sure that neither they
* nor their children are running; for cpu==-1 events it's
* sufficient to stop the event itself if it's active, since
* it can't have children.
*/
cpu = iter->cpu;
if (cpu == -1)
cpu = READ_ONCE(iter->oncpu);
if (cpu == -1)
continue;
err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
if (err == -EAGAIN) {
rcu_read_unlock();
goto restart;
}
}
rcu_read_unlock();
}
/*
* task tracking -- fork/exit
*
* enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
*/
struct perf_task_event {
struct task_struct *task;
struct perf_event_context *task_ctx;
struct {
struct perf_event_header header;
u32 pid;
u32 ppid;
u32 tid;
u32 ptid;
u64 time;
} event_id;
};
static int perf_event_task_match(struct perf_event *event)
{
return event->attr.comm || event->attr.mmap ||
event->attr.mmap2 || event->attr.mmap_data ||
event->attr.task;
}
static void perf_event_task_output(struct perf_event *event,
void *data)
{
struct perf_task_event *task_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
struct task_struct *task = task_event->task;
int ret, size = task_event->event_id.header.size;
if (!perf_event_task_match(event))
return;
perf_event_header__init_id(&task_event->event_id.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event,
task_event->event_id.header.size);
if (ret)
goto out;
task_event->event_id.pid = perf_event_pid(event, task);
task_event->event_id.tid = perf_event_tid(event, task);
if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
task_event->event_id.ppid = perf_event_pid(event,
task->real_parent);
task_event->event_id.ptid = perf_event_pid(event,
task->real_parent);
} else { /* PERF_RECORD_FORK */
task_event->event_id.ppid = perf_event_pid(event, current);
task_event->event_id.ptid = perf_event_tid(event, current);
}
task_event->event_id.time = perf_event_clock(event);
perf_output_put(&handle, task_event->event_id);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
out:
task_event->event_id.header.size = size;
}
static void perf_event_task(struct task_struct *task,
struct perf_event_context *task_ctx,
int new)
{
struct perf_task_event task_event;
if (!atomic_read(&nr_comm_events) &&
!atomic_read(&nr_mmap_events) &&
!atomic_read(&nr_task_events))
return;
task_event = (struct perf_task_event){
.task = task,
.task_ctx = task_ctx,
.event_id = {
.header = {
.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
.misc = 0,
.size = sizeof(task_event.event_id),
},
/* .pid */
/* .ppid */
/* .tid */
/* .ptid */
/* .time */
},
};
perf_iterate_sb(perf_event_task_output,
&task_event,
task_ctx);
}
void perf_event_fork(struct task_struct *task)
{
perf_event_task(task, NULL, 1);
perf_event_namespaces(task);
}
/*
* comm tracking
*/
struct perf_comm_event {
struct task_struct *task;
char *comm;
int comm_size;
struct {
struct perf_event_header header;
u32 pid;
u32 tid;
} event_id;
};
static int perf_event_comm_match(struct perf_event *event)
{
return event->attr.comm;
}
static void perf_event_comm_output(struct perf_event *event,
void *data)
{
struct perf_comm_event *comm_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
int size = comm_event->event_id.header.size;
int ret;
if (!perf_event_comm_match(event))
return;
perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event,
comm_event->event_id.header.size);
if (ret)
goto out;
comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
perf_output_put(&handle, comm_event->event_id);
__output_copy(&handle, comm_event->comm,
comm_event->comm_size);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
out:
comm_event->event_id.header.size = size;
}
static void perf_event_comm_event(struct perf_comm_event *comm_event)
{
char comm[TASK_COMM_LEN];
unsigned int size;
memset(comm, 0, sizeof(comm));
strlcpy(comm, comm_event->task->comm, sizeof(comm));
size = ALIGN(strlen(comm)+1, sizeof(u64));
comm_event->comm = comm;
comm_event->comm_size = size;
comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
perf_iterate_sb(perf_event_comm_output,
comm_event,
NULL);
}
void perf_event_comm(struct task_struct *task, bool exec)
{
struct perf_comm_event comm_event;
if (!atomic_read(&nr_comm_events))
return;
comm_event = (struct perf_comm_event){
.task = task,
/* .comm */
/* .comm_size */
.event_id = {
.header = {
.type = PERF_RECORD_COMM,
.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
/* .size */
},
/* .pid */
/* .tid */
},
};
perf_event_comm_event(&comm_event);
}
/*
* namespaces tracking
*/
struct perf_namespaces_event {
struct task_struct *task;
struct {
struct perf_event_header header;
u32 pid;
u32 tid;
u64 nr_namespaces;
struct perf_ns_link_info link_info[NR_NAMESPACES];
} event_id;
};
static int perf_event_namespaces_match(struct perf_event *event)
{
return event->attr.namespaces;
}
static void perf_event_namespaces_output(struct perf_event *event,
void *data)
{
struct perf_namespaces_event *namespaces_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
u16 header_size = namespaces_event->event_id.header.size;
int ret;
if (!perf_event_namespaces_match(event))
return;
perf_event_header__init_id(&namespaces_event->event_id.header,
&sample, event);
ret = perf_output_begin(&handle, &sample, event,
namespaces_event->event_id.header.size);
if (ret)
goto out;
namespaces_event->event_id.pid = perf_event_pid(event,
namespaces_event->task);
namespaces_event->event_id.tid = perf_event_tid(event,
namespaces_event->task);
perf_output_put(&handle, namespaces_event->event_id);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
out:
namespaces_event->event_id.header.size = header_size;
}
static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
struct task_struct *task,
const struct proc_ns_operations *ns_ops)
{
struct path ns_path;
struct inode *ns_inode;
int error;
error = ns_get_path(&ns_path, task, ns_ops);
if (!error) {
ns_inode = ns_path.dentry->d_inode;
ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
ns_link_info->ino = ns_inode->i_ino;
path_put(&ns_path);
}
}
void perf_event_namespaces(struct task_struct *task)
{
struct perf_namespaces_event namespaces_event;
struct perf_ns_link_info *ns_link_info;
if (!atomic_read(&nr_namespaces_events))
return;
namespaces_event = (struct perf_namespaces_event){
.task = task,
.event_id = {
.header = {
.type = PERF_RECORD_NAMESPACES,
.misc = 0,
.size = sizeof(namespaces_event.event_id),
},
/* .pid */
/* .tid */
.nr_namespaces = NR_NAMESPACES,
/* .link_info[NR_NAMESPACES] */
},
};
ns_link_info = namespaces_event.event_id.link_info;
perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
task, &mntns_operations);
#ifdef CONFIG_USER_NS
perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
task, &userns_operations);
#endif
#ifdef CONFIG_NET_NS
perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
task, &netns_operations);
#endif
#ifdef CONFIG_UTS_NS
perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
task, &utsns_operations);
#endif
#ifdef CONFIG_IPC_NS
perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
task, &ipcns_operations);
#endif
#ifdef CONFIG_PID_NS
perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
task, &pidns_operations);
#endif
#ifdef CONFIG_CGROUPS
perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
task, &cgroupns_operations);
#endif
perf_iterate_sb(perf_event_namespaces_output,
&namespaces_event,
NULL);
}
/*
* cgroup tracking
*/
#ifdef CONFIG_CGROUP_PERF
struct perf_cgroup_event {
char *path;
int path_size;
struct {
struct perf_event_header header;
u64 id;
char path[];
} event_id;
};
static int perf_event_cgroup_match(struct perf_event *event)
{
return event->attr.cgroup;
}
static void perf_event_cgroup_output(struct perf_event *event, void *data)
{
struct perf_cgroup_event *cgroup_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
u16 header_size = cgroup_event->event_id.header.size;
int ret;
if (!perf_event_cgroup_match(event))
return;
perf_event_header__init_id(&cgroup_event->event_id.header,
&sample, event);
ret = perf_output_begin(&handle, &sample, event,
cgroup_event->event_id.header.size);
if (ret)
goto out;
perf_output_put(&handle, cgroup_event->event_id);
__output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
out:
cgroup_event->event_id.header.size = header_size;
}
static void perf_event_cgroup(struct cgroup *cgrp)
{
struct perf_cgroup_event cgroup_event;
char path_enomem[16] = "//enomem";
char *pathname;
size_t size;
if (!atomic_read(&nr_cgroup_events))
return;
cgroup_event = (struct perf_cgroup_event){
.event_id = {
.header = {
.type = PERF_RECORD_CGROUP,
.misc = 0,
.size = sizeof(cgroup_event.event_id),
},
.id = cgroup_id(cgrp),
},
};
pathname = kmalloc(PATH_MAX, GFP_KERNEL);
if (pathname == NULL) {
cgroup_event.path = path_enomem;
} else {
/* just to be sure to have enough space for alignment */
cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
cgroup_event.path = pathname;
}
/*
* Since our buffer works in 8 byte units we need to align our string
* size to a multiple of 8. However, we must guarantee the tail end is
* zero'd out to avoid leaking random bits to userspace.
*/
size = strlen(cgroup_event.path) + 1;
while (!IS_ALIGNED(size, sizeof(u64)))
cgroup_event.path[size++] = '\0';
cgroup_event.event_id.header.size += size;
cgroup_event.path_size = size;
perf_iterate_sb(perf_event_cgroup_output,
&cgroup_event,
NULL);
kfree(pathname);
}
#endif
/*
* mmap tracking
*/
struct perf_mmap_event {
struct vm_area_struct *vma;
const char *file_name;
int file_size;
int maj, min;
u64 ino;
u64 ino_generation;
u32 prot, flags;
u8 build_id[BUILD_ID_SIZE_MAX];
u32 build_id_size;
struct {
struct perf_event_header header;
u32 pid;
u32 tid;
u64 start;
u64 len;
u64 pgoff;
} event_id;
};
static int perf_event_mmap_match(struct perf_event *event,
void *data)
{
struct perf_mmap_event *mmap_event = data;
struct vm_area_struct *vma = mmap_event->vma;
int executable = vma->vm_flags & VM_EXEC;
return (!executable && event->attr.mmap_data) ||
(executable && (event->attr.mmap || event->attr.mmap2));
}
static void perf_event_mmap_output(struct perf_event *event,
void *data)
{
struct perf_mmap_event *mmap_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
int size = mmap_event->event_id.header.size;
u32 type = mmap_event->event_id.header.type;
bool use_build_id;
int ret;
if (!perf_event_mmap_match(event, data))
return;
if (event->attr.mmap2) {
mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
mmap_event->event_id.header.size += sizeof(mmap_event->maj);
mmap_event->event_id.header.size += sizeof(mmap_event->min);
mmap_event->event_id.header.size += sizeof(mmap_event->ino);
mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
mmap_event->event_id.header.size += sizeof(mmap_event->prot);
mmap_event->event_id.header.size += sizeof(mmap_event->flags);
}
perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event,
mmap_event->event_id.header.size);
if (ret)
goto out;
mmap_event->event_id.pid = perf_event_pid(event, current);
mmap_event->event_id.tid = perf_event_tid(event, current);
use_build_id = event->attr.build_id && mmap_event->build_id_size;
if (event->attr.mmap2 && use_build_id)
mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
perf_output_put(&handle, mmap_event->event_id);
if (event->attr.mmap2) {
if (use_build_id) {
u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
__output_copy(&handle, size, 4);
__output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
} else {
perf_output_put(&handle, mmap_event->maj);
perf_output_put(&handle, mmap_event->min);
perf_output_put(&handle, mmap_event->ino);
perf_output_put(&handle, mmap_event->ino_generation);
}
perf_output_put(&handle, mmap_event->prot);
perf_output_put(&handle, mmap_event->flags);
}
__output_copy(&handle, mmap_event->file_name,
mmap_event->file_size);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
out:
mmap_event->event_id.header.size = size;
mmap_event->event_id.header.type = type;
}
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
{
struct vm_area_struct *vma = mmap_event->vma;
struct file *file = vma->vm_file;
int maj = 0, min = 0;
u64 ino = 0, gen = 0;
u32 prot = 0, flags = 0;
unsigned int size;
char tmp[16];
char *buf = NULL;
char *name;
if (vma->vm_flags & VM_READ)
prot |= PROT_READ;
if (vma->vm_flags & VM_WRITE)
prot |= PROT_WRITE;
if (vma->vm_flags & VM_EXEC)
prot |= PROT_EXEC;
if (vma->vm_flags & VM_MAYSHARE)
flags = MAP_SHARED;
else
flags = MAP_PRIVATE;
if (vma->vm_flags & VM_LOCKED)
flags |= MAP_LOCKED;
if (is_vm_hugetlb_page(vma))
flags |= MAP_HUGETLB;
if (file) {
struct inode *inode;
dev_t dev;
buf = kmalloc(PATH_MAX, GFP_KERNEL);
if (!buf) {
name = "//enomem";
goto cpy_name;
}
/*
* d_path() works from the end of the rb backwards, so we
* need to add enough zero bytes after the string to handle
* the 64bit alignment we do later.
*/
name = file_path(file, buf, PATH_MAX - sizeof(u64));
if (IS_ERR(name)) {
name = "//toolong";
goto cpy_name;
}
inode = file_inode(vma->vm_file);
dev = inode->i_sb->s_dev;
ino = inode->i_ino;
gen = inode->i_generation;
maj = MAJOR(dev);
min = MINOR(dev);
goto got_name;
} else {
if (vma->vm_ops && vma->vm_ops->name) {
name = (char *) vma->vm_ops->name(vma);
if (name)
goto cpy_name;
}
name = (char *)arch_vma_name(vma);
if (name)
goto cpy_name;
if (vma->vm_start <= vma->vm_mm->start_brk &&
vma->vm_end >= vma->vm_mm->brk) {
name = "[heap]";
goto cpy_name;
}
if (vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack) {
name = "[stack]";
goto cpy_name;
}
name = "//anon";
goto cpy_name;
}
cpy_name:
strlcpy(tmp, name, sizeof(tmp));
name = tmp;
got_name:
/*
* Since our buffer works in 8 byte units we need to align our string
* size to a multiple of 8. However, we must guarantee the tail end is
* zero'd out to avoid leaking random bits to userspace.
*/
size = strlen(name)+1;
while (!IS_ALIGNED(size, sizeof(u64)))
name[size++] = '\0';
mmap_event->file_name = name;
mmap_event->file_size = size;
mmap_event->maj = maj;
mmap_event->min = min;
mmap_event->ino = ino;
mmap_event->ino_generation = gen;
mmap_event->prot = prot;
mmap_event->flags = flags;
if (!(vma->vm_flags & VM_EXEC))
mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
if (atomic_read(&nr_build_id_events))
build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
perf_iterate_sb(perf_event_mmap_output,
mmap_event,
NULL);
kfree(buf);
}
/*
* Check whether inode and address range match filter criteria.
*/
static bool perf_addr_filter_match(struct perf_addr_filter *filter,
struct file *file, unsigned long offset,
unsigned long size)
{
/* d_inode(NULL) won't be equal to any mapped user-space file */
if (!filter->path.dentry)
return false;
if (d_inode(filter->path.dentry) != file_inode(file))
return false;
if (filter->offset > offset + size)
return false;
if (filter->offset + filter->size < offset)
return false;
return true;
}
static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
struct vm_area_struct *vma,
struct perf_addr_filter_range *fr)
{
unsigned long vma_size = vma->vm_end - vma->vm_start;
unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
struct file *file = vma->vm_file;
if (!perf_addr_filter_match(filter, file, off, vma_size))
return false;
if (filter->offset < off) {
fr->start = vma->vm_start;
fr->size = min(vma_size, filter->size - (off - filter->offset));
} else {
fr->start = vma->vm_start + filter->offset - off;
fr->size = min(vma->vm_end - fr->start, filter->size);
}
return true;
}
static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
{
struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
struct vm_area_struct *vma = data;
struct perf_addr_filter *filter;
unsigned int restart = 0, count = 0;
unsigned long flags;
if (!has_addr_filter(event))
return;
if (!vma->vm_file)
return;
raw_spin_lock_irqsave(&ifh->lock, flags);
list_for_each_entry(filter, &ifh->list, entry) {
if (perf_addr_filter_vma_adjust(filter, vma,
&event->addr_filter_ranges[count]))
restart++;
count++;
}
if (restart)
event->addr_filters_gen++;
raw_spin_unlock_irqrestore(&ifh->lock, flags);
if (restart)
perf_event_stop(event, 1);
}
/*
* Adjust all task's events' filters to the new vma
*/
static void perf_addr_filters_adjust(struct vm_area_struct *vma)
{
struct perf_event_context *ctx;
int ctxn;
/*
* Data tracing isn't supported yet and as such there is no need
* to keep track of anything that isn't related to executable code:
*/
if (!(vma->vm_flags & VM_EXEC))
return;
rcu_read_lock();
for_each_task_context_nr(ctxn) {
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
if (!ctx)
continue;
perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
}
rcu_read_unlock();
}
void perf_event_mmap(struct vm_area_struct *vma)
{
struct perf_mmap_event mmap_event;
if (!atomic_read(&nr_mmap_events))
return;
mmap_event = (struct perf_mmap_event){
.vma = vma,
/* .file_name */
/* .file_size */
.event_id = {
.header = {
.type = PERF_RECORD_MMAP,
.misc = PERF_RECORD_MISC_USER,
/* .size */
},
/* .pid */
/* .tid */
.start = vma->vm_start,
.len = vma->vm_end - vma->vm_start,
.pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
},
/* .maj (attr_mmap2 only) */
/* .min (attr_mmap2 only) */
/* .ino (attr_mmap2 only) */
/* .ino_generation (attr_mmap2 only) */
/* .prot (attr_mmap2 only) */
/* .flags (attr_mmap2 only) */
};
perf_addr_filters_adjust(vma);
perf_event_mmap_event(&mmap_event);
}
void perf_event_aux_event(struct perf_event *event, unsigned long head,
unsigned long size, u64 flags)
{
struct perf_output_handle handle;
struct perf_sample_data sample;
struct perf_aux_event {
struct perf_event_header header;
u64 offset;
u64 size;
u64 flags;
} rec = {
.header = {
.type = PERF_RECORD_AUX,
.misc = 0,
.size = sizeof(rec),
},
.offset = head,
.size = size,
.flags = flags,
};
int ret;
perf_event_header__init_id(&rec.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event, rec.header.size);
if (ret)
return;
perf_output_put(&handle, rec);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
/*
* Lost/dropped samples logging
*/
void perf_log_lost_samples(struct perf_event *event, u64 lost)
{
struct perf_output_handle handle;
struct perf_sample_data sample;
int ret;
struct {
struct perf_event_header header;
u64 lost;
} lost_samples_event = {
.header = {
.type = PERF_RECORD_LOST_SAMPLES,
.misc = 0,
.size = sizeof(lost_samples_event),
},
.lost = lost,
};
perf_event_header__init_id(&lost_samples_event.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event,
lost_samples_event.header.size);
if (ret)
return;
perf_output_put(&handle, lost_samples_event);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
/*
* context_switch tracking
*/
struct perf_switch_event {
struct task_struct *task;
struct task_struct *next_prev;
struct {
struct perf_event_header header;
u32 next_prev_pid;
u32 next_prev_tid;
} event_id;
};
static int perf_event_switch_match(struct perf_event *event)
{
return event->attr.context_switch;
}
static void perf_event_switch_output(struct perf_event *event, void *data)
{
struct perf_switch_event *se = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
int ret;
if (!perf_event_switch_match(event))
return;
/* Only CPU-wide events are allowed to see next/prev pid/tid */
if (event->ctx->task) {
se->event_id.header.type = PERF_RECORD_SWITCH;
se->event_id.header.size = sizeof(se->event_id.header);
} else {
se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
se->event_id.header.size = sizeof(se->event_id);
se->event_id.next_prev_pid =
perf_event_pid(event, se->next_prev);
se->event_id.next_prev_tid =
perf_event_tid(event, se->next_prev);
}
perf_event_header__init_id(&se->event_id.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
if (ret)
return;
if (event->ctx->task)
perf_output_put(&handle, se->event_id.header);
else
perf_output_put(&handle, se->event_id);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
static void perf_event_switch(struct task_struct *task,
struct task_struct *next_prev, bool sched_in)
{
struct perf_switch_event switch_event;
/* N.B. caller checks nr_switch_events != 0 */
switch_event = (struct perf_switch_event){
.task = task,
.next_prev = next_prev,
.event_id = {
.header = {
/* .type */
.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
/* .size */
},
/* .next_prev_pid */
/* .next_prev_tid */
},
};
if (!sched_in && task->on_rq) {
switch_event.event_id.header.misc |=
PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
}
perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
}
/*
* IRQ throttle logging
*/
static void perf_log_throttle(struct perf_event *event, int enable)
{
struct perf_output_handle handle;
struct perf_sample_data sample;
int ret;
struct {
struct perf_event_header header;
u64 time;
u64 id;
u64 stream_id;
} throttle_event = {
.header = {
.type = PERF_RECORD_THROTTLE,
.misc = 0,
.size = sizeof(throttle_event),
},
.time = perf_event_clock(event),
.id = primary_event_id(event),
.stream_id = event->id,
};
if (enable)
throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
perf_event_header__init_id(&throttle_event.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event,
throttle_event.header.size);
if (ret)
return;
perf_output_put(&handle, throttle_event);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
/*
* ksymbol register/unregister tracking
*/
struct perf_ksymbol_event {
const char *name;
int name_len;
struct {
struct perf_event_header header;
u64 addr;
u32 len;
u16 ksym_type;
u16 flags;
} event_id;
};
static int perf_event_ksymbol_match(struct perf_event *event)
{
return event->attr.ksymbol;
}
static void perf_event_ksymbol_output(struct perf_event *event, void *data)
{
struct perf_ksymbol_event *ksymbol_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
int ret;
if (!perf_event_ksymbol_match(event))
return;
perf_event_header__init_id(&ksymbol_event->event_id.header,
&sample, event);
ret = perf_output_begin(&handle, &sample, event,
ksymbol_event->event_id.header.size);
if (ret)
return;
perf_output_put(&handle, ksymbol_event->event_id);
__output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
const char *sym)
{
struct perf_ksymbol_event ksymbol_event;
char name[KSYM_NAME_LEN];
u16 flags = 0;
int name_len;
if (!atomic_read(&nr_ksymbol_events))
return;
if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
goto err;
strlcpy(name, sym, KSYM_NAME_LEN);
name_len = strlen(name) + 1;
while (!IS_ALIGNED(name_len, sizeof(u64)))
name[name_len++] = '\0';
BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
if (unregister)
flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
ksymbol_event = (struct perf_ksymbol_event){
.name = name,
.name_len = name_len,
.event_id = {
.header = {
.type = PERF_RECORD_KSYMBOL,
.size = sizeof(ksymbol_event.event_id) +
name_len,
},
.addr = addr,
.len = len,
.ksym_type = ksym_type,
.flags = flags,
},
};
perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
return;
err:
WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
}
/*
* bpf program load/unload tracking
*/
struct perf_bpf_event {
struct bpf_prog *prog;
struct {
struct perf_event_header header;
u16 type;
u16 flags;
u32 id;
u8 tag[BPF_TAG_SIZE];
} event_id;
};
static int perf_event_bpf_match(struct perf_event *event)
{
return event->attr.bpf_event;
}
static void perf_event_bpf_output(struct perf_event *event, void *data)
{
struct perf_bpf_event *bpf_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
int ret;
if (!perf_event_bpf_match(event))
return;
perf_event_header__init_id(&bpf_event->event_id.header,
&sample, event);
ret = perf_output_begin(&handle, data, event,
bpf_event->event_id.header.size);
if (ret)
return;
perf_output_put(&handle, bpf_event->event_id);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
enum perf_bpf_event_type type)
{
bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
int i;
if (prog->aux->func_cnt == 0) {
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
(u64)(unsigned long)prog->bpf_func,
prog->jited_len, unregister,
prog->aux->ksym.name);
} else {
for (i = 0; i < prog->aux->func_cnt; i++) {
struct bpf_prog *subprog = prog->aux->func[i];
perf_event_ksymbol(
PERF_RECORD_KSYMBOL_TYPE_BPF,
(u64)(unsigned long)subprog->bpf_func,
subprog->jited_len, unregister,
prog->aux->ksym.name);
}
}
}
void perf_event_bpf_event(struct bpf_prog *prog,
enum perf_bpf_event_type type,
u16 flags)
{
struct perf_bpf_event bpf_event;
if (type <= PERF_BPF_EVENT_UNKNOWN ||
type >= PERF_BPF_EVENT_MAX)
return;
switch (type) {
case PERF_BPF_EVENT_PROG_LOAD:
case PERF_BPF_EVENT_PROG_UNLOAD:
if (atomic_read(&nr_ksymbol_events))
perf_event_bpf_emit_ksymbols(prog, type);
break;
default:
break;
}
if (!atomic_read(&nr_bpf_events))
return;
bpf_event = (struct perf_bpf_event){
.prog = prog,
.event_id = {
.header = {
.type = PERF_RECORD_BPF_EVENT,
.size = sizeof(bpf_event.event_id),
},
.type = type,
.flags = flags,
.id = prog->aux->id,
},
};
BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
}
struct perf_text_poke_event {
const void *old_bytes;
const void *new_bytes;
size_t pad;
u16 old_len;
u16 new_len;
struct {
struct perf_event_header header;
u64 addr;
} event_id;
};
static int perf_event_text_poke_match(struct perf_event *event)
{
return event->attr.text_poke;
}
static void perf_event_text_poke_output(struct perf_event *event, void *data)
{
struct perf_text_poke_event *text_poke_event = data;
struct perf_output_handle handle;
struct perf_sample_data sample;
u64 padding = 0;
int ret;
if (!perf_event_text_poke_match(event))
return;
perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event,
text_poke_event->event_id.header.size);
if (ret)
return;
perf_output_put(&handle, text_poke_event->event_id);
perf_output_put(&handle, text_poke_event->old_len);
perf_output_put(&handle, text_poke_event->new_len);
__output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
__output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
if (text_poke_event->pad)
__output_copy(&handle, &padding, text_poke_event->pad);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
void perf_event_text_poke(const void *addr, const void *old_bytes,
size_t old_len, const void *new_bytes, size_t new_len)
{
struct perf_text_poke_event text_poke_event;
size_t tot, pad;
if (!atomic_read(&nr_text_poke_events))
return;
tot = sizeof(text_poke_event.old_len) + old_len;
tot += sizeof(text_poke_event.new_len) + new_len;
pad = ALIGN(tot, sizeof(u64)) - tot;
text_poke_event = (struct perf_text_poke_event){
.old_bytes = old_bytes,
.new_bytes = new_bytes,
.pad = pad,
.old_len = old_len,
.new_len = new_len,
.event_id = {
.header = {
.type = PERF_RECORD_TEXT_POKE,
.misc = PERF_RECORD_MISC_KERNEL,
.size = sizeof(text_poke_event.event_id) + tot + pad,
},
.addr = (unsigned long)addr,
},
};
perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
}
void perf_event_itrace_started(struct perf_event *event)
{
event->attach_state |= PERF_ATTACH_ITRACE;
}
static void perf_log_itrace_start(struct perf_event *event)
{
struct perf_output_handle handle;
struct perf_sample_data sample;
struct perf_aux_event {
struct perf_event_header header;
u32 pid;
u32 tid;
} rec;
int ret;
if (event->parent)
event = event->parent;
if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
event->attach_state & PERF_ATTACH_ITRACE)
return;
rec.header.type = PERF_RECORD_ITRACE_START;
rec.header.misc = 0;
rec.header.size = sizeof(rec);
rec.pid = perf_event_pid(event, current);
rec.tid = perf_event_tid(event, current);
perf_event_header__init_id(&rec.header, &sample, event);
ret = perf_output_begin(&handle, &sample, event, rec.header.size);
if (ret)
return;
perf_output_put(&handle, rec);
perf_event__output_id_sample(event, &handle, &sample);
perf_output_end(&handle);
}
static int
__perf_event_account_interrupt(struct perf_event *event, int throttle)
{
struct hw_perf_event *hwc = &event->hw;
int ret = 0;
u64 seq;
seq = __this_cpu_read(perf_throttled_seq);
if (seq != hwc->interrupts_seq) {
hwc->interrupts_seq = seq;
hwc->interrupts = 1;
} else {
hwc->interrupts++;
if (unlikely(throttle
&& hwc->interrupts >= max_samples_per_tick)) {
__this_cpu_inc(perf_throttled_count);
tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
hwc->interrupts = MAX_INTERRUPTS;
perf_log_throttle(event, 0);
ret = 1;
}
}
if (event->attr.freq) {
u64 now = perf_clock();
s64 delta = now - hwc->freq_time_stamp;
hwc->freq_time_stamp = now;
if (delta > 0 && delta < 2*TICK_NSEC)
perf_adjust_period(event, delta, hwc->last_period, true);
}
return ret;
}
int perf_event_account_interrupt(struct perf_event *event)
{
return __perf_event_account_interrupt(event, 1);
}
/*
* Generic event overflow handling, sampling.
*/
static int __perf_event_overflow(struct perf_event *event,
int throttle, struct perf_sample_data *data,
struct pt_regs *regs)
{
int events = atomic_read(&event->event_limit);
int ret = 0;
/*
* Non-sampling counters might still use the PMI to fold short
* hardware counters, ignore those.
*/
if (unlikely(!is_sampling_event(event)))
return 0;
ret = __perf_event_account_interrupt(event, throttle);
/*
* XXX event_limit might not quite work as expected on inherited
* events
*/
event->pending_kill = POLL_IN;
if (events && atomic_dec_and_test(&event->event_limit)) {
ret = 1;
event->pending_kill = POLL_HUP;
event->pending_addr = data->addr;
perf_event_disable_inatomic(event);
}
READ_ONCE(event->overflow_handler)(event, data, regs);
if (*perf_event_fasync(event) && event->pending_kill) {
event->pending_wakeup = 1;
irq_work_queue(&event->pending);
}
return ret;
}
int perf_event_overflow(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
return __perf_event_overflow(event, 1, data, regs);
}
/*
* Generic software event infrastructure
*/
struct swevent_htable {
struct swevent_hlist *swevent_hlist;
struct mutex hlist_mutex;
int hlist_refcount;
/* Recursion avoidance in each contexts */
int recursion[PERF_NR_CONTEXTS];
};
static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
/*
* We directly increment event->count and keep a second value in
* event->hw.period_left to count intervals. This period event
* is kept in the range [-sample_period, 0] so that we can use the
* sign as trigger.
*/
u64 perf_swevent_set_period(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
u64 period = hwc->last_period;
u64 nr, offset;
s64 old, val;
hwc->last_period = hwc->sample_period;
again:
old = val = local64_read(&hwc->period_left);
if (val < 0)
return 0;
nr = div64_u64(period + val, period);
offset = nr * period;
val -= offset;
if (local64_cmpxchg(&hwc->period_left, old, val) != old)
goto again;
return nr;
}
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct hw_perf_event *hwc = &event->hw;
int throttle = 0;
if (!overflow)
overflow = perf_swevent_set_period(event);
if (hwc->interrupts == MAX_INTERRUPTS)
return;
for (; overflow; overflow--) {
if (__perf_event_overflow(event, throttle,
data, regs)) {
/*
* We inhibit the overflow from happening when
* hwc->interrupts == MAX_INTERRUPTS.
*/
break;
}
throttle = 1;
}
}
static void perf_swevent_event(struct perf_event *event, u64 nr,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct hw_perf_event *hwc = &event->hw;
local64_add(nr, &event->count);
if (!regs)
return;
if (!is_sampling_event(event))
return;
if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
data->period = nr;
return perf_swevent_overflow(event, 1, data, regs);
} else
data->period = event->hw.last_period;
if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
return perf_swevent_overflow(event, 1, data, regs);
if (local64_add_negative(nr, &hwc->period_left))
return;
perf_swevent_overflow(event, 0, data, regs);
}
static int perf_exclude_event(struct perf_event *event,
struct pt_regs *regs)
{
if (event->hw.state & PERF_HES_STOPPED)
return 1;
if (regs) {
if (event->attr.exclude_user && user_mode(regs))
return 1;
if (event->attr.exclude_kernel && !user_mode(regs))
return 1;
}
return 0;
}
static int perf_swevent_match(struct perf_event *event,
enum perf_type_id type,
u32 event_id,
struct perf_sample_data *data,
struct pt_regs *regs)
{
if (event->attr.type != type)
return 0;
if (event->attr.config != event_id)
return 0;
if (perf_exclude_event(event, regs))
return 0;
return 1;
}
static inline u64 swevent_hash(u64 type, u32 event_id)
{
u64 val = event_id | (type << 32);
return hash_64(val, SWEVENT_HLIST_BITS);
}
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
{
u64 hash = swevent_hash(type, event_id);
return &hlist->heads[hash];
}
/* For the read side: events when they trigger */
static inline struct hlist_head *
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
{
struct swevent_hlist *hlist;
hlist = rcu_dereference(swhash->swevent_hlist);
if (!hlist)
return NULL;
return __find_swevent_head(hlist, type, event_id);
}
/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
{
struct swevent_hlist *hlist;
u32 event_id = event->attr.config;
u64 type = event->attr.type;
/*
* Event scheduling is always serialized against hlist allocation
* and release. Which makes the protected version suitable here.
* The context lock guarantees that.
*/
hlist = rcu_dereference_protected(swhash->swevent_hlist,
lockdep_is_held(&event->ctx->lock));
if (!hlist)
return NULL;
return __find_swevent_head(hlist, type, event_id);
}
static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
u64 nr,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
struct perf_event *event;
struct hlist_head *head;
rcu_read_lock();
head = find_swevent_head_rcu(swhash, type, event_id);
if (!head)
goto end;
hlist_for_each_entry_rcu(event, head, hlist_entry) {
if (perf_swevent_match(event, type, event_id, data, regs))
perf_swevent_event(event, nr, data, regs);
}
end:
rcu_read_unlock();
}
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
int perf_swevent_get_recursion_context(void)
{
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
return get_recursion_context(swhash->recursion);
}
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
void perf_swevent_put_recursion_context(int rctx)
{
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
put_recursion_context(swhash->recursion, rctx);
}
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
struct perf_sample_data data;
if (WARN_ON_ONCE(!regs))
return;
perf_sample_data_init(&data, addr, 0);
do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
}
void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
int rctx;
preempt_disable_notrace();
rctx = perf_swevent_get_recursion_context();
if (unlikely(rctx < 0))
goto fail;
___perf_sw_event(event_id, nr, regs, addr);
perf_swevent_put_recursion_context(rctx);
fail:
preempt_enable_notrace();
}
static void perf_swevent_read(struct perf_event *event)
{
}
static int perf_swevent_add(struct perf_event *event, int flags)
{
struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
struct hw_perf_event *hwc = &event->hw;
struct hlist_head *head;
if (is_sampling_event(event)) {
hwc->last_period = hwc->sample_period;
perf_swevent_set_period(event);
}
hwc->state = !(flags & PERF_EF_START);
head = find_swevent_head(swhash, event);
if (WARN_ON_ONCE(!head))
return -EINVAL;
hlist_add_head_rcu(&event->hlist_entry, head);
perf_event_update_userpage(event);
return 0;
}
static void perf_swevent_del(struct perf_event *event, int flags)
{
hlist_del_rcu(&event->hlist_entry);
}
static void perf_swevent_start(struct perf_event *event, int flags)
{
event->hw.state = 0;
}
static void perf_swevent_stop(struct perf_event *event, int flags)
{
event->hw.state = PERF_HES_STOPPED;
}
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
swevent_hlist_deref(struct swevent_htable *swhash)
{
return rcu_dereference_protected(swhash->swevent_hlist,
lockdep_is_held(&swhash->hlist_mutex));
}
static void swevent_hlist_release(struct swevent_htable *swhash)
{
struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
if (!hlist)
return;
RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
kfree_rcu(hlist, rcu_head);
}
static void swevent_hlist_put_cpu(int cpu)
{
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
mutex_lock(&swhash->hlist_mutex);
if (!--swhash->hlist_refcount)
swevent_hlist_release(swhash);
mutex_unlock(&swhash->hlist_mutex);
}
static void swevent_hlist_put(void)
{
int cpu;
for_each_possible_cpu(cpu)
swevent_hlist_put_cpu(cpu);
}
static int swevent_hlist_get_cpu(int cpu)
{
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
int err = 0;
mutex_lock(&swhash->hlist_mutex);
if (!swevent_hlist_deref(swhash) &&
cpumask_test_cpu(cpu, perf_online_mask)) {
struct swevent_hlist *hlist;
hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
if (!hlist) {
err = -ENOMEM;
goto exit;
}
rcu_assign_pointer(swhash->swevent_hlist, hlist);
}
swhash->hlist_refcount++;
exit:
mutex_unlock(&swhash->hlist_mutex);
return err;
}
static int swevent_hlist_get(void)
{
int err, cpu, failed_cpu;
mutex_lock(&pmus_lock);
for_each_possible_cpu(cpu) {
err = swevent_hlist_get_cpu(cpu);
if (err) {
failed_cpu = cpu;
goto fail;
}
}
mutex_unlock(&pmus_lock);
return 0;
fail:
for_each_possible_cpu(cpu) {
if (cpu == failed_cpu)
break;
swevent_hlist_put_cpu(cpu);
}
mutex_unlock(&pmus_lock);
return err;
}
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
static void sw_perf_event_destroy(struct perf_event *event)
{
u64 event_id = event->attr.config;
WARN_ON(event->parent);
static_key_slow_dec(&perf_swevent_enabled[event_id]);
swevent_hlist_put();
}
static int perf_swevent_init(struct perf_event *event)
{
u64 event_id = event->attr.config;
if (event->attr.type != PERF_TYPE_SOFTWARE)
return -ENOENT;
/*
* no branch sampling for software events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
switch (event_id) {
case PERF_COUNT_SW_CPU_CLOCK:
case PERF_COUNT_SW_TASK_CLOCK:
return -ENOENT;
default:
break;
}
if (event_id >= PERF_COUNT_SW_MAX)
return -ENOENT;
if (!event->parent) {
int err;
err = swevent_hlist_get();
if (err)
return err;
static_key_slow_inc(&perf_swevent_enabled[event_id]);
event->destroy = sw_perf_event_destroy;
}
return 0;
}
static struct pmu perf_swevent = {
.task_ctx_nr = perf_sw_context,
.capabilities = PERF_PMU_CAP_NO_NMI,
.event_init = perf_swevent_init,
.add = perf_swevent_add,
.del = perf_swevent_del,
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
};
#ifdef CONFIG_EVENT_TRACING
static int perf_tp_filter_match(struct perf_event *event,
struct perf_sample_data *data)
{
void *record = data->raw->frag.data;
/* only top level events have filters set */
if (event->parent)
event = event->parent;
if (likely(!event->filter) || filter_match_preds(event->filter, record))
return 1;
return 0;
}
static int perf_tp_event_match(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
if (event->hw.state & PERF_HES_STOPPED)
return 0;
/*
* If exclude_kernel, only trace user-space tracepoints (uprobes)
*/
if (event->attr.exclude_kernel && !user_mode(regs))
return 0;
if (!perf_tp_filter_match(event, data))
return 0;
return 1;
}
void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
struct trace_event_call *call, u64 count,
struct pt_regs *regs, struct hlist_head *head,
struct task_struct *task)
{
if (bpf_prog_array_valid(call)) {
*(struct pt_regs **)raw_data = regs;
if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
perf_swevent_put_recursion_context(rctx);
return;
}
}
perf_tp_event(call->event.type, count, raw_data, size, regs, head,
rctx, task);
}
EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
struct pt_regs *regs, struct hlist_head *head, int rctx,
struct task_struct *task)
{
struct perf_sample_data data;
struct perf_event *event;
struct perf_raw_record raw = {
.frag = {
.size = entry_size,
.data = record,
},
};
perf_sample_data_init(&data, 0, 0);
data.raw = &raw;
perf_trace_buf_update(record, event_type);
hlist_for_each_entry_rcu(event, head, hlist_entry) {
if (perf_tp_event_match(event, &data, regs))
perf_swevent_event(event, count, &data, regs);
}
/*
* If we got specified a target task, also iterate its context and
* deliver this event there too.
*/
if (task && task != current) {
struct perf_event_context *ctx;
struct trace_entry *entry = record;
rcu_read_lock();
ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
if (!ctx)
goto unlock;
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (event->cpu != smp_processor_id())
continue;
if (event->attr.type != PERF_TYPE_TRACEPOINT)
continue;
if (event->attr.config != entry->type)
continue;
/* Cannot deliver synchronous signal to other task. */
if (event->attr.sigtrap)
continue;
if (perf_tp_event_match(event, &data, regs))
perf_swevent_event(event, count, &data, regs);
}
unlock:
rcu_read_unlock();
}
perf_swevent_put_recursion_context(rctx);
}
EXPORT_SYMBOL_GPL(perf_tp_event);
static void tp_perf_event_destroy(struct perf_event *event)
{
perf_trace_destroy(event);
}
static int perf_tp_event_init(struct perf_event *event)
{
int err;
if (event->attr.type != PERF_TYPE_TRACEPOINT)
return -ENOENT;
/*
* no branch sampling for tracepoint events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
err = perf_trace_init(event);
if (err)
return err;
event->destroy = tp_perf_event_destroy;
return 0;
}
static struct pmu perf_tracepoint = {
.task_ctx_nr = perf_sw_context,
.event_init = perf_tp_event_init,
.add = perf_trace_add,
.del = perf_trace_del,
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
};
#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
/*
* Flags in config, used by dynamic PMU kprobe and uprobe
* The flags should match following PMU_FORMAT_ATTR().
*
* PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
* if not set, create kprobe/uprobe
*
* The following values specify a reference counter (or semaphore in the
* terminology of tools like dtrace, systemtap, etc.) Userspace Statically
* Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
*
* PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
* PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
*/
enum perf_probe_config {
PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
};
PMU_FORMAT_ATTR(retprobe, "config:0");
#endif
#ifdef CONFIG_KPROBE_EVENTS
static struct attribute *kprobe_attrs[] = {
&format_attr_retprobe.attr,
NULL,
};
static struct attribute_group kprobe_format_group = {
.name = "format",
.attrs = kprobe_attrs,
};
static const struct attribute_group *kprobe_attr_groups[] = {
&kprobe_format_group,
NULL,
};
static int perf_kprobe_event_init(struct perf_event *event);
static struct pmu perf_kprobe = {
.task_ctx_nr = perf_sw_context,
.event_init = perf_kprobe_event_init,
.add = perf_trace_add,
.del = perf_trace_del,
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
.attr_groups = kprobe_attr_groups,
};
static int perf_kprobe_event_init(struct perf_event *event)
{
int err;
bool is_retprobe;
if (event->attr.type != perf_kprobe.type)
return -ENOENT;
if (!perfmon_capable())
return -EACCES;
/*
* no branch sampling for probe events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
err = perf_kprobe_init(event, is_retprobe);
if (err)
return err;
event->destroy = perf_kprobe_destroy;
return 0;
}
#endif /* CONFIG_KPROBE_EVENTS */
#ifdef CONFIG_UPROBE_EVENTS
PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
static struct attribute *uprobe_attrs[] = {
&format_attr_retprobe.attr,
&format_attr_ref_ctr_offset.attr,
NULL,
};
static struct attribute_group uprobe_format_group = {
.name = "format",
.attrs = uprobe_attrs,
};
static const struct attribute_group *uprobe_attr_groups[] = {
&uprobe_format_group,
NULL,
};
static int perf_uprobe_event_init(struct perf_event *event);
static struct pmu perf_uprobe = {
.task_ctx_nr = perf_sw_context,
.event_init = perf_uprobe_event_init,
.add = perf_trace_add,
.del = perf_trace_del,
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
.attr_groups = uprobe_attr_groups,
};
static int perf_uprobe_event_init(struct perf_event *event)
{
int err;
unsigned long ref_ctr_offset;
bool is_retprobe;
if (event->attr.type != perf_uprobe.type)
return -ENOENT;
if (!perfmon_capable())
return -EACCES;
/*
* no branch sampling for probe events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
if (err)
return err;
event->destroy = perf_uprobe_destroy;
return 0;
}
#endif /* CONFIG_UPROBE_EVENTS */
static inline void perf_tp_register(void)
{
perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
#ifdef CONFIG_KPROBE_EVENTS
perf_pmu_register(&perf_kprobe, "kprobe", -1);
#endif
#ifdef CONFIG_UPROBE_EVENTS
perf_pmu_register(&perf_uprobe, "uprobe", -1);
#endif
}
static void perf_event_free_filter(struct perf_event *event)
{
ftrace_profile_free_filter(event);
}
#ifdef CONFIG_BPF_SYSCALL
static void bpf_overflow_handler(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct bpf_perf_event_data_kern ctx = {
.data = data,
.event = event,
};
struct bpf_prog *prog;
int ret = 0;
ctx.regs = perf_arch_bpf_user_pt_regs(regs);
if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
goto out;
rcu_read_lock();
prog = READ_ONCE(event->prog);
if (prog)
ret = bpf_prog_run(prog, &ctx);
rcu_read_unlock();
out:
__this_cpu_dec(bpf_prog_active);
if (!ret)
return;
event->orig_overflow_handler(event, data, regs);
}
static int perf_event_set_bpf_handler(struct perf_event *event,
struct bpf_prog *prog,
u64 bpf_cookie)
{
if (event->overflow_handler_context)
/* hw breakpoint or kernel counter */
return -EINVAL;
if (event->prog)
return -EEXIST;
if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
return -EINVAL;
if (event->attr.precise_ip &&
prog->call_get_stack &&
(!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
event->attr.exclude_callchain_kernel ||
event->attr.exclude_callchain_user)) {
/*
* On perf_event with precise_ip, calling bpf_get_stack()
* may trigger unwinder warnings and occasional crashes.
* bpf_get_[stack|stackid] works around this issue by using
* callchain attached to perf_sample_data. If the
* perf_event does not full (kernel and user) callchain
* attached to perf_sample_data, do not allow attaching BPF
* program that calls bpf_get_[stack|stackid].
*/
return -EPROTO;
}
event->prog = prog;
event->bpf_cookie = bpf_cookie;
event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
return 0;
}
static void perf_event_free_bpf_handler(struct perf_event *event)
{
struct bpf_prog *prog = event->prog;
if (!prog)
return;
WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
event->prog = NULL;
bpf_prog_put(prog);
}
#else
static int perf_event_set_bpf_handler(struct perf_event *event,
struct bpf_prog *prog,
u64 bpf_cookie)
{
return -EOPNOTSUPP;
}
static void perf_event_free_bpf_handler(struct perf_event *event)
{
}
#endif
/*
* returns true if the event is a tracepoint, or a kprobe/upprobe created
* with perf_event_open()
*/
static inline bool perf_event_is_tracing(struct perf_event *event)
{
if (event->pmu == &perf_tracepoint)
return true;
#ifdef CONFIG_KPROBE_EVENTS
if (event->pmu == &perf_kprobe)
return true;
#endif
#ifdef CONFIG_UPROBE_EVENTS
if (event->pmu == &perf_uprobe)
return true;
#endif
return false;
}
int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
u64 bpf_cookie)
{
bool is_kprobe, is_tracepoint, is_syscall_tp;
if (!perf_event_is_tracing(event))
return perf_event_set_bpf_handler(event, prog, bpf_cookie);
is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
is_syscall_tp = is_syscall_trace_event(event->tp_event);
if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
/* bpf programs can only be attached to u/kprobe or tracepoint */
return -EINVAL;
if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
(is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
(is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
return -EINVAL;
/* Kprobe override only works for kprobes, not uprobes. */
if (prog->kprobe_override &&
!(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
return -EINVAL;
if (is_tracepoint || is_syscall_tp) {
int off = trace_event_get_offsets(event->tp_event);
if (prog->aux->max_ctx_offset > off)
return -EACCES;
}
return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
}
void perf_event_free_bpf_prog(struct perf_event *event)
{
if (!perf_event_is_tracing(event)) {
perf_event_free_bpf_handler(event);
return;
}
perf_event_detach_bpf_prog(event);
}
#else
static inline void perf_tp_register(void)
{
}
static void perf_event_free_filter(struct perf_event *event)
{
}
int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
u64 bpf_cookie)
{
return -ENOENT;
}
void perf_event_free_bpf_prog(struct perf_event *event)
{
}
#endif /* CONFIG_EVENT_TRACING */
#ifdef CONFIG_HAVE_HW_BREAKPOINT
void perf_bp_event(struct perf_event *bp, void *data)
{
struct perf_sample_data sample;
struct pt_regs *regs = data;
perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
if (!bp->hw.state && !perf_exclude_event(bp, regs))
perf_swevent_event(bp, 1, &sample, regs);
}
#endif
/*
* Allocate a new address filter
*/
static struct perf_addr_filter *
perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
{
int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
struct perf_addr_filter *filter;
filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
if (!filter)
return NULL;
INIT_LIST_HEAD(&filter->entry);
list_add_tail(&filter->entry, filters);
return filter;
}
static void free_filters_list(struct list_head *filters)
{
struct perf_addr_filter *filter, *iter;
list_for_each_entry_safe(filter, iter, filters, entry) {
path_put(&filter->path);
list_del(&filter->entry);
kfree(filter);
}
}
/*
* Free existing address filters and optionally install new ones
*/
static void perf_addr_filters_splice(struct perf_event *event,
struct list_head *head)
{
unsigned long flags;
LIST_HEAD(list);
if (!has_addr_filter(event))
return;
/* don't bother with children, they don't have their own filters */
if (event->parent)
return;
raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
list_splice_init(&event->addr_filters.list, &list);
if (head)
list_splice(head, &event->addr_filters.list);
raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
free_filters_list(&list);
}
/*
* Scan through mm's vmas and see if one of them matches the
* @filter; if so, adjust filter's address range.
* Called with mm::mmap_lock down for reading.
*/
static void perf_addr_filter_apply(struct perf_addr_filter *filter,
struct mm_struct *mm,
struct perf_addr_filter_range *fr)
{
struct vm_area_struct *vma;
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (!vma->vm_file)
continue;
if (perf_addr_filter_vma_adjust(filter, vma, fr))
return;
}
}
/*
* Update event's address range filters based on the
* task's existing mappings, if any.
*/
static void perf_event_addr_filters_apply(struct perf_event *event)
{
struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
struct task_struct *task = READ_ONCE(event->ctx->task);
struct perf_addr_filter *filter;
struct mm_struct *mm = NULL;
unsigned int count = 0;
unsigned long flags;
/*
* We may observe TASK_TOMBSTONE, which means that the event tear-down
* will stop on the parent's child_mutex that our caller is also holding
*/
if (task == TASK_TOMBSTONE)
return;
if (ifh->nr_file_filters) {
mm = get_task_mm(task);
if (!mm)
goto restart;
mmap_read_lock(mm);
}
raw_spin_lock_irqsave(&ifh->lock, flags);
list_for_each_entry(filter, &ifh->list, entry) {
if (filter->path.dentry) {
/*
* Adjust base offset if the filter is associated to a
* binary that needs to be mapped:
*/
event->addr_filter_ranges[count].start = 0;
event->addr_filter_ranges[count].size = 0;
perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
} else {
event->addr_filter_ranges[count].start = filter->offset;
event->addr_filter_ranges[count].size = filter->size;
}
count++;
}
event->addr_filters_gen++;
raw_spin_unlock_irqrestore(&ifh->lock, flags);
if (ifh->nr_file_filters) {
mmap_read_unlock(mm);
mmput(mm);
}
restart:
perf_event_stop(event, 1);
}
/*
* Address range filtering: limiting the data to certain
* instruction address ranges. Filters are ioctl()ed to us from
* userspace as ascii strings.
*
* Filter string format:
*
* ACTION RANGE_SPEC
* where ACTION is one of the
* * "filter": limit the trace to this region
* * "start": start tracing from this address
* * "stop": stop tracing at this address/region;
* RANGE_SPEC is
* * for kernel addresses: <start address>[/<size>]
* * for object files: <start address>[/<size>]@</path/to/object/file>
*
* if <size> is not specified or is zero, the range is treated as a single
* address; not valid for ACTION=="filter".
*/
enum {
IF_ACT_NONE = -1,
IF_ACT_FILTER,
IF_ACT_START,
IF_ACT_STOP,
IF_SRC_FILE,
IF_SRC_KERNEL,
IF_SRC_FILEADDR,
IF_SRC_KERNELADDR,
};
enum {
IF_STATE_ACTION = 0,
IF_STATE_SOURCE,
IF_STATE_END,
};
static const match_table_t if_tokens = {
{ IF_ACT_FILTER, "filter" },
{ IF_ACT_START, "start" },
{ IF_ACT_STOP, "stop" },
{ IF_SRC_FILE, "%u/%u@%s" },
{ IF_SRC_KERNEL, "%u/%u" },
{ IF_SRC_FILEADDR, "%u@%s" },
{ IF_SRC_KERNELADDR, "%u" },
{ IF_ACT_NONE, NULL },
};
/*
* Address filter string parser
*/
static int
perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
struct list_head *filters)
{
struct perf_addr_filter *filter = NULL;
char *start, *orig, *filename = NULL;
substring_t args[MAX_OPT_ARGS];
int state = IF_STATE_ACTION, token;
unsigned int kernel = 0;
int ret = -EINVAL;
orig = fstr = kstrdup(fstr, GFP_KERNEL);
if (!fstr)
return -ENOMEM;
while ((start = strsep(&fstr, " ,\n")) != NULL) {
static const enum perf_addr_filter_action_t actions[] = {
[IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
[IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
[IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
};
ret = -EINVAL;
if (!*start)
continue;
/* filter definition begins */
if (state == IF_STATE_ACTION) {
filter = perf_addr_filter_new(event, filters);
if (!filter)
goto fail;
}
token = match_token(start, if_tokens, args);
switch (token) {
case IF_ACT_FILTER:
case IF_ACT_START:
case IF_ACT_STOP:
if (state != IF_STATE_ACTION)
goto fail;
filter->action = actions[token];
state = IF_STATE_SOURCE;
break;
case IF_SRC_KERNELADDR:
case IF_SRC_KERNEL:
kernel = 1;
fallthrough;
case IF_SRC_FILEADDR:
case IF_SRC_FILE:
if (state != IF_STATE_SOURCE)
goto fail;
*args[0].to = 0;
ret = kstrtoul(args[0].from, 0, &filter->offset);
if (ret)
goto fail;
if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
*args[1].to = 0;
ret = kstrtoul(args[1].from, 0, &filter->size);
if (ret)
goto fail;
}
if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
int fpos = token == IF_SRC_FILE ? 2 : 1;
kfree(filename);
filename = match_strdup(&args[fpos]);
if (!filename) {
ret = -ENOMEM;
goto fail;
}
}
state = IF_STATE_END;
break;
default:
goto fail;
}
/*
* Filter definition is fully parsed, validate and install it.
* Make sure that it doesn't contradict itself or the event's
* attribute.
*/
if (state == IF_STATE_END) {
ret = -EINVAL;
if (kernel && event->attr.exclude_kernel)
goto fail;
/*
* ACTION "filter" must have a non-zero length region
* specified.
*/
if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
!filter->size)
goto fail;
if (!kernel) {
if (!filename)
goto fail;
/*
* For now, we only support file-based filters
* in per-task events; doing so for CPU-wide
* events requires additional context switching
* trickery, since same object code will be
* mapped at different virtual addresses in
* different processes.
*/
ret = -EOPNOTSUPP;
if (!event->ctx->task)
goto fail;
/* look up the path and grab its inode */
ret = kern_path(filename, LOOKUP_FOLLOW,
&filter->path);
if (ret)
goto fail;
ret = -EINVAL;
if (!filter->path.dentry ||
!S_ISREG(d_inode(filter->path.dentry)
->i_mode))
goto fail;
event->addr_filters.nr_file_filters++;
}
/* ready to consume more filters */
kfree(filename);
filename = NULL;
state = IF_STATE_ACTION;
filter = NULL;
kernel = 0;
}
}
if (state != IF_STATE_ACTION)
goto fail;
kfree(filename);
kfree(orig);
return 0;
fail:
kfree(filename);
free_filters_list(filters);
kfree(orig);
return ret;
}
static int
perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
{
LIST_HEAD(filters);
int ret;
/*
* Since this is called in perf_ioctl() path, we're already holding
* ctx::mutex.
*/
lockdep_assert_held(&event->ctx->mutex);
if (WARN_ON_ONCE(event->parent))
return -EINVAL;
ret = perf_event_parse_addr_filter(event, filter_str, &filters);
if (ret)
goto fail_clear_files;
ret = event->pmu->addr_filters_validate(&filters);
if (ret)
goto fail_free_filters;
/* remove existing filters, if any */
perf_addr_filters_splice(event, &filters);
/* install new filters */
perf_event_for_each_child(event, perf_event_addr_filters_apply);
return ret;
fail_free_filters:
free_filters_list(&filters);
fail_clear_files:
event->addr_filters.nr_file_filters = 0;
return ret;
}
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
int ret = -EINVAL;
char *filter_str;
filter_str = strndup_user(arg, PAGE_SIZE);
if (IS_ERR(filter_str))
return PTR_ERR(filter_str);
#ifdef CONFIG_EVENT_TRACING
if (perf_event_is_tracing(event)) {
struct perf_event_context *ctx = event->ctx;
/*
* Beware, here be dragons!!
*
* the tracepoint muck will deadlock against ctx->mutex, but
* the tracepoint stuff does not actually need it. So
* temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
* already have a reference on ctx.
*
* This can result in event getting moved to a different ctx,
* but that does not affect the tracepoint state.
*/
mutex_unlock(&ctx->mutex);
ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
mutex_lock(&ctx->mutex);
} else
#endif
if (has_addr_filter(event))
ret = perf_event_set_addr_filter(event, filter_str);
kfree(filter_str);
return ret;
}
/*
* hrtimer based swevent callback
*/
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
{
enum hrtimer_restart ret = HRTIMER_RESTART;
struct perf_sample_data data;
struct pt_regs *regs;
struct perf_event *event;
u64 period;
event = container_of(hrtimer, struct perf_event, hw.hrtimer);
if (event->state != PERF_EVENT_STATE_ACTIVE)
return HRTIMER_NORESTART;
event->pmu->read(event);
perf_sample_data_init(&data, 0, event->hw.last_period);
regs = get_irq_regs();
if (regs && !perf_exclude_event(event, regs)) {
if (!(event->attr.exclude_idle && is_idle_task(current)))
if (__perf_event_overflow(event, 1, &data, regs))
ret = HRTIMER_NORESTART;
}
period = max_t(u64, 10000, event->hw.sample_period);
hrtimer_forward_now(hrtimer, ns_to_ktime(period));
return ret;
}
static void perf_swevent_start_hrtimer(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
s64 period;
if (!is_sampling_event(event))
return;
period = local64_read(&hwc->period_left);
if (period) {
if (period < 0)
period = 10000;
local64_set(&hwc->period_left, 0);
} else {
period = max_t(u64, 10000, hwc->sample_period);
}
hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
HRTIMER_MODE_REL_PINNED_HARD);
}
static void perf_swevent_cancel_hrtimer(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
if (is_sampling_event(event)) {
ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
local64_set(&hwc->period_left, ktime_to_ns(remaining));
hrtimer_cancel(&hwc->hrtimer);
}
}
static void perf_swevent_init_hrtimer(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
if (!is_sampling_event(event))
return;
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
hwc->hrtimer.function = perf_swevent_hrtimer;
/*
* Since hrtimers have a fixed rate, we can do a static freq->period
* mapping and avoid the whole period adjust feedback stuff.
*/
if (event->attr.freq) {
long freq = event->attr.sample_freq;
event->attr.sample_period = NSEC_PER_SEC / freq;
hwc->sample_period = event->attr.sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
hwc->last_period = hwc->sample_period;
event->attr.freq = 0;
}
}
/*
* Software event: cpu wall time clock
*/
static void cpu_clock_event_update(struct perf_event *event)
{
s64 prev;
u64 now;
now = local_clock();
prev = local64_xchg(&event->hw.prev_count, now);
local64_add(now - prev, &event->count);
}
static void cpu_clock_event_start(struct perf_event *event, int flags)
{
local64_set(&event->hw.prev_count, local_clock());
perf_swevent_start_hrtimer(event);
}
static void cpu_clock_event_stop(struct perf_event *event, int flags)
{
perf_swevent_cancel_hrtimer(event);
cpu_clock_event_update(event);
}
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
if (flags & PERF_EF_START)
cpu_clock_event_start(event, flags);
perf_event_update_userpage(event);
return 0;
}
static void cpu_clock_event_del(struct perf_event *event, int flags)
{
cpu_clock_event_stop(event, flags);
}
static void cpu_clock_event_read(struct perf_event *event)
{
cpu_clock_event_update(event);
}
static int cpu_clock_event_init(struct perf_event *event)
{
if (event->attr.type != PERF_TYPE_SOFTWARE)
return -ENOENT;
if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
return -ENOENT;
/*
* no branch sampling for software events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
perf_swevent_init_hrtimer(event);
return 0;
}
static struct pmu perf_cpu_clock = {
.task_ctx_nr = perf_sw_context,
.capabilities = PERF_PMU_CAP_NO_NMI,
.event_init = cpu_clock_event_init,
.add = cpu_clock_event_add,
.del = cpu_clock_event_del,
.start = cpu_clock_event_start,
.stop = cpu_clock_event_stop,
.read = cpu_clock_event_read,
};
/*
* Software event: task time clock
*/
static void task_clock_event_update(struct perf_event *event, u64 now)
{
u64 prev;
s64 delta;
prev = local64_xchg(&event->hw.prev_count, now);
delta = now - prev;
local64_add(delta, &event->count);
}
static void task_clock_event_start(struct perf_event *event, int flags)
{
local64_set(&event->hw.prev_count, event->ctx->time);
perf_swevent_start_hrtimer(event);
}
static void task_clock_event_stop(struct perf_event *event, int flags)
{
perf_swevent_cancel_hrtimer(event);
task_clock_event_update(event, event->ctx->time);
}
static int task_clock_event_add(struct perf_event *event, int flags)
{
if (flags & PERF_EF_START)
task_clock_event_start(event, flags);
perf_event_update_userpage(event);
return 0;
}
static void task_clock_event_del(struct perf_event *event, int flags)
{
task_clock_event_stop(event, PERF_EF_UPDATE);
}
static void task_clock_event_read(struct perf_event *event)
{
u64 now = perf_clock();
u64 delta = now - event->ctx->timestamp;
u64 time = event->ctx->time + delta;
task_clock_event_update(event, time);
}
static int task_clock_event_init(struct perf_event *event)
{
if (event->attr.type != PERF_TYPE_SOFTWARE)
return -ENOENT;
if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
return -ENOENT;
/*
* no branch sampling for software events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
perf_swevent_init_hrtimer(event);
return 0;
}
static struct pmu perf_task_clock = {
.task_ctx_nr = perf_sw_context,
.capabilities = PERF_PMU_CAP_NO_NMI,
.event_init = task_clock_event_init,
.add = task_clock_event_add,
.del = task_clock_event_del,
.start = task_clock_event_start,
.stop = task_clock_event_stop,
.read = task_clock_event_read,
};
static void perf_pmu_nop_void(struct pmu *pmu)
{
}
static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
{
}
static int perf_pmu_nop_int(struct pmu *pmu)
{
return 0;
}
static int perf_event_nop_int(struct perf_event *event, u64 value)
{
return 0;
}
static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
{
__this_cpu_write(nop_txn_flags, flags);
if (flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_disable(pmu);
}
static int perf_pmu_commit_txn(struct pmu *pmu)
{
unsigned int flags = __this_cpu_read(nop_txn_flags);
__this_cpu_write(nop_txn_flags, 0);
if (flags & ~PERF_PMU_TXN_ADD)
return 0;
perf_pmu_enable(pmu);
return 0;
}
static void perf_pmu_cancel_txn(struct pmu *pmu)
{
unsigned int flags = __this_cpu_read(nop_txn_flags);
__this_cpu_write(nop_txn_flags, 0);
if (flags & ~PERF_PMU_TXN_ADD)
return;
perf_pmu_enable(pmu);
}
static int perf_event_idx_default(struct perf_event *event)
{
return 0;
}
/*
* Ensures all contexts with the same task_ctx_nr have the same
* pmu_cpu_context too.
*/
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
{
struct pmu *pmu;
if (ctxn < 0)
return NULL;
list_for_each_entry(pmu, &pmus, entry) {
if (pmu->task_ctx_nr == ctxn)
return pmu->pmu_cpu_context;
}
return NULL;
}
static void free_pmu_context(struct pmu *pmu)
{
/*
* Static contexts such as perf_sw_context have a global lifetime
* and may be shared between different PMUs. Avoid freeing them
* when a single PMU is going away.
*/
if (pmu->task_ctx_nr > perf_invalid_context)
return;
free_percpu(pmu->pmu_cpu_context);
}
/*
* Let userspace know that this PMU supports address range filtering:
*/
static ssize_t nr_addr_filters_show(struct device *dev,
struct device_attribute *attr,
char *page)
{
struct pmu *pmu = dev_get_drvdata(dev);
return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
}
DEVICE_ATTR_RO(nr_addr_filters);
static struct idr pmu_idr;
static ssize_t
type_show(struct device *dev, struct device_attribute *attr, char *page)
{
struct pmu *pmu = dev_get_drvdata(dev);
return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
}
static DEVICE_ATTR_RO(type);
static ssize_t
perf_event_mux_interval_ms_show(struct device *dev,
struct device_attribute *attr,
char *page)
{
struct pmu *pmu = dev_get_drvdata(dev);
return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
}
static DEFINE_MUTEX(mux_interval_mutex);
static ssize_t
perf_event_mux_interval_ms_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct pmu *pmu = dev_get_drvdata(dev);
int timer, cpu, ret;
ret = kstrtoint(buf, 0, &timer);
if (ret)
return ret;
if (timer < 1)
return -EINVAL;
/* same value, noting to do */
if (timer == pmu->hrtimer_interval_ms)
return count;
mutex_lock(&mux_interval_mutex);
pmu->hrtimer_interval_ms = timer;
/* update all cpuctx for this PMU */
cpus_read_lock();
for_each_online_cpu(cpu) {
struct perf_cpu_context *cpuctx;
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
cpu_function_call(cpu,
(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
}
cpus_read_unlock();
mutex_unlock(&mux_interval_mutex);
return count;
}
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
static struct attribute *pmu_dev_attrs[] = {
&dev_attr_type.attr,
&dev_attr_perf_event_mux_interval_ms.attr,
NULL,
};
ATTRIBUTE_GROUPS(pmu_dev);
static int pmu_bus_running;
static struct bus_type pmu_bus = {
.name = "event_source",
.dev_groups = pmu_dev_groups,
};
static void pmu_dev_release(struct device *dev)
{
kfree(dev);
}
static int pmu_dev_alloc(struct pmu *pmu)
{
int ret = -ENOMEM;
pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
if (!pmu->dev)
goto out;
pmu->dev->groups = pmu->attr_groups;
device_initialize(pmu->dev);
ret = dev_set_name(pmu->dev, "%s", pmu->name);
if (ret)
goto free_dev;
dev_set_drvdata(pmu->dev, pmu);
pmu->dev->bus = &pmu_bus;
pmu->dev->release = pmu_dev_release;
ret = device_add(pmu->dev);
if (ret)
goto free_dev;
/* For PMUs with address filters, throw in an extra attribute: */
if (pmu->nr_addr_filters)
ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
if (ret)
goto del_dev;
if (pmu->attr_update)
ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
if (ret)
goto del_dev;
out:
return ret;
del_dev:
device_del(pmu->dev);
free_dev:
put_device(pmu->dev);
goto out;
}
static struct lock_class_key cpuctx_mutex;
static struct lock_class_key cpuctx_lock;
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
{
int cpu, ret, max = PERF_TYPE_MAX;
mutex_lock(&pmus_lock);
ret = -ENOMEM;
pmu->pmu_disable_count = alloc_percpu(int);
if (!pmu->pmu_disable_count)
goto unlock;
pmu->type = -1;
if (!name)
goto skip_type;
pmu->name = name;
if (type != PERF_TYPE_SOFTWARE) {
if (type >= 0)
max = type;
ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
if (ret < 0)
goto free_pdc;
WARN_ON(type >= 0 && ret != type);
type = ret;
}
pmu->type = type;
if (pmu_bus_running) {
ret = pmu_dev_alloc(pmu);
if (ret)
goto free_idr;
}
skip_type:
if (pmu->task_ctx_nr == perf_hw_context) {
static int hw_context_taken = 0;
/*
* Other than systems with heterogeneous CPUs, it never makes
* sense for two PMUs to share perf_hw_context. PMUs which are
* uncore must use perf_invalid_context.
*/
if (WARN_ON_ONCE(hw_context_taken &&
!(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
pmu->task_ctx_nr = perf_invalid_context;
hw_context_taken = 1;
}
pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
if (pmu->pmu_cpu_context)
goto got_cpu_context;
ret = -ENOMEM;
pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
if (!pmu->pmu_cpu_context)
goto free_dev;
for_each_possible_cpu(cpu) {
struct perf_cpu_context *cpuctx;
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
__perf_event_init_context(&cpuctx->ctx);
lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
cpuctx->ctx.pmu = pmu;
cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
__perf_mux_hrtimer_init(cpuctx, cpu);
cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
cpuctx->heap = cpuctx->heap_default;
}
got_cpu_context:
if (!pmu->start_txn) {
if (pmu->pmu_enable) {
/*
* If we have pmu_enable/pmu_disable calls, install
* transaction stubs that use that to try and batch
* hardware accesses.
*/
pmu->start_txn = perf_pmu_start_txn;
pmu->commit_txn = perf_pmu_commit_txn;
pmu->cancel_txn = perf_pmu_cancel_txn;
} else {
pmu->start_txn = perf_pmu_nop_txn;
pmu->commit_txn = perf_pmu_nop_int;
pmu->cancel_txn = perf_pmu_nop_void;
}
}
if (!pmu->pmu_enable) {
pmu->pmu_enable = perf_pmu_nop_void;
pmu->pmu_disable = perf_pmu_nop_void;
}
if (!pmu->check_period)
pmu->check_period = perf_event_nop_int;
if (!pmu->event_idx)
pmu->event_idx = perf_event_idx_default;
/*
* Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
* since these cannot be in the IDR. This way the linear search
* is fast, provided a valid software event is provided.
*/
if (type == PERF_TYPE_SOFTWARE || !name)
list_add_rcu(&pmu->entry, &pmus);
else
list_add_tail_rcu(&pmu->entry, &pmus);
atomic_set(&pmu->exclusive_cnt, 0);
ret = 0;
unlock:
mutex_unlock(&pmus_lock);
return ret;
free_dev:
device_del(pmu->dev);
put_device(pmu->dev);
free_idr:
if (pmu->type != PERF_TYPE_SOFTWARE)
idr_remove(&pmu_idr, pmu->type);
free_pdc:
free_percpu(pmu->pmu_disable_count);
goto unlock;
}
EXPORT_SYMBOL_GPL(perf_pmu_register);
void perf_pmu_unregister(struct pmu *pmu)
{
mutex_lock(&pmus_lock);
list_del_rcu(&pmu->entry);
/*
* We dereference the pmu list under both SRCU and regular RCU, so
* synchronize against both of those.
*/
synchronize_srcu(&pmus_srcu);
synchronize_rcu();
free_percpu(pmu->pmu_disable_count);
if (pmu->type != PERF_TYPE_SOFTWARE)
idr_remove(&pmu_idr, pmu->type);
if (pmu_bus_running) {
if (pmu->nr_addr_filters)
device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
device_del(pmu->dev);
put_device(pmu->dev);
}
free_pmu_context(pmu);
mutex_unlock(&pmus_lock);
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
static inline bool has_extended_regs(struct perf_event *event)
{
return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
(event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
}
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
struct perf_event_context *ctx = NULL;
int ret;
if (!try_module_get(pmu->module))
return -ENODEV;
/*
* A number of pmu->event_init() methods iterate the sibling_list to,
* for example, validate if the group fits on the PMU. Therefore,
* if this is a sibling event, acquire the ctx->mutex to protect
* the sibling_list.
*/
if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
/*
* This ctx->mutex can nest when we're called through
* inheritance. See the perf_event_ctx_lock_nested() comment.
*/
ctx = perf_event_ctx_lock_nested(event->group_leader,
SINGLE_DEPTH_NESTING);
BUG_ON(!ctx);
}
event->pmu = pmu;
ret = pmu->event_init(event);
if (ctx)
perf_event_ctx_unlock(event->group_leader, ctx);
if (!ret) {
if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
has_extended_regs(event))
ret = -EOPNOTSUPP;
if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
event_has_any_exclude_flag(event))
ret = -EINVAL;
if (ret && event->destroy)
event->destroy(event);
}
if (ret)
module_put(pmu->module);
return ret;
}
static struct pmu *perf_init_event(struct perf_event *event)
{
bool extended_type = false;
int idx, type, ret;
struct pmu *pmu;
idx = srcu_read_lock(&pmus_srcu);
/* Try parent's PMU first: */
if (event->parent && event->parent->pmu) {
pmu = event->parent->pmu;
ret = perf_try_init_event(pmu, event);
if (!ret)
goto unlock;
}
/*
* PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
* are often aliases for PERF_TYPE_RAW.
*/
type = event->attr.type;
if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
if (!type) {
type = PERF_TYPE_RAW;
} else {
extended_type = true;
event->attr.config &= PERF_HW_EVENT_MASK;
}
}
again:
rcu_read_lock();
pmu = idr_find(&pmu_idr, type);
rcu_read_unlock();
if (pmu) {
if (event->attr.type != type && type != PERF_TYPE_RAW &&
!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
goto fail;
ret = perf_try_init_event(pmu, event);
if (ret == -ENOENT && event->attr.type != type && !extended_type) {
type = event->attr.type;
goto again;
}
if (ret)
pmu = ERR_PTR(ret);
goto unlock;
}
list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
ret = perf_try_init_event(pmu, event);
if (!ret)
goto unlock;
if (ret != -ENOENT) {
pmu = ERR_PTR(ret);
goto unlock;
}
}
fail:
pmu = ERR_PTR(-ENOENT);
unlock:
srcu_read_unlock(&pmus_srcu, idx);
return pmu;
}
static void attach_sb_event(struct perf_event *event)
{
struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
raw_spin_lock(&pel->lock);
list_add_rcu(&event->sb_list, &pel->list);
raw_spin_unlock(&pel->lock);
}
/*
* We keep a list of all !task (and therefore per-cpu) events
* that need to receive side-band records.
*
* This avoids having to scan all the various PMU per-cpu contexts
* looking for them.
*/
static void account_pmu_sb_event(struct perf_event *event)
{
if (is_sb_event(event))
attach_sb_event(event);
}
static void account_event_cpu(struct perf_event *event, int cpu)
{
if (event->parent)
return;
if (is_cgroup_event(event))
atomic_inc(&per_cpu(perf_cgroup_events, cpu));
}
/* Freq events need the tick to stay alive (see perf_event_task_tick). */
static void account_freq_event_nohz(void)
{
#ifdef CONFIG_NO_HZ_FULL
/* Lock so we don't race with concurrent unaccount */
spin_lock(&nr_freq_lock);
if (atomic_inc_return(&nr_freq_events) == 1)
tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
spin_unlock(&nr_freq_lock);
#endif
}
static void account_freq_event(void)
{
if (tick_nohz_full_enabled())
account_freq_event_nohz();
else
atomic_inc(&nr_freq_events);
}
static void account_event(struct perf_event *event)
{
bool inc = false;
if (event->parent)
return;
if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
inc = true;
if (event->attr.mmap || event->attr.mmap_data)
atomic_inc(&nr_mmap_events);
if (event->attr.build_id)
atomic_inc(&nr_build_id_events);
if (event->attr.comm)
atomic_inc(&nr_comm_events);
if (event->attr.namespaces)
atomic_inc(&nr_namespaces_events);
if (event->attr.cgroup)
atomic_inc(&nr_cgroup_events);
if (event->attr.task)
atomic_inc(&nr_task_events);
if (event->attr.freq)
account_freq_event();
if (event->attr.context_switch) {
atomic_inc(&nr_switch_events);
inc = true;
}
if (has_branch_stack(event))
inc = true;
if (is_cgroup_event(event))
inc = true;
if (event->attr.ksymbol)
atomic_inc(&nr_ksymbol_events);
if (event->attr.bpf_event)
atomic_inc(&nr_bpf_events);
if (event->attr.text_poke)
atomic_inc(&nr_text_poke_events);
if (inc) {
/*
* We need the mutex here because static_branch_enable()
* must complete *before* the perf_sched_count increment
* becomes visible.
*/
if (atomic_inc_not_zero(&perf_sched_count))
goto enabled;
mutex_lock(&perf_sched_mutex);
if (!atomic_read(&perf_sched_count)) {
static_branch_enable(&perf_sched_events);
/*
* Guarantee that all CPUs observe they key change and
* call the perf scheduling hooks before proceeding to
* install events that need them.
*/
synchronize_rcu();
}
/*
* Now that we have waited for the sync_sched(), allow further
* increments to by-pass the mutex.
*/
atomic_inc(&perf_sched_count);
mutex_unlock(&perf_sched_mutex);
}
enabled:
account_event_cpu(event, event->cpu);
account_pmu_sb_event(event);
}
/*
* Allocate and initialize an event structure
*/
static struct perf_event *
perf_event_alloc(struct perf_event_attr *attr, int cpu,
struct task_struct *task,
struct perf_event *group_leader,
struct perf_event *parent_event,
perf_overflow_handler_t overflow_handler,
void *context, int cgroup_fd)
{
struct pmu *pmu;
struct perf_event *event;
struct hw_perf_event *hwc;
long err = -EINVAL;
int node;
if ((unsigned)cpu >= nr_cpu_ids) {
if (!task || cpu != -1)
return ERR_PTR(-EINVAL);
}
if (attr->sigtrap && !task) {
/* Requires a task: avoid signalling random tasks. */
return ERR_PTR(-EINVAL);
}
node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
node);
if (!event)
return ERR_PTR(-ENOMEM);
/*
* Single events are their own group leaders, with an
* empty sibling list:
*/
if (!group_leader)
group_leader = event;
mutex_init(&event->child_mutex);
INIT_LIST_HEAD(&event->child_list);
INIT_LIST_HEAD(&event->event_entry);
INIT_LIST_HEAD(&event->sibling_list);
INIT_LIST_HEAD(&event->active_list);
init_event_group(event);
INIT_LIST_HEAD(&event->rb_entry);
INIT_LIST_HEAD(&event->active_entry);
INIT_LIST_HEAD(&event->addr_filters.list);
INIT_HLIST_NODE(&event->hlist_entry);
init_waitqueue_head(&event->waitq);
event->pending_disable = -1;
init_irq_work(&event->pending, perf_pending_event);
mutex_init(&event->mmap_mutex);
raw_spin_lock_init(&event->addr_filters.lock);
atomic_long_set(&event->refcount, 1);
event->cpu = cpu;
event->attr = *attr;
event->group_leader = group_leader;
event->pmu = NULL;
event->oncpu = -1;
event->parent = parent_event;
event->ns = get_pid_ns(task_active_pid_ns(current));
event->id = atomic64_inc_return(&perf_event_id);
event->state = PERF_EVENT_STATE_INACTIVE;
if (event->attr.sigtrap)
atomic_set(&event->event_limit, 1);
if (task) {
event->attach_state = PERF_ATTACH_TASK;
/*
* XXX pmu::event_init needs to know what task to account to
* and we cannot use the ctx information because we need the
* pmu before we get a ctx.
*/
event->hw.target = get_task_struct(task);
}
event->clock = &local_clock;
if (parent_event)
event->clock = parent_event->clock;
if (!overflow_handler && parent_event) {
overflow_handler = parent_event->overflow_handler;
context = parent_event->overflow_handler_context;
#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
if (overflow_handler == bpf_overflow_handler) {
struct bpf_prog *prog = parent_event->prog;
bpf_prog_inc(prog);
event->prog = prog;
event->orig_overflow_handler =
parent_event->orig_overflow_handler;
}
#endif
}
if (overflow_handler) {
event->overflow_handler = overflow_handler;
event->overflow_handler_context = context;
} else if (is_write_backward(event)){
event->overflow_handler = perf_event_output_backward;
event->overflow_handler_context = NULL;
} else {
event->overflow_handler = perf_event_output_forward;
event->overflow_handler_context = NULL;
}
perf_event__state_init(event);
pmu = NULL;
hwc = &event->hw;
hwc->sample_period = attr->sample_period;
if (attr->freq && attr->sample_freq)
hwc->sample_period = 1;
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
/*
* We currently do not support PERF_SAMPLE_READ on inherited events.
* See perf_output_read().
*/
if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
goto err_ns;
if (!has_branch_stack(event))
event->attr.branch_sample_type = 0;
pmu = perf_init_event(event);
if (IS_ERR(pmu)) {
err = PTR_ERR(pmu);
goto err_ns;
}
/*
* Disallow uncore-cgroup events, they don't make sense as the cgroup will
* be different on other CPUs in the uncore mask.
*/
if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
err = -EINVAL;
goto err_pmu;
}
if (event->attr.aux_output &&
!(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
err = -EOPNOTSUPP;
goto err_pmu;
}
if (cgroup_fd != -1) {
err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
if (err)
goto err_pmu;
}
err = exclusive_event_init(event);
if (err)
goto err_pmu;
if (has_addr_filter(event)) {
event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
sizeof(struct perf_addr_filter_range),
GFP_KERNEL);
if (!event->addr_filter_ranges) {
err = -ENOMEM;
goto err_per_task;
}
/*
* Clone the parent's vma offsets: they are valid until exec()
* even if the mm is not shared with the parent.
*/
if (event->parent) {
struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
raw_spin_lock_irq(&ifh->lock);
memcpy(event->addr_filter_ranges,
event->parent->addr_filter_ranges,
pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
raw_spin_unlock_irq(&ifh->lock);
}
/* force hw sync on the address filters */
event->addr_filters_gen = 1;
}
if (!event->parent) {
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
err = get_callchain_buffers(attr->sample_max_stack);
if (err)
goto err_addr_filters;
}
}
err = security_perf_event_alloc(event);
if (err)
goto err_callchain_buffer;
/* symmetric to unaccount_event() in _free_event() */
account_event(event);
return event;
err_callchain_buffer:
if (!event->parent) {
if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
put_callchain_buffers();
}
err_addr_filters:
kfree(event->addr_filter_ranges);
err_per_task:
exclusive_event_destroy(event);
err_pmu:
if (is_cgroup_event(event))
perf_detach_cgroup(event);
if (event->destroy)
event->destroy(event);
module_put(pmu->module);
err_ns:
if (event->ns)
put_pid_ns(event->ns);
if (event->hw.target)
put_task_struct(event->hw.target);
kmem_cache_free(perf_event_cache, event);
return ERR_PTR(err);
}
static int perf_copy_attr(struct perf_event_attr __user *uattr,
struct perf_event_attr *attr)
{
u32 size;
int ret;
/* Zero the full structure, so that a short copy will be nice. */
memset(attr, 0, sizeof(*attr));
ret = get_user(size, &uattr->size);
if (ret)
return ret;
/* ABI compatibility quirk: */
if (!size)
size = PERF_ATTR_SIZE_VER0;
if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
goto err_size;
ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
if (ret) {
if (ret == -E2BIG)
goto err_size;
return ret;
}
attr->size = size;
if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
return -EINVAL;
if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
return -EINVAL;
if (attr->read_format & ~(PERF_FORMAT_MAX-1))
return -EINVAL;
if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
u64 mask = attr->branch_sample_type;
/* only using defined bits */
if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
return -EINVAL;
/* at least one branch bit must be set */
if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
return -EINVAL;
/* propagate priv level, when not set for branch */
if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
/* exclude_kernel checked on syscall entry */
if (!attr->exclude_kernel)
mask |= PERF_SAMPLE_BRANCH_KERNEL;
if (!attr->exclude_user)
mask |= PERF_SAMPLE_BRANCH_USER;
if (!attr->exclude_hv)
mask |= PERF_SAMPLE_BRANCH_HV;
/*
* adjust user setting (for HW filter setup)
*/
attr->branch_sample_type = mask;
}
/* privileged levels capture (kernel, hv): check permissions */
if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
ret = perf_allow_kernel(attr);
if (ret)
return ret;
}
}
if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
ret = perf_reg_validate(attr->sample_regs_user);
if (ret)
return ret;
}
if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
if (!arch_perf_have_user_stack_dump())
return -ENOSYS;
/*
* We have __u32 type for the size, but so far
* we can only use __u16 as maximum due to the
* __u16 sample size limit.
*/
if (attr->sample_stack_user >= USHRT_MAX)
return -EINVAL;
else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
return -EINVAL;
}
if (!attr->sample_max_stack)
attr->sample_max_stack = sysctl_perf_event_max_stack;
if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
ret = perf_reg_validate(attr->sample_regs_intr);
#ifndef CONFIG_CGROUP_PERF
if (attr->sample_type & PERF_SAMPLE_CGROUP)
return -EINVAL;
#endif
if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
(attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
return -EINVAL;
if (!attr->inherit && attr->inherit_thread)
return -EINVAL;
if (attr->remove_on_exec && attr->enable_on_exec)
return -EINVAL;
if (attr->sigtrap && !attr->remove_on_exec)
return -EINVAL;
out:
return ret;
err_size:
put_user(sizeof(*attr), &uattr->size);
ret = -E2BIG;
goto out;
}
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
{
struct perf_buffer *rb = NULL;
int ret = -EINVAL;
if (!output_event)
goto set;
/* don't allow circular references */
if (event == output_event)
goto out;
/*
* Don't allow cross-cpu buffers
*/
if (output_event->cpu != event->cpu)
goto out;
/*
* If its not a per-cpu rb, it must be the same task.
*/
if (output_event->cpu == -1 && output_event->ctx != event->ctx)
goto out;
/*
* Mixing clocks in the same buffer is trouble you don't need.
*/
if (output_event->clock != event->clock)
goto out;
/*
* Either writing ring buffer from beginning or from end.
* Mixing is not allowed.
*/
if (is_write_backward(output_event) != is_write_backward(event))
goto out;
/*
* If both events generate aux data, they must be on the same PMU
*/
if (has_aux(event) && has_aux(output_event) &&
event->pmu != output_event->pmu)
goto out;
set:
mutex_lock(&event->mmap_mutex);
/* Can't redirect output if we've got an active mmap() */
if (atomic_read(&event->mmap_count))
goto unlock;
if (output_event) {
/* get the rb we want to redirect to */
rb = ring_buffer_get(output_event);
if (!rb)
goto unlock;
}
ring_buffer_attach(event, rb);
ret = 0;
unlock:
mutex_unlock(&event->mmap_mutex);
out:
return ret;
}
static void mutex_lock_double(struct mutex *a, struct mutex *b)
{
if (b < a)
swap(a, b);
mutex_lock(a);
mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
}
static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
{
bool nmi_safe = false;
switch (clk_id) {
case CLOCK_MONOTONIC:
event->clock = &ktime_get_mono_fast_ns;
nmi_safe = true;
break;
case CLOCK_MONOTONIC_RAW:
event->clock = &ktime_get_raw_fast_ns;
nmi_safe = true;
break;
case CLOCK_REALTIME:
event->clock = &ktime_get_real_ns;
break;
case CLOCK_BOOTTIME:
event->clock = &ktime_get_boottime_ns;
break;
case CLOCK_TAI:
event->clock = &ktime_get_clocktai_ns;
break;
default:
return -EINVAL;
}
if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
return -EINVAL;
return 0;
}
/*
* Variation on perf_event_ctx_lock_nested(), except we take two context
* mutexes.
*/
static struct perf_event_context *
__perf_event_ctx_lock_double(struct perf_event *group_leader,
struct perf_event_context *ctx)
{
struct perf_event_context *gctx;
again:
rcu_read_lock();
gctx = READ_ONCE(group_leader->ctx);
if (!refcount_inc_not_zero(&gctx->refcount)) {
rcu_read_unlock();
goto again;
}
rcu_read_unlock();
mutex_lock_double(&gctx->mutex, &ctx->mutex);
if (group_leader->ctx != gctx) {
mutex_unlock(&ctx->mutex);
mutex_unlock(&gctx->mutex);
put_ctx(gctx);
goto again;
}
return gctx;
}
static bool
perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
{
unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
bool is_capable = perfmon_capable();
if (attr->sigtrap) {
/*
* perf_event_attr::sigtrap sends signals to the other task.
* Require the current task to also have CAP_KILL.
*/
rcu_read_lock();
is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
rcu_read_unlock();
/*
* If the required capabilities aren't available, checks for
* ptrace permissions: upgrade to ATTACH, since sending signals
* can effectively change the target task.
*/
ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
}
/*
* Preserve ptrace permission check for backwards compatibility. The
* ptrace check also includes checks that the current task and other
* task have matching uids, and is therefore not done here explicitly.
*/
return is_capable || ptrace_may_access(task, ptrace_mode);
}
/**
* sys_perf_event_open - open a performance event, associate it to a task/cpu
*
* @attr_uptr: event_id type attributes for monitoring/sampling
* @pid: target pid
* @cpu: target cpu
* @group_fd: group leader event fd
* @flags: perf event open flags
*/
SYSCALL_DEFINE5(perf_event_open,
struct perf_event_attr __user *, attr_uptr,
pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
{
struct perf_event *group_leader = NULL, *output_event = NULL;
struct perf_event *event, *sibling;
struct perf_event_attr attr;
struct perf_event_context *ctx, *gctx;
struct file *event_file = NULL;
struct fd group = {NULL, 0};
struct task_struct *task = NULL;
struct pmu *pmu;
int event_fd;
int move_group = 0;
int err;
int f_flags = O_RDWR;
int cgroup_fd = -1;
/* for future expandability... */
if (flags & ~PERF_FLAG_ALL)
return -EINVAL;
/* Do we allow access to perf_event_open(2) ? */
err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
if (err)
return err;
err = perf_copy_attr(attr_uptr, &attr);
if (err)
return err;
if (!attr.exclude_kernel) {
err = perf_allow_kernel(&attr);
if (err)
return err;
}
if (attr.namespaces) {
if (!perfmon_capable())
return -EACCES;
}
if (attr.freq) {
if (attr.sample_freq > sysctl_perf_event_sample_rate)
return -EINVAL;
} else {
if (attr.sample_period & (1ULL << 63))
return -EINVAL;
}
/* Only privileged users can get physical addresses */
if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
err = perf_allow_kernel(&attr);
if (err)
return err;
}
/* REGS_INTR can leak data, lockdown must prevent this */
if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
err = security_locked_down(LOCKDOWN_PERF);
if (err)
return err;
}
/*
* In cgroup mode, the pid argument is used to pass the fd
* opened to the cgroup directory in cgroupfs. The cpu argument
* designates the cpu on which to monitor threads from that
* cgroup.
*/
if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
return -EINVAL;
if (flags & PERF_FLAG_FD_CLOEXEC)
f_flags |= O_CLOEXEC;
event_fd = get_unused_fd_flags(f_flags);
if (event_fd < 0)
return event_fd;
if (group_fd != -1) {
err = perf_fget_light(group_fd, &group);
if (err)
goto err_fd;
group_leader = group.file->private_data;
if (flags & PERF_FLAG_FD_OUTPUT)
output_event = group_leader;
if (flags & PERF_FLAG_FD_NO_GROUP)
group_leader = NULL;
}
if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
task = find_lively_task_by_vpid(pid);
if (IS_ERR(task)) {
err = PTR_ERR(task);
goto err_group_fd;
}
}
if (task && group_leader &&
group_leader->attr.inherit != attr.inherit) {
err = -EINVAL;
goto err_task;
}
if (flags & PERF_FLAG_PID_CGROUP)
cgroup_fd = pid;
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
NULL, NULL, cgroup_fd);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err_task;
}
if (is_sampling_event(event)) {
if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
err = -EOPNOTSUPP;
goto err_alloc;
}
}
/*
* Special case software events and allow them to be part of
* any hardware group.
*/
pmu = event->pmu;
if (attr.use_clockid) {
err = perf_event_set_clock(event, attr.clockid);
if (err)
goto err_alloc;
}
if (pmu->task_ctx_nr == perf_sw_context)
event->event_caps |= PERF_EV_CAP_SOFTWARE;
if (group_leader) {
if (is_software_event(event) &&
!in_software_context(group_leader)) {
/*
* If the event is a sw event, but the group_leader
* is on hw context.
*
* Allow the addition of software events to hw
* groups, this is safe because software events
* never fail to schedule.
*/
pmu = group_leader->ctx->pmu;
} else if (!is_software_event(event) &&
is_software_event(group_leader) &&
(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
/*
* In case the group is a pure software group, and we
* try to add a hardware event, move the whole group to
* the hardware context.
*/
move_group = 1;
}
}
/*
* Get the target context (task or percpu):
*/
ctx = find_get_context(pmu, task, event);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto err_alloc;
}
/*
* Look up the group leader (we will attach this event to it):
*/
if (group_leader) {
err = -EINVAL;
/*
* Do not allow a recursive hierarchy (this new sibling
* becoming part of another group-sibling):
*/
if (group_leader->group_leader != group_leader)
goto err_context;
/* All events in a group should have the same clock */
if (group_leader->clock != event->clock)
goto err_context;
/*
* Make sure we're both events for the same CPU;
* grouping events for different CPUs is broken; since
* you can never concurrently schedule them anyhow.
*/
if (group_leader->cpu != event->cpu)
goto err_context;
/*
* Make sure we're both on the same task, or both
* per-CPU events.
*/
if (group_leader->ctx->task != ctx->task)
goto err_context;
/*
* Do not allow to attach to a group in a different task
* or CPU context. If we're moving SW events, we'll fix
* this up later, so allow that.
*/
if (!move_group && group_leader->ctx != ctx)
goto err_context;
/*
* Only a group leader can be exclusive or pinned
*/
if (attr.exclusive || attr.pinned)
goto err_context;
}
if (output_event) {
err = perf_event_set_output(event, output_event);
if (err)
goto err_context;
}
event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
f_flags);
if (IS_ERR(event_file)) {
err = PTR_ERR(event_file);
event_file = NULL;
goto err_context;
}
if (task) {
err = down_read_interruptible(&task->signal->exec_update_lock);
if (err)
goto err_file;
/*
* We must hold exec_update_lock across this and any potential
* perf_install_in_context() call for this new event to
* serialize against exec() altering our credentials (and the
* perf_event_exit_task() that could imply).
*/
err = -EACCES;
if (!perf_check_permission(&attr, task))
goto err_cred;
}
if (move_group) {
gctx = __perf_event_ctx_lock_double(group_leader, ctx);
if (gctx->task == TASK_TOMBSTONE) {
err = -ESRCH;
goto err_locked;
}
/*
* Check if we raced against another sys_perf_event_open() call
* moving the software group underneath us.
*/
if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
/*
* If someone moved the group out from under us, check
* if this new event wound up on the same ctx, if so
* its the regular !move_group case, otherwise fail.
*/
if (gctx != ctx) {
err = -EINVAL;
goto err_locked;
} else {
perf_event_ctx_unlock(group_leader, gctx);
move_group = 0;
}
}
/*
* Failure to create exclusive events returns -EBUSY.
*/
err = -EBUSY;
if (!exclusive_event_installable(group_leader, ctx))
goto err_locked;
for_each_sibling_event(sibling, group_leader) {
if (!exclusive_event_installable(sibling, ctx))
goto err_locked;
}
} else {
mutex_lock(&ctx->mutex);
}
if (ctx->task == TASK_TOMBSTONE) {
err = -ESRCH;
goto err_locked;
}
if (!perf_event_validate_size(event)) {
err = -E2BIG;
goto err_locked;
}
if (!task) {
/*
* Check if the @cpu we're creating an event for is online.
*
* We use the perf_cpu_context::ctx::mutex to serialize against
* the hotplug notifiers. See perf_event_{init,exit}_cpu().
*/
struct perf_cpu_context *cpuctx =
container_of(ctx, struct perf_cpu_context, ctx);
if (!cpuctx->online) {
err = -ENODEV;
goto err_locked;
}
}
if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
err = -EINVAL;
goto err_locked;
}
/*
* Must be under the same ctx::mutex as perf_install_in_context(),
* because we need to serialize with concurrent event creation.
*/
if (!exclusive_event_installable(event, ctx)) {
err = -EBUSY;
goto err_locked;
}
WARN_ON_ONCE(ctx->parent_ctx);
/*
* This is the point on no return; we cannot fail hereafter. This is
* where we start modifying current state.
*/
if (move_group) {
/*
* See perf_event_ctx_lock() for comments on the details
* of swizzling perf_event::ctx.
*/
perf_remove_from_context(group_leader, 0);
put_ctx(gctx);
for_each_sibling_event(sibling, group_leader) {
perf_remove_from_context(sibling, 0);
put_ctx(gctx);
}
/*
* Wait for everybody to stop referencing the events through
* the old lists, before installing it on new lists.
*/
synchronize_rcu();
/*
* Install the group siblings before the group leader.
*
* Because a group leader will try and install the entire group
* (through the sibling list, which is still in-tact), we can
* end up with siblings installed in the wrong context.
*
* By installing siblings first we NO-OP because they're not
* reachable through the group lists.
*/
for_each_sibling_event(sibling, group_leader) {
perf_event__state_init(sibling);
perf_install_in_context(ctx, sibling, sibling->cpu);
get_ctx(ctx);
}
/*
* Removing from the context ends up with disabled
* event. What we want here is event in the initial
* startup state, ready to be add into new context.
*/
perf_event__state_init(group_leader);
perf_install_in_context(ctx, group_leader, group_leader->cpu);
get_ctx(ctx);
}
/*
* Precalculate sample_data sizes; do while holding ctx::mutex such
* that we're serialized against further additions and before
* perf_install_in_context() which is the point the event is active and
* can use these values.
*/
perf_event__header_size(event);
perf_event__id_header_size(event);
event->owner = current;
perf_install_in_context(ctx, event, event->cpu);
perf_unpin_context(ctx);
if (move_group)
perf_event_ctx_unlock(group_leader, gctx);
mutex_unlock(&ctx->mutex);
if (task) {
up_read(&task->signal->exec_update_lock);
put_task_struct(task);
}
mutex_lock(&current->perf_event_mutex);
list_add_tail(&event->owner_entry, &current->perf_event_list);
mutex_unlock(&current->perf_event_mutex);
/*
* Drop the reference on the group_event after placing the
* new event on the sibling_list. This ensures destruction
* of the group leader will find the pointer to itself in
* perf_group_detach().
*/
fdput(group);
fd_install(event_fd, event_file);
return event_fd;
err_locked:
if (move_group)
perf_event_ctx_unlock(group_leader, gctx);
mutex_unlock(&ctx->mutex);
err_cred:
if (task)
up_read(&task->signal->exec_update_lock);
err_file:
fput(event_file);
err_context:
perf_unpin_context(ctx);
put_ctx(ctx);
err_alloc:
/*
* If event_file is set, the fput() above will have called ->release()
* and that will take care of freeing the event.
*/
if (!event_file)
free_event(event);
err_task:
if (task)
put_task_struct(task);
err_group_fd:
fdput(group);
err_fd:
put_unused_fd(event_fd);
return err;
}
/**
* perf_event_create_kernel_counter
*
* @attr: attributes of the counter to create
* @cpu: cpu in which the counter is bound
* @task: task to profile (NULL for percpu)
* @overflow_handler: callback to trigger when we hit the event
* @context: context data could be used in overflow_handler callback
*/
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
struct task_struct *task,
perf_overflow_handler_t overflow_handler,
void *context)
{
struct perf_event_context *ctx;
struct perf_event *event;
int err;
/*
* Grouping is not supported for kernel events, neither is 'AUX',
* make sure the caller's intentions are adjusted.
*/
if (attr->aux_output)
return ERR_PTR(-EINVAL);
event = perf_event_alloc(attr, cpu, task, NULL, NULL,
overflow_handler, context, -1);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err;
}
/* Mark owner so we could distinguish it from user events. */
event->owner = TASK_TOMBSTONE;
/*
* Get the target context (task or percpu):
*/
ctx = find_get_context(event->pmu, task, event);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto err_free;
}
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
if (ctx->task == TASK_TOMBSTONE) {
err = -ESRCH;
goto err_unlock;
}
if (!task) {
/*
* Check if the @cpu we're creating an event for is online.
*
* We use the perf_cpu_context::ctx::mutex to serialize against
* the hotplug notifiers. See perf_event_{init,exit}_cpu().
*/
struct perf_cpu_context *cpuctx =
container_of(ctx, struct perf_cpu_context, ctx);
if (!cpuctx->online) {
err = -ENODEV;
goto err_unlock;
}
}
if (!exclusive_event_installable(event, ctx)) {
err = -EBUSY;
goto err_unlock;
}
perf_install_in_context(ctx, event, event->cpu);
perf_unpin_context(ctx);
mutex_unlock(&ctx->mutex);
return event;
err_unlock:
mutex_unlock(&ctx->mutex);
perf_unpin_context(ctx);
put_ctx(ctx);
err_free:
free_event(event);
err:
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
{
struct perf_event_context *src_ctx;
struct perf_event_context *dst_ctx;
struct perf_event *event, *tmp;
LIST_HEAD(events);
src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
/*
* See perf_event_ctx_lock() for comments on the details
* of swizzling perf_event::ctx.
*/
mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
event_entry) {
perf_remove_from_context(event, 0);
unaccount_event_cpu(event, src_cpu);
put_ctx(src_ctx);
list_add(&event->migrate_entry, &events);
}
/*
* Wait for the events to quiesce before re-instating them.
*/
synchronize_rcu();
/*
* Re-instate events in 2 passes.
*
* Skip over group leaders and only install siblings on this first
* pass, siblings will not get enabled without a leader, however a
* leader will enable its siblings, even if those are still on the old
* context.
*/
list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
if (event->group_leader == event)
continue;
list_del(&event->migrate_entry);
if (event->state >= PERF_EVENT_STATE_OFF)
event->state = PERF_EVENT_STATE_INACTIVE;
account_event_cpu(event, dst_cpu);
perf_install_in_context(dst_ctx, event, dst_cpu);
get_ctx(dst_ctx);
}
/*
* Once all the siblings are setup properly, install the group leaders
* to make it go.
*/
list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
list_del(&event->migrate_entry);
if (event->state >= PERF_EVENT_STATE_OFF)
event->state = PERF_EVENT_STATE_INACTIVE;
account_event_cpu(event, dst_cpu);
perf_install_in_context(dst_ctx, event, dst_cpu);
get_ctx(dst_ctx);
}
mutex_unlock(&dst_ctx->mutex);
mutex_unlock(&src_ctx->mutex);
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
static void sync_child_event(struct perf_event *child_event)
{
struct perf_event *parent_event = child_event->parent;
u64 child_val;
if (child_event->attr.inherit_stat) {
struct task_struct *task = child_event->ctx->task;
if (task && task != TASK_TOMBSTONE)
perf_event_read_event(child_event, task);
}
child_val = perf_event_count(child_event);
/*
* Add back the child's count to the parent's count:
*/
atomic64_add(child_val, &parent_event->child_count);
atomic64_add(child_event->total_time_enabled,
&parent_event->child_total_time_enabled);
atomic64_add(child_event->total_time_running,
&parent_event->child_total_time_running);
}
static void
perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
{
struct perf_event *parent_event = event->parent;
unsigned long detach_flags = 0;
if (parent_event) {
/*
* Do not destroy the 'original' grouping; because of the
* context switch optimization the original events could've
* ended up in a random child task.
*
* If we were to destroy the original group, all group related
* operations would cease to function properly after this
* random child dies.
*
* Do destroy all inherited groups, we don't care about those
* and being thorough is better.
*/
detach_flags = DETACH_GROUP | DETACH_CHILD;
mutex_lock(&parent_event->child_mutex);
}
perf_remove_from_context(event, detach_flags);
raw_spin_lock_irq(&ctx->lock);
if (event->state > PERF_EVENT_STATE_EXIT)
perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
raw_spin_unlock_irq(&ctx->lock);
/*
* Child events can be freed.
*/
if (parent_event) {
mutex_unlock(&parent_event->child_mutex);
/*
* Kick perf_poll() for is_event_hup();
*/
perf_event_wakeup(parent_event);
free_event(event);
put_event(parent_event);
return;
}
/*
* Parent events are governed by their filedesc, retain them.
*/
perf_event_wakeup(event);
}
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
{
struct perf_event_context *child_ctx, *clone_ctx = NULL;
struct perf_event *child_event, *next;
WARN_ON_ONCE(child != current);
child_ctx = perf_pin_task_context(child, ctxn);
if (!child_ctx)
return;
/*
* In order to reduce the amount of tricky in ctx tear-down, we hold
* ctx::mutex over the entire thing. This serializes against almost
* everything that wants to access the ctx.
*
* The exception is sys_perf_event_open() /
* perf_event_create_kernel_count() which does find_get_context()
* without ctx::mutex (it cannot because of the move_group double mutex
* lock thing). See the comments in perf_install_in_context().
*/
mutex_lock(&child_ctx->mutex);
/*
* In a single ctx::lock section, de-schedule the events and detach the
* context from the task such that we cannot ever get it scheduled back
* in.
*/
raw_spin_lock_irq(&child_ctx->lock);
task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
/*
* Now that the context is inactive, destroy the task <-> ctx relation
* and mark the context dead.
*/
RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
put_ctx(child_ctx); /* cannot be last */
WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
put_task_struct(current); /* cannot be last */
clone_ctx = unclone_ctx(child_ctx);
raw_spin_unlock_irq(&child_ctx->lock);
if (clone_ctx)
put_ctx(clone_ctx);
/*
* Report the task dead after unscheduling the events so that we
* won't get any samples after PERF_RECORD_EXIT. We can however still
* get a few PERF_RECORD_READ events.
*/
perf_event_task(child, child_ctx, 0);
list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
perf_event_exit_event(child_event, child_ctx);
mutex_unlock(&child_ctx->mutex);
put_ctx(child_ctx);
}
/*
* When a child task exits, feed back event values to parent events.
*
* Can be called with exec_update_lock held when called from
* setup_new_exec().
*/
void perf_event_exit_task(struct task_struct *child)
{
struct perf_event *event, *tmp;
int ctxn;
mutex_lock(&child->perf_event_mutex);
list_for_each_entry_safe(event, tmp, &child->perf_event_list,
owner_entry) {
list_del_init(&event->owner_entry);
/*
* Ensure the list deletion is visible before we clear
* the owner, closes a race against perf_release() where
* we need to serialize on the owner->perf_event_mutex.
*/
smp_store_release(&event->owner, NULL);
}
mutex_unlock(&child->perf_event_mutex);
for_each_task_context_nr(ctxn)
perf_event_exit_task_context(child, ctxn);
/*
* The perf_event_exit_task_context calls perf_event_task
* with child's task_ctx, which generates EXIT events for
* child contexts and sets child->perf_event_ctxp[] to NULL.
* At this point we need to send EXIT events to cpu contexts.
*/
perf_event_task(child, NULL, 0);
}
static void perf_free_event(struct perf_event *event,
struct perf_event_context *ctx)
{
struct perf_event *parent = event->parent;
if (WARN_ON_ONCE(!parent))
return;
mutex_lock(&parent->child_mutex);
list_del_init(&event->child_list);
mutex_unlock(&parent->child_mutex);
put_event(parent);
raw_spin_lock_irq(&ctx->lock);
perf_group_detach(event);
list_del_event(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
free_event(event);
}
/*
* Free a context as created by inheritance by perf_event_init_task() below,
* used by fork() in case of fail.
*
* Even though the task has never lived, the context and events have been
* exposed through the child_list, so we must take care tearing it all down.
*/
void perf_event_free_task(struct task_struct *task)
{
struct perf_event_context *ctx;
struct perf_event *event, *tmp;
int ctxn;
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (!ctx)
continue;
mutex_lock(&ctx->mutex);
raw_spin_lock_irq(&ctx->lock);
/*
* Destroy the task <-> ctx relation and mark the context dead.
*
* This is important because even though the task hasn't been
* exposed yet the context has been (through child_list).
*/
RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
put_task_struct(task); /* cannot be last */
raw_spin_unlock_irq(&ctx->lock);
list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
perf_free_event(event, ctx);
mutex_unlock(&ctx->mutex);
/*
* perf_event_release_kernel() could've stolen some of our
* child events and still have them on its free_list. In that
* case we must wait for these events to have been freed (in
* particular all their references to this task must've been
* dropped).
*
* Without this copy_process() will unconditionally free this
* task (irrespective of its reference count) and
* _free_event()'s put_task_struct(event->hw.target) will be a
* use-after-free.
*
* Wait for all events to drop their context reference.
*/
wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
put_ctx(ctx); /* must be last */
}
}
void perf_event_delayed_put(struct task_struct *task)
{
int ctxn;
for_each_task_context_nr(ctxn)
WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
}
struct file *perf_event_get(unsigned int fd)
{
struct file *file = fget(fd);
if (!file)
return ERR_PTR(-EBADF);
if (file->f_op != &perf_fops) {
fput(file);
return ERR_PTR(-EBADF);
}
return file;
}
const struct perf_event *perf_get_event(struct file *file)
{
if (file->f_op != &perf_fops)
return ERR_PTR(-EINVAL);
return file->private_data;
}
const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
{
if (!event)
return ERR_PTR(-EINVAL);
return &event->attr;
}
/*
* Inherit an event from parent task to child task.
*
* Returns:
* - valid pointer on success
* - NULL for orphaned events
* - IS_ERR() on error
*/
static struct perf_event *
inherit_event(struct perf_event *parent_event,
struct task_struct *parent,
struct perf_event_context *parent_ctx,
struct task_struct *child,
struct perf_event *group_leader,
struct perf_event_context *child_ctx)
{
enum perf_event_state parent_state = parent_event->state;
struct perf_event *child_event;
unsigned long flags;
/*
* Instead of creating recursive hierarchies of events,
* we link inherited events back to the original parent,
* which has a filp for sure, which we use as the reference
* count:
*/
if (parent_event->parent)
parent_event = parent_event->parent;
child_event = perf_event_alloc(&parent_event->attr,
parent_event->cpu,
child,
group_leader, parent_event,
NULL, NULL, -1);
if (IS_ERR(child_event))
return child_event;
if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
!child_ctx->task_ctx_data) {
struct pmu *pmu = child_event->pmu;
child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
if (!child_ctx->task_ctx_data) {
free_event(child_event);
return ERR_PTR(-ENOMEM);
}
}
/*
* is_orphaned_event() and list_add_tail(&parent_event->child_list)
* must be under the same lock in order to serialize against
* perf_event_release_kernel(), such that either we must observe
* is_orphaned_event() or they will observe us on the child_list.
*/
mutex_lock(&parent_event->child_mutex);
if (is_orphaned_event(parent_event) ||
!atomic_long_inc_not_zero(&parent_event->refcount)) {
mutex_unlock(&parent_event->child_mutex);
/* task_ctx_data is freed with child_ctx */
free_event(child_event);
return NULL;
}
get_ctx(child_ctx);
/*
* Make the child state follow the state of the parent event,
* not its attr.disabled bit. We hold the parent's mutex,
* so we won't race with perf_event_{en, dis}able_family.
*/
if (parent_state >= PERF_EVENT_STATE_INACTIVE)
child_event->state = PERF_EVENT_STATE_INACTIVE;
else
child_event->state = PERF_EVENT_STATE_OFF;
if (parent_event->attr.freq) {
u64 sample_period = parent_event->hw.sample_period;
struct hw_perf_event *hwc = &child_event->hw;
hwc->sample_period = sample_period;
hwc->last_period = sample_period;
local64_set(&hwc->period_left, sample_period);
}
child_event->ctx = child_ctx;
child_event->overflow_handler = parent_event->overflow_handler;
child_event->overflow_handler_context
= parent_event->overflow_handler_context;
/*
* Precalculate sample_data sizes
*/
perf_event__header_size(child_event);
perf_event__id_header_size(child_event);
/*
* Link it up in the child's context:
*/
raw_spin_lock_irqsave(&child_ctx->lock, flags);
add_event_to_ctx(child_event, child_ctx);
child_event->attach_state |= PERF_ATTACH_CHILD;
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
/*
* Link this into the parent event's child list
*/
list_add_tail(&child_event->child_list, &parent_event->child_list);
mutex_unlock(&parent_event->child_mutex);
return child_event;
}
/*
* Inherits an event group.
*
* This will quietly suppress orphaned events; !inherit_event() is not an error.
* This matches with perf_event_release_kernel() removing all child events.
*
* Returns:
* - 0 on success
* - <0 on error
*/
static int inherit_group(struct perf_event *parent_event,
struct task_struct *parent,
struct perf_event_context *parent_ctx,
struct task_struct *child,
struct perf_event_context *child_ctx)
{
struct perf_event *leader;
struct perf_event *sub;
struct perf_event *child_ctr;
leader = inherit_event(parent_event, parent, parent_ctx,
child, NULL, child_ctx);
if (IS_ERR(leader))
return PTR_ERR(leader);
/*
* @leader can be NULL here because of is_orphaned_event(). In this
* case inherit_event() will create individual events, similar to what
* perf_group_detach() would do anyway.
*/
for_each_sibling_event(sub, parent_event) {
child_ctr = inherit_event(sub, parent, parent_ctx,
child, leader, child_ctx);
if (IS_ERR(child_ctr))
return PTR_ERR(child_ctr);
if (sub->aux_event == parent_event && child_ctr &&
!perf_get_aux_event(child_ctr, leader))
return -EINVAL;
}
return 0;
}
/*
* Creates the child task context and tries to inherit the event-group.
*
* Clears @inherited_all on !attr.inherited or error. Note that we'll leave
* inherited_all set when we 'fail' to inherit an orphaned event; this is
* consistent with perf_event_release_kernel() removing all child events.
*
* Returns:
* - 0 on success
* - <0 on error
*/
static int
inherit_task_group(struct perf_event *event, struct task_struct *parent,
struct perf_event_context *parent_ctx,
struct task_struct *child, int ctxn,
u64 clone_flags, int *inherited_all)
{
int ret;
struct perf_event_context *child_ctx;
if (!event->attr.inherit ||
(event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
/* Do not inherit if sigtrap and signal handlers were cleared. */
(event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
*inherited_all = 0;
return 0;
}
child_ctx = child->perf_event_ctxp[ctxn];
if (!child_ctx) {
/*
* This is executed from the parent task context, so
* inherit events that have been marked for cloning.
* First allocate and initialize a context for the
* child.
*/
child_ctx = alloc_perf_context(parent_ctx->pmu, child);
if (!child_ctx)
return -ENOMEM;
child->perf_event_ctxp[ctxn] = child_ctx;
}
ret = inherit_group(event, parent, parent_ctx,
child, child_ctx);
if (ret)
*inherited_all = 0;
return ret;
}
/*
* Initialize the perf_event context in task_struct
*/
static int perf_event_init_context(struct task_struct *child, int ctxn,
u64 clone_flags)
{
struct perf_event_context *child_ctx, *parent_ctx;
struct perf_event_context *cloned_ctx;
struct perf_event *event;
struct task_struct *parent = current;
int inherited_all = 1;
unsigned long flags;
int ret = 0;
if (likely(!parent->perf_event_ctxp[ctxn]))
return 0;
/*
* If the parent's context is a clone, pin it so it won't get
* swapped under us.
*/
parent_ctx = perf_pin_task_context(parent, ctxn);
if (!parent_ctx)
return 0;
/*
* No need to check if parent_ctx != NULL here; since we saw
* it non-NULL earlier, the only reason for it to become NULL
* is if we exit, and since we're currently in the middle of
* a fork we can't be exiting at the same time.
*/
/*
* Lock the parent list. No need to lock the child - not PID
* hashed yet and not running, so nobody can access it.
*/
mutex_lock(&parent_ctx->mutex);
/*
* We dont have to disable NMIs - we are only looking at
* the list, not manipulating it:
*/
perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, clone_flags,
&inherited_all);
if (ret)
goto out_unlock;
}
/*
* We can't hold ctx->lock when iterating the ->flexible_group list due
* to allocations, but we need to prevent rotation because
* rotate_ctx() will change the list from interrupt context.
*/
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
parent_ctx->rotate_disable = 1;
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, clone_flags,
&inherited_all);
if (ret)
goto out_unlock;
}
raw_spin_lock_irqsave(&parent_ctx->lock, flags);
parent_ctx->rotate_disable = 0;
child_ctx = child->perf_event_ctxp[ctxn];
if (child_ctx && inherited_all) {
/*
* Mark the child context as a clone of the parent
* context, or of whatever the parent is a clone of.
*
* Note that if the parent is a clone, the holding of
* parent_ctx->lock avoids it from being uncloned.
*/
cloned_ctx = parent_ctx->parent_ctx;
if (cloned_ctx) {
child_ctx->parent_ctx = cloned_ctx;
child_ctx->parent_gen = parent_ctx->parent_gen;
} else {
child_ctx->parent_ctx = parent_ctx;
child_ctx->parent_gen = parent_ctx->generation;
}
get_ctx(child_ctx->parent_ctx);
}
raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
out_unlock:
mutex_unlock(&parent_ctx->mutex);
perf_unpin_context(parent_ctx);
put_ctx(parent_ctx);
return ret;
}
/*
* Initialize the perf_event context in task_struct
*/
int perf_event_init_task(struct task_struct *child, u64 clone_flags)
{
int ctxn, ret;
memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
mutex_init(&child->perf_event_mutex);
INIT_LIST_HEAD(&child->perf_event_list);
for_each_task_context_nr(ctxn) {
ret = perf_event_init_context(child, ctxn, clone_flags);
if (ret) {
perf_event_free_task(child);
return ret;
}
}
return 0;
}
static void __init perf_event_init_all_cpus(void)
{
struct swevent_htable *swhash;
int cpu;
zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
for_each_possible_cpu(cpu) {
swhash = &per_cpu(swevent_htable, cpu);
mutex_init(&swhash->hlist_mutex);
INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
#ifdef CONFIG_CGROUP_PERF
INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
#endif
INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
}
}
static void perf_swevent_init_cpu(unsigned int cpu)
{
struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
mutex_lock(&swhash->hlist_mutex);
if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
struct swevent_hlist *hlist;
hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
WARN_ON(!hlist);
rcu_assign_pointer(swhash->swevent_hlist, hlist);
}
mutex_unlock(&swhash->hlist_mutex);
}
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
static void __perf_event_exit_context(void *__info)
{
struct perf_event_context *ctx = __info;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct perf_event *event;
raw_spin_lock(&ctx->lock);
ctx_sched_out(ctx, cpuctx, EVENT_TIME);
list_for_each_entry(event, &ctx->event_list, event_entry)
__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
raw_spin_unlock(&ctx->lock);
}
static void perf_event_exit_cpu_context(int cpu)
{
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
struct pmu *pmu;
mutex_lock(&pmus_lock);
list_for_each_entry(pmu, &pmus, entry) {
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
ctx = &cpuctx->ctx;
mutex_lock(&ctx->mutex);
smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
cpuctx->online = 0;
mutex_unlock(&ctx->mutex);
}
cpumask_clear_cpu(cpu, perf_online_mask);
mutex_unlock(&pmus_lock);
}
#else
static void perf_event_exit_cpu_context(int cpu) { }
#endif
int perf_event_init_cpu(unsigned int cpu)
{
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
struct pmu *pmu;
perf_swevent_init_cpu(cpu);
mutex_lock(&pmus_lock);
cpumask_set_cpu(cpu, perf_online_mask);
list_for_each_entry(pmu, &pmus, entry) {
cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
ctx = &cpuctx->ctx;
mutex_lock(&ctx->mutex);
cpuctx->online = 1;
mutex_unlock(&ctx->mutex);
}
mutex_unlock(&pmus_lock);
return 0;
}
int perf_event_exit_cpu(unsigned int cpu)
{
perf_event_exit_cpu_context(cpu);
return 0;
}
static int
perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
{
int cpu;
for_each_online_cpu(cpu)
perf_event_exit_cpu(cpu);
return NOTIFY_OK;
}
/*
* Run the perf reboot notifier at the very last possible moment so that
* the generic watchdog code runs as long as possible.
*/
static struct notifier_block perf_reboot_notifier = {
.notifier_call = perf_reboot,
.priority = INT_MIN,
};
void __init perf_event_init(void)
{
int ret;
idr_init(&pmu_idr);
perf_event_init_all_cpus();
init_srcu_struct(&pmus_srcu);
perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
perf_pmu_register(&perf_cpu_clock, NULL, -1);
perf_pmu_register(&perf_task_clock, NULL, -1);
perf_tp_register();
perf_event_init_cpu(smp_processor_id());
register_reboot_notifier(&perf_reboot_notifier);
ret = init_hw_breakpoint();
WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
/*
* Build time assertion that we keep the data_head at the intended
* location. IOW, validation we got the __reserved[] size right.
*/
BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
!= 1024);
}
ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
char *page)
{
struct perf_pmu_events_attr *pmu_attr =
container_of(attr, struct perf_pmu_events_attr, attr);
if (pmu_attr->event_str)
return sprintf(page, "%s\n", pmu_attr->event_str);
return 0;
}
EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
static int __init perf_event_sysfs_init(void)
{
struct pmu *pmu;
int ret;
mutex_lock(&pmus_lock);
ret = bus_register(&pmu_bus);
if (ret)
goto unlock;
list_for_each_entry(pmu, &pmus, entry) {
if (!pmu->name || pmu->type < 0)
continue;
ret = pmu_dev_alloc(pmu);
WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
}
pmu_bus_running = 1;
ret = 0;
unlock:
mutex_unlock(&pmus_lock);
return ret;
}
device_initcall(perf_event_sysfs_init);
#ifdef CONFIG_CGROUP_PERF
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct perf_cgroup *jc;
jc = kzalloc(sizeof(*jc), GFP_KERNEL);
if (!jc)
return ERR_PTR(-ENOMEM);
jc->info = alloc_percpu(struct perf_cgroup_info);
if (!jc->info) {
kfree(jc);
return ERR_PTR(-ENOMEM);
}
return &jc->css;
}
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
{
struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
free_percpu(jc->info);
kfree(jc);
}
static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
{
perf_event_cgroup(css->cgroup);
return 0;
}
static int __perf_cgroup_move(void *info)
{
struct task_struct *task = info;
rcu_read_lock();
perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
rcu_read_unlock();
return 0;
}
static void perf_cgroup_attach(struct cgroup_taskset *tset)
{
struct task_struct *task;
struct cgroup_subsys_state *css;
cgroup_taskset_for_each(task, css, tset)
task_function_call(task, __perf_cgroup_move, task);
}
struct cgroup_subsys perf_event_cgrp_subsys = {
.css_alloc = perf_cgroup_css_alloc,
.css_free = perf_cgroup_css_free,
.css_online = perf_cgroup_css_online,
.attach = perf_cgroup_attach,
/*
* Implicitly enable on dfl hierarchy so that perf events can
* always be filtered by cgroup2 path as long as perf_event
* controller is not mounted on a legacy hierarchy.
*/
.implicit_on_dfl = true,
.threaded = true,
};
#endif /* CONFIG_CGROUP_PERF */
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