367 строки
8.4 KiB
C
367 строки
8.4 KiB
C
#include <linux/errno.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/module.h>
|
|
#include <linux/pm.h>
|
|
#include <linux/clockchips.h>
|
|
#include <asm/system.h>
|
|
|
|
unsigned long idle_halt;
|
|
EXPORT_SYMBOL(idle_halt);
|
|
unsigned long idle_nomwait;
|
|
EXPORT_SYMBOL(idle_nomwait);
|
|
|
|
struct kmem_cache *task_xstate_cachep;
|
|
static int force_mwait __cpuinitdata;
|
|
|
|
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
|
|
{
|
|
*dst = *src;
|
|
if (src->thread.xstate) {
|
|
dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
|
|
GFP_KERNEL);
|
|
if (!dst->thread.xstate)
|
|
return -ENOMEM;
|
|
WARN_ON((unsigned long)dst->thread.xstate & 15);
|
|
memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void free_thread_xstate(struct task_struct *tsk)
|
|
{
|
|
if (tsk->thread.xstate) {
|
|
kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
|
|
tsk->thread.xstate = NULL;
|
|
}
|
|
}
|
|
|
|
void free_thread_info(struct thread_info *ti)
|
|
{
|
|
free_thread_xstate(ti->task);
|
|
free_pages((unsigned long)ti, get_order(THREAD_SIZE));
|
|
}
|
|
|
|
void arch_task_cache_init(void)
|
|
{
|
|
task_xstate_cachep =
|
|
kmem_cache_create("task_xstate", xstate_size,
|
|
__alignof__(union thread_xstate),
|
|
SLAB_PANIC, NULL);
|
|
}
|
|
|
|
/*
|
|
* Idle related variables and functions
|
|
*/
|
|
unsigned long boot_option_idle_override = 0;
|
|
EXPORT_SYMBOL(boot_option_idle_override);
|
|
|
|
/*
|
|
* Powermanagement idle function, if any..
|
|
*/
|
|
void (*pm_idle)(void);
|
|
EXPORT_SYMBOL(pm_idle);
|
|
|
|
#ifdef CONFIG_X86_32
|
|
/*
|
|
* This halt magic was a workaround for ancient floppy DMA
|
|
* wreckage. It should be safe to remove.
|
|
*/
|
|
static int hlt_counter;
|
|
void disable_hlt(void)
|
|
{
|
|
hlt_counter++;
|
|
}
|
|
EXPORT_SYMBOL(disable_hlt);
|
|
|
|
void enable_hlt(void)
|
|
{
|
|
hlt_counter--;
|
|
}
|
|
EXPORT_SYMBOL(enable_hlt);
|
|
|
|
static inline int hlt_use_halt(void)
|
|
{
|
|
return (!hlt_counter && boot_cpu_data.hlt_works_ok);
|
|
}
|
|
#else
|
|
static inline int hlt_use_halt(void)
|
|
{
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* We use this if we don't have any better
|
|
* idle routine..
|
|
*/
|
|
void default_idle(void)
|
|
{
|
|
if (hlt_use_halt()) {
|
|
current_thread_info()->status &= ~TS_POLLING;
|
|
/*
|
|
* TS_POLLING-cleared state must be visible before we
|
|
* test NEED_RESCHED:
|
|
*/
|
|
smp_mb();
|
|
|
|
if (!need_resched())
|
|
safe_halt(); /* enables interrupts racelessly */
|
|
else
|
|
local_irq_enable();
|
|
current_thread_info()->status |= TS_POLLING;
|
|
} else {
|
|
local_irq_enable();
|
|
/* loop is done by the caller */
|
|
cpu_relax();
|
|
}
|
|
}
|
|
#ifdef CONFIG_APM_MODULE
|
|
EXPORT_SYMBOL(default_idle);
|
|
#endif
|
|
|
|
static void do_nothing(void *unused)
|
|
{
|
|
}
|
|
|
|
/*
|
|
* cpu_idle_wait - Used to ensure that all the CPUs discard old value of
|
|
* pm_idle and update to new pm_idle value. Required while changing pm_idle
|
|
* handler on SMP systems.
|
|
*
|
|
* Caller must have changed pm_idle to the new value before the call. Old
|
|
* pm_idle value will not be used by any CPU after the return of this function.
|
|
*/
|
|
void cpu_idle_wait(void)
|
|
{
|
|
smp_mb();
|
|
/* kick all the CPUs so that they exit out of pm_idle */
|
|
smp_call_function(do_nothing, NULL, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_idle_wait);
|
|
|
|
/*
|
|
* This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
|
|
* which can obviate IPI to trigger checking of need_resched.
|
|
* We execute MONITOR against need_resched and enter optimized wait state
|
|
* through MWAIT. Whenever someone changes need_resched, we would be woken
|
|
* up from MWAIT (without an IPI).
|
|
*
|
|
* New with Core Duo processors, MWAIT can take some hints based on CPU
|
|
* capability.
|
|
*/
|
|
void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
|
|
{
|
|
if (!need_resched()) {
|
|
__monitor((void *)¤t_thread_info()->flags, 0, 0);
|
|
smp_mb();
|
|
if (!need_resched())
|
|
__mwait(ax, cx);
|
|
}
|
|
}
|
|
|
|
/* Default MONITOR/MWAIT with no hints, used for default C1 state */
|
|
static void mwait_idle(void)
|
|
{
|
|
if (!need_resched()) {
|
|
__monitor((void *)¤t_thread_info()->flags, 0, 0);
|
|
smp_mb();
|
|
if (!need_resched())
|
|
__sti_mwait(0, 0);
|
|
else
|
|
local_irq_enable();
|
|
} else
|
|
local_irq_enable();
|
|
}
|
|
|
|
/*
|
|
* On SMP it's slightly faster (but much more power-consuming!)
|
|
* to poll the ->work.need_resched flag instead of waiting for the
|
|
* cross-CPU IPI to arrive. Use this option with caution.
|
|
*/
|
|
static void poll_idle(void)
|
|
{
|
|
local_irq_enable();
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* mwait selection logic:
|
|
*
|
|
* It depends on the CPU. For AMD CPUs that support MWAIT this is
|
|
* wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings
|
|
* then depend on a clock divisor and current Pstate of the core. If
|
|
* all cores of a processor are in halt state (C1) the processor can
|
|
* enter the C1E (C1 enhanced) state. If mwait is used this will never
|
|
* happen.
|
|
*
|
|
* idle=mwait overrides this decision and forces the usage of mwait.
|
|
*/
|
|
static int __cpuinitdata force_mwait;
|
|
|
|
#define MWAIT_INFO 0x05
|
|
#define MWAIT_ECX_EXTENDED_INFO 0x01
|
|
#define MWAIT_EDX_C1 0xf0
|
|
|
|
static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
|
|
{
|
|
u32 eax, ebx, ecx, edx;
|
|
|
|
if (force_mwait)
|
|
return 1;
|
|
|
|
if (c->cpuid_level < MWAIT_INFO)
|
|
return 0;
|
|
|
|
cpuid(MWAIT_INFO, &eax, &ebx, &ecx, &edx);
|
|
/* Check, whether EDX has extended info about MWAIT */
|
|
if (!(ecx & MWAIT_ECX_EXTENDED_INFO))
|
|
return 1;
|
|
|
|
/*
|
|
* edx enumeratios MONITOR/MWAIT extensions. Check, whether
|
|
* C1 supports MWAIT
|
|
*/
|
|
return (edx & MWAIT_EDX_C1);
|
|
}
|
|
|
|
/*
|
|
* Check for AMD CPUs, which have potentially C1E support
|
|
*/
|
|
static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
|
|
{
|
|
if (c->x86_vendor != X86_VENDOR_AMD)
|
|
return 0;
|
|
|
|
if (c->x86 < 0x0F)
|
|
return 0;
|
|
|
|
/* Family 0x0f models < rev F do not have C1E */
|
|
if (c->x86 == 0x0f && c->x86_model < 0x40)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* C1E aware idle routine. We check for C1E active in the interrupt
|
|
* pending message MSR. If we detect C1E, then we handle it the same
|
|
* way as C3 power states (local apic timer and TSC stop)
|
|
*/
|
|
static void c1e_idle(void)
|
|
{
|
|
static cpumask_t c1e_mask = CPU_MASK_NONE;
|
|
static int c1e_detected;
|
|
|
|
if (need_resched())
|
|
return;
|
|
|
|
if (!c1e_detected) {
|
|
u32 lo, hi;
|
|
|
|
rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
|
|
if (lo & K8_INTP_C1E_ACTIVE_MASK) {
|
|
c1e_detected = 1;
|
|
mark_tsc_unstable("TSC halt in C1E");
|
|
printk(KERN_INFO "System has C1E enabled\n");
|
|
}
|
|
}
|
|
|
|
if (c1e_detected) {
|
|
int cpu = smp_processor_id();
|
|
|
|
if (!cpu_isset(cpu, c1e_mask)) {
|
|
cpu_set(cpu, c1e_mask);
|
|
/*
|
|
* Force broadcast so ACPI can not interfere. Needs
|
|
* to run with interrupts enabled as it uses
|
|
* smp_function_call.
|
|
*/
|
|
local_irq_enable();
|
|
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
|
|
&cpu);
|
|
printk(KERN_INFO "Switch to broadcast mode on CPU%d\n",
|
|
cpu);
|
|
local_irq_disable();
|
|
}
|
|
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
|
|
|
|
default_idle();
|
|
|
|
/*
|
|
* The switch back from broadcast mode needs to be
|
|
* called with interrupts disabled.
|
|
*/
|
|
local_irq_disable();
|
|
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
|
|
local_irq_enable();
|
|
} else
|
|
default_idle();
|
|
}
|
|
|
|
void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
|
|
{
|
|
#ifdef CONFIG_X86_SMP
|
|
if (pm_idle == poll_idle && smp_num_siblings > 1) {
|
|
printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
|
|
" performance may degrade.\n");
|
|
}
|
|
#endif
|
|
if (pm_idle)
|
|
return;
|
|
|
|
if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
|
|
/*
|
|
* One CPU supports mwait => All CPUs supports mwait
|
|
*/
|
|
printk(KERN_INFO "using mwait in idle threads.\n");
|
|
pm_idle = mwait_idle;
|
|
} else if (check_c1e_idle(c)) {
|
|
printk(KERN_INFO "using C1E aware idle routine\n");
|
|
pm_idle = c1e_idle;
|
|
} else
|
|
pm_idle = default_idle;
|
|
}
|
|
|
|
static int __init idle_setup(char *str)
|
|
{
|
|
if (!str)
|
|
return -EINVAL;
|
|
|
|
if (!strcmp(str, "poll")) {
|
|
printk("using polling idle threads.\n");
|
|
pm_idle = poll_idle;
|
|
} else if (!strcmp(str, "mwait"))
|
|
force_mwait = 1;
|
|
else if (!strcmp(str, "halt")) {
|
|
/*
|
|
* When the boot option of idle=halt is added, halt is
|
|
* forced to be used for CPU idle. In such case CPU C2/C3
|
|
* won't be used again.
|
|
* To continue to load the CPU idle driver, don't touch
|
|
* the boot_option_idle_override.
|
|
*/
|
|
pm_idle = default_idle;
|
|
idle_halt = 1;
|
|
return 0;
|
|
} else if (!strcmp(str, "nomwait")) {
|
|
/*
|
|
* If the boot option of "idle=nomwait" is added,
|
|
* it means that mwait will be disabled for CPU C2/C3
|
|
* states. In such case it won't touch the variable
|
|
* of boot_option_idle_override.
|
|
*/
|
|
idle_nomwait = 1;
|
|
return 0;
|
|
} else
|
|
return -1;
|
|
|
|
boot_option_idle_override = 1;
|
|
return 0;
|
|
}
|
|
early_param("idle", idle_setup);
|
|
|