479 строки
12 KiB
C
479 строки
12 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2005
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* Jeff Muizelaar, 2006, 2007
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* Pekka Paalanen, 2008 <pq@iki.fi>
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*
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* Derived from the read-mod example from relay-examples by Tom Zanussi.
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*/
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#define pr_fmt(fmt) "mmiotrace: " fmt
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#define DEBUG 1
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#include <linux/moduleparam.h>
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#include <linux/debugfs.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/kallsyms.h>
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#include <asm/pgtable.h>
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#include <linux/mmiotrace.h>
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#include <asm/e820/api.h> /* for ISA_START_ADDRESS */
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#include <linux/atomic.h>
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#include <linux/percpu.h>
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#include <linux/cpu.h>
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#include "pf_in.h"
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struct trap_reason {
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unsigned long addr;
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unsigned long ip;
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enum reason_type type;
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int active_traces;
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};
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struct remap_trace {
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struct list_head list;
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struct kmmio_probe probe;
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resource_size_t phys;
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unsigned long id;
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};
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/* Accessed per-cpu. */
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static DEFINE_PER_CPU(struct trap_reason, pf_reason);
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static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
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static DEFINE_MUTEX(mmiotrace_mutex);
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static DEFINE_SPINLOCK(trace_lock);
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static atomic_t mmiotrace_enabled;
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static LIST_HEAD(trace_list); /* struct remap_trace */
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/*
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* Locking in this file:
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* - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections.
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* - mmiotrace_enabled may be modified only when holding mmiotrace_mutex
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* and trace_lock.
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* - Routines depending on is_enabled() must take trace_lock.
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* - trace_list users must hold trace_lock.
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* - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
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* - pre/post callbacks assume the effect of is_enabled() being true.
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*/
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/* module parameters */
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static unsigned long filter_offset;
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static bool nommiotrace;
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static bool trace_pc;
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module_param(filter_offset, ulong, 0);
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module_param(nommiotrace, bool, 0);
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module_param(trace_pc, bool, 0);
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MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
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MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
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MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
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static bool is_enabled(void)
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{
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return atomic_read(&mmiotrace_enabled);
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}
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static void print_pte(unsigned long address)
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{
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unsigned int level;
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pte_t *pte = lookup_address(address, &level);
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if (!pte) {
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pr_err("Error in %s: no pte for page 0x%08lx\n",
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__func__, address);
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return;
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}
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if (level == PG_LEVEL_2M) {
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pr_emerg("4MB pages are not currently supported: 0x%08lx\n",
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address);
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BUG();
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}
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pr_info("pte for 0x%lx: 0x%llx 0x%llx\n",
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address,
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(unsigned long long)pte_val(*pte),
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(unsigned long long)pte_val(*pte) & _PAGE_PRESENT);
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}
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/*
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* For some reason the pre/post pairs have been called in an
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* unmatched order. Report and die.
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*/
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static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
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{
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const struct trap_reason *my_reason = &get_cpu_var(pf_reason);
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pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
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addr, my_reason->addr);
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print_pte(addr);
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print_symbol(KERN_EMERG "faulting IP is at %s\n", regs->ip);
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print_symbol(KERN_EMERG "last faulting IP was at %s\n", my_reason->ip);
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#ifdef __i386__
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pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
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regs->ax, regs->bx, regs->cx, regs->dx);
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pr_emerg("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
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regs->si, regs->di, regs->bp, regs->sp);
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#else
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pr_emerg("rax: %016lx rcx: %016lx rdx: %016lx\n",
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regs->ax, regs->cx, regs->dx);
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pr_emerg("rsi: %016lx rdi: %016lx rbp: %016lx rsp: %016lx\n",
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regs->si, regs->di, regs->bp, regs->sp);
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#endif
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put_cpu_var(pf_reason);
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BUG();
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}
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static void pre(struct kmmio_probe *p, struct pt_regs *regs,
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unsigned long addr)
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{
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struct trap_reason *my_reason = &get_cpu_var(pf_reason);
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struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
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const unsigned long instptr = instruction_pointer(regs);
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const enum reason_type type = get_ins_type(instptr);
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struct remap_trace *trace = p->private;
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/* it doesn't make sense to have more than one active trace per cpu */
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if (my_reason->active_traces)
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die_kmmio_nesting_error(regs, addr);
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else
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my_reason->active_traces++;
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my_reason->type = type;
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my_reason->addr = addr;
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my_reason->ip = instptr;
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my_trace->phys = addr - trace->probe.addr + trace->phys;
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my_trace->map_id = trace->id;
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/*
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* Only record the program counter when requested.
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* It may taint clean-room reverse engineering.
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*/
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if (trace_pc)
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my_trace->pc = instptr;
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else
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my_trace->pc = 0;
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/*
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* XXX: the timestamp recorded will be *after* the tracing has been
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* done, not at the time we hit the instruction. SMP implications
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* on event ordering?
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*/
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switch (type) {
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case REG_READ:
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my_trace->opcode = MMIO_READ;
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my_trace->width = get_ins_mem_width(instptr);
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break;
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case REG_WRITE:
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my_trace->opcode = MMIO_WRITE;
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my_trace->width = get_ins_mem_width(instptr);
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my_trace->value = get_ins_reg_val(instptr, regs);
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break;
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case IMM_WRITE:
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my_trace->opcode = MMIO_WRITE;
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my_trace->width = get_ins_mem_width(instptr);
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my_trace->value = get_ins_imm_val(instptr);
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break;
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default:
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{
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unsigned char *ip = (unsigned char *)instptr;
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my_trace->opcode = MMIO_UNKNOWN_OP;
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my_trace->width = 0;
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my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
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*(ip + 2);
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}
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}
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put_cpu_var(cpu_trace);
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put_cpu_var(pf_reason);
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}
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static void post(struct kmmio_probe *p, unsigned long condition,
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struct pt_regs *regs)
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{
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struct trap_reason *my_reason = &get_cpu_var(pf_reason);
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struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
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/* this should always return the active_trace count to 0 */
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my_reason->active_traces--;
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if (my_reason->active_traces) {
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pr_emerg("unexpected post handler");
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BUG();
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}
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switch (my_reason->type) {
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case REG_READ:
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my_trace->value = get_ins_reg_val(my_reason->ip, regs);
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break;
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default:
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break;
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}
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mmio_trace_rw(my_trace);
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put_cpu_var(cpu_trace);
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put_cpu_var(pf_reason);
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}
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static void ioremap_trace_core(resource_size_t offset, unsigned long size,
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void __iomem *addr)
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{
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static atomic_t next_id;
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struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
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/* These are page-unaligned. */
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struct mmiotrace_map map = {
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.phys = offset,
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.virt = (unsigned long)addr,
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.len = size,
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.opcode = MMIO_PROBE
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};
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if (!trace) {
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pr_err("kmalloc failed in ioremap\n");
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return;
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}
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*trace = (struct remap_trace) {
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.probe = {
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.addr = (unsigned long)addr,
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.len = size,
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.pre_handler = pre,
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.post_handler = post,
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.private = trace
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},
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.phys = offset,
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.id = atomic_inc_return(&next_id)
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};
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map.map_id = trace->id;
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spin_lock_irq(&trace_lock);
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if (!is_enabled()) {
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kfree(trace);
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goto not_enabled;
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}
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mmio_trace_mapping(&map);
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list_add_tail(&trace->list, &trace_list);
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if (!nommiotrace)
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register_kmmio_probe(&trace->probe);
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not_enabled:
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spin_unlock_irq(&trace_lock);
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}
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void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
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void __iomem *addr)
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{
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if (!is_enabled()) /* recheck and proper locking in *_core() */
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return;
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pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n",
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(unsigned long long)offset, size, addr);
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if ((filter_offset) && (offset != filter_offset))
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return;
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ioremap_trace_core(offset, size, addr);
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}
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static void iounmap_trace_core(volatile void __iomem *addr)
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{
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struct mmiotrace_map map = {
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.phys = 0,
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.virt = (unsigned long)addr,
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.len = 0,
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.opcode = MMIO_UNPROBE
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};
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struct remap_trace *trace;
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struct remap_trace *tmp;
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struct remap_trace *found_trace = NULL;
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pr_debug("Unmapping %p.\n", addr);
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spin_lock_irq(&trace_lock);
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if (!is_enabled())
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goto not_enabled;
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list_for_each_entry_safe(trace, tmp, &trace_list, list) {
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if ((unsigned long)addr == trace->probe.addr) {
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if (!nommiotrace)
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unregister_kmmio_probe(&trace->probe);
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list_del(&trace->list);
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found_trace = trace;
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break;
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}
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}
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map.map_id = (found_trace) ? found_trace->id : -1;
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mmio_trace_mapping(&map);
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not_enabled:
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spin_unlock_irq(&trace_lock);
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if (found_trace) {
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synchronize_rcu(); /* unregister_kmmio_probe() requirement */
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kfree(found_trace);
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}
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}
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void mmiotrace_iounmap(volatile void __iomem *addr)
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{
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might_sleep();
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if (is_enabled()) /* recheck and proper locking in *_core() */
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iounmap_trace_core(addr);
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}
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int mmiotrace_printk(const char *fmt, ...)
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{
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int ret = 0;
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va_list args;
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unsigned long flags;
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va_start(args, fmt);
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spin_lock_irqsave(&trace_lock, flags);
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if (is_enabled())
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ret = mmio_trace_printk(fmt, args);
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spin_unlock_irqrestore(&trace_lock, flags);
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va_end(args);
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return ret;
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}
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EXPORT_SYMBOL(mmiotrace_printk);
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static void clear_trace_list(void)
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{
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struct remap_trace *trace;
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struct remap_trace *tmp;
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/*
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* No locking required, because the caller ensures we are in a
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* critical section via mutex, and is_enabled() is false,
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* i.e. nothing can traverse or modify this list.
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* Caller also ensures is_enabled() cannot change.
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*/
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list_for_each_entry(trace, &trace_list, list) {
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pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n",
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trace->probe.addr, trace->probe.len);
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if (!nommiotrace)
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unregister_kmmio_probe(&trace->probe);
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}
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synchronize_rcu(); /* unregister_kmmio_probe() requirement */
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list_for_each_entry_safe(trace, tmp, &trace_list, list) {
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list_del(&trace->list);
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kfree(trace);
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}
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static cpumask_var_t downed_cpus;
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static void enter_uniprocessor(void)
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{
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int cpu;
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int err;
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if (downed_cpus == NULL &&
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!alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
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pr_notice("Failed to allocate mask\n");
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goto out;
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}
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get_online_cpus();
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cpumask_copy(downed_cpus, cpu_online_mask);
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cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
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if (num_online_cpus() > 1)
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pr_notice("Disabling non-boot CPUs...\n");
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put_online_cpus();
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for_each_cpu(cpu, downed_cpus) {
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err = cpu_down(cpu);
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if (!err)
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pr_info("CPU%d is down.\n", cpu);
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else
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pr_err("Error taking CPU%d down: %d\n", cpu, err);
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}
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out:
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if (num_online_cpus() > 1)
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pr_warning("multiple CPUs still online, may miss events.\n");
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}
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static void leave_uniprocessor(void)
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{
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int cpu;
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int err;
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if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
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return;
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pr_notice("Re-enabling CPUs...\n");
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for_each_cpu(cpu, downed_cpus) {
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err = cpu_up(cpu);
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if (!err)
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pr_info("enabled CPU%d.\n", cpu);
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else
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pr_err("cannot re-enable CPU%d: %d\n", cpu, err);
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}
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}
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#else /* !CONFIG_HOTPLUG_CPU */
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static void enter_uniprocessor(void)
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{
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if (num_online_cpus() > 1)
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pr_warning("multiple CPUs are online, may miss events. "
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"Suggest booting with maxcpus=1 kernel argument.\n");
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}
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static void leave_uniprocessor(void)
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{
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}
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#endif
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void enable_mmiotrace(void)
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{
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mutex_lock(&mmiotrace_mutex);
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if (is_enabled())
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goto out;
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if (nommiotrace)
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pr_info("MMIO tracing disabled.\n");
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kmmio_init();
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enter_uniprocessor();
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spin_lock_irq(&trace_lock);
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atomic_inc(&mmiotrace_enabled);
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spin_unlock_irq(&trace_lock);
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pr_info("enabled.\n");
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out:
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mutex_unlock(&mmiotrace_mutex);
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}
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void disable_mmiotrace(void)
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{
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mutex_lock(&mmiotrace_mutex);
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if (!is_enabled())
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goto out;
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spin_lock_irq(&trace_lock);
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atomic_dec(&mmiotrace_enabled);
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BUG_ON(is_enabled());
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spin_unlock_irq(&trace_lock);
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clear_trace_list(); /* guarantees: no more kmmio callbacks */
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leave_uniprocessor();
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kmmio_cleanup();
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pr_info("disabled.\n");
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out:
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mutex_unlock(&mmiotrace_mutex);
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}
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