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#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/ptrace.h>
#include <linux/ratelimit.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/stacktrace.h>
#include <linux/linkage.h>
#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
#include <asm/memory.h>
#include <asm/stacktrace.h>
#include <asm/traps.h>
#include <linux/semaphore.h>
#include <linux/delay.h>
#include <linux/mrdump.h>
#include "aed.h"
struct bt_sync {
atomic_t cpus_report;
atomic_t cpus_lock;
};
static void per_cpu_get_bt(void *info)
{
int timeout_max = 500000;
struct bt_sync *s = (struct bt_sync *)info;
if (atomic_read(&s->cpus_lock) == 0)
return;
atomic_dec(&s->cpus_report);
while (atomic_read(&s->cpus_lock) == 1) {
if (timeout_max-- > 0) {
udelay(1);
} else {
break;
}
}
atomic_dec(&s->cpus_report);
}
static int aed_save_trace(struct stackframe *frame, void *d)
{
struct aee_process_bt *trace = d;
unsigned long addr = frame->pc;
unsigned int id = trace->nr_entries;
struct pt_regs *excp_regs;
/* use static var, not support concurrency */
static unsigned long stack;
int ret = 0;
if (id >= AEE_NR_FRAME)
return -1;
if (id == 0)
stack = frame->sp;
if (frame->fp < stack || frame->fp > ALIGN(stack, THREAD_SIZE))
ret = -1;
#if 0
if (ret == 0 && in_exception_text(addr)) {
#ifdef __aarch64__
excp_regs = (void *)(frame->fp + 0x10);
frame->pc = excp_regs->reg_pc - 4;
#else
excp_regs = (void *)(frame->fp + 4);
frame->pc = excp_regs->reg_pc;
frame->lr = excp_regs->reg_lr;
#endif
frame->sp = excp_regs->reg_sp;
frame->fp = excp_regs->reg_fp;
}
#endif
trace->entries[id].pc = frame->pc;
snprintf(trace->entries[id].pc_symbol, AEE_SZ_SYMBOL_S, "%pS", (void *)frame->pc);
#ifndef __aarch64__
trace->entries[id].lr = frame->lr;
snprintf(trace->entries[id].lr_symbol, AEE_SZ_SYMBOL_L, "%pS", (void *)frame->lr);
#endif
++trace->nr_entries;
return ret;
}
static void aed_get_bt(struct task_struct *tsk, struct aee_process_bt *bt)
{
struct stackframe frame;
unsigned long stack_address;
static struct aee_bt_frame aed_backtrace_buffer[AEE_NR_FRAME];
bt->nr_entries = 0;
bt->entries = aed_backtrace_buffer;
memset(&frame, 0, sizeof(struct stackframe));
if (tsk != current) {
frame.fp = thread_saved_fp(tsk);
frame.sp = thread_saved_sp(tsk);
#ifdef __aarch64__
frame.pc = thread_saved_pc(tsk);
#else
frame.lr = thread_saved_pc(tsk);
frame.pc = 0xffffffff;
#endif
} else {
register unsigned long current_sp asm("sp");
frame.fp = (unsigned long)__builtin_frame_address(0);
frame.sp = current_sp;
#ifdef __aarch64__
frame.pc = (unsigned long)__builtin_return_address(0);
#else
frame.lr = (unsigned long)__builtin_return_address(0);
frame.pc = (unsigned long)aed_get_bt;
#endif
}
stack_address = ALIGN(frame.sp, THREAD_SIZE);
if ((stack_address >= (PAGE_OFFSET + THREAD_SIZE)) && virt_addr_valid(stack_address)) {
walk_stackframe(&frame, aed_save_trace, bt);
} else {
LOGD("%s: Invalid sp value %lx\n", __func__, frame.sp);
}
}
static DEFINE_SEMAPHORE(process_bt_sem);
int aed_get_process_bt(struct aee_process_bt *bt)
{
int nr_cpus, err;
struct bt_sync s;
struct task_struct *task;
int timeout_max = 500000;
if (down_interruptible(&process_bt_sem) < 0) {
return -ERESTARTSYS;
}
err = 0;
if (bt->pid > 0) {
task = find_task_by_vpid(bt->pid);
if (task == NULL) {
err = -EINVAL;
goto exit;
}
} else {
err = -EINVAL;
goto exit;
}
err = mutex_lock_killable(&task->signal->cred_guard_mutex);
if (err)
goto exit;
if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
mutex_unlock(&task->signal->cred_guard_mutex);
err = -EPERM;
goto exit;
}
mutex_unlock(&task->signal->cred_guard_mutex);
get_online_cpus();
preempt_disable();
nr_cpus = num_online_cpus();
atomic_set(&s.cpus_report, nr_cpus - 1);
atomic_set(&s.cpus_lock, 1);
smp_call_function(per_cpu_get_bt, &s, 0);
while (atomic_read(&s.cpus_report) != 0) {
if (timeout_max-- > 0) {
udelay(1);
} else {
break;
}
}
aed_get_bt(task, bt);
atomic_set(&s.cpus_report, nr_cpus - 1);
atomic_set(&s.cpus_lock, 0);
timeout_max = 500000;
while (atomic_read(&s.cpus_report) != 0) {
if (timeout_max-- > 0) {
udelay(1);
} else {
break;
}
}
preempt_enable();
put_online_cpus();
exit:
up(&process_bt_sem);
return err;
}
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