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#include <linux/module.h>
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include "stacktrace.h"
int walk_stackframe(unsigned long fp, unsigned long low, unsigned long high,
int (*fn)(struct stackframe *, void *), void *data)
{
struct stackframe *frame;
do {
/*
* Check current frame pointer is within bounds
*/
if (fp < (low + 12) || fp + 4 >= high)
break;
frame = (struct stackframe *)(fp - 12);
if (fn(frame, data))
break;
/*
* Update the low bound - the next frame must always
* be at a higher address than the current frame.
*/
low = fp + 4;
fp = frame->fp;
} while (fp);
return 0;
}
EXPORT_SYMBOL(walk_stackframe);
#ifdef CONFIG_STACKTRACE
struct stack_trace_data {
struct stack_trace *trace;
unsigned int no_sched_functions;
unsigned int skip;
};
static int save_trace(struct stackframe *frame, void *d)
{
struct stack_trace_data *data = d;
struct stack_trace *trace = data->trace;
unsigned long addr = frame->lr;
if (data->no_sched_functions && in_sched_functions(addr))
return 0;
if (data->skip) {
data->skip--;
return 0;
}
trace->entries[trace->nr_entries++] = addr;
return trace->nr_entries >= trace->max_entries;
}
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
struct stack_trace_data data;
unsigned long fp, base;
data.trace = trace;
data.skip = trace->skip;
base = (unsigned long)task_stack_page(tsk);
if (tsk != current) {
#ifdef CONFIG_SMP
/*
* What guarantees do we have here that 'tsk'
* is not running on another CPU?
*/
BUG();
#else
data.no_sched_functions = 1;
fp = thread_saved_fp(tsk);
#endif
} else {
data.no_sched_functions = 0;
asm("mov %0, fp" : "=r" (fp));
}
walk_stackframe(fp, base, base + THREAD_SIZE, save_trace, &data);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace(struct stack_trace *trace)
{
save_stack_trace_tsk(current, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
#endif
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