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/**
* @file backtrace.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon
* @author David Smith
*/
#include <linux/oprofile.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/ptrace.h>
#include <asm/uaccess.h>
#include <asm/stacktrace.h>
static void backtrace_warning_symbol(void *data, char *msg,
unsigned long symbol)
{
/* Ignore warnings */
}
static void backtrace_warning(void *data, char *msg)
{
/* Ignore warnings */
}
static int backtrace_stack(void *data, char *name)
{
/* Yes, we want all stacks */
return 0;
}
static void backtrace_address(void *data, unsigned long addr, int reliable)
{
unsigned int *depth = data;
if ((*depth)--)
oprofile_add_trace(addr);
}
static struct stacktrace_ops backtrace_ops = {
.warning = backtrace_warning,
.warning_symbol = backtrace_warning_symbol,
.stack = backtrace_stack,
.address = backtrace_address,
.walk_stack = print_context_stack,
};
struct frame_head {
struct frame_head *bp;
unsigned long ret;
} __attribute__((packed));
static struct frame_head *dump_user_backtrace(struct frame_head *head)
{
struct frame_head bufhead[2];
/* Also check accessibility of one struct frame_head beyond */
if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
return NULL;
if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
return NULL;
oprofile_add_trace(bufhead[0].ret);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
if (head >= bufhead[0].bp)
return NULL;
return bufhead[0].bp;
}
void
x86_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct frame_head *head = (struct frame_head *)frame_pointer(regs);
if (!user_mode_vm(regs)) {
unsigned long stack = kernel_stack_pointer(regs);
if (depth)
dump_trace(NULL, regs, (unsigned long *)stack, 0,
&backtrace_ops, &depth);
return;
}
while (depth-- && head)
head = dump_user_backtrace(head);
}
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