linux/arch/x86/oprofile/backtrace.c
Peter Zijlstra 0a196848ca perf: Fix arch_perf_out_copy_user default
The arch_perf_output_copy_user() default of
__copy_from_user_inatomic() returns bytes not copied, while all other
argument functions given DEFINE_OUTPUT_COPY() return bytes copied.

Since copy_from_user_nmi() is the odd duck out by returning bytes
copied where all other *copy_{to,from}* functions return bytes not
copied, change it over and ammend DEFINE_OUTPUT_COPY() to expect bytes
not copied.

Oddly enough DEFINE_OUTPUT_COPY() already returned bytes not copied
while expecting its worker functions to return bytes copied.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: will.deacon@arm.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20131030201622.GR16117@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06 12:34:25 +01:00

128 lines
2.7 KiB
C

/**
* @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 <linux/compat.h>
#include <linux/uaccess.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
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 = {
.stack = backtrace_stack,
.address = backtrace_address,
.walk_stack = print_context_stack,
};
#ifdef CONFIG_COMPAT
static struct stack_frame_ia32 *
dump_user_backtrace_32(struct stack_frame_ia32 *head)
{
/* Also check accessibility of one struct frame_head beyond: */
struct stack_frame_ia32 bufhead[2];
struct stack_frame_ia32 *fp;
unsigned long bytes;
bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
if (bytes != 0)
return NULL;
fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame);
oprofile_add_trace(bufhead[0].return_address);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
if (head >= fp)
return NULL;
return fp;
}
static inline int
x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
{
struct stack_frame_ia32 *head;
/* User process is IA32 */
if (!current || !test_thread_flag(TIF_IA32))
return 0;
head = (struct stack_frame_ia32 *) regs->bp;
while (depth-- && head)
head = dump_user_backtrace_32(head);
return 1;
}
#else
static inline int
x86_backtrace_32(struct pt_regs * const regs, unsigned int depth)
{
return 0;
}
#endif /* CONFIG_COMPAT */
static struct stack_frame *dump_user_backtrace(struct stack_frame *head)
{
/* Also check accessibility of one struct frame_head beyond: */
struct stack_frame bufhead[2];
unsigned long bytes;
bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead));
if (bytes != 0)
return NULL;
oprofile_add_trace(bufhead[0].return_address);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
if (head >= bufhead[0].next_frame)
return NULL;
return bufhead[0].next_frame;
}
void
x86_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct stack_frame *head = (struct stack_frame *)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;
}
if (x86_backtrace_32(regs, depth))
return;
while (depth-- && head)
head = dump_user_backtrace(head);
}