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x86: Eliminate bp argument from the stack tracing routines

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The various stack tracing routines take a 'bp' argument in which the
caller is supposed to provide the base pointer to use, or 0 if doesn't
have one. Since bp is garbage whenever CONFIG_FRAME_POINTER is not
defined, this means all callers in principle should either always pass
0, or be conditional on CONFIG_FRAME_POINTER.

However, there are only really three use cases for stack tracing:

(a) Trace the current task, including IRQ stack if any
(b) Trace the current task, but skip IRQ stack
(c) Trace some other task

In all cases, if CONFIG_FRAME_POINTER is not defined, bp should just
be 0.  If it _is_ defined, then

- in case (a) bp should be gotten directly from the CPU's register, so
  the caller should pass NULL for regs,

- in case (b) the caller should should pass the IRQ registers to
  dump_trace(),

- in case (c) bp should be gotten from the top of the task's stack, so
  the caller should pass NULL for regs.

Hence, the bp argument is not necessary because the combination of
task and regs is sufficient to determine an appropriate value for bp.

This patch introduces a new inline function stack_frame(task, regs)
that computes the desired bp. This function is then called from the
two versions of dump_stack().

Signed-off-by: Soren Sandmann <ssp@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>,
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
LKML-Reference: <m3oc9rop28.fsf@dhcp-100-3-82.bos.redhat.com>>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Soeren Sandmann Pedersen
2010-11-05 05:59:39 -04:00
committed by Frederic Weisbecker
parent 3985c7ce85
commit 9c0729dc80
11 changed files with 62 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
arch/x86/include/asm/stacktrace.h
View File

@@ -7,6 +7,7 @@
#define _ASM_X86_STACKTRACE_H
#include <linux/uaccess.h>
#include <linux/ptrace.h>
extern int kstack_depth_to_print;
@@ -46,7 +47,7 @@ struct stacktrace_ops {
};
void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
unsigned long *stack,
const struct stacktrace_ops *ops, void *data);
#ifdef CONFIG_X86_32
@@ -57,13 +58,39 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
#define get_bp(bp) asm("movq %%rbp, %0" : "=r" (bp) :)
#endif
#ifdef CONFIG_FRAME_POINTER
static inline unsigned long
stack_frame(struct task_struct *task, struct pt_regs *regs)
{
unsigned long bp;
if (regs)
return regs->bp;
if (task == current) {
/* Grab bp right from our regs */
get_bp(bp);
return bp;
}
/* bp is the last reg pushed by switch_to */
return *(unsigned long *)task->thread.sp;
}
#else
static inline unsigned long
stack_frame(struct task_struct *task, struct pt_regs *regs)
{
return 0;
}
#endif
extern void
show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp, char *log_lvl);
unsigned long *stack, char *log_lvl);
extern void
show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp, unsigned long bp, char *log_lvl);
unsigned long *sp, char *log_lvl);
extern unsigned int code_bytes;