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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
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/include/asm/kdebug.h
View file

@ -28,7 +28,7 @@ extern void die(const char *, struct pt_regs *,long);
extern int __must_check __die(const char *, struct pt_regs *, long);
extern void show_registers(struct pt_regs *regs);
extern void show_trace(struct task_struct *t, struct pt_regs *regs,
unsigned long *sp, unsigned long bp);
unsigned long *sp);
extern void __show_regs(struct pt_regs *regs, int all);
extern void show_regs(struct pt_regs *regs);
extern unsigned long oops_begin(void);

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;

2
arch/x86/kernel/cpu/perf_event.c
View file

@ -1666,7 +1666,7 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
perf_callchain_store(entry, regs->ip);
dump_trace(NULL, regs, NULL, regs->bp, &backtrace_ops, entry);
dump_trace(NULL, regs, NULL, &backtrace_ops, entry);
}
#ifdef CONFIG_COMPAT

12
arch/x86/kernel/dumpstack.c
View file

@ -175,21 +175,21 @@ static const struct stacktrace_ops print_trace_ops = {
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)
{
printk("%sCall Trace:\n", log_lvl);
dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
dump_trace(task, regs, stack, &print_trace_ops, log_lvl);
}
void show_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp)
unsigned long *stack)
{
show_trace_log_lvl(task, regs, stack, bp, "");
show_trace_log_lvl(task, regs, stack, "");
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
show_stack_log_lvl(task, NULL, sp, 0, "");
show_stack_log_lvl(task, NULL, sp, "");
}
/*
@ -210,7 +210,7 @@ void dump_stack(void)
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
show_trace(NULL, NULL, &stack, bp);
show_trace(NULL, NULL, &stack);
}
EXPORT_SYMBOL(dump_stack);

25
arch/x86/kernel/dumpstack_32.c
View file

@ -17,11 +17,12 @@
#include <asm/stacktrace.h>
void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
void dump_trace(struct task_struct *task,
struct pt_regs *regs, unsigned long *stack,
const struct stacktrace_ops *ops, void *data)
{
int graph = 0;
unsigned long bp;
if (!task)
task = current;
@ -34,18 +35,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
stack = (unsigned long *)task->thread.sp;
}
#ifdef CONFIG_FRAME_POINTER
if (!bp) {
if (task == current) {
/* Grab bp right from our regs */
get_bp(bp);
} else {
/* bp is the last reg pushed by switch_to */
bp = *(unsigned long *) task->thread.sp;
}
}
#endif
bp = stack_frame(task, regs);
for (;;) {
struct thread_info *context;
@ -65,7 +55,7 @@ EXPORT_SYMBOL(dump_trace);
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)
{
unsigned long *stack;
int i;
@ -87,7 +77,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
touch_nmi_watchdog();
}
printk(KERN_CONT "\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
show_trace_log_lvl(task, regs, sp, log_lvl);
}
@ -112,8 +102,7 @@ void show_registers(struct pt_regs *regs)
u8 *ip;
printk(KERN_EMERG "Stack:\n");
show_stack_log_lvl(NULL, regs, &regs->sp,
0, KERN_EMERG);
show_stack_log_lvl(NULL, regs, &regs->sp, KERN_EMERG);
printk(KERN_EMERG "Code: ");

24
arch/x86/kernel/dumpstack_64.c
View file

@ -139,8 +139,8 @@ fixup_bp_irq_link(unsigned long bp, unsigned long *stack,
* severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
*/
void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
void dump_trace(struct task_struct *task,
struct pt_regs *regs, unsigned long *stack,
const struct stacktrace_ops *ops, void *data)
{
const unsigned cpu = get_cpu();
@ -149,6 +149,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned used = 0;
struct thread_info *tinfo;
int graph = 0;
unsigned long bp;
if (!task)
task = current;
@ -160,18 +161,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
stack = (unsigned long *)task->thread.sp;
}
#ifdef CONFIG_FRAME_POINTER
if (!bp) {
if (task == current) {
/* Grab bp right from our regs */
get_bp(bp);
} else {
/* bp is the last reg pushed by switch_to */
bp = *(unsigned long *) task->thread.sp;
}
}
#endif
bp = stack_frame(task, regs);
/*
* Print function call entries in all stacks, starting at the
* current stack address. If the stacks consist of nested
@ -235,7 +225,7 @@ EXPORT_SYMBOL(dump_trace);
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)
{
unsigned long *irq_stack_end;
unsigned long *irq_stack;
@ -279,7 +269,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
preempt_enable();
printk(KERN_CONT "\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
show_trace_log_lvl(task, regs, sp, log_lvl);
}
void show_registers(struct pt_regs *regs)
@ -308,7 +298,7 @@ void show_registers(struct pt_regs *regs)
printk(KERN_EMERG "Stack:\n");
show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
regs->bp, KERN_EMERG);
KERN_EMERG);
printk(KERN_EMERG "Code: ");

3
arch/x86/kernel/process.c
View file

@ -91,8 +91,7 @@ void exit_thread(void)
void show_regs(struct pt_regs *regs)
{
show_registers(regs);
show_trace(NULL, regs, (unsigned long *)kernel_stack_pointer(regs),
regs->bp);
show_trace(NULL, regs, (unsigned long *)kernel_stack_pointer(regs));
}
void show_regs_common(void)

8
arch/x86/kernel/stacktrace.c
View file

@ -73,22 +73,22 @@ static const struct stacktrace_ops save_stack_ops_nosched = {
*/
void save_stack_trace(struct stack_trace *trace)
{
dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
dump_trace(current, NULL, NULL, &save_stack_ops, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_bp(struct stack_trace *trace, unsigned long bp)
void save_stack_trace_regs(struct stack_trace *trace, struct pt_regs *regs)
{
dump_trace(current, NULL, NULL, bp, &save_stack_ops, trace);
dump_trace(current, regs, NULL, &save_stack_ops, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
dump_trace(tsk, NULL, NULL, &save_stack_ops_nosched, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}

2
arch/x86/mm/kmemcheck/error.c
View file

@ -185,7 +185,7 @@ void kmemcheck_error_save(enum kmemcheck_shadow state,
e->trace.entries = e->trace_entries;
e->trace.max_entries = ARRAY_SIZE(e->trace_entries);
e->trace.skip = 0;
save_stack_trace_bp(&e->trace, regs->bp);
save_stack_trace_regs(&e->trace, regs);
/* Round address down to nearest 16 bytes */
shadow_copy = kmemcheck_shadow_lookup(address

2
arch/x86/oprofile/backtrace.c
View file

@ -126,7 +126,7 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
if (!user_mode_vm(regs)) {
unsigned long stack = kernel_stack_pointer(regs);
if (depth)
dump_trace(NULL, regs, (unsigned long *)stack, 0,
dump_trace(NULL, regs, (unsigned long *)stack,
&backtrace_ops, &depth);
return;
}

4
include/linux/stacktrace.h
View file

@ -2,6 +2,7 @@
#define __LINUX_STACKTRACE_H
struct task_struct;
struct pt_regs;
#ifdef CONFIG_STACKTRACE
struct task_struct;
@ -13,7 +14,8 @@ struct stack_trace {
};
extern void save_stack_trace(struct stack_trace *trace);
extern void save_stack_trace_bp(struct stack_trace *trace, unsigned long bp);
extern void save_stack_trace_regs(struct stack_trace *trace,
struct pt_regs *regs);
extern void save_stack_trace_tsk(struct task_struct *tsk,
struct stack_trace *trace);