android_kernel_motorola_sm6225/arch/mips/kernel/stacktrace.c
Ken Chen 2ec220e27f proc: add /proc/*/stack
/proc/*/stack adds the ability to query a task's stack trace. It is more
useful than /proc/*/wchan as it provides full stack trace instead of single
depth. Example output:

	$ cat /proc/self/stack
	[<c010a271>] save_stack_trace_tsk+0x17/0x35
	[<c01827b4>] proc_pid_stack+0x4a/0x76
	[<c018312d>] proc_single_show+0x4a/0x5e
	[<c016bdec>] seq_read+0xf3/0x29f
	[<c015a004>] vfs_read+0x6d/0x91
	[<c015a0c1>] sys_read+0x3b/0x60
	[<c0102eda>] syscall_call+0x7/0xb
	[<ffffffff>] 0xffffffff

[add save_stack_trace_tsk() on mips, ACK Ralf --adobriyan]
Signed-off-by: Ken Chen <kenchen@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-01-05 12:27:44 +03:00

89 lines
2.1 KiB
C

/*
* arch/mips/kernel/stacktrace.c
*
* Stack trace management functions
*
* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
*/
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/module.h>
#include <asm/stacktrace.h>
/*
* Save stack-backtrace addresses into a stack_trace buffer:
*/
static void save_raw_context_stack(struct stack_trace *trace,
unsigned long reg29)
{
unsigned long *sp = (unsigned long *)reg29;
unsigned long addr;
while (!kstack_end(sp)) {
addr = *sp++;
if (__kernel_text_address(addr)) {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = addr;
if (trace->nr_entries >= trace->max_entries)
break;
}
}
}
static void save_context_stack(struct stack_trace *trace,
struct task_struct *tsk, struct pt_regs *regs)
{
unsigned long sp = regs->regs[29];
#ifdef CONFIG_KALLSYMS
unsigned long ra = regs->regs[31];
unsigned long pc = regs->cp0_epc;
if (raw_show_trace || !__kernel_text_address(pc)) {
unsigned long stack_page =
(unsigned long)task_stack_page(tsk);
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
save_raw_context_stack(trace, sp);
return;
}
do {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = pc;
if (trace->nr_entries >= trace->max_entries)
break;
pc = unwind_stack(tsk, &sp, pc, &ra);
} while (pc);
#else
save_raw_context_stack(trace, sp);
#endif
}
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace(struct stack_trace *trace)
{
save_stack_trace_tsk(current, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
struct pt_regs dummyregs;
struct pt_regs *regs = &dummyregs;
WARN_ON(trace->nr_entries || !trace->max_entries);
if (tsk != current) {
regs->regs[29] = tsk->thread.reg29;
regs->regs[31] = 0;
regs->cp0_epc = tsk->thread.reg31;
} else
prepare_frametrace(regs);
save_context_stack(trace, tsk, regs);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);