blob: d52ff77baf3f8b22f169f8e4aba269fbff2c6941 [file] [log] [blame]
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +09001/*
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +09002 * Stack trace management functions
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 */
6#include <linux/sched.h>
7#include <linux/stacktrace.h>
Andrew Morton36bd53d2008-07-23 00:58:13 -07008#include <linux/module.h>
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +09009#include <asm/stacktrace.h>
10
11/*
12 * Save stack-backtrace addresses into a stack_trace buffer:
13 */
14static void save_raw_context_stack(struct stack_trace *trace,
Atsushi Nemoto23126692006-09-28 19:15:33 +090015 unsigned long reg29)
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090016{
17 unsigned long *sp = (unsigned long *)reg29;
18 unsigned long addr;
19
20 while (!kstack_end(sp)) {
21 addr = *sp++;
22 if (__kernel_text_address(addr)) {
Atsushi Nemoto23126692006-09-28 19:15:33 +090023 if (trace->skip > 0)
24 trace->skip--;
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090025 else
Atsushi Nemoto23126692006-09-28 19:15:33 +090026 trace->entries[trace->nr_entries++] = addr;
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090027 if (trace->nr_entries >= trace->max_entries)
28 break;
29 }
30 }
31}
32
Ken Chen2ec220e2008-11-10 11:26:08 +030033static void save_context_stack(struct stack_trace *trace,
34 struct task_struct *tsk, struct pt_regs *regs)
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090035{
36 unsigned long sp = regs->regs[29];
37#ifdef CONFIG_KALLSYMS
38 unsigned long ra = regs->regs[31];
39 unsigned long pc = regs->cp0_epc;
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090040
41 if (raw_show_trace || !__kernel_text_address(pc)) {
Atsushi Nemoto19246002006-09-29 18:02:51 +090042 unsigned long stack_page =
Ken Chen2ec220e2008-11-10 11:26:08 +030043 (unsigned long)task_stack_page(tsk);
Atsushi Nemoto23126692006-09-28 19:15:33 +090044 if (stack_page && sp >= stack_page &&
45 sp <= stack_page + THREAD_SIZE - 32)
46 save_raw_context_stack(trace, sp);
Atsushi Nemoto19246002006-09-29 18:02:51 +090047 return;
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090048 }
49 do {
Atsushi Nemoto23126692006-09-28 19:15:33 +090050 if (trace->skip > 0)
51 trace->skip--;
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090052 else
Atsushi Nemoto23126692006-09-28 19:15:33 +090053 trace->entries[trace->nr_entries++] = pc;
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090054 if (trace->nr_entries >= trace->max_entries)
55 break;
Ken Chen2ec220e2008-11-10 11:26:08 +030056 pc = unwind_stack(tsk, &sp, pc, &ra);
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090057 } while (pc);
58#else
Atsushi Nemotoeea32d42006-10-16 22:48:49 +090059 save_raw_context_stack(trace, sp);
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090060#endif
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090061}
62
63/*
64 * Save stack-backtrace addresses into a stack_trace buffer.
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090065 */
Christoph Hellwigab1b6f02007-05-08 00:23:29 -070066void save_stack_trace(struct stack_trace *trace)
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090067{
Ken Chen2ec220e2008-11-10 11:26:08 +030068 save_stack_trace_tsk(current, trace);
69}
70EXPORT_SYMBOL_GPL(save_stack_trace);
71
72void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
73{
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090074 struct pt_regs dummyregs;
75 struct pt_regs *regs = &dummyregs;
76
77 WARN_ON(trace->nr_entries || !trace->max_entries);
78
Ken Chen2ec220e2008-11-10 11:26:08 +030079 if (tsk != current) {
80 regs->regs[29] = tsk->thread.reg29;
81 regs->regs[31] = 0;
82 regs->cp0_epc = tsk->thread.reg31;
83 } else
84 prepare_frametrace(regs);
85 save_context_stack(trace, tsk, regs);
Atsushi Nemoto1df0f0f2006-09-26 23:44:01 +090086}
Ken Chen2ec220e2008-11-10 11:26:08 +030087EXPORT_SYMBOL_GPL(save_stack_trace_tsk);