Linux Kernel  3.7.1
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stacktrace.c
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1 /*
2  * Stack trace management functions
3  *
4  * Copyright (C) 2009 Helge Deller <[email protected]>
5  * based on arch/x86/kernel/stacktrace.c by Ingo Molnar <[email protected]>
6  * and parisc unwind functions by Randolph Chung <[email protected]>
7  *
8  * TODO: Userspace stacktrace (CONFIG_USER_STACKTRACE_SUPPORT)
9  */
10 #include <linux/module.h>
11 #include <linux/stacktrace.h>
12 
13 #include <asm/unwind.h>
14 
15 static void dump_trace(struct task_struct *task, struct stack_trace *trace)
16 {
17  struct unwind_frame_info info;
18 
19  /* initialize unwind info */
20  if (task == current) {
21  unsigned long sp;
22  struct pt_regs r;
23 HERE:
24  asm volatile ("copy %%r30, %0" : "=r"(sp));
25  memset(&r, 0, sizeof(struct pt_regs));
26  r.iaoq[0] = (unsigned long)&&HERE;
27  r.gr[2] = (unsigned long)__builtin_return_address(0);
28  r.gr[30] = sp;
29  unwind_frame_init(&info, task, &r);
30  } else {
32  }
33 
34  /* unwind stack and save entries in stack_trace struct */
35  trace->nr_entries = 0;
36  while (trace->nr_entries < trace->max_entries) {
37  if (unwind_once(&info) < 0 || info.ip == 0)
38  break;
39 
41  trace->entries[trace->nr_entries++] = info.ip;
42  }
43 }
44 
45 
46 /*
47  * Save stack-backtrace addresses into a stack_trace buffer.
48  */
49 void save_stack_trace(struct stack_trace *trace)
50 {
51  dump_trace(current, trace);
52  if (trace->nr_entries < trace->max_entries)
53  trace->entries[trace->nr_entries++] = ULONG_MAX;
54 }
56 
57 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
58 {
59  dump_trace(tsk, trace);
60  if (trace->nr_entries < trace->max_entries)
61  trace->entries[trace->nr_entries++] = ULONG_MAX;
62 }