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) 2006 Atsushi Nemoto <[email protected]>
5  */
6 #include <linux/sched.h>
7 #include <linux/stacktrace.h>
8 #include <linux/export.h>
9 #include <asm/stacktrace.h>
10 
11 /*
12  * Save stack-backtrace addresses into a stack_trace buffer:
13  */
14 static void save_raw_context_stack(struct stack_trace *trace,
15  unsigned long reg29)
16 {
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)) {
23  if (trace->skip > 0)
24  trace->skip--;
25  else
26  trace->entries[trace->nr_entries++] = addr;
27  if (trace->nr_entries >= trace->max_entries)
28  break;
29  }
30  }
31 }
32 
33 static void save_context_stack(struct stack_trace *trace,
34  struct task_struct *tsk, struct pt_regs *regs)
35 {
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;
40 
42  unsigned long stack_page =
43  (unsigned long)task_stack_page(tsk);
44  if (stack_page && sp >= stack_page &&
45  sp <= stack_page + THREAD_SIZE - 32)
46  save_raw_context_stack(trace, sp);
47  return;
48  }
49  do {
50  if (trace->skip > 0)
51  trace->skip--;
52  else
53  trace->entries[trace->nr_entries++] = pc;
54  if (trace->nr_entries >= trace->max_entries)
55  break;
56  pc = unwind_stack(tsk, &sp, pc, &ra);
57  } while (pc);
58 #else
59  save_raw_context_stack(trace, sp);
60 #endif
61 }
62 
63 /*
64  * Save stack-backtrace addresses into a stack_trace buffer.
65  */
66 void save_stack_trace(struct stack_trace *trace)
67 {
69 }
71 
72 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
73 {
74  struct pt_regs dummyregs;
75  struct pt_regs *regs = &dummyregs;
76 
77  WARN_ON(trace->nr_entries || !trace->max_entries);
78 
79  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);
86 }