Commit | Line | Data |
---|---|---|
4a7c7197 IM |
1 | /* |
2 | * arch/i386/kernel/stacktrace.c | |
3 | * | |
4 | * Stack trace management functions | |
5 | * | |
6 | * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> | |
7 | */ | |
8 | #include <linux/sched.h> | |
9 | #include <linux/stacktrace.h> | |
10 | ||
11 | static inline int valid_stack_ptr(struct thread_info *tinfo, void *p) | |
12 | { | |
13 | return p > (void *)tinfo && | |
14 | p < (void *)tinfo + THREAD_SIZE - 3; | |
15 | } | |
16 | ||
17 | /* | |
18 | * Save stack-backtrace addresses into a stack_trace buffer: | |
19 | */ | |
20 | static inline unsigned long | |
21 | save_context_stack(struct stack_trace *trace, unsigned int skip, | |
22 | struct thread_info *tinfo, unsigned long *stack, | |
23 | unsigned long ebp) | |
24 | { | |
25 | unsigned long addr; | |
26 | ||
27 | #ifdef CONFIG_FRAME_POINTER | |
28 | while (valid_stack_ptr(tinfo, (void *)ebp)) { | |
29 | addr = *(unsigned long *)(ebp + 4); | |
30 | if (!skip) | |
31 | trace->entries[trace->nr_entries++] = addr; | |
32 | else | |
33 | skip--; | |
34 | if (trace->nr_entries >= trace->max_entries) | |
35 | break; | |
36 | /* | |
37 | * break out of recursive entries (such as | |
38 | * end_of_stack_stop_unwind_function): | |
39 | */ | |
40 | if (ebp == *(unsigned long *)ebp) | |
41 | break; | |
42 | ||
43 | ebp = *(unsigned long *)ebp; | |
44 | } | |
45 | #else | |
46 | while (valid_stack_ptr(tinfo, stack)) { | |
47 | addr = *stack++; | |
48 | if (__kernel_text_address(addr)) { | |
49 | if (!skip) | |
50 | trace->entries[trace->nr_entries++] = addr; | |
51 | else | |
52 | skip--; | |
53 | if (trace->nr_entries >= trace->max_entries) | |
54 | break; | |
55 | } | |
56 | } | |
57 | #endif | |
58 | ||
59 | return ebp; | |
60 | } | |
61 | ||
62 | /* | |
63 | * Save stack-backtrace addresses into a stack_trace buffer. | |
4a7c7197 | 64 | */ |
5a1b3999 | 65 | void save_stack_trace(struct stack_trace *trace, struct task_struct *task) |
4a7c7197 IM |
66 | { |
67 | unsigned long ebp; | |
68 | unsigned long *stack = &ebp; | |
69 | ||
70 | WARN_ON(trace->nr_entries || !trace->max_entries); | |
71 | ||
72 | if (!task || task == current) { | |
73 | /* Grab ebp right from our regs: */ | |
74 | asm ("movl %%ebp, %0" : "=r" (ebp)); | |
75 | } else { | |
76 | /* ebp is the last reg pushed by switch_to(): */ | |
77 | ebp = *(unsigned long *) task->thread.esp; | |
78 | } | |
79 | ||
80 | while (1) { | |
81 | struct thread_info *context = (struct thread_info *) | |
82 | ((unsigned long)stack & (~(THREAD_SIZE - 1))); | |
83 | ||
5a1b3999 | 84 | ebp = save_context_stack(trace, trace->skip, context, stack, ebp); |
4a7c7197 | 85 | stack = (unsigned long *)context->previous_esp; |
5a1b3999 | 86 | if (!stack || trace->nr_entries >= trace->max_entries) |
4a7c7197 IM |
87 | break; |
88 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
89 | if (trace->nr_entries >= trace->max_entries) | |
90 | break; | |
91 | } | |
92 | } | |
93 |