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1df0f0ff AN |
1 | /* |
2 | * arch/mips/kernel/stacktrace.c | |
3 | * | |
4 | * Stack trace management functions | |
5 | * | |
6 | * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> | |
7 | */ | |
8 | #include <linux/sched.h> | |
9 | #include <linux/stacktrace.h> | |
10 | #include <asm/stacktrace.h> | |
11 | ||
12 | /* | |
13 | * Save stack-backtrace addresses into a stack_trace buffer: | |
14 | */ | |
15 | static void save_raw_context_stack(struct stack_trace *trace, | |
16 | unsigned int skip, unsigned long reg29) | |
17 | { | |
18 | unsigned long *sp = (unsigned long *)reg29; | |
19 | unsigned long addr; | |
20 | ||
21 | while (!kstack_end(sp)) { | |
22 | addr = *sp++; | |
23 | if (__kernel_text_address(addr)) { | |
24 | if (!skip) | |
25 | trace->entries[trace->nr_entries++] = addr; | |
26 | else | |
27 | skip--; | |
28 | if (trace->nr_entries >= trace->max_entries) | |
29 | break; | |
30 | } | |
31 | } | |
32 | } | |
33 | ||
34 | static struct pt_regs * save_context_stack(struct stack_trace *trace, | |
35 | unsigned int skip, struct task_struct *task, struct pt_regs *regs) | |
36 | { | |
37 | unsigned long sp = regs->regs[29]; | |
38 | #ifdef CONFIG_KALLSYMS | |
39 | unsigned long ra = regs->regs[31]; | |
40 | unsigned long pc = regs->cp0_epc; | |
41 | extern void ret_from_irq(void); | |
42 | ||
43 | if (raw_show_trace || !__kernel_text_address(pc)) { | |
44 | save_raw_context_stack(trace, skip, sp); | |
45 | return NULL; | |
46 | } | |
47 | do { | |
48 | if (!skip) | |
49 | trace->entries[trace->nr_entries++] = pc; | |
50 | else | |
51 | skip--; | |
52 | if (trace->nr_entries >= trace->max_entries) | |
53 | break; | |
54 | /* | |
55 | * If we reached the bottom of interrupt context, | |
56 | * return saved pt_regs. | |
57 | */ | |
58 | if (pc == (unsigned long)ret_from_irq) { | |
59 | unsigned long stack_page = | |
60 | (unsigned long)task_stack_page(task); | |
61 | if (!stack_page || | |
62 | sp < stack_page || | |
63 | sp > stack_page + THREAD_SIZE - 32) | |
64 | break; | |
65 | return (struct pt_regs *)sp; | |
66 | } | |
67 | pc = unwind_stack(task, &sp, pc, ra); | |
68 | ra = 0; | |
69 | } while (pc); | |
70 | #else | |
71 | save_raw_context_stack(sp); | |
72 | #endif | |
73 | ||
74 | return NULL; | |
75 | } | |
76 | ||
77 | /* | |
78 | * Save stack-backtrace addresses into a stack_trace buffer. | |
79 | * If all_contexts is set, all contexts (hardirq, softirq and process) | |
80 | * are saved. If not set then only the current context is saved. | |
81 | */ | |
82 | void save_stack_trace(struct stack_trace *trace, | |
83 | struct task_struct *task, int all_contexts, | |
84 | unsigned int skip) | |
85 | { | |
86 | struct pt_regs dummyregs; | |
87 | struct pt_regs *regs = &dummyregs; | |
88 | ||
89 | WARN_ON(trace->nr_entries || !trace->max_entries); | |
90 | ||
91 | if (task && task != current) { | |
92 | regs->regs[29] = task->thread.reg29; | |
93 | regs->regs[31] = 0; | |
94 | regs->cp0_epc = task->thread.reg31; | |
95 | } else { | |
96 | if (!task) | |
97 | task = current; | |
98 | prepare_frametrace(regs); | |
99 | } | |
100 | ||
101 | while (1) { | |
102 | regs = save_context_stack(trace, skip, task, regs); | |
103 | if (!all_contexts || !regs || | |
104 | trace->nr_entries >= trace->max_entries) | |
105 | break; | |
106 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
107 | if (trace->nr_entries >= trace->max_entries) | |
108 | break; | |
109 | skip = 0; | |
110 | } | |
111 | } |