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f73670e8 G |
1 | /* |
2 | * linux/arch/unicore32/kernel/stacktrace.c | |
3 | * | |
4 | * Code specific to PKUnity SoC and UniCore ISA | |
5 | * | |
6 | * Copyright (C) 2001-2010 GUAN Xue-tao | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/sched.h> | |
b17b0153 | 14 | #include <linux/sched/debug.h> |
f73670e8 G |
15 | #include <linux/stacktrace.h> |
16 | ||
17 | #include <asm/stacktrace.h> | |
18 | ||
19 | #if defined(CONFIG_FRAME_POINTER) | |
20 | /* | |
21 | * Unwind the current stack frame and store the new register values in the | |
22 | * structure passed as argument. Unwinding is equivalent to a function return, | |
23 | * hence the new PC value rather than LR should be used for backtrace. | |
24 | * | |
25 | * With framepointer enabled, a simple function prologue looks like this: | |
26 | * mov ip, sp | |
27 | * stmdb sp!, {fp, ip, lr, pc} | |
28 | * sub fp, ip, #4 | |
29 | * | |
30 | * A simple function epilogue looks like this: | |
31 | * ldm sp, {fp, sp, pc} | |
32 | * | |
33 | * Note that with framepointer enabled, even the leaf functions have the same | |
34 | * prologue and epilogue, therefore we can ignore the LR value in this case. | |
35 | */ | |
36 | int notrace unwind_frame(struct stackframe *frame) | |
37 | { | |
38 | unsigned long high, low; | |
39 | unsigned long fp = frame->fp; | |
40 | ||
41 | /* only go to a higher address on the stack */ | |
42 | low = frame->sp; | |
43 | high = ALIGN(low, THREAD_SIZE); | |
44 | ||
45 | /* check current frame pointer is within bounds */ | |
46 | if (fp < (low + 12) || fp + 4 >= high) | |
47 | return -EINVAL; | |
48 | ||
49 | /* restore the registers from the stack frame */ | |
50 | frame->fp = *(unsigned long *)(fp - 12); | |
51 | frame->sp = *(unsigned long *)(fp - 8); | |
52 | frame->pc = *(unsigned long *)(fp - 4); | |
53 | ||
54 | return 0; | |
55 | } | |
56 | #endif | |
57 | ||
58 | void notrace walk_stackframe(struct stackframe *frame, | |
59 | int (*fn)(struct stackframe *, void *), void *data) | |
60 | { | |
61 | while (1) { | |
62 | int ret; | |
63 | ||
64 | if (fn(frame, data)) | |
65 | break; | |
66 | ret = unwind_frame(frame); | |
67 | if (ret < 0) | |
68 | break; | |
69 | } | |
70 | } | |
71 | EXPORT_SYMBOL(walk_stackframe); | |
72 | ||
73 | #ifdef CONFIG_STACKTRACE | |
74 | struct stack_trace_data { | |
75 | struct stack_trace *trace; | |
76 | unsigned int no_sched_functions; | |
77 | unsigned int skip; | |
78 | }; | |
79 | ||
80 | static int save_trace(struct stackframe *frame, void *d) | |
81 | { | |
82 | struct stack_trace_data *data = d; | |
83 | struct stack_trace *trace = data->trace; | |
84 | unsigned long addr = frame->pc; | |
85 | ||
86 | if (data->no_sched_functions && in_sched_functions(addr)) | |
87 | return 0; | |
88 | if (data->skip) { | |
89 | data->skip--; | |
90 | return 0; | |
91 | } | |
92 | ||
93 | trace->entries[trace->nr_entries++] = addr; | |
94 | ||
95 | return trace->nr_entries >= trace->max_entries; | |
96 | } | |
97 | ||
98 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) | |
99 | { | |
100 | struct stack_trace_data data; | |
101 | struct stackframe frame; | |
102 | ||
103 | data.trace = trace; | |
104 | data.skip = trace->skip; | |
105 | ||
106 | if (tsk != current) { | |
107 | data.no_sched_functions = 1; | |
108 | frame.fp = thread_saved_fp(tsk); | |
109 | frame.sp = thread_saved_sp(tsk); | |
110 | frame.lr = 0; /* recovered from the stack */ | |
111 | frame.pc = thread_saved_pc(tsk); | |
112 | } else { | |
113 | register unsigned long current_sp asm("sp"); | |
114 | ||
115 | data.no_sched_functions = 0; | |
116 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
117 | frame.sp = current_sp; | |
118 | frame.lr = (unsigned long)__builtin_return_address(0); | |
119 | frame.pc = (unsigned long)save_stack_trace_tsk; | |
120 | } | |
121 | ||
122 | walk_stackframe(&frame, save_trace, &data); | |
123 | if (trace->nr_entries < trace->max_entries) | |
124 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
125 | } | |
126 | ||
127 | void save_stack_trace(struct stack_trace *trace) | |
128 | { | |
129 | save_stack_trace_tsk(current, trace); | |
130 | } | |
131 | EXPORT_SYMBOL_GPL(save_stack_trace); | |
132 | #endif |