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ecea4ab6 | 1 | #include <linux/export.h> |
f16fb1ec | 2 | #include <linux/sched.h> |
b17b0153 | 3 | #include <linux/sched/debug.h> |
f16fb1ec RK |
4 | #include <linux/stacktrace.h> |
5 | ||
2d7c11bf | 6 | #include <asm/stacktrace.h> |
07b40341 | 7 | #include <asm/traps.h> |
2d7c11bf CM |
8 | |
9 | #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) | |
10 | /* | |
11 | * Unwind the current stack frame and store the new register values in the | |
12 | * structure passed as argument. Unwinding is equivalent to a function return, | |
13 | * hence the new PC value rather than LR should be used for backtrace. | |
14 | * | |
15 | * With framepointer enabled, a simple function prologue looks like this: | |
16 | * mov ip, sp | |
17 | * stmdb sp!, {fp, ip, lr, pc} | |
18 | * sub fp, ip, #4 | |
19 | * | |
20 | * A simple function epilogue looks like this: | |
21 | * ldm sp, {fp, sp, pc} | |
22 | * | |
23 | * Note that with framepointer enabled, even the leaf functions have the same | |
24 | * prologue and epilogue, therefore we can ignore the LR value in this case. | |
25 | */ | |
4bf1fa5a | 26 | int notrace unwind_frame(struct stackframe *frame) |
f16fb1ec | 27 | { |
2d7c11bf CM |
28 | unsigned long high, low; |
29 | unsigned long fp = frame->fp; | |
f16fb1ec | 30 | |
2d7c11bf CM |
31 | /* only go to a higher address on the stack */ |
32 | low = frame->sp; | |
d33aadbf | 33 | high = ALIGN(low, THREAD_SIZE); |
f16fb1ec | 34 | |
2d7c11bf | 35 | /* check current frame pointer is within bounds */ |
3abb6671 | 36 | if (fp < low + 12 || fp > high - 4) |
2d7c11bf | 37 | return -EINVAL; |
f16fb1ec | 38 | |
2d7c11bf CM |
39 | /* restore the registers from the stack frame */ |
40 | frame->fp = *(unsigned long *)(fp - 12); | |
41 | frame->sp = *(unsigned long *)(fp - 8); | |
42 | frame->pc = *(unsigned long *)(fp - 4); | |
f16fb1ec RK |
43 | |
44 | return 0; | |
45 | } | |
2d7c11bf CM |
46 | #endif |
47 | ||
4bf1fa5a | 48 | void notrace walk_stackframe(struct stackframe *frame, |
2d7c11bf CM |
49 | int (*fn)(struct stackframe *, void *), void *data) |
50 | { | |
51 | while (1) { | |
52 | int ret; | |
53 | ||
54 | if (fn(frame, data)) | |
55 | break; | |
56 | ret = unwind_frame(frame); | |
57 | if (ret < 0) | |
58 | break; | |
59 | } | |
60 | } | |
7b104bcb | 61 | EXPORT_SYMBOL(walk_stackframe); |
f16fb1ec RK |
62 | |
63 | #ifdef CONFIG_STACKTRACE | |
64 | struct stack_trace_data { | |
65 | struct stack_trace *trace; | |
07b40341 | 66 | unsigned long last_pc; |
f76e9154 | 67 | unsigned int no_sched_functions; |
f16fb1ec RK |
68 | unsigned int skip; |
69 | }; | |
70 | ||
71 | static int save_trace(struct stackframe *frame, void *d) | |
72 | { | |
73 | struct stack_trace_data *data = d; | |
74 | struct stack_trace *trace = data->trace; | |
07b40341 | 75 | struct pt_regs *regs; |
2d7c11bf | 76 | unsigned long addr = frame->pc; |
f16fb1ec | 77 | |
f76e9154 NP |
78 | if (data->no_sched_functions && in_sched_functions(addr)) |
79 | return 0; | |
f16fb1ec RK |
80 | if (data->skip) { |
81 | data->skip--; | |
82 | return 0; | |
83 | } | |
84 | ||
f76e9154 | 85 | trace->entries[trace->nr_entries++] = addr; |
f16fb1ec | 86 | |
07b40341 RK |
87 | if (trace->nr_entries >= trace->max_entries) |
88 | return 1; | |
89 | ||
90 | /* | |
91 | * in_exception_text() is designed to test if the PC is one of | |
92 | * the functions which has an exception stack above it, but | |
93 | * unfortunately what is in frame->pc is the return LR value, | |
94 | * not the saved PC value. So, we need to track the previous | |
95 | * frame PC value when doing this. | |
96 | */ | |
97 | addr = data->last_pc; | |
98 | data->last_pc = frame->pc; | |
99 | if (!in_exception_text(addr)) | |
100 | return 0; | |
101 | ||
102 | regs = (struct pt_regs *)frame->sp; | |
103 | ||
104 | trace->entries[trace->nr_entries++] = regs->ARM_pc; | |
105 | ||
f16fb1ec RK |
106 | return trace->nr_entries >= trace->max_entries; |
107 | } | |
108 | ||
3683f44c RK |
109 | /* This must be noinline to so that our skip calculation works correctly */ |
110 | static noinline void __save_stack_trace(struct task_struct *tsk, | |
111 | struct stack_trace *trace, unsigned int nosched) | |
f16fb1ec RK |
112 | { |
113 | struct stack_trace_data data; | |
2d7c11bf | 114 | struct stackframe frame; |
f16fb1ec RK |
115 | |
116 | data.trace = trace; | |
07b40341 | 117 | data.last_pc = ULONG_MAX; |
f16fb1ec | 118 | data.skip = trace->skip; |
3683f44c | 119 | data.no_sched_functions = nosched; |
f76e9154 NP |
120 | |
121 | if (tsk != current) { | |
122 | #ifdef CONFIG_SMP | |
123 | /* | |
d5996b2f RK |
124 | * What guarantees do we have here that 'tsk' is not |
125 | * running on another CPU? For now, ignore it as we | |
126 | * can't guarantee we won't explode. | |
f76e9154 | 127 | */ |
d5996b2f RK |
128 | if (trace->nr_entries < trace->max_entries) |
129 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
130 | return; | |
f76e9154 | 131 | #else |
2d7c11bf CM |
132 | frame.fp = thread_saved_fp(tsk); |
133 | frame.sp = thread_saved_sp(tsk); | |
134 | frame.lr = 0; /* recovered from the stack */ | |
135 | frame.pc = thread_saved_pc(tsk); | |
f76e9154 NP |
136 | #endif |
137 | } else { | |
3683f44c RK |
138 | /* We don't want this function nor the caller */ |
139 | data.skip += 2; | |
2d7c11bf | 140 | frame.fp = (unsigned long)__builtin_frame_address(0); |
74dbeee0 | 141 | frame.sp = current_stack_pointer; |
2d7c11bf | 142 | frame.lr = (unsigned long)__builtin_return_address(0); |
3683f44c | 143 | frame.pc = (unsigned long)__save_stack_trace; |
f76e9154 | 144 | } |
f16fb1ec | 145 | |
2d7c11bf | 146 | walk_stackframe(&frame, save_trace, &data); |
f76e9154 NP |
147 | if (trace->nr_entries < trace->max_entries) |
148 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
149 | } | |
150 | ||
9c986661 LY |
151 | void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) |
152 | { | |
153 | struct stack_trace_data data; | |
154 | struct stackframe frame; | |
155 | ||
156 | data.trace = trace; | |
157 | data.skip = trace->skip; | |
158 | data.no_sched_functions = 0; | |
159 | ||
160 | frame.fp = regs->ARM_fp; | |
161 | frame.sp = regs->ARM_sp; | |
162 | frame.lr = regs->ARM_lr; | |
163 | frame.pc = regs->ARM_pc; | |
164 | ||
165 | walk_stackframe(&frame, save_trace, &data); | |
166 | if (trace->nr_entries < trace->max_entries) | |
167 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
168 | } | |
169 | ||
3683f44c RK |
170 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
171 | { | |
172 | __save_stack_trace(tsk, trace, 1); | |
173 | } | |
174 | ||
f76e9154 NP |
175 | void save_stack_trace(struct stack_trace *trace) |
176 | { | |
3683f44c | 177 | __save_stack_trace(current, trace, 0); |
f16fb1ec | 178 | } |
7b4c9505 | 179 | EXPORT_SYMBOL_GPL(save_stack_trace); |
f16fb1ec | 180 | #endif |