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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f73670e8 G |
2 | /* |
3 | * linux/arch/unicore32/kernel/stacktrace.c | |
4 | * | |
5 | * Code specific to PKUnity SoC and UniCore ISA | |
6 | * | |
7 | * Copyright (C) 2001-2010 GUAN Xue-tao | |
f73670e8 G |
8 | */ |
9 | #include <linux/module.h> | |
10 | #include <linux/sched.h> | |
b17b0153 | 11 | #include <linux/sched/debug.h> |
f73670e8 G |
12 | #include <linux/stacktrace.h> |
13 | ||
14 | #include <asm/stacktrace.h> | |
15 | ||
16 | #if defined(CONFIG_FRAME_POINTER) | |
17 | /* | |
18 | * Unwind the current stack frame and store the new register values in the | |
19 | * structure passed as argument. Unwinding is equivalent to a function return, | |
20 | * hence the new PC value rather than LR should be used for backtrace. | |
21 | * | |
22 | * With framepointer enabled, a simple function prologue looks like this: | |
23 | * mov ip, sp | |
24 | * stmdb sp!, {fp, ip, lr, pc} | |
25 | * sub fp, ip, #4 | |
26 | * | |
27 | * A simple function epilogue looks like this: | |
28 | * ldm sp, {fp, sp, pc} | |
29 | * | |
30 | * Note that with framepointer enabled, even the leaf functions have the same | |
31 | * prologue and epilogue, therefore we can ignore the LR value in this case. | |
32 | */ | |
33 | int notrace unwind_frame(struct stackframe *frame) | |
34 | { | |
35 | unsigned long high, low; | |
36 | unsigned long fp = frame->fp; | |
37 | ||
38 | /* only go to a higher address on the stack */ | |
39 | low = frame->sp; | |
40 | high = ALIGN(low, THREAD_SIZE); | |
41 | ||
42 | /* check current frame pointer is within bounds */ | |
43 | if (fp < (low + 12) || fp + 4 >= high) | |
44 | return -EINVAL; | |
45 | ||
46 | /* restore the registers from the stack frame */ | |
47 | frame->fp = *(unsigned long *)(fp - 12); | |
48 | frame->sp = *(unsigned long *)(fp - 8); | |
49 | frame->pc = *(unsigned long *)(fp - 4); | |
50 | ||
51 | return 0; | |
52 | } | |
53 | #endif | |
54 | ||
55 | void notrace walk_stackframe(struct stackframe *frame, | |
56 | int (*fn)(struct stackframe *, void *), void *data) | |
57 | { | |
58 | while (1) { | |
59 | int ret; | |
60 | ||
61 | if (fn(frame, data)) | |
62 | break; | |
63 | ret = unwind_frame(frame); | |
64 | if (ret < 0) | |
65 | break; | |
66 | } | |
67 | } | |
68 | EXPORT_SYMBOL(walk_stackframe); | |
69 | ||
70 | #ifdef CONFIG_STACKTRACE | |
71 | struct stack_trace_data { | |
72 | struct stack_trace *trace; | |
73 | unsigned int no_sched_functions; | |
74 | unsigned int skip; | |
75 | }; | |
76 | ||
77 | static int save_trace(struct stackframe *frame, void *d) | |
78 | { | |
79 | struct stack_trace_data *data = d; | |
80 | struct stack_trace *trace = data->trace; | |
81 | unsigned long addr = frame->pc; | |
82 | ||
83 | if (data->no_sched_functions && in_sched_functions(addr)) | |
84 | return 0; | |
85 | if (data->skip) { | |
86 | data->skip--; | |
87 | return 0; | |
88 | } | |
89 | ||
90 | trace->entries[trace->nr_entries++] = addr; | |
91 | ||
92 | return trace->nr_entries >= trace->max_entries; | |
93 | } | |
94 | ||
95 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) | |
96 | { | |
97 | struct stack_trace_data data; | |
98 | struct stackframe frame; | |
99 | ||
100 | data.trace = trace; | |
101 | data.skip = trace->skip; | |
102 | ||
103 | if (tsk != current) { | |
104 | data.no_sched_functions = 1; | |
105 | frame.fp = thread_saved_fp(tsk); | |
106 | frame.sp = thread_saved_sp(tsk); | |
107 | frame.lr = 0; /* recovered from the stack */ | |
108 | frame.pc = thread_saved_pc(tsk); | |
109 | } else { | |
110 | register unsigned long current_sp asm("sp"); | |
111 | ||
112 | data.no_sched_functions = 0; | |
113 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
114 | frame.sp = current_sp; | |
115 | frame.lr = (unsigned long)__builtin_return_address(0); | |
116 | frame.pc = (unsigned long)save_stack_trace_tsk; | |
117 | } | |
118 | ||
119 | walk_stackframe(&frame, save_trace, &data); | |
f73670e8 G |
120 | } |
121 | ||
122 | void save_stack_trace(struct stack_trace *trace) | |
123 | { | |
124 | save_stack_trace_tsk(current, trace); | |
125 | } | |
126 | EXPORT_SYMBOL_GPL(save_stack_trace); | |
127 | #endif |