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e8de3486 JH |
1 | #include <linux/export.h> |
2 | #include <linux/sched.h> | |
b17b0153 | 3 | #include <linux/sched/debug.h> |
3f8c2452 | 4 | #include <linux/sched/task_stack.h> |
e8de3486 JH |
5 | #include <linux/stacktrace.h> |
6 | ||
7 | #include <asm/stacktrace.h> | |
8 | ||
9 | #if defined(CONFIG_FRAME_POINTER) | |
10 | ||
11 | #ifdef CONFIG_KALLSYMS | |
12 | #include <linux/kallsyms.h> | |
13 | #include <linux/module.h> | |
14 | ||
15 | static unsigned long tbi_boing_addr; | |
16 | static unsigned long tbi_boing_size; | |
17 | ||
18 | static void tbi_boing_init(void) | |
19 | { | |
20 | /* We need to know where TBIBoingVec is and it's size */ | |
21 | unsigned long size; | |
22 | unsigned long offset; | |
23 | char modname[MODULE_NAME_LEN]; | |
24 | char name[KSYM_NAME_LEN]; | |
25 | tbi_boing_addr = kallsyms_lookup_name("___TBIBoingVec"); | |
26 | if (!tbi_boing_addr) | |
27 | tbi_boing_addr = 1; | |
28 | else if (!lookup_symbol_attrs(tbi_boing_addr, &size, | |
29 | &offset, modname, name)) | |
30 | tbi_boing_size = size; | |
31 | } | |
32 | #endif | |
33 | ||
e8de3486 JH |
34 | /* |
35 | * Unwind the current stack frame and store the new register values in the | |
36 | * structure passed as argument. Unwinding is equivalent to a function return, | |
37 | * hence the new PC value rather than LR should be used for backtrace. | |
38 | */ | |
39 | int notrace unwind_frame(struct stackframe *frame) | |
40 | { | |
41 | struct metag_frame *fp = (struct metag_frame *)frame->fp; | |
42 | unsigned long lr; | |
43 | unsigned long fpnew; | |
44 | ||
45 | if (frame->fp & 0x7) | |
46 | return -EINVAL; | |
47 | ||
48 | fpnew = fp->fp; | |
49 | lr = fp->lr - 4; | |
50 | ||
51 | #ifdef CONFIG_KALLSYMS | |
52 | /* If we've reached TBIBoingVec then we're at an interrupt | |
53 | * entry point or a syscall entry point. The frame pointer | |
54 | * points to a pt_regs which can be used to continue tracing on | |
55 | * the other side of the boing. | |
56 | */ | |
57 | if (!tbi_boing_addr) | |
58 | tbi_boing_init(); | |
59 | if (tbi_boing_size && lr >= tbi_boing_addr && | |
60 | lr < tbi_boing_addr + tbi_boing_size) { | |
61 | struct pt_regs *regs = (struct pt_regs *)fpnew; | |
62 | if (user_mode(regs)) | |
63 | return -EINVAL; | |
64 | fpnew = regs->ctx.AX[1].U0; | |
65 | lr = regs->ctx.DX[4].U1; | |
66 | } | |
67 | #endif | |
68 | ||
69 | /* stack grows up, so frame pointers must decrease */ | |
70 | if (fpnew < (ALIGN_DOWN((unsigned long)fp, THREAD_SIZE) + | |
71 | sizeof(struct thread_info)) || fpnew >= (unsigned long)fp) | |
72 | return -EINVAL; | |
73 | ||
74 | /* restore the registers from the stack frame */ | |
75 | frame->fp = fpnew; | |
76 | frame->pc = lr; | |
77 | ||
78 | return 0; | |
79 | } | |
80 | #else | |
81 | int notrace unwind_frame(struct stackframe *frame) | |
82 | { | |
83 | struct metag_frame *sp = (struct metag_frame *)frame->sp; | |
84 | ||
85 | if (frame->sp & 0x7) | |
86 | return -EINVAL; | |
87 | ||
88 | while (!kstack_end(sp)) { | |
89 | unsigned long addr = sp->lr - 4; | |
90 | sp--; | |
91 | ||
92 | if (__kernel_text_address(addr)) { | |
93 | frame->sp = (unsigned long)sp; | |
94 | frame->pc = addr; | |
95 | return 0; | |
96 | } | |
97 | } | |
98 | return -EINVAL; | |
99 | } | |
100 | #endif | |
101 | ||
102 | void notrace walk_stackframe(struct stackframe *frame, | |
103 | int (*fn)(struct stackframe *, void *), void *data) | |
104 | { | |
105 | while (1) { | |
106 | int ret; | |
107 | ||
108 | if (fn(frame, data)) | |
109 | break; | |
110 | ret = unwind_frame(frame); | |
111 | if (ret < 0) | |
112 | break; | |
113 | } | |
114 | } | |
115 | EXPORT_SYMBOL(walk_stackframe); | |
116 | ||
117 | #ifdef CONFIG_STACKTRACE | |
118 | struct stack_trace_data { | |
119 | struct stack_trace *trace; | |
120 | unsigned int no_sched_functions; | |
121 | unsigned int skip; | |
122 | }; | |
123 | ||
124 | static int save_trace(struct stackframe *frame, void *d) | |
125 | { | |
126 | struct stack_trace_data *data = d; | |
127 | struct stack_trace *trace = data->trace; | |
128 | unsigned long addr = frame->pc; | |
129 | ||
130 | if (data->no_sched_functions && in_sched_functions(addr)) | |
131 | return 0; | |
132 | if (data->skip) { | |
133 | data->skip--; | |
134 | return 0; | |
135 | } | |
136 | ||
137 | trace->entries[trace->nr_entries++] = addr; | |
138 | ||
139 | return trace->nr_entries >= trace->max_entries; | |
140 | } | |
141 | ||
142 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) | |
143 | { | |
144 | struct stack_trace_data data; | |
145 | struct stackframe frame; | |
146 | ||
147 | data.trace = trace; | |
148 | data.skip = trace->skip; | |
149 | ||
150 | if (tsk != current) { | |
151 | #ifdef CONFIG_SMP | |
152 | /* | |
153 | * What guarantees do we have here that 'tsk' is not | |
154 | * running on another CPU? For now, ignore it as we | |
155 | * can't guarantee we won't explode. | |
156 | */ | |
157 | if (trace->nr_entries < trace->max_entries) | |
158 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
159 | return; | |
160 | #else | |
161 | data.no_sched_functions = 1; | |
162 | frame.fp = thread_saved_fp(tsk); | |
163 | frame.sp = thread_saved_sp(tsk); | |
164 | frame.lr = 0; /* recovered from the stack */ | |
165 | frame.pc = thread_saved_pc(tsk); | |
166 | #endif | |
167 | } else { | |
168 | register unsigned long current_sp asm ("A0StP"); | |
169 | ||
170 | data.no_sched_functions = 0; | |
171 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
172 | frame.sp = current_sp; | |
173 | frame.lr = (unsigned long)__builtin_return_address(0); | |
174 | frame.pc = (unsigned long)save_stack_trace_tsk; | |
175 | } | |
176 | ||
177 | walk_stackframe(&frame, save_trace, &data); | |
178 | if (trace->nr_entries < trace->max_entries) | |
179 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
180 | } | |
181 | ||
182 | void save_stack_trace(struct stack_trace *trace) | |
183 | { | |
184 | save_stack_trace_tsk(current, trace); | |
185 | } | |
186 | EXPORT_SYMBOL_GPL(save_stack_trace); | |
187 | #endif |