projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 60ffc30d CM |
1 | /* |
| 2 | * Stack tracing support | |
| 3 | * | |
| 4 | * Copyright (C) 2012 ARM Ltd. | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or modify | |
| 7 | * it under the terms of the GNU General Public License version 2 as | |
| 8 | * published by the Free Software Foundation. | |
| 9 | * | |
| 10 | * This program is distributed in the hope that it will be useful, | |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 13 | * GNU General Public License for more details. | |
| 14 | * | |
| 15 | * You should have received a copy of the GNU General Public License | |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
| 17 | */ | |
| 18 | #include <linux/kernel.h> | |
| 19 | #include <linux/export.h> | |
| 20 | #include <linux/sched.h> | |
| 21 | #include <linux/stacktrace.h> | |
| 22 | ||
| 23 | #include <asm/stacktrace.h> | |
| 24 | ||
| 25 | /* | |
| 26 | * AArch64 PCS assigns the frame pointer to x29. | |
| 27 | * | |
| 28 | * A simple function prologue looks like this: | |
| 29 | * sub sp, sp, #0x10 | |
| 30 | * stp x29, x30, [sp] | |
| 31 | * mov x29, sp | |
| 32 | * | |
| 33 | * A simple function epilogue looks like this: | |
| 34 | * mov sp, x29 | |
| 35 | * ldp x29, x30, [sp] | |
| 36 | * add sp, sp, #0x10 | |
| 37 | */ | |
| 38 | int unwind_frame(struct stackframe *frame) | |
| 39 | { | |
| 40 | unsigned long high, low; | |
| 41 | unsigned long fp = frame->fp; | |
| 42 | ||
| 43 | low = frame->sp; | |
| 44 | high = ALIGN(low, THREAD_SIZE); | |
| 45 | ||
| 46 | if (fp < low || fp > high || fp & 0xf) | |
| 47 | return -EINVAL; | |
| 48 | ||
| 49 | frame->sp = fp + 0x10; | |
| 50 | frame->fp = *(unsigned long *)(fp); | |
| 51 | frame->pc = *(unsigned long *)(fp + 8); | |
| 52 | ||
| 53 | return 0; | |
| 54 | } | |
| 55 | ||
| 56 | void notrace walk_stackframe(struct stackframe *frame, | |
| 57 | int (*fn)(struct stackframe *, void *), void *data) | |
| 58 | { | |
| 59 | while (1) { | |
| 60 | int ret; | |
| 61 | ||
| 62 | if (fn(frame, data)) | |
| 63 | break; | |
| 64 | ret = unwind_frame(frame); | |
| 65 | if (ret < 0) | |
| 66 | break; | |
| 67 | } | |
| 68 | } | |
| 69 | EXPORT_SYMBOL(walk_stackframe); | |
| 70 | ||
| 71 | #ifdef CONFIG_STACKTRACE | |
| 72 | struct stack_trace_data { | |
| 73 | struct stack_trace *trace; | |
| 74 | unsigned int no_sched_functions; | |
| 75 | unsigned int skip; | |
| 76 | }; | |
| 77 | ||
| 78 | static int save_trace(struct stackframe *frame, void *d) | |
| 79 | { | |
| 80 | struct stack_trace_data *data = d; | |
| 81 | struct stack_trace *trace = data->trace; | |
| 82 | unsigned long addr = frame->pc; | |
| 83 | ||
| 84 | if (data->no_sched_functions && in_sched_functions(addr)) | |
| 85 | return 0; | |
| 86 | if (data->skip) { | |
| 87 | data->skip--; | |
| 88 | return 0; | |
| 89 | } | |
| 90 | ||
| 91 | trace->entries[trace->nr_entries++] = addr; | |
| 92 | ||
| 93 | return trace->nr_entries >= trace->max_entries; | |
| 94 | } | |
| 95 | ||
| 96 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) | |
| 97 | { | |
| 98 | struct stack_trace_data data; | |
| 99 | struct stackframe frame; | |
| 100 | ||
| 101 | data.trace = trace; | |
| 102 | data.skip = trace->skip; | |
| 103 | ||
| 104 | if (tsk != current) { | |
| 105 | data.no_sched_functions = 1; | |
| 106 | frame.fp = thread_saved_fp(tsk); | |
| 107 | frame.sp = thread_saved_sp(tsk); | |
| 108 | frame.pc = thread_saved_pc(tsk); | |
| 109 | } else { | |
| 110 | register unsigned long current_sp asm("sp"); | |
| 111 | data.no_sched_functions = 0; | |
| 112 | frame.fp = (unsigned long)__builtin_frame_address(0); | |
| 113 | frame.sp = current_sp; | |
| 114 | frame.pc = (unsigned long)save_stack_trace_tsk; | |
| 115 | } | |
| 116 | ||
| 117 | walk_stackframe(&frame, save_trace, &data); | |
| 118 | if (trace->nr_entries < trace->max_entries) | |
| 119 | trace->entries[trace->nr_entries++] = ULONG_MAX; | |
| 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 |