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