| Atsushi Nemoto | 1df0f0f | 2006-09-26 23:44:01 +0900 | [diff] [blame^] | 1 | /* |
| 2 | * arch/mips/kernel/stacktrace.c |
| 3 | * |
| 4 | * Stack trace management functions |
| 5 | * |
| 6 | * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> |
| 7 | */ |
| 8 | #include <linux/sched.h> |
| 9 | #include <linux/stacktrace.h> |
| 10 | #include <asm/stacktrace.h> |
| 11 | |
| 12 | /* |
| 13 | * Save stack-backtrace addresses into a stack_trace buffer: |
| 14 | */ |
| 15 | static void save_raw_context_stack(struct stack_trace *trace, |
| 16 | unsigned int skip, unsigned long reg29) |
| 17 | { |
| 18 | unsigned long *sp = (unsigned long *)reg29; |
| 19 | unsigned long addr; |
| 20 | |
| 21 | while (!kstack_end(sp)) { |
| 22 | addr = *sp++; |
| 23 | if (__kernel_text_address(addr)) { |
| 24 | if (!skip) |
| 25 | trace->entries[trace->nr_entries++] = addr; |
| 26 | else |
| 27 | skip--; |
| 28 | if (trace->nr_entries >= trace->max_entries) |
| 29 | break; |
| 30 | } |
| 31 | } |
| 32 | } |
| 33 | |
| 34 | static struct pt_regs * save_context_stack(struct stack_trace *trace, |
| 35 | unsigned int skip, struct task_struct *task, struct pt_regs *regs) |
| 36 | { |
| 37 | unsigned long sp = regs->regs[29]; |
| 38 | #ifdef CONFIG_KALLSYMS |
| 39 | unsigned long ra = regs->regs[31]; |
| 40 | unsigned long pc = regs->cp0_epc; |
| 41 | extern void ret_from_irq(void); |
| 42 | |
| 43 | if (raw_show_trace || !__kernel_text_address(pc)) { |
| 44 | save_raw_context_stack(trace, skip, sp); |
| 45 | return NULL; |
| 46 | } |
| 47 | do { |
| 48 | if (!skip) |
| 49 | trace->entries[trace->nr_entries++] = pc; |
| 50 | else |
| 51 | skip--; |
| 52 | if (trace->nr_entries >= trace->max_entries) |
| 53 | break; |
| 54 | /* |
| 55 | * If we reached the bottom of interrupt context, |
| 56 | * return saved pt_regs. |
| 57 | */ |
| 58 | if (pc == (unsigned long)ret_from_irq) { |
| 59 | unsigned long stack_page = |
| 60 | (unsigned long)task_stack_page(task); |
| 61 | if (!stack_page || |
| 62 | sp < stack_page || |
| 63 | sp > stack_page + THREAD_SIZE - 32) |
| 64 | break; |
| 65 | return (struct pt_regs *)sp; |
| 66 | } |
| 67 | pc = unwind_stack(task, &sp, pc, ra); |
| 68 | ra = 0; |
| 69 | } while (pc); |
| 70 | #else |
| 71 | save_raw_context_stack(sp); |
| 72 | #endif |
| 73 | |
| 74 | return NULL; |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Save stack-backtrace addresses into a stack_trace buffer. |
| 79 | * If all_contexts is set, all contexts (hardirq, softirq and process) |
| 80 | * are saved. If not set then only the current context is saved. |
| 81 | */ |
| 82 | void save_stack_trace(struct stack_trace *trace, |
| 83 | struct task_struct *task, int all_contexts, |
| 84 | unsigned int skip) |
| 85 | { |
| 86 | struct pt_regs dummyregs; |
| 87 | struct pt_regs *regs = &dummyregs; |
| 88 | |
| 89 | WARN_ON(trace->nr_entries || !trace->max_entries); |
| 90 | |
| 91 | if (task && task != current) { |
| 92 | regs->regs[29] = task->thread.reg29; |
| 93 | regs->regs[31] = 0; |
| 94 | regs->cp0_epc = task->thread.reg31; |
| 95 | } else { |
| 96 | if (!task) |
| 97 | task = current; |
| 98 | prepare_frametrace(regs); |
| 99 | } |
| 100 | |
| 101 | while (1) { |
| 102 | regs = save_context_stack(trace, skip, task, regs); |
| 103 | if (!all_contexts || !regs || |
| 104 | trace->nr_entries >= trace->max_entries) |
| 105 | break; |
| 106 | trace->entries[trace->nr_entries++] = ULONG_MAX; |
| 107 | if (trace->nr_entries >= trace->max_entries) |
| 108 | break; |
| 109 | skip = 0; |
| 110 | } |
| 111 | } |