| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 2 | /* |
| 3 | * Stack trace management functions |
| 4 | * |
| 5 | * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> |
| 6 | */ |
| 7 | #include <linux/sched.h> |
| 8 | #include <linux/sched/debug.h> |
| 9 | #include <linux/sched/task_stack.h> |
| 10 | #include <linux/stacktrace.h> |
| 11 | #include <linux/export.h> |
| 12 | #include <asm/stacktrace.h> |
| 13 | |
| 14 | /* |
| 15 | * Save stack-backtrace addresses into a stack_trace buffer: |
| 16 | */ |
| 17 | static void save_raw_context_stack(struct stack_trace *trace, |
| 18 | unsigned long reg29, int savesched) |
| 19 | { |
| 20 | unsigned long *sp = (unsigned long *)reg29; |
| 21 | unsigned long addr; |
| 22 | |
| 23 | while (!kstack_end(sp)) { |
| 24 | addr = *sp++; |
| 25 | if (__kernel_text_address(addr) && |
| 26 | (savesched || !in_sched_functions(addr))) { |
| 27 | if (trace->skip > 0) |
| 28 | trace->skip--; |
| 29 | else |
| 30 | trace->entries[trace->nr_entries++] = addr; |
| 31 | if (trace->nr_entries >= trace->max_entries) |
| 32 | break; |
| 33 | } |
| 34 | } |
| 35 | } |
| 36 | |
| 37 | static void save_context_stack(struct stack_trace *trace, |
| 38 | struct task_struct *tsk, struct pt_regs *regs, int savesched) |
| 39 | { |
| 40 | unsigned long sp = regs->regs[29]; |
| 41 | #ifdef CONFIG_KALLSYMS |
| 42 | unsigned long ra = regs->regs[31]; |
| 43 | unsigned long pc = regs->cp0_epc; |
| 44 | |
| 45 | if (raw_show_trace || !__kernel_text_address(pc)) { |
| 46 | unsigned long stack_page = |
| 47 | (unsigned long)task_stack_page(tsk); |
| 48 | if (stack_page && sp >= stack_page && |
| 49 | sp <= stack_page + THREAD_SIZE - 32) |
| 50 | save_raw_context_stack(trace, sp, savesched); |
| 51 | return; |
| 52 | } |
| 53 | do { |
| 54 | if (savesched || !in_sched_functions(pc)) { |
| 55 | if (trace->skip > 0) |
| 56 | trace->skip--; |
| 57 | else |
| 58 | trace->entries[trace->nr_entries++] = pc; |
| 59 | if (trace->nr_entries >= trace->max_entries) |
| 60 | break; |
| 61 | } |
| 62 | pc = unwind_stack(tsk, &sp, pc, &ra); |
| 63 | } while (pc); |
| 64 | #else |
| 65 | save_raw_context_stack(trace, sp, savesched); |
| 66 | #endif |
| 67 | } |
| 68 | |
| 69 | /* |
| 70 | * Save stack-backtrace addresses into a stack_trace buffer. |
| 71 | */ |
| 72 | void save_stack_trace(struct stack_trace *trace) |
| 73 | { |
| 74 | save_stack_trace_tsk(current, trace); |
| 75 | } |
| 76 | EXPORT_SYMBOL_GPL(save_stack_trace); |
| 77 | |
| 78 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
| 79 | { |
| 80 | struct pt_regs dummyregs; |
| 81 | struct pt_regs *regs = &dummyregs; |
| 82 | |
| 83 | WARN_ON(trace->nr_entries || !trace->max_entries); |
| 84 | |
| 85 | if (tsk != current) { |
| 86 | regs->regs[29] = tsk->thread.reg29; |
| 87 | regs->regs[31] = 0; |
| 88 | regs->cp0_epc = tsk->thread.reg31; |
| 89 | } else |
| 90 | prepare_frametrace(regs); |
| 91 | save_context_stack(trace, tsk, regs, tsk == current); |
| 92 | } |
| 93 | EXPORT_SYMBOL_GPL(save_stack_trace_tsk); |