![Guo Ren](/assets/img/avatar_default.png)
The gcc option "-mbacktrace" will push fp(r8),lr into stack and we could unwind the stack with: fp = *fp lr = (unsigned int *)fp[1] Signed-off-by: Guo Ren <ren_guo@c-sky.com>
58 lines
1.3 KiB
C
58 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. */
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#include <linux/sched/debug.h>
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#include <linux/sched/task_stack.h>
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#include <linux/stacktrace.h>
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#include <linux/ftrace.h>
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void save_stack_trace(struct stack_trace *trace)
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{
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save_stack_trace_tsk(current, trace);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace);
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void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
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{
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unsigned long *fp, *stack_start, *stack_end;
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unsigned long addr;
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int skip = trace->skip;
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int savesched;
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int graph_idx = 0;
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if (tsk == current) {
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asm volatile("mov %0, r8\n":"=r"(fp));
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savesched = 1;
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} else {
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fp = (unsigned long *)thread_saved_fp(tsk);
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savesched = 0;
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}
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addr = (unsigned long) fp & THREAD_MASK;
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stack_start = (unsigned long *) addr;
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stack_end = (unsigned long *) (addr + THREAD_SIZE);
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while (fp > stack_start && fp < stack_end) {
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unsigned long lpp, fpp;
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fpp = fp[0];
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lpp = fp[1];
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if (!__kernel_text_address(lpp))
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break;
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else
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lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL);
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if (savesched || !in_sched_functions(lpp)) {
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if (skip) {
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skip--;
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} else {
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trace->entries[trace->nr_entries++] = lpp;
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if (trace->nr_entries >= trace->max_entries)
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break;
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}
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}
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fp = (unsigned long *)fpp;
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}
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}
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EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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