160 lines
3.6 KiB
C
160 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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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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#include <linux/ptrace.h>
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#ifdef CONFIG_FRAME_POINTER
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struct stackframe {
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unsigned long fp;
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unsigned long ra;
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};
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void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
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bool (*fn)(unsigned long, void *), void *arg)
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{
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unsigned long fp, sp, pc;
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if (regs) {
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fp = frame_pointer(regs);
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sp = user_stack_pointer(regs);
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pc = instruction_pointer(regs);
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} else if (task == NULL || task == current) {
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const register unsigned long current_sp __asm__ ("sp");
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const register unsigned long current_fp __asm__ ("r8");
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fp = current_fp;
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sp = current_sp;
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pc = (unsigned long)walk_stackframe;
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} else {
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/* task blocked in __switch_to */
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fp = thread_saved_fp(task);
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sp = thread_saved_sp(task);
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pc = thread_saved_lr(task);
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}
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for (;;) {
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unsigned long low, high;
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struct stackframe *frame;
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if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
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break;
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/* Validate frame pointer */
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low = sp;
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high = ALIGN(sp, THREAD_SIZE);
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if (unlikely(fp < low || fp > high || fp & 0x3))
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break;
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/* Unwind stack frame */
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frame = (struct stackframe *)fp;
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sp = fp;
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fp = frame->fp;
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pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
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(unsigned long *)(fp - 8));
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}
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}
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#else /* !CONFIG_FRAME_POINTER */
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static void notrace walk_stackframe(struct task_struct *task,
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struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
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{
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unsigned long sp, pc;
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unsigned long *ksp;
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if (regs) {
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sp = user_stack_pointer(regs);
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pc = instruction_pointer(regs);
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} else if (task == NULL || task == current) {
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const register unsigned long current_sp __asm__ ("sp");
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sp = current_sp;
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pc = (unsigned long)walk_stackframe;
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} else {
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/* task blocked in __switch_to */
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sp = thread_saved_sp(task);
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pc = thread_saved_lr(task);
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}
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if (unlikely(sp & 0x3))
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return;
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ksp = (unsigned long *)sp;
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while (!kstack_end(ksp)) {
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if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
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break;
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pc = (*ksp++) - 0x4;
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}
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}
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#endif /* CONFIG_FRAME_POINTER */
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static bool print_trace_address(unsigned long pc, void *arg)
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{
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print_ip_sym((const char *)arg, pc);
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return false;
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}
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void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
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{
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pr_cont("Call Trace:\n");
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walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
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}
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static bool save_wchan(unsigned long pc, void *arg)
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{
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if (!in_sched_functions(pc)) {
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unsigned long *p = arg;
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*p = pc;
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return true;
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}
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return false;
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}
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unsigned long get_wchan(struct task_struct *task)
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{
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unsigned long pc = 0;
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if (likely(task && task != current && task->state != TASK_RUNNING))
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walk_stackframe(task, NULL, save_wchan, &pc);
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return pc;
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}
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#ifdef CONFIG_STACKTRACE
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static bool __save_trace(unsigned long pc, void *arg, bool nosched)
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{
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struct stack_trace *trace = arg;
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if (unlikely(nosched && in_sched_functions(pc)))
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return false;
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if (unlikely(trace->skip > 0)) {
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trace->skip--;
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return false;
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}
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trace->entries[trace->nr_entries++] = pc;
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return (trace->nr_entries >= trace->max_entries);
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}
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static bool save_trace(unsigned long pc, void *arg)
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{
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return __save_trace(pc, arg, false);
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}
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/*
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* Save stack-backtrace addresses into a stack_trace buffer.
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*/
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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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walk_stackframe(tsk, NULL, save_trace, trace);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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void save_stack_trace(struct stack_trace *trace)
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{
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save_stack_trace_tsk(NULL, trace);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace);
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#endif /* CONFIG_STACKTRACE */
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