// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Stack trace management functions
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*
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* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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*/
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#include <linux/sched.h>
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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/export.h>
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#include <asm/stacktrace.h>
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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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static void save_raw_context_stack(struct stack_trace *trace,
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unsigned long reg29, int savesched)
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{
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unsigned long *sp = (unsigned long *)reg29;
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unsigned long addr;
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while (!kstack_end(sp)) {
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addr = *sp++;
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if (__kernel_text_address(addr) &&
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(savesched || !in_sched_functions(addr))) {
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if (trace->skip > 0)
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trace->skip--;
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else
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trace->entries[trace->nr_entries++] = addr;
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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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}
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static void save_context_stack(struct stack_trace *trace,
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struct task_struct *tsk, struct pt_regs *regs, int savesched)
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{
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unsigned long sp = regs->regs[29];
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#ifdef CONFIG_KALLSYMS
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unsigned long ra = regs->regs[31];
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unsigned long pc = regs->cp0_epc;
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if (raw_show_trace || !__kernel_text_address(pc)) {
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unsigned long stack_page =
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(unsigned long)task_stack_page(tsk);
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if (stack_page && sp >= stack_page &&
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sp <= stack_page + THREAD_SIZE - 32)
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save_raw_context_stack(trace, sp, savesched);
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return;
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}
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do {
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if (savesched || !in_sched_functions(pc)) {
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if (trace->skip > 0)
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trace->skip--;
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else
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trace->entries[trace->nr_entries++] = pc;
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if (trace->nr_entries >= trace->max_entries)
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break;
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}
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pc = unwind_stack(tsk, &sp, pc, &ra);
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} while (pc);
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#else
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save_raw_context_stack(trace, sp, savesched);
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#endif
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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(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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struct pt_regs dummyregs;
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struct pt_regs *regs = &dummyregs;
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WARN_ON(trace->nr_entries || !trace->max_entries);
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if (tsk != current) {
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regs->regs[29] = tsk->thread.reg29;
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regs->regs[31] = 0;
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regs->cp0_epc = tsk->thread.reg31;
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} else
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prepare_frametrace(regs);
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save_context_stack(trace, tsk, regs, tsk == current);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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