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Name "guess unwinder" comes from x86, it scans the stack and reports every kernel text address it finds. Unwinders can be used by dump_stack() and other stacktrace functions. Three stages when we do unwind, 1) unwind_start(), the prapare of unwinding, fill unwind_state. 2) unwind_done(), judge whether the unwind process is finished or not. 3) unwind_next_frame(), unwind the next frame. Add get_stack_info() to get stack info. At present we have irq stack and task stack. The next_sp is the key info between two types of stacks. Dividing unwinder helps to add new unwinders in the future. Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2022 Loongson Technology Corporation Limited
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*/
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#include <linux/kernel.h>
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#include <asm/unwind.h>
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unsigned long unwind_get_return_address(struct unwind_state *state)
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{
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if (unwind_done(state))
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return 0;
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else if (state->first)
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return state->pc;
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return *(unsigned long *)(state->sp);
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}
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EXPORT_SYMBOL_GPL(unwind_get_return_address);
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void unwind_start(struct unwind_state *state, struct task_struct *task,
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struct pt_regs *regs)
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{
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memset(state, 0, sizeof(*state));
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if (regs) {
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state->sp = regs->regs[3];
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state->pc = regs->csr_era;
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}
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state->task = task;
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state->first = true;
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get_stack_info(state->sp, state->task, &state->stack_info);
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if (!unwind_done(state) && !__kernel_text_address(state->pc))
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unwind_next_frame(state);
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}
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EXPORT_SYMBOL_GPL(unwind_start);
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bool unwind_next_frame(struct unwind_state *state)
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{
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struct stack_info *info = &state->stack_info;
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unsigned long addr;
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if (unwind_done(state))
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return false;
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if (state->first)
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state->first = false;
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do {
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for (state->sp += sizeof(unsigned long);
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state->sp < info->end;
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state->sp += sizeof(unsigned long)) {
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addr = *(unsigned long *)(state->sp);
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if (__kernel_text_address(addr))
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return true;
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}
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state->sp = info->next_sp;
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} while (!get_stack_info(state->sp, state->task, info));
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return false;
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}
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EXPORT_SYMBOL_GPL(unwind_next_frame);
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