49232773d8
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
|
|
/*
|
|
* Copyright (C) 2022 Loongson Technology Corporation Limited
|
|
*/
|
|
#include <linux/kernel.h>
|
|
|
|
#include <asm/unwind.h>
|
|
|
|
unsigned long unwind_get_return_address(struct unwind_state *state)
|
|
{
|
|
if (unwind_done(state))
|
|
return 0;
|
|
else if (state->first)
|
|
return state->pc;
|
|
|
|
return *(unsigned long *)(state->sp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_get_return_address);
|
|
|
|
void unwind_start(struct unwind_state *state, struct task_struct *task,
|
|
struct pt_regs *regs)
|
|
{
|
|
memset(state, 0, sizeof(*state));
|
|
|
|
if (regs) {
|
|
state->sp = regs->regs[3];
|
|
state->pc = regs->csr_era;
|
|
}
|
|
|
|
state->task = task;
|
|
state->first = true;
|
|
|
|
get_stack_info(state->sp, state->task, &state->stack_info);
|
|
|
|
if (!unwind_done(state) && !__kernel_text_address(state->pc))
|
|
unwind_next_frame(state);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_start);
|
|
|
|
bool unwind_next_frame(struct unwind_state *state)
|
|
{
|
|
struct stack_info *info = &state->stack_info;
|
|
unsigned long addr;
|
|
|
|
if (unwind_done(state))
|
|
return false;
|
|
|
|
if (state->first)
|
|
state->first = false;
|
|
|
|
do {
|
|
for (state->sp += sizeof(unsigned long);
|
|
state->sp < info->end;
|
|
state->sp += sizeof(unsigned long)) {
|
|
addr = *(unsigned long *)(state->sp);
|
|
|
|
if (__kernel_text_address(addr))
|
|
return true;
|
|
}
|
|
|
|
state->sp = info->next_sp;
|
|
|
|
} while (!get_stack_info(state->sp, state->task, info));
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_next_frame);
|