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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
#include <linux/kernel.h>
#include <linux/ftrace.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);
state->pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
addr, (unsigned long *)(state->sp - GRAPH_FAKE_OFFSET));
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);
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