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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Most of this ideas comes from x86.
*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
#ifndef _ASM_UNWIND_H
#define _ASM_UNWIND_H
#include <linux/sched.h>
#include <linux/ftrace.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
enum unwinder_type {
UNWINDER_GUESS,
UNWINDER_PROLOGUE,
};
struct unwind_state {
char type; /* UNWINDER_XXX */
struct stack_info stack_info;
struct task_struct *task;
bool first, error, reset;
int graph_idx;
unsigned long sp, pc, ra;
};
bool default_next_frame(struct unwind_state *state);
void unwind_start(struct unwind_state *state,
struct task_struct *task, struct pt_regs *regs);
bool unwind_next_frame(struct unwind_state *state);
unsigned long unwind_get_return_address(struct unwind_state *state);
static inline bool unwind_done(struct unwind_state *state)
{
return state->stack_info.type == STACK_TYPE_UNKNOWN;
}
static inline bool unwind_error(struct unwind_state *state)
{
return state->error;
}
#define GRAPH_FAKE_OFFSET (sizeof(struct pt_regs) - offsetof(struct pt_regs, regs[1]))
static inline unsigned long unwind_graph_addr(struct unwind_state *state,
unsigned long pc, unsigned long cfa)
{
return ftrace_graph_ret_addr(state->task, &state->graph_idx,
pc, (unsigned long *)(cfa - GRAPH_FAKE_OFFSET));
}
static __always_inline 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->ra = regs->regs[1];
} else if (task && task != current) {
state->sp = thread_saved_fp(task);
state->pc = thread_saved_ra(task);
state->ra = 0;
} else {
state->sp = (unsigned long)__builtin_frame_address(0);
state->pc = (unsigned long)__builtin_return_address(0);
state->ra = 0;
}
state->task = task;
get_stack_info(state->sp, state->task, &state->stack_info);
state->pc = unwind_graph_addr(state, state->pc, state->sp);
}
static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
{
return unwind_done(state) ? 0 : state->pc;
}
#endif /* _ASM_UNWIND_H */
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