1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2022 Loongson Technology Corporation Limited
4 */
5 #include <linux/kernel.h>
6
7 #include <asm/unwind.h>
8
unwind_get_return_address(struct unwind_state * state)9 unsigned long unwind_get_return_address(struct unwind_state *state)
10 {
11 if (unwind_done(state))
12 return 0;
13 else if (state->first)
14 return state->pc;
15
16 return *(unsigned long *)(state->sp);
17 }
18 EXPORT_SYMBOL_GPL(unwind_get_return_address);
19
unwind_start(struct unwind_state * state,struct task_struct * task,struct pt_regs * regs)20 void unwind_start(struct unwind_state *state, struct task_struct *task,
21 struct pt_regs *regs)
22 {
23 memset(state, 0, sizeof(*state));
24
25 if (regs) {
26 state->sp = regs->regs[3];
27 state->pc = regs->csr_era;
28 }
29
30 state->task = task;
31 state->first = true;
32
33 get_stack_info(state->sp, state->task, &state->stack_info);
34
35 if (!unwind_done(state) && !__kernel_text_address(state->pc))
36 unwind_next_frame(state);
37 }
38 EXPORT_SYMBOL_GPL(unwind_start);
39
unwind_next_frame(struct unwind_state * state)40 bool unwind_next_frame(struct unwind_state *state)
41 {
42 struct stack_info *info = &state->stack_info;
43 unsigned long addr;
44
45 if (unwind_done(state))
46 return false;
47
48 if (state->first)
49 state->first = false;
50
51 do {
52 for (state->sp += sizeof(unsigned long);
53 state->sp < info->end;
54 state->sp += sizeof(unsigned long)) {
55 addr = *(unsigned long *)(state->sp);
56
57 if (__kernel_text_address(addr))
58 return true;
59 }
60
61 state->sp = info->next_sp;
62
63 } while (!get_stack_info(state->sp, state->task, info));
64
65 return false;
66 }
67 EXPORT_SYMBOL_GPL(unwind_next_frame);
68