1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/sched.h> |
3 | #include <linux/ftrace.h> |
4 | #include <asm/ptrace.h> |
5 | #include <asm/bitops.h> |
6 | #include <asm/stacktrace.h> |
7 | #include <asm/unwind.h> |
8 | |
9 | unsigned long unwind_get_return_address(struct unwind_state *state) |
10 | { |
11 | unsigned long addr; |
12 | |
13 | if (unwind_done(state)) |
14 | return 0; |
15 | |
16 | addr = READ_ONCE_NOCHECK(*state->sp); |
17 | |
18 | return unwind_recover_ret_addr(state, addr, addr_p: state->sp); |
19 | } |
20 | EXPORT_SYMBOL_GPL(unwind_get_return_address); |
21 | |
22 | unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) |
23 | { |
24 | return NULL; |
25 | } |
26 | |
27 | bool unwind_next_frame(struct unwind_state *state) |
28 | { |
29 | struct stack_info *info = &state->stack_info; |
30 | |
31 | if (unwind_done(state)) |
32 | return false; |
33 | |
34 | do { |
35 | for (state->sp++; state->sp < info->end; state->sp++) { |
36 | unsigned long addr = READ_ONCE_NOCHECK(*state->sp); |
37 | |
38 | if (__kernel_text_address(addr)) |
39 | return true; |
40 | } |
41 | |
42 | state->sp = PTR_ALIGN(info->next_sp, sizeof(long)); |
43 | |
44 | } while (!get_stack_info(stack: state->sp, task: state->task, info, |
45 | visit_mask: &state->stack_mask)); |
46 | |
47 | return false; |
48 | } |
49 | EXPORT_SYMBOL_GPL(unwind_next_frame); |
50 | |
51 | void __unwind_start(struct unwind_state *state, struct task_struct *task, |
52 | struct pt_regs *regs, unsigned long *first_frame) |
53 | { |
54 | memset(state, 0, sizeof(*state)); |
55 | |
56 | state->task = task; |
57 | state->sp = PTR_ALIGN(first_frame, sizeof(long)); |
58 | |
59 | get_stack_info(stack: first_frame, task: state->task, info: &state->stack_info, |
60 | visit_mask: &state->stack_mask); |
61 | |
62 | /* |
63 | * The caller can provide the address of the first frame directly |
64 | * (first_frame) or indirectly (regs->sp) to indicate which stack frame |
65 | * to start unwinding at. Skip ahead until we reach it. |
66 | */ |
67 | if (!unwind_done(state) && |
68 | (!on_stack(info: &state->stack_info, addr: first_frame, len: sizeof(long)) || |
69 | !__kernel_text_address(addr: *first_frame))) |
70 | unwind_next_frame(state); |
71 | } |
72 | EXPORT_SYMBOL_GPL(__unwind_start); |
73 | |