1/* Copyright (C) 1997-2022 Free Software Foundation, Inc.
2
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sysdep.h>
20#include <jmpbuf-offsets.h>
21#include <stap-probe.h>
22
23/* __longjmp(jmpbuf, val) */
24
25ENTRY (__longjmp)
26 cfi_def_cfa(x0, 0)
27 cfi_offset(x19, JB_X19<<3)
28 cfi_offset(x20, JB_X20<<3)
29 cfi_offset(x21, JB_X21<<3)
30 cfi_offset(x22, JB_X22<<3)
31 cfi_offset(x23, JB_X23<<3)
32 cfi_offset(x24, JB_X24<<3)
33 cfi_offset(x25, JB_X25<<3)
34 cfi_offset(x26, JB_X26<<3)
35 cfi_offset(x27, JB_X27<<3)
36 cfi_offset(x28, JB_X28<<3)
37 cfi_offset(x29, JB_X29<<3)
38 cfi_offset(x30, JB_LR<<3)
39
40 cfi_offset( d8, JB_D8<<3)
41 cfi_offset( d9, JB_D9<<3)
42 cfi_offset(d10, JB_D10<<3)
43 cfi_offset(d11, JB_D11<<3)
44 cfi_offset(d12, JB_D12<<3)
45 cfi_offset(d13, JB_D13<<3)
46 cfi_offset(d14, JB_D14<<3)
47 cfi_offset(d15, JB_D15<<3)
48
49 PTR_ARG (0)
50
51 ldp x19, x20, [x0, #JB_X19<<3]
52 ldp x21, x22, [x0, #JB_X21<<3]
53 ldp x23, x24, [x0, #JB_X23<<3]
54 ldp x25, x26, [x0, #JB_X25<<3]
55 ldp x27, x28, [x0, #JB_X27<<3]
56#ifdef PTR_DEMANGLE
57 ldp x29, x4, [x0, #JB_X29<<3]
58 PTR_DEMANGLE (30, 4, 3, 2)
59#else
60 ldp x29, x30, [x0, #JB_X29<<3]
61#endif
62 /* longjmp probe takes 3 arguments, address of jump buffer as
63 first argument (8@x0), return value as second argument (-4@x1),
64 and target address (8@x30), respectively. */
65 LIBC_PROBE (longjmp, 3, 8@x0, -4@x1, 8@x30)
66 ldp d8, d9, [x0, #JB_D8<<3]
67 ldp d10, d11, [x0, #JB_D10<<3]
68 ldp d12, d13, [x0, #JB_D12<<3]
69 ldp d14, d15, [x0, #JB_D14<<3]
70
71 /* Originally this was implemented with a series of
72 .cfi_restore() directives.
73
74 The theory was that cfi_restore should revert to previous
75 frame value is the same as the current value. In practice
76 this doesn't work, even after cfi_restore() gdb continues
77 to try to recover a previous frame value offset from x0,
78 which gets stuffed after a few more instructions. The
79 cfi_same_value() mechanism appears to work fine. */
80
81 cfi_same_value(x19)
82 cfi_same_value(x20)
83 cfi_same_value(x21)
84 cfi_same_value(x22)
85 cfi_same_value(x23)
86 cfi_same_value(x24)
87 cfi_same_value(x25)
88 cfi_same_value(x26)
89 cfi_same_value(x27)
90 cfi_same_value(x28)
91 cfi_same_value(x29)
92 cfi_same_value(x30)
93 cfi_same_value(d8)
94 cfi_same_value(d9)
95 cfi_same_value(d10)
96 cfi_same_value(d11)
97 cfi_same_value(d12)
98 cfi_same_value(d13)
99 cfi_same_value(d14)
100 cfi_same_value(d15)
101#ifdef PTR_DEMANGLE
102 ldr x4, [x0, #JB_SP<<3]
103 PTR_DEMANGLE (5, 4, 3, 2)
104#else
105 ldr x5, [x0, #JB_SP<<3]
106#endif
107 mov sp, x5
108
109 /* longjmp_target probe takes 3 arguments, address of jump buffer
110 as first argument (8@x0), return value as second argument (-4@x1),
111 and target address (8@x30), respectively. */
112 LIBC_PROBE (longjmp_target, 3, 8@x0, -4@x1, 8@x30)
113 cmp x1, #0
114 mov x0, #1
115 csel x0, x1, x0, ne
116 /* Use br instead of ret because ret is guaranteed to mispredict */
117 br x30
118END (__longjmp)
119

source code of glibc/sysdeps/aarch64/__longjmp.S