1/* Copyright (C) 1997-2024 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 <pointer_guard.h>
21#include <jmpbuf-offsets.h>
22#include <stap-probe.h>
23
24/* __longjmp(jmpbuf, val) */
25
26ENTRY (__longjmp)
27 cfi_def_cfa(x0, 0)
28 cfi_offset(x19, JB_X19<<3)
29 cfi_offset(x20, JB_X20<<3)
30 cfi_offset(x21, JB_X21<<3)
31 cfi_offset(x22, JB_X22<<3)
32 cfi_offset(x23, JB_X23<<3)
33 cfi_offset(x24, JB_X24<<3)
34 cfi_offset(x25, JB_X25<<3)
35 cfi_offset(x26, JB_X26<<3)
36 cfi_offset(x27, JB_X27<<3)
37 cfi_offset(x28, JB_X28<<3)
38 cfi_offset(x29, JB_X29<<3)
39 cfi_offset(x30, JB_LR<<3)
40
41 cfi_offset( d8, JB_D8<<3)
42 cfi_offset( d9, JB_D9<<3)
43 cfi_offset(d10, JB_D10<<3)
44 cfi_offset(d11, JB_D11<<3)
45 cfi_offset(d12, JB_D12<<3)
46 cfi_offset(d13, JB_D13<<3)
47 cfi_offset(d14, JB_D14<<3)
48 cfi_offset(d15, JB_D15<<3)
49
50 PTR_ARG (0)
51
52#if IS_IN(libc)
53 /* Disable ZA state of SME in libc.a and libc.so, but not in ld.so. */
54# if HAVE_AARCH64_PAC_RET
55 PACIASP
56 cfi_window_save
57# endif
58 stp x29, x30, [sp, -16]!
59 cfi_adjust_cfa_offset (16)
60 cfi_rel_offset (x29, 0)
61 cfi_rel_offset (x30, 8)
62 mov x29, sp
63 bl __libc_arm_za_disable
64 ldp x29, x30, [sp], 16
65 cfi_adjust_cfa_offset (-16)
66 cfi_restore (x29)
67 cfi_restore (x30)
68# if HAVE_AARCH64_PAC_RET
69 AUTIASP
70 cfi_window_save
71# endif
72#endif
73
74 ldp x19, x20, [x0, #JB_X19<<3]
75 ldp x21, x22, [x0, #JB_X21<<3]
76 ldp x23, x24, [x0, #JB_X23<<3]
77 ldp x25, x26, [x0, #JB_X25<<3]
78 ldp x27, x28, [x0, #JB_X27<<3]
79#ifdef PTR_DEMANGLE
80 ldp x29, x4, [x0, #JB_X29<<3]
81 PTR_DEMANGLE (30, 4, 3, 2)
82#else
83 ldp x29, x30, [x0, #JB_X29<<3]
84#endif
85 /* longjmp probe takes 3 arguments, address of jump buffer as
86 first argument (8@x0), return value as second argument (-4@x1),
87 and target address (8@x30), respectively. */
88 LIBC_PROBE (longjmp, 3, 8@x0, -4@x1, 8@x30)
89 ldp d8, d9, [x0, #JB_D8<<3]
90 ldp d10, d11, [x0, #JB_D10<<3]
91 ldp d12, d13, [x0, #JB_D12<<3]
92 ldp d14, d15, [x0, #JB_D14<<3]
93
94 /* Originally this was implemented with a series of
95 .cfi_restore() directives.
96
97 The theory was that cfi_restore should revert to previous
98 frame value is the same as the current value. In practice
99 this doesn't work, even after cfi_restore() gdb continues
100 to try to recover a previous frame value offset from x0,
101 which gets stuffed after a few more instructions. The
102 cfi_same_value() mechanism appears to work fine. */
103
104 cfi_same_value(x19)
105 cfi_same_value(x20)
106 cfi_same_value(x21)
107 cfi_same_value(x22)
108 cfi_same_value(x23)
109 cfi_same_value(x24)
110 cfi_same_value(x25)
111 cfi_same_value(x26)
112 cfi_same_value(x27)
113 cfi_same_value(x28)
114 cfi_same_value(x29)
115 cfi_same_value(x30)
116 cfi_same_value(d8)
117 cfi_same_value(d9)
118 cfi_same_value(d10)
119 cfi_same_value(d11)
120 cfi_same_value(d12)
121 cfi_same_value(d13)
122 cfi_same_value(d14)
123 cfi_same_value(d15)
124#ifdef PTR_DEMANGLE
125 ldr x4, [x0, #JB_SP<<3]
126 PTR_DEMANGLE (5, 4, 3, 2)
127#else
128 ldr x5, [x0, #JB_SP<<3]
129#endif
130 mov sp, x5
131
132 /* longjmp_target probe takes 3 arguments, address of jump buffer
133 as first argument (8@x0), return value as second argument (-4@x1),
134 and target address (8@x30), respectively. */
135 LIBC_PROBE (longjmp_target, 3, 8@x0, -4@x1, 8@x30)
136 cmp x1, #0
137 mov x0, #1
138 csel x0, x1, x0, ne
139 /* Use br instead of ret because ret is guaranteed to mispredict */
140 br x30
141END (__longjmp)
142

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