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a3931336 | 1 | /* Definition for thread-local data handling. nptl/x86_64 version. |
dff8da6b | 2 | Copyright (C) 2002-2024 Free Software Foundation, Inc. |
a3931336 UD |
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 | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the 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 | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
a3931336 UD |
18 | |
19 | #ifndef _TLS_H | |
20 | #define _TLS_H 1 | |
21 | ||
22 | #ifndef __ASSEMBLER__ | |
16a1d952 | 23 | # include <asm/prctl.h> /* For ARCH_SET_FS. */ |
9dcafc55 | 24 | # include <stdbool.h> |
a3931336 UD |
25 | # include <stddef.h> |
26 | # include <stdint.h> | |
33b5d0cc | 27 | # include <stdlib.h> |
df94b641 | 28 | # include <sysdep.h> |
9090848d | 29 | # include <libc-pointer-arith.h> /* For cast_to_integer. */ |
5a8075b1 | 30 | # include <kernel-features.h> |
aca1daef | 31 | # include <dl-dtv.h> |
f62c8abc L |
32 | |
33 | /* Replacement type for __m128 since this file is included by ld.so, | |
34 | which is compiled with -mno-sse. It must not change the alignment | |
35 | of rtld_savespace_sse. */ | |
36 | typedef struct | |
37 | { | |
38 | int i[4]; | |
39 | } __128bits; | |
a3931336 UD |
40 | |
41 | ||
a3931336 UD |
42 | typedef struct |
43 | { | |
46d51e9b | 44 | void *tcb; /* Pointer to the TCB. Not necessarily the |
a3931336 UD |
45 | thread descriptor used by libpthread. */ |
46 | dtv_t *dtv; | |
47 | void *self; /* Pointer to the thread descriptor. */ | |
bbde8527 | 48 | int multiple_threads; |
df94b641 | 49 | int gscope_flag; |
35f1e827 UD |
50 | uintptr_t sysinfo; |
51 | uintptr_t stack_guard; | |
827b7087 | 52 | uintptr_t pointer_guard; |
501bdb5d | 53 | unsigned long int unused_vgetcpu_cache[2]; |
ebff9c5c L |
54 | /* Bit 0: X86_FEATURE_1_IBT. |
55 | Bit 1: X86_FEATURE_1_SHSTK. | |
56 | */ | |
57 | unsigned int feature_1; | |
2ec0e7ea | 58 | int __glibc_unused1; |
71bb2639 | 59 | /* Reservation of some values for the TM ABI. */ |
ecbf4342 AJ |
60 | void *__private_tm[4]; |
61 | /* GCC split stack support. */ | |
62 | void *__private_ss; | |
edb5e0c8 | 63 | /* The marker for the current shadow stack. */ |
9aa3113a | 64 | unsigned long long int ssp_base; |
f3dcae82 L |
65 | /* Must be kept even if it is no longer used by glibc since programs, |
66 | like AddressSanitizer, depend on the size of tcbhead_t. */ | |
67 | __128bits __glibc_unused2[8][4] __attribute__ ((aligned (32))); | |
b48a267b UD |
68 | |
69 | void *__padding[8]; | |
a3931336 | 70 | } tcbhead_t; |
bbde8527 | 71 | |
0221ce2a L |
72 | # ifdef __ILP32__ |
73 | /* morestack.S in libgcc uses offset 0x40 to access __private_ss, */ | |
74 | _Static_assert (offsetof (tcbhead_t, __private_ss) == 0x40, | |
75 | "offset of __private_ss != 0x40"); | |
9aa3113a L |
76 | /* NB: ssp_base used to be "long int __glibc_reserved2", which was |
77 | changed from 32 bits to 64 bits. Make sure that the offset of the | |
78 | next field, __glibc_unused2, is unchanged. */ | |
79 | _Static_assert (offsetof (tcbhead_t, __glibc_unused2) == 0x60, | |
80 | "offset of __glibc_unused2 != 0x60"); | |
0221ce2a L |
81 | # else |
82 | /* morestack.S in libgcc uses offset 0x70 to access __private_ss, */ | |
83 | _Static_assert (offsetof (tcbhead_t, __private_ss) == 0x70, | |
84 | "offset of __private_ss != 0x70"); | |
9aa3113a L |
85 | _Static_assert (offsetof (tcbhead_t, __glibc_unused2) == 0x80, |
86 | "offset of __glibc_unused2 != 0x80"); | |
0221ce2a L |
87 | # endif |
88 | ||
d0369fb8 UD |
89 | #else /* __ASSEMBLER__ */ |
90 | # include <tcb-offsets.h> | |
a3931336 UD |
91 | #endif |
92 | ||
93 | ||
a3931336 UD |
94 | /* Alignment requirement for the stack. */ |
95 | #define STACK_ALIGN 16 | |
96 | ||
97 | ||
98 | #ifndef __ASSEMBLER__ | |
99 | /* Get system call information. */ | |
100 | # include <sysdep.h> | |
101 | ||
0f34d426 | 102 | #define LOCK_PREFIX "lock;" |
bd4f43b4 | 103 | |
f7d78e18 UD |
104 | /* This is the size of the initial TCB. Can't be just sizeof (tcbhead_t), |
105 | because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole | |
106 | struct pthread even when not linked with -lpthread. */ | |
107 | # define TLS_INIT_TCB_SIZE sizeof (struct pthread) | |
a3931336 | 108 | |
a3931336 UD |
109 | /* This is the size of the TCB. */ |
110 | # define TLS_TCB_SIZE sizeof (struct pthread) | |
111 | ||
a3931336 UD |
112 | /* The TCB can have any size and the memory following the address the |
113 | thread pointer points to is unspecified. Allocate the TCB there. */ | |
114 | # define TLS_TCB_AT_TP 1 | |
498a2233 RM |
115 | # define TLS_DTV_AT_TP 0 |
116 | ||
117 | /* Get the thread descriptor definition. */ | |
118 | # include <nptl/descr.h> | |
a3931336 UD |
119 | |
120 | ||
121 | /* Install the dtv pointer. The pointer passed is to the element with | |
122 | index -1 which contain the length. */ | |
123 | # define INSTALL_DTV(descr, dtvp) \ | |
d4f64e1a | 124 | ((tcbhead_t *) (descr))->dtv = (dtvp) + 1 |
a3931336 UD |
125 | |
126 | /* Install new dtv for current thread. */ | |
d4f64e1a | 127 | # define INSTALL_NEW_DTV(dtvp) \ |
a3931336 | 128 | ({ struct pthread *__pd; \ |
55c11fbd | 129 | THREAD_SETMEM (__pd, header.dtv, (dtvp)); }) |
a3931336 UD |
130 | |
131 | /* Return dtv of given thread descriptor. */ | |
132 | # define GET_DTV(descr) \ | |
133 | (((tcbhead_t *) (descr))->dtv) | |
134 | ||
135 | ||
a3931336 UD |
136 | /* Code to initially initialize the thread pointer. This might need |
137 | special attention since 'errno' is not yet available and if the | |
138 | operation can cause a failure 'errno' must not be touched. | |
139 | ||
140 | We have to make the syscall for both uses of the macro since the | |
141 | address might be (and probably is) different. */ | |
774f9285 | 142 | # define TLS_INIT_TP(thrdescr) \ |
a3931336 UD |
143 | ({ void *_thrdescr = (thrdescr); \ |
144 | tcbhead_t *_head = _thrdescr; \ | |
145 | int _result; \ | |
146 | \ | |
147 | _head->tcb = _thrdescr; \ | |
148 | /* For now the thread descriptor is at the same address. */ \ | |
149 | _head->self = _thrdescr; \ | |
150 | \ | |
151 | /* It is a simple syscall to set the %fs value for the thread. */ \ | |
152 | asm volatile ("syscall" \ | |
153 | : "=a" (_result) \ | |
154 | : "0" ((unsigned long int) __NR_arch_prctl), \ | |
155 | "D" ((unsigned long int) ARCH_SET_FS), \ | |
3e976b96 | 156 | "S" (_thrdescr) \ |
a3931336 UD |
157 | : "memory", "cc", "r11", "cx"); \ |
158 | \ | |
1f34a232 | 159 | _result == 0; \ |
fde89ad0 | 160 | }) |
a3931336 | 161 | |
962b744d RM |
162 | # define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd) |
163 | ||
a3931336 UD |
164 | |
165 | /* Return the address of the dtv for the current thread. */ | |
166 | # define THREAD_DTV() \ | |
167 | ({ struct pthread *__pd; \ | |
55c11fbd | 168 | THREAD_GETMEM (__pd, header.dtv); }) |
a3931336 UD |
169 | |
170 | ||
171 | /* Return the thread descriptor for the current thread. | |
172 | ||
173 | The contained asm must *not* be marked volatile since otherwise | |
174 | assignments like | |
84088310 | 175 | pthread_descr self = thread_self(); |
a3931336 | 176 | do not get optimized away. */ |
1d9cbb96 JJ |
177 | # if __GNUC_PREREQ (6, 0) |
178 | # define THREAD_SELF \ | |
179 | (*(struct pthread *__seg_fs *) offsetof (struct pthread, header.self)) | |
180 | # else | |
181 | # define THREAD_SELF \ | |
a3931336 | 182 | ({ struct pthread *__self; \ |
512ec530 | 183 | asm ("mov %%fs:%c1,%0" : "=r" (__self) \ |
55c11fbd | 184 | : "i" (offsetof (struct pthread, header.self))); \ |
a3931336 | 185 | __self;}) |
1d9cbb96 | 186 | # endif |
a3931336 | 187 | |
7f08f55a RM |
188 | /* Magic for libthread_db to know how to do THREAD_SELF. */ |
189 | # define DB_THREAD_SELF_INCLUDE <sys/reg.h> /* For the FS constant. */ | |
190 | # define DB_THREAD_SELF CONST_THREAD_AREA (64, FS) | |
a3931336 | 191 | |
ce2248ab | 192 | # include <tcb-access.h> |
a3931336 | 193 | |
35f1e827 UD |
194 | /* Set the stack guard field in TCB head. */ |
195 | # define THREAD_SET_STACK_GUARD(value) \ | |
196 | THREAD_SETMEM (THREAD_SELF, header.stack_guard, value) | |
197 | # define THREAD_COPY_STACK_GUARD(descr) \ | |
198 | ((descr)->header.stack_guard \ | |
199 | = THREAD_GETMEM (THREAD_SELF, header.stack_guard)) | |
200 | ||
827b7087 UD |
201 | |
202 | /* Set the pointer guard field in the TCB head. */ | |
b48a267b | 203 | # define THREAD_SET_POINTER_GUARD(value) \ |
827b7087 | 204 | THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value) |
b48a267b | 205 | # define THREAD_COPY_POINTER_GUARD(descr) \ |
827b7087 UD |
206 | ((descr)->header.pointer_guard \ |
207 | = THREAD_GETMEM (THREAD_SELF, header.pointer_guard)) | |
208 | ||
209 | ||
df94b641 | 210 | /* Get and set the global scope generation counter in the TCB head. */ |
b48a267b UD |
211 | # define THREAD_GSCOPE_FLAG_UNUSED 0 |
212 | # define THREAD_GSCOPE_FLAG_USED 1 | |
213 | # define THREAD_GSCOPE_FLAG_WAIT 2 | |
214 | # define THREAD_GSCOPE_RESET_FLAG() \ | |
df94b641 UD |
215 | do \ |
216 | { int __res; \ | |
217 | asm volatile ("xchgl %0, %%fs:%P1" \ | |
218 | : "=r" (__res) \ | |
219 | : "i" (offsetof (struct pthread, header.gscope_flag)), \ | |
220 | "0" (THREAD_GSCOPE_FLAG_UNUSED)); \ | |
221 | if (__res == THREAD_GSCOPE_FLAG_WAIT) \ | |
085a4412 | 222 | lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); \ |
df94b641 UD |
223 | } \ |
224 | while (0) | |
b48a267b | 225 | # define THREAD_GSCOPE_SET_FLAG() \ |
df94b641 | 226 | THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED) |
df94b641 | 227 | |
a3931336 UD |
228 | #endif /* __ASSEMBLER__ */ |
229 | ||
230 | #endif /* tls.h */ |