1 /* $NetBSD: tls.c,v 1.16 2024/11/30 01:04:04 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2011 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Joerg Sonnenberger.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: tls.c,v 1.16 2024/11/30 01:04:04 christos Exp $");
34
35 #include "namespace.h"
36
37 #define _rtld_tls_allocate __libc_rtld_tls_allocate
38 #define _rtld_tls_free __libc_rtld_tls_free
39
40 #include <sys/tls.h>
41
42 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
43
44 #include <sys/param.h>
45 #include <sys/mman.h>
46 #include <link_elf.h>
47 #include <lwp.h>
48 #include <stdbool.h>
49 #include <stdalign.h>
50 #include <stddef.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54
55 #include <machine/lwp_private.h>
56
57 __dso_hidden void __libc_static_tls_setup(void);
58
59 static bool is_dynamic;
60 static const void *tls_initaddr;
61 static size_t tls_initsize;
62 static size_t tls_size;
63 static size_t tls_allocation;
64 static void *initial_thread_tcb;
65
66 void * __libc_tls_get_addr(void);
67
__weak_alias(__tls_get_addr,__libc_tls_get_addr)68 __weak_alias(__tls_get_addr, __libc_tls_get_addr)
69 #ifdef __i386__
70 __weak_alias(___tls_get_addr, __libc_tls_get_addr)
71 #endif
72
73 void *
74 __libc_tls_get_addr(void)
75 {
76
77 abort();
78 /* NOTREACHED */
79 }
80
__weak_alias(_rtld_tls_allocate,__libc_rtld_tls_allocate)81 __weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate)
82
83 struct tls_tcb *
84 _rtld_tls_allocate(void)
85 {
86 struct tls_tcb *tcb;
87 uint8_t *p;
88
89 if (initial_thread_tcb == NULL) {
90 #ifdef __HAVE_TLS_VARIANT_I
91 tls_allocation = tls_size;
92 #else
93 tls_allocation = roundup2(tls_size, alignof(max_align_t));
94 #endif
95
96 initial_thread_tcb = p = mmap(NULL,
97 tls_allocation + sizeof(*tcb), PROT_READ | PROT_WRITE,
98 MAP_ANON, -1, 0);
99 if (p == MAP_FAILED)
100 initial_thread_tcb = p = NULL;
101 } else {
102 p = calloc(1, tls_allocation + sizeof(*tcb));
103 }
104 if (p == NULL) {
105 static const char msg[] = "TLS allocation failed, terminating\n";
106 write(STDERR_FILENO, msg, sizeof(msg));
107 _exit(127);
108 }
109 #ifdef __HAVE_TLS_VARIANT_I
110 /* LINTED */
111 tcb = (struct tls_tcb *)p;
112 p += sizeof(struct tls_tcb);
113 #else
114 /* LINTED tls_size is rounded above */
115 tcb = (struct tls_tcb *)(p + tls_allocation);
116 p = (uint8_t *)tcb - tls_size;
117 tcb->tcb_self = tcb;
118 #endif
119 memcpy(p, tls_initaddr, tls_initsize);
120
121 return tcb;
122 }
123
__weak_alias(_rtld_tls_free,__libc_rtld_tls_free)124 __weak_alias(_rtld_tls_free, __libc_rtld_tls_free)
125
126 void
127 _rtld_tls_free(struct tls_tcb *tcb)
128 {
129 uint8_t *p;
130
131 #ifdef __HAVE_TLS_VARIANT_I
132 /* LINTED */
133 p = (uint8_t *)tcb;
134 #else
135 /* LINTED */
136 p = (uint8_t *)tcb - tls_allocation;
137 #endif
138 if (p == initial_thread_tcb)
139 munmap(p, tls_allocation + sizeof(*tcb));
140 else
141 free(p);
142 }
143
144 static int __section(".text.startup")
145 /*ARGSUSED*/
__libc_static_tls_setup_cb(struct dl_phdr_info * data,size_t len,void * cookie)146 __libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie)
147 {
148 const Elf_Phdr *phdr = data->dlpi_phdr;
149 const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum;
150
151 for (; phdr < phlimit; ++phdr) {
152 if (phdr->p_type == PT_INTERP) {
153 is_dynamic = true;
154 return -1;
155 }
156 if (phdr->p_type != PT_TLS)
157 continue;
158 tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr);
159 tls_initsize = phdr->p_filesz;
160 #ifdef __HAVE_TLS_VARIANT_I
161 tls_size = phdr->p_memsz;
162 #else
163 tls_size = roundup2(phdr->p_memsz, phdr->p_align);
164 #endif
165 }
166 return 0;
167 }
168
169 void
__libc_static_tls_setup(void)170 __libc_static_tls_setup(void)
171 {
172 struct tls_tcb *tcb;
173
174 dl_iterate_phdr(__libc_static_tls_setup_cb, NULL);
175 if (is_dynamic)
176 return;
177
178 tcb = _rtld_tls_allocate();
179 #ifdef __HAVE___LWP_SETTCB
180 __lwp_settcb(tcb);
181 #else
182 _lwp_setprivate(tcb);
183 #endif
184 }
185
186 #endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */
187