tls.c revision 1.16
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 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 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 } 123 124 __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*/ 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 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
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