1 /* $NetBSD: tls.c,v 1.6 2011/04/07 02:19:28 matt 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 1.6 2011/04/07 02:19:28 matt 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 <stddef.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <unistd.h> 52 53 __dso_hidden void __libc_static_tls_setup(void); 54 55 static const void *tls_initaddr; 56 static size_t tls_initsize; 57 static size_t tls_size; 58 static size_t tls_allocation; 59 static void *initial_thread_tcb; 60 61 void * __libc_tls_get_addr(void); 62 63 __weak_alias(__tls_get_addr, __libc_tls_get_addr) 64 #ifdef __i386__ 65 __weak_alias(___tls_get_addr, __libc_tls_get_addr) 66 #endif 67 68 void * 69 __libc_tls_get_addr(void) 70 { 71 72 abort(); 73 /* NOTREACHED */ 74 } 75 76 __weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate) 77 78 struct tls_tcb * 79 _rtld_tls_allocate(void) 80 { 81 struct tls_tcb *tcb; 82 uint8_t *p; 83 84 if (initial_thread_tcb == NULL) { 85 #ifdef __HAVE_TLS_VARIANT_II 86 tls_size = roundup2(tls_size, sizeof(void *)); 87 #endif 88 tls_allocation = tls_size + sizeof(*tcb); 89 90 initial_thread_tcb = p = mmap(NULL, tls_allocation, 91 PROT_READ | PROT_WRITE, MAP_ANON, -1, 0); 92 } else { 93 p = calloc(1, tls_allocation); 94 } 95 if (p == NULL) { 96 static const char msg[] = "TLS allocation failed, terminating\n"; 97 write(STDERR_FILENO, msg, sizeof(msg)); 98 _exit(127); 99 } 100 #ifdef __HAVE_TLS_VARIANT_I 101 /* LINTED */ 102 tcb = (struct tls_tcb *)p; 103 p += sizeof(struct tls_tcb); 104 #else 105 /* LINTED tls_size is rounded above */ 106 tcb = (struct tls_tcb *)(p + tls_size); 107 tcb->tcb_self = tcb; 108 #endif 109 memcpy(p, tls_initaddr, tls_initsize); 110 111 return tcb; 112 } 113 114 __weak_alias(_rtld_tls_free, __libc_rtld_tls_free) 115 116 void 117 _rtld_tls_free(struct tls_tcb *tcb) 118 { 119 uint8_t *p; 120 121 #ifdef __HAVE_TLS_VARIANT_I 122 /* LINTED */ 123 p = (uint8_t *)tcb; 124 #else 125 /* LINTED */ 126 p = (uint8_t *)tcb - tls_size; 127 #endif 128 if (p == initial_thread_tcb) 129 munmap(p, tls_allocation); 130 else 131 free(p); 132 } 133 134 __weakref_visible int rtld_DYNAMIC __weak_reference(_DYNAMIC); 135 136 static int 137 __libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie) 138 { 139 const Elf_Phdr *phdr = data->dlpi_phdr; 140 const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum; 141 142 for (; phdr < phlimit; ++phdr) { 143 if (phdr->p_type != PT_TLS) 144 continue; 145 tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr); 146 tls_initsize = phdr->p_filesz; 147 tls_size = phdr->p_memsz; 148 } 149 return 0; 150 } 151 152 void 153 __libc_static_tls_setup(void) 154 { 155 struct tls_tcb *tcb; 156 157 if (&rtld_DYNAMIC != NULL) { 158 #ifdef __powerpc__ 159 /* 160 * Old powerpc crt0's are going to overwrite r2 so we need to 161 * restore it but only do so if the saved value isn't NULL (if 162 * it is NULL, ld.elf_so doesn't have the matching change). 163 */ 164 if ((tcb = _lwp_getprivate()) != NULL) 165 __lwp_settcb(tcb); 166 #endif 167 return; 168 } 169 170 dl_iterate_phdr(__libc_static_tls_setup_cb, NULL); 171 172 tcb = _rtld_tls_allocate(); 173 #ifdef __HAVE___LWP_SETTCB 174 __lwp_settcb(tcb); 175 #else 176 _lwp_setprivate(tcb); 177 #endif 178 } 179 180 #endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */ 181