1 /*- 2 * Copyright (c) 2004 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/lib/libc/gen/tls.c,v 1.7 2005/03/01 23:42:00 davidxu Exp $ 27 * $DragonFly: src/lib/libc/gen/tls.c,v 1.6 2005/03/29 23:04:36 joerg Exp $ 28 */ 29 30 /* 31 * Define stubs for TLS internals so that programs and libraries can 32 * link. These functions will be replaced by functional versions at 33 * runtime from ld-elf.so.1. 34 */ 35 36 #include <sys/cdefs.h> 37 #include <sys/tls.h> 38 39 #include <machine/tls.h> 40 41 #include <stdlib.h> 42 #include <string.h> 43 #include <elf.h> 44 #include <assert.h> 45 46 #include "libc_private.h" 47 48 __weak_reference(__libc_allocate_tls, _rtld_allocate_tls); 49 __weak_reference(__libc_free_tls, _rtld_free_tls); 50 #ifdef __i386__ 51 __weak_reference(___libc_tls_get_addr, ___tls_get_addr); 52 #endif 53 __weak_reference(__libc_tls_get_addr, __tls_get_addr); 54 55 struct tls_tcb *__libc_allocate_tls(struct tls_tcb *old_tcb); 56 void __libc_free_tls(struct tls_tcb *tcb); 57 58 #if !defined(RTLD_STATIC_TLS_VARIANT_II) 59 #error "Unsupported TLS layout" 60 #endif 61 62 #ifndef PIC 63 64 #define round(size, align) \ 65 (((size) + (align) - 1) & ~((align) - 1)) 66 67 static size_t tls_static_space; 68 static size_t tls_init_size; 69 static void *tls_init; 70 #endif 71 72 #ifdef __i386__ 73 74 /* GNU ABI */ 75 76 void *___libc_tls_get_addr(void *ti) __attribute__((__regparm__(1))); 77 78 __attribute__((__regparm__(1))) 79 void * 80 ___libc_tls_get_addr(void *ti __unused) 81 { 82 return (0); 83 } 84 85 #endif 86 87 void *__libc_tls_get_addr(void *ti); 88 89 void * 90 __libc_tls_get_addr(void *ti __unused) 91 { 92 return (0); 93 } 94 95 #ifndef PIC 96 97 /* 98 * Free Static TLS 99 */ 100 void 101 __libc_free_tls(struct tls_tcb *tcb) 102 { 103 size_t data_size; 104 105 if (tcb->tcb_dtv) 106 free(tcb->tcb_dtv); 107 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 108 ~RTLD_STATIC_TLS_ALIGN_MASK; 109 free((char *)tcb - data_size); 110 } 111 112 /* 113 * Allocate Static TLS. 114 */ 115 struct tls_tcb * 116 __libc_allocate_tls(struct tls_tcb *old_tcb) 117 { 118 size_t data_size; 119 struct tls_tcb *tcb; 120 Elf_Addr *dtv; 121 122 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 123 ~RTLD_STATIC_TLS_ALIGN_MASK; 124 tcb = malloc(data_size + sizeof(*tcb)); 125 tcb = (struct tls_tcb *)((char *)tcb + data_size); 126 dtv = malloc(3 * sizeof(Elf_Addr)); 127 128 #ifdef RTLD_TCB_HAS_SELF_POINTER 129 tcb->tcb_self = tcb; 130 #endif 131 tcb->tcb_dtv = dtv; 132 tcb->tcb_pthread = NULL; 133 134 dtv[0] = 1; 135 dtv[1] = 1; 136 dtv[2] = (Elf_Addr)((char *)tcb - tls_static_space); 137 138 if (old_tcb) { 139 /* 140 * Copy the static TLS block over whole. 141 */ 142 memcpy((char *)tcb - tls_static_space, 143 (char *)old_tcb - tls_static_space, 144 tls_static_space); 145 146 /* 147 * We assume that this block was the one we created with 148 * allocate_initial_tls(). 149 */ 150 _rtld_free_tls(old_tcb); 151 } else { 152 memcpy((char *)tcb - tls_static_space, 153 tls_init, tls_init_size); 154 memset((char *)tcb - tls_static_space + tls_init_size, 155 0, tls_static_space - tls_init_size); 156 } 157 return (tcb); 158 } 159 160 #else 161 162 struct tls_tcb * 163 __libc_allocate_tls(struct tls_tcb *old_tls __unused) 164 { 165 return (0); 166 } 167 168 void 169 __libc_free_tls(struct tls_tcb *tcb __unused) 170 { 171 } 172 173 #endif /* PIC */ 174 175 extern char **environ; 176 177 void 178 _init_tls() 179 { 180 #ifndef PIC 181 Elf_Addr *sp; 182 Elf_Auxinfo *aux, *auxp; 183 Elf_Phdr *phdr; 184 size_t phent, phnum; 185 int i; 186 struct tls_tcb *tcb; 187 188 sp = (Elf_Addr *) environ; 189 while (*sp++ != 0) 190 ; 191 aux = (Elf_Auxinfo *) sp; 192 phdr = 0; 193 phent = phnum = 0; 194 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 195 switch (auxp->a_type) { 196 case AT_PHDR: 197 phdr = auxp->a_un.a_ptr; 198 break; 199 200 case AT_PHENT: 201 phent = auxp->a_un.a_val; 202 break; 203 204 case AT_PHNUM: 205 phnum = auxp->a_un.a_val; 206 break; 207 } 208 } 209 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 210 return; 211 212 for (i = 0; (unsigned)i < phnum; i++) { 213 if (phdr[i].p_type == PT_TLS) { 214 tls_static_space = round(phdr[i].p_memsz, 215 phdr[i].p_align); 216 tls_init_size = phdr[i].p_filesz; 217 tls_init = (void*) phdr[i].p_vaddr; 218 } 219 } 220 221 if (tls_static_space) { 222 tcb = _rtld_allocate_tls(NULL); 223 tls_set_tcb(tcb); 224 } 225 #endif 226 } 227