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 * $FreeBSD$ 27 */ 28 29 /* 30 * Define stubs for TLS internals so that programs and libraries can 31 * link. These functions will be replaced by functional versions at 32 * runtime from ld-elf.so.1. 33 */ 34 35 #include <stdlib.h> 36 #include <string.h> 37 #include <elf.h> 38 #include <assert.h> 39 #include "libc_private.h" 40 41 /* XXX not sure what variants to use for arm. */ 42 43 #if defined(__ia64__) || defined(__alpha__) || defined(__powerpc__) 44 #define TLS_VARIANT_I 45 #endif 46 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 47 #define TLS_VARIANT_II 48 #endif 49 50 #ifndef PIC 51 52 #define round(size, align) \ 53 (((size) + (align) - 1) & ~((align) - 1)) 54 55 static size_t tls_static_space; 56 static size_t tls_init_size; 57 #ifdef TLS_VARIANT_I 58 static size_t tls_init_offset; 59 #endif 60 static void *tls_init; 61 62 void _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign); 63 #endif 64 65 #ifdef __i386__ 66 67 extern void *___tls_get_addr(void *ti) __attribute__((__regparm__(1))); 68 69 #pragma weak ___tls_get_addr 70 __attribute__((__regparm__(1))) 71 void * 72 ___tls_get_addr(void *ti) 73 { 74 return (0); 75 } 76 77 #endif 78 79 #pragma weak __tls_get_addr 80 void * 81 __tls_get_addr() 82 { 83 return (0); 84 } 85 86 #ifdef TLS_VARIANT_I 87 88 void 89 _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign) 90 { 91 #ifndef PIC 92 Elf_Addr* dtv; 93 94 dtv = ((Elf_Addr**)tls)[0]; 95 free(tls); 96 free(dtv); 97 #endif 98 } 99 100 /* 101 * Allocate Static TLS using the Variant I method. 102 */ 103 void * 104 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 105 { 106 #ifndef PIC 107 size_t size; 108 char *tls; 109 Elf_Addr *dtv; 110 111 size = tls_static_space; 112 if (size < tcbsize) 113 size = tcbsize; 114 115 tls = malloc(size); 116 dtv = malloc(3 * sizeof(Elf_Addr)); 117 118 *(Elf_Addr**) tls = dtv; 119 120 dtv[0] = 1; 121 dtv[1] = 1; 122 dtv[2] = (Elf_Addr)(tls + tls_init_offset); 123 if (oldtls) { 124 /* 125 * Copy the static TLS block over whole. 126 */ 127 memcpy(tls + tls_init_offset, 128 (char*) oldtls + tls_init_offset, 129 tls_static_space - tls_init_offset); 130 131 /* 132 * We assume that this block was the one we created with 133 * allocate_initial_tls(). 134 */ 135 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 136 } else { 137 memcpy(tls + tls_init_offset, tls_init, tls_init_size); 138 memset(tls + tls_init_offset + tls_init_size, 139 0, tls_static_space - tls_init_size); 140 } 141 142 return tls; 143 #else 144 return (0); 145 #endif 146 } 147 148 #endif 149 150 #ifdef TLS_VARIANT_II 151 152 /* 153 * Free Static TLS using the Variant II method. 154 */ 155 #pragma weak _rtld_free_tls 156 void 157 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 158 { 159 #ifndef PIC 160 size_t size; 161 Elf_Addr* dtv; 162 Elf_Addr tlsstart, tlsend; 163 164 /* 165 * Figure out the size of the initial TLS block so that we can 166 * find stuff which ___tls_get_addr() allocated dynamically. 167 */ 168 size = round(tls_static_space, tcbalign); 169 170 dtv = ((Elf_Addr**)tcb)[1]; 171 tlsend = (Elf_Addr) tcb; 172 tlsstart = tlsend - size; 173 free((void*) tlsstart); 174 free(dtv); 175 #endif 176 } 177 178 #pragma weak _rtld_allocate_tls 179 /* 180 * Allocate Static TLS using the Variant II method. 181 */ 182 void * 183 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 184 { 185 #ifndef PIC 186 size_t size; 187 char *tls; 188 Elf_Addr *dtv; 189 Elf_Addr segbase, oldsegbase; 190 191 size = round(tls_static_space, tcbalign); 192 193 assert(tcbsize >= 2*sizeof(Elf_Addr)); 194 tls = malloc(size + tcbsize); 195 dtv = malloc(3 * sizeof(Elf_Addr)); 196 197 segbase = (Elf_Addr)(tls + size); 198 ((Elf_Addr*)segbase)[0] = segbase; 199 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 200 201 dtv[0] = 1; 202 dtv[1] = 1; 203 dtv[2] = segbase - tls_static_space; 204 205 if (oldtls) { 206 /* 207 * Copy the static TLS block over whole. 208 */ 209 oldsegbase = (Elf_Addr) oldtls; 210 memcpy((void *)(segbase - tls_static_space), 211 (const void *)(oldsegbase - tls_static_space), 212 tls_static_space); 213 214 /* 215 * We assume that this block was the one we created with 216 * allocate_initial_tls(). 217 */ 218 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 219 } else { 220 memcpy((void *)(segbase - tls_static_space), 221 tls_init, tls_init_size); 222 memset((void *)(segbase - tls_static_space + tls_init_size), 223 0, tls_static_space - tls_init_size); 224 } 225 226 return (void*) segbase; 227 #else 228 return (0); 229 #endif 230 } 231 232 #endif 233 234 void 235 _init_tls() 236 { 237 #ifndef PIC 238 extern char **environ; 239 Elf_Addr *sp; 240 Elf_Auxinfo *aux, *auxp; 241 Elf_Phdr *phdr; 242 size_t phent, phnum; 243 int i; 244 void *tls; 245 246 sp = (Elf_Addr *) environ; 247 while (*sp++ != 0) 248 ; 249 aux = (Elf_Auxinfo *) sp; 250 phdr = 0; 251 phent = phnum = 0; 252 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 253 switch (auxp->a_type) { 254 case AT_PHDR: 255 phdr = auxp->a_un.a_ptr; 256 break; 257 258 case AT_PHENT: 259 phent = auxp->a_un.a_val; 260 break; 261 262 case AT_PHNUM: 263 phnum = auxp->a_un.a_val; 264 break; 265 } 266 } 267 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 268 return; 269 270 for (i = 0; i < phnum; i++) { 271 if (phdr[i].p_type == PT_TLS) { 272 #ifdef TLS_VARIANT_I 273 tls_static_space = round(2*sizeof(Elf_Addr), 274 phdr[i].p_align) + phdr[i].p_memsz; 275 tls_init_offset = round(2*sizeof(Elf_Addr), 276 phdr[i].p_align); 277 #else 278 tls_static_space = round(phdr[i].p_memsz, 279 phdr[i].p_align); 280 #endif 281 tls_init_size = phdr[i].p_filesz; 282 tls_init = (void*) phdr[i].p_vaddr; 283 } 284 } 285 286 tls = _rtld_allocate_tls(NULL, 2*sizeof(Elf_Addr), 287 sizeof(Elf_Addr)); 288 289 _set_tp(tls); 290 #endif 291 } 292