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 <sys/cdefs.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <elf.h> 39 #include <assert.h> 40 41 #include "libc_private.h" 42 43 __weak_reference(__libc_allocate_tls, _rtld_allocate_tls); 44 __weak_reference(__libc_free_tls, _rtld_free_tls); 45 46 #ifdef __i386__ 47 48 __weak_reference(___libc_tls_get_addr, ___tls_get_addr); 49 __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *); 50 51 #endif 52 53 void * __libc_tls_get_addr(void *); 54 __weak_reference(__libc_tls_get_addr, __tls_get_addr); 55 56 void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 57 void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 58 void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 59 void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 60 61 #if defined(__ia64__) || defined(__alpha__) || defined(__powerpc__) 62 #define TLS_VARIANT_I 63 #endif 64 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 65 defined(__arm__) 66 #define TLS_VARIANT_II 67 #endif 68 69 #ifndef PIC 70 71 #define round(size, align) \ 72 (((size) + (align) - 1) & ~((align) - 1)) 73 74 static size_t tls_static_space; 75 static size_t tls_init_size; 76 #ifdef TLS_VARIANT_I 77 static size_t tls_init_offset; 78 #endif 79 static void *tls_init; 80 #endif 81 82 #ifdef __i386__ 83 84 /* GNU ABI */ 85 86 __attribute__((__regparm__(1))) 87 void * 88 ___libc_tls_get_addr(void *ti __unused) 89 { 90 return (0); 91 } 92 93 #endif 94 95 void * 96 __libc_tls_get_addr(void *ti __unused) 97 { 98 return (0); 99 } 100 101 #ifndef PIC 102 103 #ifdef TLS_VARIANT_I 104 105 /* 106 * Free Static TLS using the Variant I method. 107 */ 108 void 109 __libc_free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign __unused) 110 { 111 Elf_Addr* dtv; 112 113 dtv = ((Elf_Addr**)tls)[0]; 114 free(tls); 115 free(dtv); 116 } 117 118 /* 119 * Allocate Static TLS using the Variant I method. 120 */ 121 void * 122 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign __unused) 123 { 124 size_t size; 125 char *tls; 126 Elf_Addr *dtv; 127 128 size = tls_static_space; 129 if (size < tcbsize) 130 size = tcbsize; 131 132 tls = calloc(1, size); 133 dtv = malloc(3 * sizeof(Elf_Addr)); 134 135 *(Elf_Addr **) tls = dtv; 136 137 dtv[0] = 1; 138 dtv[1] = 1; 139 dtv[2] = (Elf_Addr)(tls + tls_init_offset); 140 if (oldtls) { 141 /* 142 * Copy the static TLS block over whole. 143 */ 144 memcpy(tls + tls_init_offset, 145 (char *)oldtls + tls_init_offset, 146 tls_static_space - tls_init_offset); 147 148 /* 149 * We assume that this block was the one we created with 150 * allocate_initial_tls(). 151 */ 152 _rtld_free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 153 } else { 154 memcpy(tls + tls_init_offset, tls_init, tls_init_size); 155 memset(tls + tls_init_offset + tls_init_size, 156 0, tls_static_space - tls_init_size); 157 } 158 159 return tls; 160 } 161 162 #endif 163 164 #ifdef TLS_VARIANT_II 165 166 /* 167 * Free Static TLS using the Variant II method. 168 */ 169 void 170 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 171 { 172 size_t size; 173 Elf_Addr* dtv; 174 Elf_Addr tlsstart, tlsend; 175 176 /* 177 * Figure out the size of the initial TLS block so that we can 178 * find stuff which ___tls_get_addr() allocated dynamically. 179 */ 180 size = round(tls_static_space, tcbalign); 181 182 dtv = ((Elf_Addr**)tcb)[1]; 183 tlsend = (Elf_Addr) tcb; 184 tlsstart = tlsend - size; 185 free((void*) tlsstart); 186 free(dtv); 187 } 188 189 /* 190 * Allocate Static TLS using the Variant II method. 191 */ 192 void * 193 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 194 { 195 size_t size; 196 char *tls; 197 Elf_Addr *dtv; 198 Elf_Addr segbase, oldsegbase; 199 200 size = round(tls_static_space, tcbalign); 201 202 assert(tcbsize >= 2*sizeof(Elf_Addr)); 203 tls = calloc(1, size + tcbsize); 204 dtv = malloc(3 * sizeof(Elf_Addr)); 205 206 segbase = (Elf_Addr)(tls + size); 207 ((Elf_Addr*)segbase)[0] = segbase; 208 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 209 210 dtv[0] = 1; 211 dtv[1] = 1; 212 dtv[2] = segbase - tls_static_space; 213 214 if (oldtls) { 215 /* 216 * Copy the static TLS block over whole. 217 */ 218 oldsegbase = (Elf_Addr) oldtls; 219 memcpy((void *)(segbase - tls_static_space), 220 (const void *)(oldsegbase - tls_static_space), 221 tls_static_space); 222 223 /* 224 * We assume that this block was the one we created with 225 * allocate_initial_tls(). 226 */ 227 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 228 } else { 229 memcpy((void *)(segbase - tls_static_space), 230 tls_init, tls_init_size); 231 memset((void *)(segbase - tls_static_space + tls_init_size), 232 0, tls_static_space - tls_init_size); 233 } 234 235 return (void*) segbase; 236 } 237 238 #endif /* TLS_VARIANT_II */ 239 240 #else 241 242 void * 243 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 244 size_t tcbalign __unused) 245 { 246 return (0); 247 } 248 249 void 250 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 251 size_t tcbalign __unused) 252 { 253 } 254 255 #endif /* PIC */ 256 257 extern char **environ; 258 259 void 260 _init_tls() 261 { 262 #ifndef PIC 263 Elf_Addr *sp; 264 Elf_Auxinfo *aux, *auxp; 265 Elf_Phdr *phdr; 266 size_t phent, phnum; 267 int i; 268 void *tls; 269 270 sp = (Elf_Addr *) environ; 271 while (*sp++ != 0) 272 ; 273 aux = (Elf_Auxinfo *) sp; 274 phdr = 0; 275 phent = phnum = 0; 276 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 277 switch (auxp->a_type) { 278 case AT_PHDR: 279 phdr = auxp->a_un.a_ptr; 280 break; 281 282 case AT_PHENT: 283 phent = auxp->a_un.a_val; 284 break; 285 286 case AT_PHNUM: 287 phnum = auxp->a_un.a_val; 288 break; 289 } 290 } 291 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 292 return; 293 294 for (i = 0; (unsigned) i < phnum; i++) { 295 if (phdr[i].p_type == PT_TLS) { 296 #ifdef TLS_VARIANT_I 297 tls_static_space = round(2*sizeof(Elf_Addr), 298 phdr[i].p_align) + phdr[i].p_memsz; 299 tls_init_offset = round(2*sizeof(Elf_Addr), 300 phdr[i].p_align); 301 #else 302 tls_static_space = round(phdr[i].p_memsz, 303 phdr[i].p_align); 304 #endif 305 tls_init_size = phdr[i].p_filesz; 306 tls_init = (void*) phdr[i].p_vaddr; 307 } 308 } 309 310 tls = _rtld_allocate_tls(NULL, 3*sizeof(Elf_Addr), 311 sizeof(Elf_Addr)); 312 313 _set_tp(tls); 314 #endif 315 } 316