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(__amd64__) 62 #define TLS_TCB_ALIGN 16 63 #elif defined(__powerpc__) || defined(__i386__) || defined(__arm__) || \ 64 defined(__sparc64__) 65 #define TLS_TCB_ALIGN sizeof(void *) 66 #else 67 #error TLS_TCB_ALIGN undefined for target architecture 68 #endif 69 70 #if defined(__ia64__) || defined(__powerpc__) 71 #define TLS_VARIANT_I 72 #endif 73 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 74 defined(__arm__) 75 #define TLS_VARIANT_II 76 #endif 77 78 #ifndef PIC 79 80 #define round(size, align) \ 81 (((size) + (align) - 1) & ~((align) - 1)) 82 83 static size_t tls_static_space; 84 static size_t tls_init_size; 85 static void *tls_init; 86 #endif 87 88 #ifdef __i386__ 89 90 /* GNU ABI */ 91 92 __attribute__((__regparm__(1))) 93 void * 94 ___libc_tls_get_addr(void *ti __unused) 95 { 96 return (0); 97 } 98 99 #endif 100 101 void * 102 __libc_tls_get_addr(void *ti __unused) 103 { 104 return (0); 105 } 106 107 #ifndef PIC 108 109 #ifdef TLS_VARIANT_I 110 111 #define TLS_TCB_SIZE (2 * sizeof(void *)) 112 113 /* 114 * Free Static TLS using the Variant I method. 115 */ 116 void 117 __libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 118 { 119 Elf_Addr *dtv; 120 Elf_Addr **tls; 121 122 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE); 123 dtv = tls[0]; 124 free(dtv); 125 free(tcb); 126 } 127 128 /* 129 * Allocate Static TLS using the Variant I method. 130 */ 131 void * 132 __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused) 133 { 134 Elf_Addr *dtv; 135 Elf_Addr **tls; 136 char *tcb; 137 138 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 139 return (oldtcb); 140 141 tcb = calloc(1, tls_static_space + tcbsize); 142 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 143 144 if (oldtcb != NULL) { 145 memcpy(tls, oldtcb, tls_static_space + TLS_TCB_SIZE); 146 free(oldtcb); 147 148 /* Adjust the DTV. */ 149 dtv = tls[0]; 150 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 151 } else { 152 dtv = malloc(3 * sizeof(Elf_Addr)); 153 tls[0] = dtv; 154 dtv[0] = 1; 155 dtv[1] = 1; 156 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 157 158 if (tls_init_size > 0) 159 memcpy((void*)dtv[2], tls_init, tls_init_size); 160 if (tls_static_space > tls_init_size) 161 memset((void*)(dtv[2] + tls_init_size), 0, 162 tls_static_space - tls_init_size); 163 } 164 165 return(tcb); 166 } 167 168 #endif 169 170 #ifdef TLS_VARIANT_II 171 172 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 173 174 /* 175 * Free Static TLS using the Variant II method. 176 */ 177 void 178 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 179 { 180 size_t size; 181 Elf_Addr* dtv; 182 Elf_Addr tlsstart, tlsend; 183 184 /* 185 * Figure out the size of the initial TLS block so that we can 186 * find stuff which ___tls_get_addr() allocated dynamically. 187 */ 188 size = round(tls_static_space, tcbalign); 189 190 dtv = ((Elf_Addr**)tcb)[1]; 191 tlsend = (Elf_Addr) tcb; 192 tlsstart = tlsend - size; 193 free((void*) tlsstart); 194 free(dtv); 195 } 196 197 /* 198 * Allocate Static TLS using the Variant II method. 199 */ 200 void * 201 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 202 { 203 size_t size; 204 char *tls; 205 Elf_Addr *dtv; 206 Elf_Addr segbase, oldsegbase; 207 208 size = round(tls_static_space, tcbalign); 209 210 assert(tcbsize >= 2*sizeof(Elf_Addr)); 211 tls = calloc(1, size + tcbsize); 212 dtv = malloc(3 * sizeof(Elf_Addr)); 213 214 segbase = (Elf_Addr)(tls + size); 215 ((Elf_Addr*)segbase)[0] = segbase; 216 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 217 218 dtv[0] = 1; 219 dtv[1] = 1; 220 dtv[2] = segbase - tls_static_space; 221 222 if (oldtls) { 223 /* 224 * Copy the static TLS block over whole. 225 */ 226 oldsegbase = (Elf_Addr) oldtls; 227 memcpy((void *)(segbase - tls_static_space), 228 (const void *)(oldsegbase - tls_static_space), 229 tls_static_space); 230 231 /* 232 * We assume that this block was the one we created with 233 * allocate_initial_tls(). 234 */ 235 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 236 } else { 237 memcpy((void *)(segbase - tls_static_space), 238 tls_init, tls_init_size); 239 memset((void *)(segbase - tls_static_space + tls_init_size), 240 0, tls_static_space - tls_init_size); 241 } 242 243 return (void*) segbase; 244 } 245 246 #endif /* TLS_VARIANT_II */ 247 248 #else 249 250 void * 251 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 252 size_t tcbalign __unused) 253 { 254 return (0); 255 } 256 257 void 258 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 259 size_t tcbalign __unused) 260 { 261 } 262 263 #endif /* PIC */ 264 265 extern char **environ; 266 267 void 268 _init_tls() 269 { 270 #ifndef PIC 271 Elf_Addr *sp; 272 Elf_Auxinfo *aux, *auxp; 273 Elf_Phdr *phdr; 274 size_t phent, phnum; 275 int i; 276 void *tls; 277 278 sp = (Elf_Addr *) environ; 279 while (*sp++ != 0) 280 ; 281 aux = (Elf_Auxinfo *) sp; 282 phdr = 0; 283 phent = phnum = 0; 284 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 285 switch (auxp->a_type) { 286 case AT_PHDR: 287 phdr = auxp->a_un.a_ptr; 288 break; 289 290 case AT_PHENT: 291 phent = auxp->a_un.a_val; 292 break; 293 294 case AT_PHNUM: 295 phnum = auxp->a_un.a_val; 296 break; 297 } 298 } 299 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 300 return; 301 302 for (i = 0; (unsigned) i < phnum; i++) { 303 if (phdr[i].p_type == PT_TLS) { 304 tls_static_space = round(phdr[i].p_memsz, 305 phdr[i].p_align); 306 tls_init_size = phdr[i].p_filesz; 307 tls_init = (void*) phdr[i].p_vaddr; 308 } 309 } 310 311 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); 312 313 _set_tp(tls); 314 #endif 315 } 316