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