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 40 #include "libc_private.h" 41 42 /* Provided by jemalloc to avoid bootstrapping issues. */ 43 void *__je_a0malloc(size_t size); 44 void *__je_a0calloc(size_t num, size_t size); 45 void __je_a0free(void *ptr); 46 47 __weak_reference(__libc_allocate_tls, _rtld_allocate_tls); 48 __weak_reference(__libc_free_tls, _rtld_free_tls); 49 50 #ifdef __i386__ 51 52 __weak_reference(___libc_tls_get_addr, ___tls_get_addr); 53 __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *); 54 55 #endif 56 57 void * __libc_tls_get_addr(void *); 58 __weak_reference(__libc_tls_get_addr, __tls_get_addr); 59 60 void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 61 void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 62 void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 63 void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 64 65 #if defined(__amd64__) 66 #define TLS_TCB_ALIGN 16 67 #elif defined(__powerpc__) || defined(__i386__) || defined(__arm__) || \ 68 defined(__sparc64__) || defined(__mips__) 69 #define TLS_TCB_ALIGN sizeof(void *) 70 #else 71 #error TLS_TCB_ALIGN undefined for target architecture 72 #endif 73 74 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__) 75 #define TLS_VARIANT_I 76 #endif 77 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 78 #define TLS_VARIANT_II 79 #endif 80 81 #ifndef PIC 82 83 #define round(size, align) \ 84 (((size) + (align) - 1) & ~((align) - 1)) 85 86 static size_t tls_static_space; 87 static size_t tls_init_size; 88 static void *tls_init; 89 #endif 90 91 #ifdef __i386__ 92 93 /* GNU ABI */ 94 95 __attribute__((__regparm__(1))) 96 void * 97 ___libc_tls_get_addr(void *ti __unused) 98 { 99 return (0); 100 } 101 102 #endif 103 104 void * 105 __libc_tls_get_addr(void *ti __unused) 106 { 107 return (0); 108 } 109 110 #ifndef PIC 111 112 #ifdef TLS_VARIANT_I 113 114 #define TLS_TCB_SIZE (2 * sizeof(void *)) 115 116 /* 117 * Free Static TLS using the Variant I method. 118 */ 119 void 120 __libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 121 { 122 Elf_Addr *dtv; 123 Elf_Addr **tls; 124 125 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE); 126 dtv = tls[0]; 127 __je_a0free(dtv); 128 __je_a0free(tcb); 129 } 130 131 /* 132 * Allocate Static TLS using the Variant I method. 133 */ 134 void * 135 __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused) 136 { 137 Elf_Addr *dtv; 138 Elf_Addr **tls; 139 char *tcb; 140 141 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 142 return (oldtcb); 143 144 tcb = __je_a0calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE); 145 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 146 147 if (oldtcb != NULL) { 148 memcpy(tls, oldtcb, tls_static_space); 149 __je_a0free(oldtcb); 150 151 /* Adjust the DTV. */ 152 dtv = tls[0]; 153 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 154 } else { 155 dtv = __je_a0malloc(3 * sizeof(Elf_Addr)); 156 tls[0] = dtv; 157 dtv[0] = 1; 158 dtv[1] = 1; 159 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 160 161 if (tls_init_size > 0) 162 memcpy((void*)dtv[2], tls_init, tls_init_size); 163 if (tls_static_space > tls_init_size) 164 memset((void*)(dtv[2] + tls_init_size), 0, 165 tls_static_space - tls_init_size); 166 } 167 168 return(tcb); 169 } 170 171 #endif 172 173 #ifdef TLS_VARIANT_II 174 175 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 176 177 /* 178 * Free Static TLS using the Variant II method. 179 */ 180 void 181 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 182 { 183 size_t size; 184 Elf_Addr* dtv; 185 Elf_Addr tlsstart, tlsend; 186 187 /* 188 * Figure out the size of the initial TLS block so that we can 189 * find stuff which ___tls_get_addr() allocated dynamically. 190 */ 191 size = round(tls_static_space, tcbalign); 192 193 dtv = ((Elf_Addr**)tcb)[1]; 194 tlsend = (Elf_Addr) tcb; 195 tlsstart = tlsend - size; 196 __je_a0free((void*) tlsstart); 197 __je_a0free(dtv); 198 } 199 200 /* 201 * Allocate Static TLS using the Variant II method. 202 */ 203 void * 204 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 205 { 206 size_t size; 207 char *tls; 208 Elf_Addr *dtv; 209 Elf_Addr segbase, oldsegbase; 210 211 size = round(tls_static_space, tcbalign); 212 213 if (tcbsize < 2 * sizeof(Elf_Addr)) 214 tcbsize = 2 * sizeof(Elf_Addr); 215 tls = __je_a0calloc(1, size + tcbsize); 216 dtv = __je_a0malloc(3 * sizeof(Elf_Addr)); 217 218 segbase = (Elf_Addr)(tls + size); 219 ((Elf_Addr*)segbase)[0] = segbase; 220 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 221 222 dtv[0] = 1; 223 dtv[1] = 1; 224 dtv[2] = segbase - tls_static_space; 225 226 if (oldtls) { 227 /* 228 * Copy the static TLS block over whole. 229 */ 230 oldsegbase = (Elf_Addr) oldtls; 231 memcpy((void *)(segbase - tls_static_space), 232 (const void *)(oldsegbase - tls_static_space), 233 tls_static_space); 234 235 /* 236 * We assume that this block was the one we created with 237 * allocate_initial_tls(). 238 */ 239 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 240 } else { 241 memcpy((void *)(segbase - tls_static_space), 242 tls_init, tls_init_size); 243 memset((void *)(segbase - tls_static_space + tls_init_size), 244 0, tls_static_space - tls_init_size); 245 } 246 247 return (void*) segbase; 248 } 249 250 #endif /* TLS_VARIANT_II */ 251 252 #else 253 254 void * 255 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 256 size_t tcbalign __unused) 257 { 258 return (0); 259 } 260 261 void 262 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 263 size_t tcbalign __unused) 264 { 265 } 266 267 #endif /* PIC */ 268 269 extern char **environ; 270 271 void 272 _init_tls() 273 { 274 #ifndef PIC 275 Elf_Addr *sp; 276 Elf_Auxinfo *aux, *auxp; 277 Elf_Phdr *phdr; 278 size_t phent, phnum; 279 int i; 280 void *tls; 281 282 sp = (Elf_Addr *) environ; 283 while (*sp++ != 0) 284 ; 285 aux = (Elf_Auxinfo *) sp; 286 phdr = 0; 287 phent = phnum = 0; 288 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 289 switch (auxp->a_type) { 290 case AT_PHDR: 291 phdr = auxp->a_un.a_ptr; 292 break; 293 294 case AT_PHENT: 295 phent = auxp->a_un.a_val; 296 break; 297 298 case AT_PHNUM: 299 phnum = auxp->a_un.a_val; 300 break; 301 } 302 } 303 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 304 return; 305 306 for (i = 0; (unsigned) i < phnum; i++) { 307 if (phdr[i].p_type == PT_TLS) { 308 tls_static_space = round(phdr[i].p_memsz, 309 phdr[i].p_align); 310 tls_init_size = phdr[i].p_filesz; 311 tls_init = (void*) phdr[i].p_vaddr; 312 } 313 } 314 315 #ifdef TLS_VARIANT_I 316 /* 317 * tls_static_space should include space for TLS structure 318 */ 319 tls_static_space += TLS_TCB_SIZE; 320 #endif 321 322 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); 323 324 _set_tp(tls); 325 #endif 326 } 327