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_bootstrap_malloc(size_t size); 44 void *__je_bootstrap_calloc(size_t num, size_t size); 45 void __je_bootstrap_free(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__) || defined(__aarch64__) 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 defined(__aarch64__) 76 #define TLS_VARIANT_I 77 #endif 78 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 79 #define TLS_VARIANT_II 80 #endif 81 82 #ifndef PIC 83 84 #define round(size, align) \ 85 (((size) + (align) - 1) & ~((align) - 1)) 86 87 static size_t tls_static_space; 88 static size_t tls_init_size; 89 static void *tls_init; 90 #endif 91 92 #ifdef __i386__ 93 94 /* GNU ABI */ 95 96 __attribute__((__regparm__(1))) 97 void * 98 ___libc_tls_get_addr(void *ti __unused) 99 { 100 return (0); 101 } 102 103 #endif 104 105 void * 106 __libc_tls_get_addr(void *ti __unused) 107 { 108 return (0); 109 } 110 111 #ifndef PIC 112 113 #ifdef TLS_VARIANT_I 114 115 #define TLS_TCB_SIZE (2 * sizeof(void *)) 116 117 /* 118 * Free Static TLS using the Variant I method. 119 */ 120 void 121 __libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 122 { 123 Elf_Addr *dtv; 124 Elf_Addr **tls; 125 126 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE); 127 dtv = tls[0]; 128 __je_bootstrap_free(dtv); 129 __je_bootstrap_free(tcb); 130 } 131 132 /* 133 * Allocate Static TLS using the Variant I method. 134 */ 135 void * 136 __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused) 137 { 138 Elf_Addr *dtv; 139 Elf_Addr **tls; 140 char *tcb; 141 142 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 143 return (oldtcb); 144 145 tcb = __je_bootstrap_calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE); 146 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 147 148 if (oldtcb != NULL) { 149 memcpy(tls, oldtcb, tls_static_space); 150 __je_bootstrap_free(oldtcb); 151 152 /* Adjust the DTV. */ 153 dtv = tls[0]; 154 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 155 } else { 156 dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); 157 tls[0] = dtv; 158 dtv[0] = 1; 159 dtv[1] = 1; 160 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 161 162 if (tls_init_size > 0) 163 memcpy((void*)dtv[2], tls_init, tls_init_size); 164 if (tls_static_space > tls_init_size) 165 memset((void*)(dtv[2] + tls_init_size), 0, 166 tls_static_space - tls_init_size); 167 } 168 169 return(tcb); 170 } 171 172 #endif 173 174 #ifdef TLS_VARIANT_II 175 176 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 177 178 /* 179 * Free Static TLS using the Variant II method. 180 */ 181 void 182 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 183 { 184 size_t size; 185 Elf_Addr* dtv; 186 Elf_Addr tlsstart, tlsend; 187 188 /* 189 * Figure out the size of the initial TLS block so that we can 190 * find stuff which ___tls_get_addr() allocated dynamically. 191 */ 192 size = round(tls_static_space, tcbalign); 193 194 dtv = ((Elf_Addr**)tcb)[1]; 195 tlsend = (Elf_Addr) tcb; 196 tlsstart = tlsend - size; 197 __je_bootstrap_free((void*) tlsstart); 198 __je_bootstrap_free(dtv); 199 } 200 201 /* 202 * Allocate Static TLS using the Variant II method. 203 */ 204 void * 205 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 206 { 207 size_t size; 208 char *tls; 209 Elf_Addr *dtv; 210 Elf_Addr segbase, oldsegbase; 211 212 size = round(tls_static_space, tcbalign); 213 214 if (tcbsize < 2 * sizeof(Elf_Addr)) 215 tcbsize = 2 * sizeof(Elf_Addr); 216 tls = __je_bootstrap_calloc(1, size + tcbsize); 217 dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); 218 219 segbase = (Elf_Addr)(tls + size); 220 ((Elf_Addr*)segbase)[0] = segbase; 221 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 222 223 dtv[0] = 1; 224 dtv[1] = 1; 225 dtv[2] = segbase - tls_static_space; 226 227 if (oldtls) { 228 /* 229 * Copy the static TLS block over whole. 230 */ 231 oldsegbase = (Elf_Addr) oldtls; 232 memcpy((void *)(segbase - tls_static_space), 233 (const void *)(oldsegbase - tls_static_space), 234 tls_static_space); 235 236 /* 237 * We assume that this block was the one we created with 238 * allocate_initial_tls(). 239 */ 240 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 241 } else { 242 memcpy((void *)(segbase - tls_static_space), 243 tls_init, tls_init_size); 244 memset((void *)(segbase - tls_static_space + tls_init_size), 245 0, tls_static_space - tls_init_size); 246 } 247 248 return (void*) segbase; 249 } 250 251 #endif /* TLS_VARIANT_II */ 252 253 #else 254 255 void * 256 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 257 size_t tcbalign __unused) 258 { 259 return (0); 260 } 261 262 void 263 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 264 size_t tcbalign __unused) 265 { 266 } 267 268 #endif /* PIC */ 269 270 extern char **environ; 271 272 void 273 _init_tls(void) 274 { 275 #ifndef PIC 276 Elf_Addr *sp; 277 Elf_Auxinfo *aux, *auxp; 278 Elf_Phdr *phdr; 279 size_t phent, phnum; 280 int i; 281 void *tls; 282 283 sp = (Elf_Addr *) environ; 284 while (*sp++ != 0) 285 ; 286 aux = (Elf_Auxinfo *) sp; 287 phdr = 0; 288 phent = phnum = 0; 289 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 290 switch (auxp->a_type) { 291 case AT_PHDR: 292 phdr = auxp->a_un.a_ptr; 293 break; 294 295 case AT_PHENT: 296 phent = auxp->a_un.a_val; 297 break; 298 299 case AT_PHNUM: 300 phnum = auxp->a_un.a_val; 301 break; 302 } 303 } 304 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 305 return; 306 307 for (i = 0; (unsigned) i < phnum; i++) { 308 if (phdr[i].p_type == PT_TLS) { 309 tls_static_space = round(phdr[i].p_memsz, 310 phdr[i].p_align); 311 tls_init_size = phdr[i].p_filesz; 312 tls_init = (void*) phdr[i].p_vaddr; 313 } 314 } 315 316 #ifdef TLS_VARIANT_I 317 /* 318 * tls_static_space should include space for TLS structure 319 */ 320 tls_static_space += TLS_TCB_SIZE; 321 #endif 322 323 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); 324 325 _set_tp(tls); 326 #endif 327 } 328