tls.c revision 203946
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: head/lib/libc/gen/tls.c 203946 2010-02-16 02:22:59Z marcel $ 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__weak_reference(__libc_allocate_tls, _rtld_allocate_tls); 43__weak_reference(__libc_free_tls, _rtld_free_tls); 44 45#ifdef __i386__ 46 47__weak_reference(___libc_tls_get_addr, ___tls_get_addr); 48__attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *); 49 50#endif 51 52void * __libc_tls_get_addr(void *); 53__weak_reference(__libc_tls_get_addr, __tls_get_addr); 54 55void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 56void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 57void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 58void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 59 60#if defined(__ia64__) || defined(__amd64__) 61#define TLS_TCB_ALIGN 16 62#elif defined(__powerpc__) || defined(__i386__) || defined(__arm__) || \ 63 defined(__sparc64__) || defined(__mips__) 64#define TLS_TCB_ALIGN sizeof(void *) 65#else 66#error TLS_TCB_ALIGN undefined for target architecture 67#endif 68 69#if defined(__ia64__) || defined(__powerpc__) 70#define TLS_VARIANT_I 71#endif 72#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 73 defined(__arm__) || defined(__mips__) 74#define TLS_VARIANT_II 75#endif 76 77#ifndef PIC 78 79#define round(size, align) \ 80 (((size) + (align) - 1) & ~((align) - 1)) 81 82static size_t tls_static_space; 83static size_t tls_init_size; 84static void *tls_init; 85#endif 86 87#ifdef __i386__ 88 89/* GNU ABI */ 90 91__attribute__((__regparm__(1))) 92void * 93___libc_tls_get_addr(void *ti __unused) 94{ 95 return (0); 96} 97 98#endif 99 100void * 101__libc_tls_get_addr(void *ti __unused) 102{ 103 return (0); 104} 105 106#ifndef PIC 107 108#ifdef TLS_VARIANT_I 109 110#define TLS_TCB_SIZE (2 * sizeof(void *)) 111 112/* 113 * Free Static TLS using the Variant I method. 114 */ 115void 116__libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 117{ 118 Elf_Addr *dtv; 119 Elf_Addr **tls; 120 121 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE); 122 dtv = tls[0]; 123 free(dtv); 124 free(tcb); 125} 126 127/* 128 * Allocate Static TLS using the Variant I method. 129 */ 130void * 131__libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused) 132{ 133 Elf_Addr *dtv; 134 Elf_Addr **tls; 135 char *tcb; 136 137 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 138 return (oldtcb); 139 140 tcb = calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE); 141 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 142 143 if (oldtcb != NULL) { 144 memcpy(tls, oldtcb, tls_static_space); 145 free(oldtcb); 146 147 /* Adjust the DTV. */ 148 dtv = tls[0]; 149 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 150 } else { 151 dtv = malloc(3 * sizeof(Elf_Addr)); 152 tls[0] = dtv; 153 dtv[0] = 1; 154 dtv[1] = 1; 155 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 156 157 if (tls_init_size > 0) 158 memcpy((void*)dtv[2], tls_init, tls_init_size); 159 if (tls_static_space > tls_init_size) 160 memset((void*)(dtv[2] + tls_init_size), 0, 161 tls_static_space - tls_init_size); 162 } 163 164 return(tcb); 165} 166 167#endif 168 169#ifdef TLS_VARIANT_II 170 171#define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 172 173/* 174 * Free Static TLS using the Variant II method. 175 */ 176void 177__libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 178{ 179 size_t size; 180 Elf_Addr* dtv; 181 Elf_Addr tlsstart, tlsend; 182 183 /* 184 * Figure out the size of the initial TLS block so that we can 185 * find stuff which ___tls_get_addr() allocated dynamically. 186 */ 187 size = round(tls_static_space, tcbalign); 188 189 dtv = ((Elf_Addr**)tcb)[1]; 190 tlsend = (Elf_Addr) tcb; 191 tlsstart = tlsend - size; 192 free((void*) tlsstart); 193 free(dtv); 194} 195 196/* 197 * Allocate Static TLS using the Variant II method. 198 */ 199void * 200__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 201{ 202 size_t size; 203 char *tls; 204 Elf_Addr *dtv; 205 Elf_Addr segbase, oldsegbase; 206 207 size = round(tls_static_space, tcbalign); 208 209 if (tcbsize < 2 * sizeof(Elf_Addr)) 210 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 250void * 251__libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 252 size_t tcbalign __unused) 253{ 254 return (0); 255} 256 257void 258__libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 259 size_t tcbalign __unused) 260{ 261} 262 263#endif /* PIC */ 264 265extern char **environ; 266 267void 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