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: stable/10/lib/libc/gen/tls.c 324617 2017-10-14 16:49:39Z brooks $ 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. */ 43void *__jemalloc_a0malloc(size_t size); 44void *__jemalloc_a0calloc(size_t num, size_t size); 45void __jemalloc_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 57void * __libc_tls_get_addr(void *); 58__weak_reference(__libc_tls_get_addr, __tls_get_addr); 59 60void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 61void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 62void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 63void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 64 65#if defined(__ia64__) || 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(__ia64__) || defined(__mips__) || \ 75 defined(__powerpc__) 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 87static size_t tls_static_space; 88static size_t tls_init_size; 89static void *tls_init; 90#endif 91 92#ifdef __i386__ 93 94/* GNU ABI */ 95 96__attribute__((__regparm__(1))) 97void * 98___libc_tls_get_addr(void *ti __unused) 99{ 100 return (0); 101} 102 103#endif 104 105void * 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 */ 120void 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 __jemalloc_a0free(dtv); 129 __jemalloc_a0free(tcb); 130} 131 132/* 133 * Allocate Static TLS using the Variant I method. 134 */ 135void * 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 = __jemalloc_a0calloc(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 __jemalloc_a0free(oldtcb); 151 152 /* Adjust the DTV. */ 153 dtv = tls[0]; 154 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 155 } else { 156 dtv = __jemalloc_a0malloc(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 } 165 166 return(tcb); 167} 168 169#endif 170 171#ifdef TLS_VARIANT_II 172 173#define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 174 175/* 176 * Free Static TLS using the Variant II method. 177 */ 178void 179__libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 180{ 181 size_t size; 182 Elf_Addr* dtv; 183 Elf_Addr tlsstart, tlsend; 184 185 /* 186 * Figure out the size of the initial TLS block so that we can 187 * find stuff which ___tls_get_addr() allocated dynamically. 188 */ 189 size = round(tls_static_space, tcbalign); 190 191 dtv = ((Elf_Addr**)tcb)[1]; 192 tlsend = (Elf_Addr) tcb; 193 tlsstart = tlsend - size; 194 __jemalloc_a0free((void*) tlsstart); 195 __jemalloc_a0free(dtv); 196} 197 198/* 199 * Allocate Static TLS using the Variant II method. 200 */ 201void * 202__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 203{ 204 size_t size; 205 char *tls; 206 Elf_Addr *dtv; 207 Elf_Addr segbase, oldsegbase; 208 209 size = round(tls_static_space, tcbalign); 210 211 if (tcbsize < 2 * sizeof(Elf_Addr)) 212 tcbsize = 2 * sizeof(Elf_Addr); 213 tls = __jemalloc_a0calloc(1, size + tcbsize); 214 dtv = __jemalloc_a0malloc(3 * sizeof(Elf_Addr)); 215 216 segbase = (Elf_Addr)(tls + size); 217 ((Elf_Addr*)segbase)[0] = segbase; 218 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 219 220 dtv[0] = 1; 221 dtv[1] = 1; 222 dtv[2] = segbase - tls_static_space; 223 224 if (oldtls) { 225 /* 226 * Copy the static TLS block over whole. 227 */ 228 oldsegbase = (Elf_Addr) oldtls; 229 memcpy((void *)(segbase - tls_static_space), 230 (const void *)(oldsegbase - tls_static_space), 231 tls_static_space); 232 233 /* 234 * We assume that this block was the one we created with 235 * allocate_initial_tls(). 236 */ 237 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 238 } else { 239 memcpy((void *)(segbase - tls_static_space), 240 tls_init, tls_init_size); 241 memset((void *)(segbase - tls_static_space + tls_init_size), 242 0, tls_static_space - tls_init_size); 243 } 244 245 return (void*) segbase; 246} 247 248#endif /* TLS_VARIANT_II */ 249 250#else 251 252void * 253__libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 254 size_t tcbalign __unused) 255{ 256 return (0); 257} 258 259void 260__libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 261 size_t tcbalign __unused) 262{ 263} 264 265#endif /* PIC */ 266 267extern char **environ; 268 269void 270_init_tls() 271{ 272#ifndef PIC 273 Elf_Addr *sp; 274 Elf_Auxinfo *aux, *auxp; 275 Elf_Phdr *phdr; 276 size_t phent, phnum; 277 int i; 278 void *tls; 279 280 sp = (Elf_Addr *) environ; 281 while (*sp++ != 0) 282 ; 283 aux = (Elf_Auxinfo *) sp; 284 phdr = NULL; 285 phent = phnum = 0; 286 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 287 switch (auxp->a_type) { 288 case AT_PHDR: 289 phdr = auxp->a_un.a_ptr; 290 break; 291 292 case AT_PHENT: 293 phent = auxp->a_un.a_val; 294 break; 295 296 case AT_PHNUM: 297 phnum = auxp->a_un.a_val; 298 break; 299 } 300 } 301 if (phdr == NULL || phent != sizeof(Elf_Phdr) || phnum == 0) 302 return; 303 304 for (i = 0; (unsigned) i < phnum; i++) { 305 if (phdr[i].p_type == PT_TLS) { 306 tls_static_space = round(phdr[i].p_memsz, 307 phdr[i].p_align); 308 tls_init_size = phdr[i].p_filesz; 309 tls_init = (void*) phdr[i].p_vaddr; 310 } 311 } 312 313#ifdef TLS_VARIANT_I 314 /* 315 * tls_static_space should include space for TLS structure 316 */ 317 tls_static_space += TLS_TCB_SIZE; 318#endif 319 320 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); 321 322 _set_tp(tls); 323#endif 324} 325