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 <sys/param.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <elf.h> 40 41 #include "libc_private.h" 42 43 /* Provided by jemalloc to avoid bootstrapping issues. */ 44 void *__je_bootstrap_malloc(size_t size); 45 void *__je_bootstrap_calloc(size_t num, size_t size); 46 void __je_bootstrap_free(void *ptr); 47 48 __weak_reference(__libc_allocate_tls, _rtld_allocate_tls); 49 __weak_reference(__libc_free_tls, _rtld_free_tls); 50 51 #ifdef __i386__ 52 53 __weak_reference(___libc_tls_get_addr, ___tls_get_addr); 54 __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *); 55 56 #endif 57 58 void * __libc_tls_get_addr(void *); 59 __weak_reference(__libc_tls_get_addr, __tls_get_addr); 60 61 void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 62 void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 63 void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); 64 void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign); 65 66 #if defined(__amd64__) 67 #define TLS_TCB_ALIGN 16 68 #elif defined(__aarch64__) || defined(__arm__) || defined(__i386__) || \ 69 defined(__mips__) || defined(__powerpc__) || defined(__riscv) || \ 70 defined(__sparc64__) 71 #define TLS_TCB_ALIGN sizeof(void *) 72 #else 73 #error TLS_TCB_ALIGN undefined for target architecture 74 #endif 75 76 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 77 defined(__powerpc__) || defined(__riscv) 78 #define TLS_VARIANT_I 79 #endif 80 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 81 #define TLS_VARIANT_II 82 #endif 83 84 #ifndef PIC 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_bootstrap_free(dtv); 128 __je_bootstrap_free(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_bootstrap_calloc(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_bootstrap_free(oldtcb); 150 151 /* Adjust the DTV. */ 152 dtv = tls[0]; 153 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 154 } else { 155 dtv = __je_bootstrap_malloc(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 } 164 165 return(tcb); 166 } 167 168 #endif 169 170 #ifdef TLS_VARIANT_II 171 172 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 173 174 /* 175 * Free Static TLS using the Variant II method. 176 */ 177 void 178 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 179 { 180 size_t size; 181 Elf_Addr* dtv; 182 Elf_Addr tlsstart, tlsend; 183 184 /* 185 * Figure out the size of the initial TLS block so that we can 186 * find stuff which ___tls_get_addr() allocated dynamically. 187 */ 188 size = roundup2(tls_static_space, tcbalign); 189 190 dtv = ((Elf_Addr**)tcb)[1]; 191 tlsend = (Elf_Addr) tcb; 192 tlsstart = tlsend - size; 193 __je_bootstrap_free((void*) tlsstart); 194 __je_bootstrap_free(dtv); 195 } 196 197 /* 198 * Allocate Static TLS using the Variant II method. 199 */ 200 void * 201 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 202 { 203 size_t size; 204 char *tls; 205 Elf_Addr *dtv; 206 Elf_Addr segbase, oldsegbase; 207 208 size = roundup2(tls_static_space, tcbalign); 209 210 if (tcbsize < 2 * sizeof(Elf_Addr)) 211 tcbsize = 2 * sizeof(Elf_Addr); 212 tls = __je_bootstrap_calloc(1, size + tcbsize); 213 dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); 214 215 segbase = (Elf_Addr)(tls + size); 216 ((Elf_Addr*)segbase)[0] = segbase; 217 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 218 219 dtv[0] = 1; 220 dtv[1] = 1; 221 dtv[2] = segbase - tls_static_space; 222 223 if (oldtls) { 224 /* 225 * Copy the static TLS block over whole. 226 */ 227 oldsegbase = (Elf_Addr) oldtls; 228 memcpy((void *)(segbase - tls_static_space), 229 (const void *)(oldsegbase - tls_static_space), 230 tls_static_space); 231 232 /* 233 * We assume that this block was the one we created with 234 * allocate_initial_tls(). 235 */ 236 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 237 } else { 238 memcpy((void *)(segbase - tls_static_space), 239 tls_init, tls_init_size); 240 memset((void *)(segbase - tls_static_space + tls_init_size), 241 0, tls_static_space - tls_init_size); 242 } 243 244 return (void*) segbase; 245 } 246 247 #endif /* TLS_VARIANT_II */ 248 249 #else 250 251 void * 252 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 253 size_t tcbalign __unused) 254 { 255 return (0); 256 } 257 258 void 259 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 260 size_t tcbalign __unused) 261 { 262 } 263 264 #endif /* PIC */ 265 266 extern char **environ; 267 268 void 269 _init_tls(void) 270 { 271 #ifndef PIC 272 Elf_Addr *sp; 273 Elf_Auxinfo *aux, *auxp; 274 Elf_Phdr *phdr; 275 size_t phent, phnum; 276 int i; 277 void *tls; 278 279 sp = (Elf_Addr *) environ; 280 while (*sp++ != 0) 281 ; 282 aux = (Elf_Auxinfo *) sp; 283 phdr = NULL; 284 phent = phnum = 0; 285 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 286 switch (auxp->a_type) { 287 case AT_PHDR: 288 phdr = auxp->a_un.a_ptr; 289 break; 290 291 case AT_PHENT: 292 phent = auxp->a_un.a_val; 293 break; 294 295 case AT_PHNUM: 296 phnum = auxp->a_un.a_val; 297 break; 298 } 299 } 300 if (phdr == NULL || phent != sizeof(Elf_Phdr) || phnum == 0) 301 return; 302 303 for (i = 0; (unsigned) i < phnum; i++) { 304 if (phdr[i].p_type == PT_TLS) { 305 tls_static_space = roundup2(phdr[i].p_memsz, 306 phdr[i].p_align); 307 tls_init_size = phdr[i].p_filesz; 308 tls_init = (void*) phdr[i].p_vaddr; 309 } 310 } 311 312 #ifdef TLS_VARIANT_I 313 /* 314 * tls_static_space should include space for TLS structure 315 */ 316 tls_static_space += TLS_TCB_SIZE; 317 #endif 318 319 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); 320 321 _set_tp(tls); 322 #endif 323 } 324