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(__aarch64__) || defined(__arm__) || defined(__i386__) || \ 68 defined(__mips__) || defined(__powerpc__) || defined(__riscv__) || \ 69 defined(__sparc64__) 70 #define TLS_TCB_ALIGN sizeof(void *) 71 #else 72 #error TLS_TCB_ALIGN undefined for target architecture 73 #endif 74 75 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 76 defined(__powerpc__) || defined(__riscv__) 77 #define TLS_VARIANT_I 78 #endif 79 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 80 #define TLS_VARIANT_II 81 #endif 82 83 #ifndef PIC 84 85 #define round(size, align) \ 86 (((size) + (align) - 1) & ~((align) - 1)) 87 88 static size_t tls_static_space; 89 static size_t tls_init_size; 90 static void *tls_init; 91 #endif 92 93 #ifdef __i386__ 94 95 /* GNU ABI */ 96 97 __attribute__((__regparm__(1))) 98 void * 99 ___libc_tls_get_addr(void *ti __unused) 100 { 101 return (0); 102 } 103 104 #endif 105 106 void * 107 __libc_tls_get_addr(void *ti __unused) 108 { 109 return (0); 110 } 111 112 #ifndef PIC 113 114 #ifdef TLS_VARIANT_I 115 116 #define TLS_TCB_SIZE (2 * sizeof(void *)) 117 118 /* 119 * Free Static TLS using the Variant I method. 120 */ 121 void 122 __libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 123 { 124 Elf_Addr *dtv; 125 Elf_Addr **tls; 126 127 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE); 128 dtv = tls[0]; 129 __je_bootstrap_free(dtv); 130 __je_bootstrap_free(tcb); 131 } 132 133 /* 134 * Allocate Static TLS using the Variant I method. 135 */ 136 void * 137 __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused) 138 { 139 Elf_Addr *dtv; 140 Elf_Addr **tls; 141 char *tcb; 142 143 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 144 return (oldtcb); 145 146 tcb = __je_bootstrap_calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE); 147 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 148 149 if (oldtcb != NULL) { 150 memcpy(tls, oldtcb, tls_static_space); 151 __je_bootstrap_free(oldtcb); 152 153 /* Adjust the DTV. */ 154 dtv = tls[0]; 155 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 156 } else { 157 dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); 158 tls[0] = dtv; 159 dtv[0] = 1; 160 dtv[1] = 1; 161 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE; 162 163 if (tls_init_size > 0) 164 memcpy((void*)dtv[2], tls_init, tls_init_size); 165 if (tls_static_space > tls_init_size) 166 memset((void*)(dtv[2] + tls_init_size), 0, 167 tls_static_space - tls_init_size); 168 } 169 170 return(tcb); 171 } 172 173 #endif 174 175 #ifdef TLS_VARIANT_II 176 177 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) 178 179 /* 180 * Free Static TLS using the Variant II method. 181 */ 182 void 183 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) 184 { 185 size_t size; 186 Elf_Addr* dtv; 187 Elf_Addr tlsstart, tlsend; 188 189 /* 190 * Figure out the size of the initial TLS block so that we can 191 * find stuff which ___tls_get_addr() allocated dynamically. 192 */ 193 size = round(tls_static_space, tcbalign); 194 195 dtv = ((Elf_Addr**)tcb)[1]; 196 tlsend = (Elf_Addr) tcb; 197 tlsstart = tlsend - size; 198 __je_bootstrap_free((void*) tlsstart); 199 __je_bootstrap_free(dtv); 200 } 201 202 /* 203 * Allocate Static TLS using the Variant II method. 204 */ 205 void * 206 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 207 { 208 size_t size; 209 char *tls; 210 Elf_Addr *dtv; 211 Elf_Addr segbase, oldsegbase; 212 213 size = round(tls_static_space, tcbalign); 214 215 if (tcbsize < 2 * sizeof(Elf_Addr)) 216 tcbsize = 2 * sizeof(Elf_Addr); 217 tls = __je_bootstrap_calloc(1, size + tcbsize); 218 dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); 219 220 segbase = (Elf_Addr)(tls + size); 221 ((Elf_Addr*)segbase)[0] = segbase; 222 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 223 224 dtv[0] = 1; 225 dtv[1] = 1; 226 dtv[2] = segbase - tls_static_space; 227 228 if (oldtls) { 229 /* 230 * Copy the static TLS block over whole. 231 */ 232 oldsegbase = (Elf_Addr) oldtls; 233 memcpy((void *)(segbase - tls_static_space), 234 (const void *)(oldsegbase - tls_static_space), 235 tls_static_space); 236 237 /* 238 * We assume that this block was the one we created with 239 * allocate_initial_tls(). 240 */ 241 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 242 } else { 243 memcpy((void *)(segbase - tls_static_space), 244 tls_init, tls_init_size); 245 memset((void *)(segbase - tls_static_space + tls_init_size), 246 0, tls_static_space - tls_init_size); 247 } 248 249 return (void*) segbase; 250 } 251 252 #endif /* TLS_VARIANT_II */ 253 254 #else 255 256 void * 257 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, 258 size_t tcbalign __unused) 259 { 260 return (0); 261 } 262 263 void 264 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, 265 size_t tcbalign __unused) 266 { 267 } 268 269 #endif /* PIC */ 270 271 extern char **environ; 272 273 void 274 _init_tls(void) 275 { 276 #ifndef PIC 277 Elf_Addr *sp; 278 Elf_Auxinfo *aux, *auxp; 279 Elf_Phdr *phdr; 280 size_t phent, phnum; 281 int i; 282 void *tls; 283 284 sp = (Elf_Addr *) environ; 285 while (*sp++ != 0) 286 ; 287 aux = (Elf_Auxinfo *) sp; 288 phdr = 0; 289 phent = phnum = 0; 290 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 291 switch (auxp->a_type) { 292 case AT_PHDR: 293 phdr = auxp->a_un.a_ptr; 294 break; 295 296 case AT_PHENT: 297 phent = auxp->a_un.a_val; 298 break; 299 300 case AT_PHNUM: 301 phnum = auxp->a_un.a_val; 302 break; 303 } 304 } 305 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0) 306 return; 307 308 for (i = 0; (unsigned) i < phnum; i++) { 309 if (phdr[i].p_type == PT_TLS) { 310 tls_static_space = round(phdr[i].p_memsz, 311 phdr[i].p_align); 312 tls_init_size = phdr[i].p_filesz; 313 tls_init = (void*) phdr[i].p_vaddr; 314 } 315 } 316 317 #ifdef TLS_VARIANT_I 318 /* 319 * tls_static_space should include space for TLS structure 320 */ 321 tls_static_space += TLS_TCB_SIZE; 322 #endif 323 324 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); 325 326 _set_tp(tls); 327 #endif 328 } 329