2 * Copyright (c) 2004 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
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.
35 #include <sys/cdefs.h>
41 #include "libc_private.h"
43 __weak_reference(__libc_allocate_tls, _rtld_allocate_tls);
44 __weak_reference(__libc_free_tls, _rtld_free_tls);
48 __weak_reference(___libc_tls_get_addr, ___tls_get_addr);
49 __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *);
53 void * __libc_tls_get_addr(void *);
54 __weak_reference(__libc_tls_get_addr, __tls_get_addr);
56 void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
57 void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
58 void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
59 void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
61 #if defined(__ia64__) || defined(__amd64__)
62 #define TLS_TCB_ALIGN 16
63 #elif defined(__powerpc__) || defined(__i386__) || defined(__arm__) || \
65 #define TLS_TCB_ALIGN sizeof(void *)
67 #error TLS_TCB_ALIGN undefined for target architecture
70 #if defined(__ia64__) || defined(__powerpc__)
73 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
75 #define TLS_VARIANT_II
80 #define round(size, align) \
81 (((size) + (align) - 1) & ~((align) - 1))
83 static size_t tls_static_space;
84 static size_t tls_init_size;
85 static void *tls_init;
92 __attribute__((__regparm__(1)))
94 ___libc_tls_get_addr(void *ti __unused)
102 __libc_tls_get_addr(void *ti __unused)
111 #define TLS_TCB_SIZE (2 * sizeof(void *))
114 * Free Static TLS using the Variant I method.
117 __libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
122 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE);
129 * Allocate Static TLS using the Variant I method.
132 __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused)
138 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
141 tcb = calloc(1, tls_static_space + tcbsize);
142 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
144 if (oldtcb != NULL) {
145 memcpy(tls, oldtcb, tls_static_space + TLS_TCB_SIZE);
148 /* Adjust the DTV. */
150 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
152 dtv = malloc(3 * sizeof(Elf_Addr));
156 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
158 if (tls_init_size > 0)
159 memcpy((void*)dtv[2], tls_init, tls_init_size);
160 if (tls_static_space > tls_init_size)
161 memset((void*)(dtv[2] + tls_init_size), 0,
162 tls_static_space - tls_init_size);
170 #ifdef TLS_VARIANT_II
172 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr))
175 * Free Static TLS using the Variant II method.
178 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
182 Elf_Addr tlsstart, tlsend;
185 * Figure out the size of the initial TLS block so that we can
186 * find stuff which ___tls_get_addr() allocated dynamically.
188 size = round(tls_static_space, tcbalign);
190 dtv = ((Elf_Addr**)tcb)[1];
191 tlsend = (Elf_Addr) tcb;
192 tlsstart = tlsend - size;
193 free((void*) tlsstart);
198 * Allocate Static TLS using the Variant II method.
201 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
206 Elf_Addr segbase, oldsegbase;
208 size = round(tls_static_space, tcbalign);
210 assert(tcbsize >= 2*sizeof(Elf_Addr));
211 tls = calloc(1, size + tcbsize);
212 dtv = malloc(3 * sizeof(Elf_Addr));
214 segbase = (Elf_Addr)(tls + size);
215 ((Elf_Addr*)segbase)[0] = segbase;
216 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
220 dtv[2] = segbase - tls_static_space;
224 * Copy the static TLS block over whole.
226 oldsegbase = (Elf_Addr) oldtls;
227 memcpy((void *)(segbase - tls_static_space),
228 (const void *)(oldsegbase - tls_static_space),
232 * We assume that this block was the one we created with
233 * allocate_initial_tls().
235 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
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);
243 return (void*) segbase;
246 #endif /* TLS_VARIANT_II */
251 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused,
252 size_t tcbalign __unused)
258 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused,
259 size_t tcbalign __unused)
265 extern char **environ;
272 Elf_Auxinfo *aux, *auxp;
278 sp = (Elf_Addr *) environ;
281 aux = (Elf_Auxinfo *) sp;
284 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
285 switch (auxp->a_type) {
287 phdr = auxp->a_un.a_ptr;
291 phent = auxp->a_un.a_val;
295 phnum = auxp->a_un.a_val;
299 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
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,
306 tls_init_size = phdr[i].p_filesz;
307 tls_init = (void*) phdr[i].p_vaddr;
311 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN);