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>
40 #include "libc_private.h"
42 __weak_reference(__libc_allocate_tls, _rtld_allocate_tls);
43 __weak_reference(__libc_free_tls, _rtld_free_tls);
47 __weak_reference(___libc_tls_get_addr, ___tls_get_addr);
48 __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *);
52 void * __libc_tls_get_addr(void *);
53 __weak_reference(__libc_tls_get_addr, __tls_get_addr);
55 void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
56 void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
57 void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
58 void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
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 *)
66 #error TLS_TCB_ALIGN undefined for target architecture
69 #if defined(__ia64__) || defined(__powerpc__)
72 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
73 defined(__arm__) || defined(__mips__)
74 #define TLS_VARIANT_II
79 #define round(size, align) \
80 (((size) + (align) - 1) & ~((align) - 1))
82 static size_t tls_static_space;
83 static size_t tls_init_size;
84 static void *tls_init;
91 __attribute__((__regparm__(1)))
93 ___libc_tls_get_addr(void *ti __unused)
101 __libc_tls_get_addr(void *ti __unused)
110 #define TLS_TCB_SIZE (2 * sizeof(void *))
113 * Free Static TLS using the Variant I method.
116 __libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
121 tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE);
128 * Allocate Static TLS using the Variant I method.
131 __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused)
137 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
140 tcb = calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE);
141 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
143 if (oldtcb != NULL) {
144 memcpy(tls, oldtcb, tls_static_space);
147 /* Adjust the DTV. */
149 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
151 dtv = malloc(3 * sizeof(Elf_Addr));
155 dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
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);
169 #ifdef TLS_VARIANT_II
171 #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr))
174 * Free Static TLS using the Variant II method.
177 __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
181 Elf_Addr tlsstart, tlsend;
184 * Figure out the size of the initial TLS block so that we can
185 * find stuff which ___tls_get_addr() allocated dynamically.
187 size = round(tls_static_space, tcbalign);
189 dtv = ((Elf_Addr**)tcb)[1];
190 tlsend = (Elf_Addr) tcb;
191 tlsstart = tlsend - size;
192 free((void*) tlsstart);
197 * Allocate Static TLS using the Variant II method.
200 __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
205 Elf_Addr segbase, oldsegbase;
207 size = round(tls_static_space, tcbalign);
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));
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);