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(__arm__) || defined(__ia64__) || \
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 - TLS_TCB_SIZE);
142 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
144 if (oldtcb != NULL) {
145 memcpy(tls, oldtcb, tls_static_space);
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 if (tcbsize < 2 * sizeof(Elf_Addr))
211 tcbsize = 2 * sizeof(Elf_Addr);
212 tls = calloc(1, size + tcbsize);
213 dtv = malloc(3 * sizeof(Elf_Addr));
215 segbase = (Elf_Addr)(tls + size);
216 ((Elf_Addr*)segbase)[0] = segbase;
217 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
221 dtv[2] = segbase - tls_static_space;
225 * Copy the static TLS block over whole.
227 oldsegbase = (Elf_Addr) oldtls;
228 memcpy((void *)(segbase - tls_static_space),
229 (const void *)(oldsegbase - tls_static_space),
233 * We assume that this block was the one we created with
234 * allocate_initial_tls().
236 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
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);
244 return (void*) segbase;
247 #endif /* TLS_VARIANT_II */
252 __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused,
253 size_t tcbalign __unused)
259 __libc_free_tls(void *tcb __unused, size_t tcbsize __unused,
260 size_t tcbalign __unused)
266 extern char **environ;
273 Elf_Auxinfo *aux, *auxp;
279 sp = (Elf_Addr *) environ;
282 aux = (Elf_Auxinfo *) sp;
285 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
286 switch (auxp->a_type) {
288 phdr = auxp->a_un.a_ptr;
292 phent = auxp->a_un.a_val;
296 phnum = auxp->a_un.a_val;
300 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
303 for (i = 0; (unsigned) i < phnum; i++) {
304 if (phdr[i].p_type == PT_TLS) {
305 tls_static_space = round(phdr[i].p_memsz,
307 tls_init_size = phdr[i].p_filesz;
308 tls_init = (void*) phdr[i].p_vaddr;
314 * tls_static_space should include space for TLS structure
316 tls_static_space += TLS_TCB_SIZE;
319 tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN);