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