Use fixed-width type to ensure correct wraparound for
[dragonfly.git] / lib / libc / gen / tls.c
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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: src/lib/libc/gen/tls.c,v 1.7 2005/03/01 23:42:00 davidxu Exp $
27 * $DragonFly: src/lib/libc/gen/tls.c,v 1.1 2005/03/08 13:04:38 davidxu Exp $
28 */
29
30/*
31 * Define stubs for TLS internals so that programs and libraries can
32 * link. These functions will be replaced by functional versions at
33 * runtime from ld-elf.so.1.
34 */
35
36#include <stdlib.h>
37#include <string.h>
38#include <elf.h>
39#include <assert.h>
40#include "libc_private.h"
41
42/* XXX not sure what variants to use for arm. */
43
44#if defined(__ia64__) || defined(__powerpc__)
45#define TLS_VARIANT_I
46#endif
47#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
48 defined(__arm__)
49#define TLS_VARIANT_II
50#endif
51
52#ifndef PIC
53
54#define round(size, align) \
55 (((size) + (align) - 1) & ~((align) - 1))
56
57static size_t tls_static_space;
58static size_t tls_init_size;
59#ifdef TLS_VARIANT_I
60static size_t tls_init_offset;
61#endif
62static void *tls_init;
63#endif
64
65void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
66void _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign);
67void *__tls_get_addr(void *);
68
69#ifdef __i386__
70
71extern void *___tls_get_addr(void *ti) __attribute__((__regparm__(1)));
72
73#pragma weak ___tls_get_addr
74__attribute__((__regparm__(1)))
75void *
76___tls_get_addr(void *ti __unused)
77{
78 return (0);
79}
80
81#endif
82
83#pragma weak __tls_get_addr
84void *
85__tls_get_addr(void *ti __unused)
86{
87 return (0);
88}
89
90#ifdef TLS_VARIANT_I
91
92#pragma weak _rtld_free_tls
93/*
94 * Free Static TLS using the Variant I method.
95 */
96void
97_rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign)
98{
99#ifndef PIC
100 Elf_Addr* dtv;
101
102 dtv = ((Elf_Addr**)tls)[0];
103 free(tls);
104 free(dtv);
105#endif
106}
107
108#pragma weak _rtld_allocate_tls
109/*
110 * Allocate Static TLS using the Variant I method.
111 */
112void *
113_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
114{
115#ifndef PIC
116 size_t size;
117 char *tls;
118 Elf_Addr *dtv;
119
120 size = tls_static_space;
121 if (size < tcbsize)
122 size = tcbsize;
123
124 tls = malloc(size);
125 dtv = malloc(3 * sizeof(Elf_Addr));
126
127 *(Elf_Addr**) tls = dtv;
128
129 dtv[0] = 1;
130 dtv[1] = 1;
131 dtv[2] = (Elf_Addr)(tls + tls_init_offset);
132 if (oldtls) {
133 /*
134 * Copy the static TLS block over whole.
135 */
136 memcpy(tls + tls_init_offset,
137 (char*) oldtls + tls_init_offset,
138 tls_static_space - tls_init_offset);
139
140 /*
141 * We assume that this block was the one we created with
142 * allocate_initial_tls().
143 */
144 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
145 } else {
146 memcpy(tls + tls_init_offset, tls_init, tls_init_size);
147 memset(tls + tls_init_offset + tls_init_size,
148 0, tls_static_space - tls_init_size);
149 }
150
151 return tls;
152#else
153 return (0);
154#endif
155}
156
157#endif
158
159#ifdef TLS_VARIANT_II
160
161/*
162 * Free Static TLS using the Variant II method.
163 */
164#pragma weak _rtld_free_tls
165void
166_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
167{
168#ifndef PIC
169 size_t size;
170 Elf_Addr* dtv;
171 Elf_Addr tlsstart, tlsend;
172
173 /*
174 * Figure out the size of the initial TLS block so that we can
175 * find stuff which ___tls_get_addr() allocated dynamically.
176 */
177 size = round(tls_static_space, tcbalign);
178
179 dtv = ((Elf_Addr**)tcb)[1];
180 tlsend = (Elf_Addr) tcb;
181 tlsstart = tlsend - size;
182 free((void*) tlsstart);
183 free(dtv);
184#endif
185}
186
187#pragma weak _rtld_allocate_tls
188/*
189 * Allocate Static TLS using the Variant II method.
190 */
191void *
192_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
193{
194#ifndef PIC
195 size_t size;
196 char *tls;
197 Elf_Addr *dtv;
198 Elf_Addr segbase, oldsegbase;
199
200 size = round(tls_static_space, tcbalign);
201
202 assert(tcbsize >= 2*sizeof(Elf_Addr));
203 tls = malloc(size + tcbsize);
204 dtv = malloc(3 * sizeof(Elf_Addr));
205
206 segbase = (Elf_Addr)(tls + size);
207 ((Elf_Addr*)segbase)[0] = segbase;
208 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
209
210 dtv[0] = 1;
211 dtv[1] = 1;
212 dtv[2] = segbase - tls_static_space;
213
214 if (oldtls) {
215 /*
216 * Copy the static TLS block over whole.
217 */
218 oldsegbase = (Elf_Addr) oldtls;
219 memcpy((void *)(segbase - tls_static_space),
220 (const void *)(oldsegbase - tls_static_space),
221 tls_static_space);
222
223 /*
224 * We assume that this block was the one we created with
225 * allocate_initial_tls().
226 */
227 _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
228 } else {
229 memcpy((void *)(segbase - tls_static_space),
230 tls_init, tls_init_size);
231 memset((void *)(segbase - tls_static_space + tls_init_size),
232 0, tls_static_space - tls_init_size);
233 }
234
235 return (void*) segbase;
236#else
237 return (0);
238#endif
239}
240
241#endif /* TLS_VARIANT_II */
242
243extern char **environ;
244
245void
246_init_tls()
247{
248#ifndef PIC
249 Elf_Addr *sp;
250 Elf_Auxinfo *aux, *auxp;
251 Elf_Phdr *phdr;
252 size_t phent, phnum;
253 int i;
254 void *tls;
255
256 sp = (Elf_Addr *) environ;
257 while (*sp++ != 0)
258 ;
259 aux = (Elf_Auxinfo *) sp;
260 phdr = 0;
261 phent = phnum = 0;
262 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
263 switch (auxp->a_type) {
264 case AT_PHDR:
265 phdr = auxp->a_un.a_ptr;
266 break;
267
268 case AT_PHENT:
269 phent = auxp->a_un.a_val;
270 break;
271
272 case AT_PHNUM:
273 phnum = auxp->a_un.a_val;
274 break;
275 }
276 }
277 if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
278 return;
279
280 for (i = 0; (unsigned)i < phnum; i++) {
281 if (phdr[i].p_type == PT_TLS) {
282#ifdef TLS_VARIANT_I
283 tls_static_space = round(2*sizeof(Elf_Addr),
284 phdr[i].p_align) + phdr[i].p_memsz;
285 tls_init_offset = round(2*sizeof(Elf_Addr),
286 phdr[i].p_align);
287#else
288 tls_static_space = round(phdr[i].p_memsz,
289 phdr[i].p_align);
290#endif
291 tls_init_size = phdr[i].p_filesz;
292 tls_init = (void*) phdr[i].p_vaddr;
293 }
294 }
295
296 tls = _rtld_allocate_tls(NULL, 2*sizeof(Elf_Addr),
297 sizeof(Elf_Addr));
298
299 _set_tp(tls, 2 * sizeof(Elf_Addr));
300#endif
301}