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__weak_reference(__libc_allocate_tls, _rtld_allocate_tls);
43__weak_reference(__libc_free_tls, _rtld_free_tls);
44
45#ifdef __i386__
46
47__weak_reference(___libc_tls_get_addr, ___tls_get_addr);
48__attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *);
49
50#endif
51
52void * __libc_tls_get_addr(void *);
53__weak_reference(__libc_tls_get_addr, __tls_get_addr);
54
55void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
56void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
57void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign);
58void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign);
59
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 *)
65#else
66#error TLS_TCB_ALIGN undefined for target architecture
67#endif
68
69#if defined(__arm__) || defined(__ia64__) || \
70    defined(__powerpc__)
71#define TLS_VARIANT_I
72#endif
73#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
74    defined(__mips__)
75#define TLS_VARIANT_II
76#endif
77
78#ifndef PIC
79
80#define round(size, align) \
81	(((size) + (align) - 1) & ~((align) - 1))
82
83static size_t tls_static_space;
84static size_t tls_init_size;
85static void *tls_init;
86#endif
87
88#ifdef __i386__
89
90/* GNU ABI */
91
92__attribute__((__regparm__(1)))
93void *
94___libc_tls_get_addr(void *ti __unused)
95{
96	return (0);
97}
98
99#endif
100
101void *
102__libc_tls_get_addr(void *ti __unused)
103{
104	return (0);
105}
106
107#ifndef PIC
108
109#ifdef TLS_VARIANT_I
110
111#define	TLS_TCB_SIZE	(2 * sizeof(void *))
112
113/*
114 * Free Static TLS using the Variant I method.
115 */
116void
117__libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
118{
119	Elf_Addr *dtv;
120	Elf_Addr **tls;
121
122	tls = (Elf_Addr **)((Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE);
123	dtv = tls[0];
124	free(dtv);
125	free(tcb);
126}
127
128/*
129 * Allocate Static TLS using the Variant I method.
130 */
131void *
132__libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign __unused)
133{
134	Elf_Addr *dtv;
135	Elf_Addr **tls;
136	char *tcb;
137
138	if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
139		return (oldtcb);
140
141	tcb = calloc(1, tls_static_space + tcbsize - TLS_TCB_SIZE);
142	tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
143
144	if (oldtcb != NULL) {
145		memcpy(tls, oldtcb, tls_static_space);
146		free(oldtcb);
147
148		/* Adjust the DTV. */
149		dtv = tls[0];
150		dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
151	} else {
152		dtv = malloc(3 * sizeof(Elf_Addr));
153		tls[0] = dtv;
154		dtv[0] = 1;
155		dtv[1] = 1;
156		dtv[2] = (Elf_Addr)tls + TLS_TCB_SIZE;
157
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);
163	}
164
165	return(tcb);
166}
167
168#endif
169
170#ifdef TLS_VARIANT_II
171
172#define	TLS_TCB_SIZE	(3 * sizeof(Elf_Addr))
173
174/*
175 * Free Static TLS using the Variant II method.
176 */
177void
178__libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
179{
180	size_t size;
181	Elf_Addr* dtv;
182	Elf_Addr tlsstart, tlsend;
183
184	/*
185	 * Figure out the size of the initial TLS block so that we can
186	 * find stuff which ___tls_get_addr() allocated dynamically.
187	 */
188	size = round(tls_static_space, tcbalign);
189
190	dtv = ((Elf_Addr**)tcb)[1];
191	tlsend = (Elf_Addr) tcb;
192	tlsstart = tlsend - size;
193	free((void*) tlsstart);
194	free(dtv);
195}
196
197/*
198 * Allocate Static TLS using the Variant II method.
199 */
200void *
201__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
202{
203	size_t size;
204	char *tls;
205	Elf_Addr *dtv;
206	Elf_Addr segbase, oldsegbase;
207
208	size = round(tls_static_space, tcbalign);
209
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));
214
215	segbase = (Elf_Addr)(tls + size);
216	((Elf_Addr*)segbase)[0] = segbase;
217	((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
218
219	dtv[0] = 1;
220	dtv[1] = 1;
221	dtv[2] = segbase - tls_static_space;
222
223	if (oldtls) {
224		/*
225		 * Copy the static TLS block over whole.
226		 */
227		oldsegbase = (Elf_Addr) oldtls;
228		memcpy((void *)(segbase - tls_static_space),
229		    (const void *)(oldsegbase - tls_static_space),
230		    tls_static_space);
231
232		/*
233		 * We assume that this block was the one we created with
234		 * allocate_initial_tls().
235		 */
236		_rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
237	} else {
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);
242	}
243
244	return (void*) segbase;
245}
246
247#endif /* TLS_VARIANT_II */
248
249#else
250
251void *
252__libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused,
253	size_t tcbalign __unused)
254{
255	return (0);
256}
257
258void
259__libc_free_tls(void *tcb __unused, size_t tcbsize __unused,
260	size_t tcbalign __unused)
261{
262}
263
264#endif /* PIC */
265
266extern char **environ;
267
268void
269_init_tls()
270{
271#ifndef PIC
272	Elf_Addr *sp;
273	Elf_Auxinfo *aux, *auxp;
274	Elf_Phdr *phdr;
275	size_t phent, phnum;
276	int i;
277	void *tls;
278
279	sp = (Elf_Addr *) environ;
280	while (*sp++ != 0)
281		;
282	aux = (Elf_Auxinfo *) sp;
283	phdr = 0;
284	phent = phnum = 0;
285	for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
286		switch (auxp->a_type) {
287		case AT_PHDR:
288			phdr = auxp->a_un.a_ptr;
289			break;
290
291		case AT_PHENT:
292			phent = auxp->a_un.a_val;
293			break;
294
295		case AT_PHNUM:
296			phnum = auxp->a_un.a_val;
297			break;
298		}
299	}
300	if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
301		return;
302
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,
306			    phdr[i].p_align);
307			tls_init_size = phdr[i].p_filesz;
308			tls_init = (void*) phdr[i].p_vaddr;
309		}
310	}
311
312#ifdef TLS_VARIANT_I
313	/*
314	 * tls_static_space should include space for TLS structure
315	 */
316	tls_static_space += TLS_TCB_SIZE;
317#endif
318
319	tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN);
320
321	_set_tp(tls);
322#endif
323}
324