1/*	$NetBSD: tls.c,v 1.15 2024/01/20 14:52:49 christos Exp $	*/
2
3/*-
4 * Copyright (c) 2011 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Joerg Sonnenberger.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__RCSID("$NetBSD: tls.c,v 1.15 2024/01/20 14:52:49 christos Exp $");
34
35#include "namespace.h"
36
37#define	_rtld_tls_allocate	__libc_rtld_tls_allocate
38#define	_rtld_tls_free		__libc_rtld_tls_free
39
40#include <sys/tls.h>
41
42#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
43
44#include <sys/param.h>
45#include <sys/mman.h>
46#include <link_elf.h>
47#include <lwp.h>
48#include <stdbool.h>
49#include <stdalign.h>
50#include <stddef.h>
51#include <stdlib.h>
52#include <string.h>
53#include <unistd.h>
54
55__dso_hidden void	__libc_static_tls_setup(void);
56
57static bool is_dynamic;
58static const void *tls_initaddr;
59static size_t tls_initsize;
60static size_t tls_size;
61static size_t tls_allocation;
62static void *initial_thread_tcb;
63
64void * __libc_tls_get_addr(void);
65
66__weak_alias(__tls_get_addr, __libc_tls_get_addr)
67#ifdef __i386__
68__weak_alias(___tls_get_addr, __libc_tls_get_addr)
69#endif
70
71void *
72__libc_tls_get_addr(void)
73{
74
75	abort();
76	/* NOTREACHED */
77}
78
79__weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate)
80
81struct tls_tcb *
82_rtld_tls_allocate(void)
83{
84	struct tls_tcb *tcb;
85	uint8_t *p;
86
87	if (initial_thread_tcb == NULL) {
88#ifdef __HAVE_TLS_VARIANT_I
89		tls_allocation = tls_size;
90#else
91		tls_allocation = roundup2(tls_size, alignof(max_align_t));
92#endif
93
94		initial_thread_tcb = p = mmap(NULL,
95		    tls_allocation + sizeof(*tcb), PROT_READ | PROT_WRITE,
96		    MAP_ANON, -1, 0);
97		if (p == MAP_FAILED)
98			initial_thread_tcb = p = NULL;
99	} else {
100		p = calloc(1, tls_allocation + sizeof(*tcb));
101	}
102	if (p == NULL) {
103		static const char msg[] =  "TLS allocation failed, terminating\n";
104		write(STDERR_FILENO, msg, sizeof(msg));
105		_exit(127);
106	}
107#ifdef __HAVE_TLS_VARIANT_I
108	/* LINTED */
109	tcb = (struct tls_tcb *)p;
110	p += sizeof(struct tls_tcb);
111#else
112	/* LINTED tls_size is rounded above */
113	tcb = (struct tls_tcb *)(p + tls_allocation);
114	p = (uint8_t *)tcb - tls_size;
115	tcb->tcb_self = tcb;
116#endif
117	memcpy(p, tls_initaddr, tls_initsize);
118
119	return tcb;
120}
121
122__weak_alias(_rtld_tls_free, __libc_rtld_tls_free)
123
124void
125_rtld_tls_free(struct tls_tcb *tcb)
126{
127	uint8_t *p;
128
129#ifdef __HAVE_TLS_VARIANT_I
130	/* LINTED */
131	p = (uint8_t *)tcb;
132#else
133	/* LINTED */
134	p = (uint8_t *)tcb - tls_allocation;
135#endif
136	if (p == initial_thread_tcb)
137		munmap(p, tls_allocation + sizeof(*tcb));
138	else
139		free(p);
140}
141
142static int __section(".text.startup")
143/*ARGSUSED*/
144__libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie)
145{
146	const Elf_Phdr *phdr = data->dlpi_phdr;
147	const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum;
148
149	for (; phdr < phlimit; ++phdr) {
150		if (phdr->p_type == PT_INTERP) {
151			is_dynamic = true;
152			return -1;
153		}
154		if (phdr->p_type != PT_TLS)
155			continue;
156		tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr);
157		tls_initsize = phdr->p_filesz;
158#ifdef __HAVE_TLS_VARIANT_I
159		tls_size = phdr->p_memsz;
160#else
161		tls_size = roundup2(phdr->p_memsz, phdr->p_align);
162#endif
163	}
164	return 0;
165}
166
167void
168__libc_static_tls_setup(void)
169{
170	struct tls_tcb *tcb;
171
172	dl_iterate_phdr(__libc_static_tls_setup_cb, NULL);
173	if (is_dynamic)
174		return;
175
176	tcb = _rtld_tls_allocate();
177#ifdef __HAVE___LWP_SETTCB
178	__lwp_settcb(tcb);
179#else
180	_lwp_setprivate(tcb);
181#endif
182}
183
184#endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */
185