lib/libc/tls/tls.c

   1 /*      $NetBSD: tls.c,v 1.6 2011/04/07 02:19:28 matt 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 1.6 2011/04/07 02:19:28 matt 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 <stddef.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52
  53 __dso_hidden void       __libc_static_tls_setup(void);
  54
  55 static const void *tls_initaddr;
  56 static size_t tls_initsize;
  57 static size_t tls_size;
  58 static size_t tls_allocation;
  59 static void *initial_thread_tcb;
  60
  61 void * __libc_tls_get_addr(void);
  62
  63 __weak_alias(__tls_get_addr, __libc_tls_get_addr)
  64 #ifdef __i386__
  65 __weak_alias(___tls_get_addr, __libc_tls_get_addr)
  66 #endif
  67
  68 void *
  69 __libc_tls_get_addr(void)
  70 {
  71
  72         abort();
  73         /* NOTREACHED */
  74 }
  75
  76 __weak_alias(_rtld_tls_allocate, __libc_rtld_tls_allocate)
  77
  78 struct tls_tcb *
  79 _rtld_tls_allocate(void)
  80 {
  81         struct tls_tcb *tcb;
  82         uint8_t *p;
  83
  84         if (initial_thread_tcb == NULL) {
  85 #ifdef __HAVE_TLS_VARIANT_II
  86                 tls_size = roundup2(tls_size, sizeof(void *));
  87 #endif
  88                 tls_allocation = tls_size + sizeof(*tcb);
  89
  90                 initial_thread_tcb = p = mmap(NULL, tls_allocation,
  91                     PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
  92         } else {
  93                 p = calloc(1, tls_allocation);
  94         }
  95         if (p == NULL) {
  96                 static const char msg[] =  "TLS allocation failed, terminating\n";
  97                 write(STDERR_FILENO, msg, sizeof(msg));
  98                 _exit(127);
  99         }
 100 #ifdef __HAVE_TLS_VARIANT_I
 101         /* LINTED */
 102         tcb = (struct tls_tcb *)p;
 103         p += sizeof(struct tls_tcb);
 104 #else
 105         /* LINTED tls_size is rounded above */
 106         tcb = (struct tls_tcb *)(p + tls_size);
 107         tcb->tcb_self = tcb;
 108 #endif
 109         memcpy(p, tls_initaddr, tls_initsize);
 110
 111         return tcb;
 112 }
 113
 114 __weak_alias(_rtld_tls_free, __libc_rtld_tls_free)
 115
 116 void
 117 _rtld_tls_free(struct tls_tcb *tcb)
 118 {
 119         uint8_t *p;
 120
 121 #ifdef __HAVE_TLS_VARIANT_I
 122         /* LINTED */
 123         p = (uint8_t *)tcb;
 124 #else
 125         /* LINTED */
 126         p = (uint8_t *)tcb - tls_size;
 127 #endif
 128         if (p == initial_thread_tcb)
 129                 munmap(p, tls_allocation);
 130         else
 131                 free(p);
 132 }
 133
 134 __weakref_visible int rtld_DYNAMIC __weak_reference(_DYNAMIC);
 135
 136 static int
 137 __libc_static_tls_setup_cb(struct dl_phdr_info *data, size_t len, void *cookie)
 138 {
 139         const Elf_Phdr *phdr = data->dlpi_phdr;
 140         const Elf_Phdr *phlimit = data->dlpi_phdr + data->dlpi_phnum;
 141
 142         for (; phdr < phlimit; ++phdr) {
 143                 if (phdr->p_type != PT_TLS)
 144                         continue;
 145                 tls_initaddr = (void *)(phdr->p_vaddr + data->dlpi_addr);
 146                 tls_initsize = phdr->p_filesz;
 147                 tls_size = phdr->p_memsz;
 148         }
 149         return 0;
 150 }
 151
 152 void
 153 __libc_static_tls_setup(void)
 154 {
 155         struct tls_tcb *tcb;
 156
 157         if (&rtld_DYNAMIC != NULL) {
 158 #ifdef __powerpc__
 159                 /*
 160                  * Old powerpc crt0's are going to overwrite r2 so we need to
 161                  * restore it but only do so if the saved value isn't NULL (if
 162                  * it is NULL, ld.elf_so doesn't have the matching change).
 163                  */
 164                 if ((tcb = _lwp_getprivate()) != NULL)
 165                         __lwp_settcb(tcb);
 166 #endif
 167                 return;
 168         }
 169
 170         dl_iterate_phdr(__libc_static_tls_setup_cb, NULL);
 171
 172         tcb = _rtld_tls_allocate();
 173 #ifdef __HAVE___LWP_SETTCB
 174         __lwp_settcb(tcb);
 175 #else
 176         _lwp_setprivate(tcb);
 177 #endif
 178 }
 179
 180 #endif /* __HAVE_TLS_VARIANT_I || __HAVE_TLS_VARIANT_II */