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authorJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
committerJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
commit0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch)
tree2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /csu/libc-tls.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
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2.5-18.1
Diffstat (limited to 'csu/libc-tls.c')
-rw-r--r--csu/libc-tls.c263
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diff --git a/csu/libc-tls.c b/csu/libc-tls.c
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+/* Initialization code for TLS in statically linked application.
+ Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <ldsodefs.h>
+#include <tls.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/param.h>
+
+
+#ifdef SHARED
+ #error makefile bug, this file is for static only
+#endif
+
+#ifdef USE_TLS
+extern ElfW(Phdr) *_dl_phdr;
+extern size_t _dl_phnum;
+
+
+static dtv_t static_dtv[2 + TLS_SLOTINFO_SURPLUS];
+
+
+static struct
+{
+ struct dtv_slotinfo_list si;
+ /* The dtv_slotinfo_list data structure does not include the actual
+ information since it is defined as an array of size zero. We define
+ here the necessary entries. Note that it is not important whether
+ there is padding or not since we will always access the information
+ through the 'si' element. */
+ struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];
+} static_slotinfo;
+
+/* Fake link map for the application. */
+static struct link_map static_map;
+
+
+/* Highest dtv index currently needed. */
+size_t _dl_tls_max_dtv_idx;
+/* Flag signalling whether there are gaps in the module ID allocation. */
+bool _dl_tls_dtv_gaps;
+/* Information about the dtv slots. */
+struct dtv_slotinfo_list *_dl_tls_dtv_slotinfo_list;
+/* Number of modules in the static TLS block. */
+size_t _dl_tls_static_nelem;
+/* Size of the static TLS block. Giving this initialized value
+ preallocates some surplus bytes in the static TLS area. */
+size_t _dl_tls_static_size = 2048;
+/* Size actually allocated in the static TLS block. */
+size_t _dl_tls_static_used;
+/* Alignment requirement of the static TLS block. */
+size_t _dl_tls_static_align;
+
+/* Generation counter for the dtv. */
+size_t _dl_tls_generation;
+
+
+/* Additional definitions needed by TLS initialization. */
+#ifdef TLS_INIT_HELPER
+TLS_INIT_HELPER
+#endif
+
+static inline void
+init_slotinfo (void)
+{
+ /* Create the slotinfo list. */
+ static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)
+ - (char *) &static_slotinfo.si.slotinfo[0])
+ / sizeof static_slotinfo.si.slotinfo[0]);
+ // static_slotinfo.si.next = NULL; already zero
+
+ /* The slotinfo list. Will be extended by the code doing dynamic
+ linking. */
+ GL(dl_tls_max_dtv_idx) = 1;
+ GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;
+}
+
+static inline void
+init_static_tls (size_t memsz, size_t align)
+{
+ /* That is the size of the TLS memory for this object. The initialized
+ value of _dl_tls_static_size is provided by dl-open.c to request some
+ surplus that permits dynamic loading of modules with IE-model TLS. */
+ GL(dl_tls_static_size) = roundup (memsz + GL(dl_tls_static_size),
+ TLS_TCB_ALIGN);
+ GL(dl_tls_static_used) = memsz;
+ /* The alignment requirement for the static TLS block. */
+ GL(dl_tls_static_align) = align;
+ /* Number of elements in the static TLS block. */
+ GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
+}
+
+void
+__libc_setup_tls (size_t tcbsize, size_t tcbalign)
+{
+ void *tlsblock;
+ size_t memsz = 0;
+ size_t filesz = 0;
+ void *initimage = NULL;
+ size_t align = 0;
+ size_t max_align = tcbalign;
+ size_t tcb_offset;
+ ElfW(Phdr) *phdr;
+
+ /* Look through the TLS segment if there is any. */
+ if (_dl_phdr != NULL)
+ for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
+ if (phdr->p_type == PT_TLS)
+ {
+ /* Remember the values we need. */
+ memsz = phdr->p_memsz;
+ filesz = phdr->p_filesz;
+ initimage = (void *) phdr->p_vaddr;
+ align = phdr->p_align;
+ if (phdr->p_align > max_align)
+ max_align = phdr->p_align;
+ break;
+ }
+
+ /* We have to set up the TCB block which also (possibly) contains
+ 'errno'. Therefore we avoid 'malloc' which might touch 'errno'.
+ Instead we use 'sbrk' which would only uses 'errno' if it fails.
+ In this case we are right away out of memory and the user gets
+ what she/he deserves.
+
+ The initialized value of _dl_tls_static_size is provided by dl-open.c
+ to request some surplus that permits dynamic loading of modules with
+ IE-model TLS. */
+# if TLS_TCB_AT_TP
+ tcb_offset = roundup (memsz + GL(dl_tls_static_size), tcbalign);
+ tlsblock = __sbrk (tcb_offset + tcbsize + max_align);
+# elif TLS_DTV_AT_TP
+ tcb_offset = roundup (tcbsize, align ?: 1);
+ tlsblock = __sbrk (tcb_offset + memsz + max_align
+ + TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));
+ tlsblock += TLS_PRE_TCB_SIZE;
+# else
+ /* In case a model with a different layout for the TCB and DTV
+ is defined add another #elif here and in the following #ifs. */
+# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+# endif
+
+ /* Align the TLS block. */
+ tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
+ & ~(max_align - 1));
+
+ /* Initialize the dtv. [0] is the length, [1] the generation counter. */
+ static_dtv[0].counter = (sizeof (static_dtv) / sizeof (static_dtv[0])) - 2;
+ // static_dtv[1].counter = 0; would be needed if not already done
+
+ /* Initialize the TLS block. */
+# if TLS_TCB_AT_TP
+ static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset
+ - roundup (memsz, align ?: 1));
+ static_map.l_tls_offset = roundup (memsz, align ?: 1);
+# elif TLS_DTV_AT_TP
+ static_dtv[2].pointer.val = (char *) tlsblock + tcb_offset;
+ static_map.l_tls_offset = tcb_offset;
+# else
+# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+# endif
+ static_dtv[2].pointer.is_static = true;
+ /* sbrk gives us zero'd memory, so we don't need to clear the remainder. */
+ memcpy (static_dtv[2].pointer.val, initimage, filesz);
+
+ /* Install the pointer to the dtv. */
+
+ /* Initialize the thread pointer. */
+# if TLS_TCB_AT_TP
+ INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv);
+
+ const char *lossage = TLS_INIT_TP ((char *) tlsblock + tcb_offset, 0);
+# elif TLS_DTV_AT_TP
+ INSTALL_DTV (tlsblock, static_dtv);
+ const char *lossage = TLS_INIT_TP (tlsblock, 0);
+# else
+# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+# endif
+ if (__builtin_expect (lossage != NULL, 0))
+ __libc_fatal (lossage);
+
+ /* We have to create a fake link map which normally would be created
+ by the dynamic linker. It just has to have enough information to
+ make the TLS routines happy. */
+ static_map.l_tls_align = align;
+ static_map.l_tls_blocksize = memsz;
+ static_map.l_tls_initimage = initimage;
+ static_map.l_tls_initimage_size = filesz;
+ static_map.l_type = lt_executable;
+ static_map.l_tls_modid = 1;
+
+ init_slotinfo ();
+ // static_slotinfo.si.slotinfo[1].gen = 0; already zero
+ static_slotinfo.si.slotinfo[1].map = &static_map;
+
+ memsz = roundup (memsz, align ?: 1);
+
+# if TLS_TCB_AT_TP
+ memsz += tcbsize;
+# elif TLS_DTV_AT_TP
+ memsz += tcb_offset;
+# endif
+
+ init_static_tls (memsz, MAX (TLS_TCB_ALIGN, max_align));
+}
+
+/* This is called only when the data structure setup was skipped at startup,
+ when there was no need for it then. Now we have dynamically loaded
+ something needing TLS, or libpthread needs it. */
+int
+internal_function
+_dl_tls_setup (void)
+{
+ init_slotinfo ();
+ init_static_tls (
+# if TLS_TCB_AT_TP
+ TLS_TCB_SIZE,
+# else
+ 0,
+# endif
+ TLS_TCB_ALIGN);
+ return 0;
+}
+
+
+/* This is the minimal initialization function used when libpthread is
+ not used. */
+void
+__attribute__ ((weak))
+__pthread_initialize_minimal (void)
+{
+ __libc_setup_tls (TLS_INIT_TCB_SIZE, TLS_INIT_TCB_ALIGN);
+}
+
+#elif defined NONTLS_INIT_TP
+
+/* This is the minimal initialization function used when libpthread is
+ not used. */
+void
+__attribute__ ((weak))
+__pthread_initialize_minimal (void)
+{
+ NONTLS_INIT_TP;
+}
+
+#endif