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Diffstat (limited to 'csu/libc-tls.c')
| -rw-r--r-- | csu/libc-tls.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/csu/libc-tls.c b/csu/libc-tls.c new file mode 100644 index 0000000..3544e39 --- /dev/null +++ b/csu/libc-tls.c @@ -0,0 +1,263 @@ +/* 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 |