/* 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, see . */ #include #include #include #include #include #include #include #include #include #include #ifdef SHARED #error makefile bug, this file is for static only #endif #if 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. */ size_t _dl_tls_static_size; /* 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 __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 defined(TLS_TCB_AT_TP) tcb_offset = roundup (memsz + GL(dl_tls_static_size), tcbalign); tlsblock = sbrk (tcb_offset + tcbsize + max_align); # elif defined(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 defined(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 defined(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 defined(TLS_TCB_AT_TP) INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv); const char *lossage = TLS_INIT_TP ((char *) tlsblock + tcb_offset, 0); # elif defined(TLS_DTV_AT_TP) INSTALL_DTV (tlsblock, static_dtv); const char *lossage = (char *)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)) abort(); /* 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_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 defined(TLS_TCB_AT_TP) memsz += tcbsize; # elif defined(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 defined(TLS_TCB_AT_TP) TLS_TCB_SIZE, # else 0, # endif TLS_TCB_ALIGN); return 0; } extern void __pthread_initialize_minimal(void) __attribute__((weak)); /* 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); } #endif