/* Definition for thread-local data handling. linuxthreads/i386 version. 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. */ #ifndef _TLS_H #define _TLS_H # include <pt-machine.h> #ifndef __ASSEMBLER__ # include <stdbool.h> # include <stddef.h> # include <stdint.h> /* Type for the dtv. */ typedef union dtv { size_t counter; void *pointer; } dtv_t; typedef struct { void *tcb; /* Pointer to the TCB. Not necessary the thread descriptor used by libpthread. */ dtv_t *dtv; void *self; /* Pointer to the thread descriptor. */ } tcbhead_t; #endif /* We can support TLS only if the floating-stack support is available. */ #if defined FLOATING_STACKS && defined HAVE_TLS_SUPPORT /* Signal that TLS support is available. */ //# define USE_TLS 1 # ifndef __ASSEMBLER__ /* Get system call information. */ # include <sysdep.h> /* Get the thread descriptor definition. */ # include <linuxthreads/descr.h> /* This is the size of the initial TCB. */ # define TLS_INIT_TCB_SIZE sizeof (tcbhead_t) /* Alignment requirements for the initial TCB. */ # define TLS_INIT_TCB_ALIGN __alignof__ (tcbhead_t) /* This is the size of the TCB. */ # define TLS_TCB_SIZE sizeof (struct _pthread_descr_struct) /* Alignment requirements for the TCB. */ # define TLS_TCB_ALIGN __alignof__ (struct _pthread_descr_struct) /* The TCB can have any size and the memory following the address the thread pointer points to is unspecified. Allocate the TCB there. */ # define TLS_TCB_AT_TP 1 /* Install the dtv pointer. The pointer passed is to the element with index -1 which contain the length. */ # define INSTALL_DTV(descr, dtvp) \ ((tcbhead_t *) (descr))->dtv = (dtvp) + 1 /* Install new dtv for current thread. */ # define INSTALL_NEW_DTV(dtv) \ ({ struct _pthread_descr_struct *__descr; \ THREAD_SETMEM (__descr, p_header.data.dtvp, (dtv)); }) /* Return dtv of given thread descriptor. */ # define GET_DTV(descr) \ (((tcbhead_t *) (descr))->dtv) # ifdef __PIC__ # define TLS_EBX_ARG "r" # define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t" # else # define TLS_EBX_ARG "b" # define TLS_LOAD_EBX # endif # define TLS_DO_MODIFY_LDT(descr, nr) \ ({ \ struct modify_ldt_ldt_s ldt_entry = \ { nr, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \ 1, 0, 0, 1, 0, 1, 0 }; \ int result; \ asm volatile (TLS_LOAD_EBX \ "int $0x80\n\t" \ TLS_LOAD_EBX \ : "=a" (result) \ : "0" (__NR_modify_ldt), \ /* The extra argument with the "m" constraint is necessary \ to let the compiler know that we are accessing LDT_ENTRY \ here. */ \ "m" (ldt_entry), TLS_EBX_ARG (1), "c" (&ldt_entry), \ "d" (sizeof (ldt_entry))); \ __builtin_expect (result, 0) != 0 ? -1 : nr * 8 + 7; \ }) # define TLS_DO_SET_THREAD_AREA(descr, secondcall) \ ({ \ struct modify_ldt_ldt_s ldt_entry = \ { -1, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \ 1, 0, 0, 1, 0, 1, 0 }; \ int result; \ if (secondcall) \ ldt_entry.entry_number = ({ int _gs; \ asm ("movw %%gs, %w0" : "=q" (_gs)); \ (_gs & 0xffff) >> 3; }); \ asm volatile (TLS_LOAD_EBX \ "int $0x80\n\t" \ TLS_LOAD_EBX \ : "=a" (result), "=m" (ldt_entry.entry_number) \ : "0" (__NR_set_thread_area), \ /* The extra argument with the "m" constraint is necessary \ to let the compiler know that we are accessing LDT_ENTRY \ here. */ \ TLS_EBX_ARG (&ldt_entry), "m" (ldt_entry)); \ __builtin_expect (result, 0) == 0 ? ldt_entry.entry_number * 8 + 3 : -1; \ }) # ifdef __ASSUME_SET_THREAD_AREA_SYSCALL # define TLS_SETUP_GS_SEGMENT(descr, secondcall) \ TLS_DO_SET_THREAD_AREA (descr, firstcall) # elif defined __NR_set_thread_area # define TLS_SETUP_GS_SEGMENT(descr, secondcall) \ ({ int __seg = TLS_DO_SET_THREAD_AREA (descr, secondcall); \ __seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; }) # else # define TLS_SETUP_GS_SEGMENT(descr, secondcall) \ TLS_DO_MODIFY_LDT ((descr), 0) # endif /* Code to initially initialize the thread pointer. This might need special attention since 'errno' is not yet available and if the operation can cause a failure 'errno' must not be touched. */ # define TLS_INIT_TP(descr, secondcall) \ ({ \ void *_descr = (descr); \ tcbhead_t *head = _descr; \ int __gs; \ \ head->tcb = _descr; \ /* For now the thread descriptor is at the same address. */ \ head->self = _descr; \ \ __gs = TLS_SETUP_GS_SEGMENT (_descr, secondcall); \ if (__builtin_expect (__gs, 7) != -1) \ { \ asm ("movw %w0, %%gs" : : "q" (__gs)); \ __gs = 0; \ } \ __gs; \ }) /* Return the address of the dtv for the current thread. */ # define THREAD_DTV() \ ({ struct _pthread_descr_struct *__descr; \ THREAD_GETMEM (__descr, p_header.data.dtvp); }) # endif /* FLOATING_STACKS && HAVE_TLS_SUPPORT */ #endif /* __ASSEMBLER__ */ #endif /* tls.h */