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phoenix |
/* Definition for thread-local data handling. linuxthreads/i386 version.
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Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#ifndef _TLS_H
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#define _TLS_H
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# include <pt-machine.h>
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#ifndef __ASSEMBLER__
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# include <stddef.h>
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/* Type for the dtv. */
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typedef union dtv
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{
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size_t counter;
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void *pointer;
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} dtv_t;
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typedef struct
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{
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void *tcb; /* Pointer to the TCB. Not necessary the
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thread descriptor used by libpthread. */
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dtv_t *dtv;
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void *self; /* Pointer to the thread descriptor. */
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} tcbhead_t;
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#endif
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/* We can support TLS only if the floating-stack support is available. */
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#if defined FLOATING_STACKS && defined HAVE_TLS_SUPPORT
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/* Signal that TLS support is available. */
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//# define USE_TLS 1
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# ifndef __ASSEMBLER__
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/* Get system call information. */
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# include <sysdep.h>
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/* Get the thread descriptor definition. */
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# include <linuxthreads/descr.h>
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/* This is the size of the initial TCB. */
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# define TLS_INIT_TCB_SIZE sizeof (tcbhead_t)
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/* Alignment requirements for the initial TCB. */
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# define TLS_INIT_TCB_ALIGN __alignof__ (tcbhead_t)
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/* This is the size of the TCB. */
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# define TLS_TCB_SIZE sizeof (struct _pthread_descr_struct)
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/* Alignment requirements for the TCB. */
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# define TLS_TCB_ALIGN __alignof__ (struct _pthread_descr_struct)
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/* The TCB can have any size and the memory following the address the
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thread pointer points to is unspecified. Allocate the TCB there. */
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# define TLS_TCB_AT_TP 1
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/* Install the dtv pointer. The pointer passed is to the element with
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index -1 which contain the length. */
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# define INSTALL_DTV(descr, dtvp) \
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((tcbhead_t *) (descr))->dtv = (dtvp) + 1
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/* Install new dtv for current thread. */
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# define INSTALL_NEW_DTV(dtv) \
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({ struct _pthread_descr_struct *__descr; \
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THREAD_SETMEM (__descr, p_header.data.dtvp, (dtv)); })
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/* Return dtv of given thread descriptor. */
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# define GET_DTV(descr) \
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(((tcbhead_t *) (descr))->dtv)
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# ifdef __PIC__
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# define TLS_EBX_ARG "r"
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# define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
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# else
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# define TLS_EBX_ARG "b"
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# define TLS_LOAD_EBX
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# endif
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# define TLS_DO_MODIFY_LDT(descr, nr) \
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({ \
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struct modify_ldt_ldt_s ldt_entry = \
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{ nr, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
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1, 0, 0, 1, 0, 1, 0 }; \
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int result; \
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asm volatile (TLS_LOAD_EBX \
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"int $0x80\n\t" \
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TLS_LOAD_EBX \
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: "=a" (result) \
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: "0" (__NR_modify_ldt), \
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/* The extra argument with the "m" constraint is necessary \
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to let the compiler know that we are accessing LDT_ENTRY \
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here. */ \
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"m" (ldt_entry), TLS_EBX_ARG (1), "c" (&ldt_entry), \
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"d" (sizeof (ldt_entry))); \
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__builtin_expect (result, 0) != 0 ? -1 : nr * 8 + 7; \
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})
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# define TLS_DO_SET_THREAD_AREA(descr, secondcall) \
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({ \
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struct modify_ldt_ldt_s ldt_entry = \
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{ -1, (unsigned long int) (descr), 0xfffff /* 4GB in pages */, \
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1, 0, 0, 1, 0, 1, 0 }; \
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int result; \
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if (secondcall) \
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ldt_entry.entry_number = ({ int _gs; \
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asm ("movw %%gs, %w0" : "=q" (_gs)); \
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(_gs & 0xffff) >> 3; }); \
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asm volatile (TLS_LOAD_EBX \
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"int $0x80\n\t" \
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TLS_LOAD_EBX \
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: "=a" (result), "=m" (ldt_entry.entry_number) \
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: "0" (__NR_set_thread_area), \
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/* The extra argument with the "m" constraint is necessary \
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to let the compiler know that we are accessing LDT_ENTRY \
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here. */ \
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TLS_EBX_ARG (&ldt_entry), "m" (ldt_entry)); \
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__builtin_expect (result, 0) == 0 ? ldt_entry.entry_number * 8 + 3 : -1; \
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})
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# ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
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# define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
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TLS_DO_SET_THREAD_AREA (descr, firstcall)
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# elif defined __NR_set_thread_area
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# define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
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({ int __seg = TLS_DO_SET_THREAD_AREA (descr, secondcall); \
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__seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
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# else
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# define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
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TLS_DO_MODIFY_LDT ((descr), 0)
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# endif
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/* Code to initially initialize the thread pointer. This might need
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special attention since 'errno' is not yet available and if the
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operation can cause a failure 'errno' must not be touched. */
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# define TLS_INIT_TP(descr, secondcall) \
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({ \
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void *_descr = (descr); \
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tcbhead_t *head = _descr; \
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int __gs; \
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\
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head->tcb = _descr; \
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/* For now the thread descriptor is at the same address. */ \
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head->self = _descr; \
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\
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__gs = TLS_SETUP_GS_SEGMENT (_descr, secondcall); \
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if (__builtin_expect (__gs, 7) != -1) \
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{ \
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asm ("movw %w0, %%gs" : : "q" (__gs)); \
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__gs = 0; \
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} \
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__gs; \
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})
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/* Return the address of the dtv for the current thread. */
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# define THREAD_DTV() \
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({ struct _pthread_descr_struct *__descr; \
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THREAD_GETMEM (__descr, p_header.data.dtvp); })
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# endif /* FLOATING_STACKS && HAVE_TLS_SUPPORT */
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#endif /* __ASSEMBLER__ */
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#endif /* tls.h */
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