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/* Definition for thread-local data handling. linuxthreads/i386 version.
Copyright (C) 2002 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 <stddef.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), sizeof (struct _pthread_descr_struct), \
1, 0, 0, 0, 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, firstcall) \
({ \
struct modify_ldt_ldt_s ldt_entry = \
{ -1, (unsigned long int) (descr), sizeof (struct _pthread_descr_struct), \
1, 0, 0, 0, 0, 1, 0 }; \
int result; \
if (!firstcall) \
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, firstcall) \
TLS_DO_SET_THREAD_AREA (descr, firstcall)
# elif defined __NR_set_thread_area
# define TLS_SETUP_GS_SEGMENT(descr, firstcall) \
({ int __seg = TLS_DO_SET_THREAD_AREA (descr, firstcall); \
__seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
# else
# define TLS_SETUP_GS_SEGMENT(descr) 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, firstcall) \
({ \
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, firstcall); \
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 */
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