linuxthreads/sysdeps/x86_64/tls.h

   1 /* Definitions for thread-local data handling.  linuxthreads/x86-64 version.
   2    Copyright (C) 2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _TLS_H
  21 #define _TLS_H
  22
  23 #ifndef __ASSEMBLER__
  24
  25 # include <pt-machine.h>
  26 # include <stddef.h>
  27
  28 /* Type for the dtv.  */
  29 typedef union dtv
  30 {
  31   size_t counter;
  32   void *pointer;
  33 } dtv_t;
  34
  35
  36 typedef struct
  37 {
  38   void *tcb;            /* Pointer to the TCB.  Not necessary the
  39                            thread descriptor used by libpthread.  */
  40   dtv_t *dtv;
  41   void *self;           /* Pointer to the thread descriptor.  */
  42   int multiple_threads;
  43 } tcbhead_t;
  44
  45 #else /* __ASSEMBLER__ */
  46 # include <tcb-offsets.h>
  47 #endif
  48
  49
  50 #ifdef HAVE_TLS_SUPPORT
  51
  52 /* Signal that TLS support is available.  */
  53 # define USE_TLS        1
  54
  55 # ifndef __ASSEMBLER__
  56 /* Get system call information.  */
  57 #  include <sysdep.h>
  58
  59 /* Get the thread descriptor definition.  */
  60 #  include <linuxthreads/descr.h>
  61
  62 /* This is the size of the initial TCB.  */
  63 #  define TLS_INIT_TCB_SIZE sizeof (tcbhead_t)
  64
  65 /* Alignment requirements for the initial TCB.  */
  66 #  define TLS_INIT_TCB_ALIGN __alignof__ (tcbhead_t)
  67
  68 /* This is the size of the TCB.  */
  69 #  define TLS_TCB_SIZE sizeof (struct _pthread_descr_struct)
  70
  71 /* Alignment requirements for the TCB.  */
  72 #  define TLS_TCB_ALIGN __alignof__ (struct _pthread_descr_struct)
  73
  74 /* The TCB can have any size and the memory following the address the
  75    thread pointer points to is unspecified.  Allocate the TCB there.  */
  76 #  define TLS_TCB_AT_TP 1
  77
  78
  79 /* Install the dtv pointer.  The pointer passed is to the element with
  80    index -1 which contain the length.  */
  81 #  define INSTALL_DTV(descr, dtvp) \
  82   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
  83
  84 /* Install new dtv for current thread.  */
  85 #  define INSTALL_NEW_DTV(dtv) \
  86   ({ struct _pthread_descr_struct *__descr;                                   \
  87      THREAD_SETMEM (__descr, p_header.data.dtvp, (dtv)); })
  88
  89 /* Return dtv of given thread descriptor.  */
  90 #  define GET_DTV(descr) \
  91   (((tcbhead_t *) (descr))->dtv)
  92
  93 /* Code to initially initialize the thread pointer.  This might need
  94    special attention since 'errno' is not yet available and if the
  95    operation can cause a failure 'errno' must not be touched.  */
  96 # define TLS_INIT_TP(descr, secondcall)                                       \
  97   ({                                                                          \
  98     void *_descr = (descr);                                                   \
  99     tcbhead_t *head = _descr;                                                 \
 100     long int _result;                                                         \
 101                                                                               \
 102     head->tcb = _descr;                                                       \
 103     /* For now the thread descriptor is at the same address.  */              \
 104     head->self = _descr;                                                      \
 105                                                                               \
 106     asm volatile ("syscall"                                                   \
 107                   : "=a" (_result)                                            \
 108                   : "0" ((unsigned long int) __NR_arch_prctl),                \
 109                     "D" ((unsigned long int) ARCH_SET_FS),                    \
 110                     "S" (_descr)                                              \
 111                   : "memory", "cc", "r11", "cx");                             \
 112                                                                               \
 113     _result ? "cannot set %fs base address for thread-local storage" : 0;     \
 114   })
 115
 116 /* Indicate that dynamic linker shouldn't try to initialize TLS even
 117    when no PT_TLS segments are found in the program and libraries
 118    it is linked against.  */
 119 #  define TLS_INIT_TP_EXPENSIVE 1
 120
 121 /* Return the address of the dtv for the current thread.  */
 122 #  define THREAD_DTV() \
 123   ({ struct _pthread_descr_struct *__descr;                                   \
 124      THREAD_GETMEM (__descr, p_header.data.dtvp); })
 125
 126 # endif /* HAVE_TLS_SUPPORT */
 127 #endif /* __ASSEMBLER__ */
 128
 129 #endif  /* tls.h */