linuxthreads/sysdeps/s390/tls.h

   1 /* Definitions for thread-local data handling.  linuxthreads/s390 version.
   2    Copyright (C) 2002, 2003 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 typedef struct
  36 {
  37   void *tcb;            /* Pointer to the TCB.  Not necessary the
  38                            thread descriptor used by libpthread.  */
  39   dtv_t *dtv;
  40   void *self;           /* Pointer to the thread descriptor.  */
  41   int multiple_threads;
  42 } tcbhead_t;
  43
  44 #else /* __ASSEMBLER__ */
  45 # include <tcb-offsets.h>
  46 #endif /* __ASSEMBLER__ */
  47
  48 /* TLS is always supported if the tools support it.  There are no
  49    kernel dependencies.  To avoid bothering with the TLS support code
  50    at all, use configure --without-tls.
  51
  52    We need USE_TLS to be consistently defined, for ldsodefs.h
  53    conditionals.  */
  54
  55 #ifdef HAVE_TLS_SUPPORT
  56
  57 /* Signal that TLS support is available.  */
  58 # define USE_TLS        1
  59
  60 # ifndef __ASSEMBLER__
  61 /* Get system call information.  */
  62 #  include <sysdep.h>
  63
  64
  65 /* Get the thread descriptor definition.  */
  66 #  include <linuxthreads/descr.h>
  67
  68 /* This is the size of the initial TCB.  */
  69 #  define TLS_INIT_TCB_SIZE sizeof (tcbhead_t)
  70
  71 /* Alignment requirements for the initial TCB.  */
  72 #  define TLS_INIT_TCB_ALIGN __alignof__ (tcbhead_t)
  73
  74 /* This is the size of the TCB.  */
  75 #  ifndef IS_IN_rtld
  76 #   define TLS_TCB_SIZE sizeof (struct _pthread_descr_struct)
  77 #  else
  78 #   include <nptl-struct-pthread.h>
  79 #   define TLS_TCB_SIZE \
  80   (sizeof (struct _pthread_descr_struct) > NPTL_STRUCT_PTHREAD_SIZE     \
  81    ? sizeof (struct _pthread_descr_struct) : NPTL_STRUCT_PTHREAD_SIZE)
  82 #  endif
  83
  84 /* Alignment requirements for the TCB.  */
  85 #  define TLS_TCB_ALIGN __alignof__ (struct _pthread_descr_struct)
  86
  87 /* The TCB can have any size and the memory following the address the
  88    thread pointer points to is unspecified.  Allocate the TCB there.  */
  89 #  define TLS_TCB_AT_TP 1
  90
  91
  92 /* Install the dtv pointer.  The pointer passed is to the element with
  93    index -1 which contain the length.  */
  94 #  define INSTALL_DTV(descr, dtvp) \
  95   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
  96
  97 /* Install new dtv for current thread.  */
  98 #  define INSTALL_NEW_DTV(dtv) \
  99   (((tcbhead_t *) __builtin_thread_pointer ())->dtv = (dtv))
 100
 101 /* Return dtv of given thread descriptor.  */
 102 #  define GET_DTV(descr) \
 103   (((tcbhead_t *) (descr))->dtv)
 104
 105 /* Code to initially initialize the thread pointer.  This might need
 106    special attention since 'errno' is not yet available and if the
 107    operation can cause a failure 'errno' must not be touched.
 108
 109    The value of this macro is null if successful, or an error string.  */
 110 #  define TLS_INIT_TP(descr, secondcall)                                      \
 111   ({                                                                          \
 112     void *_descr = (descr);                                                   \
 113     tcbhead_t *head = _descr;                                                 \
 114                                                                               \
 115     head->tcb = _descr;                                                       \
 116     /* For now the thread descriptor is at the same address.  */              \
 117     head->self = _descr;                                                      \
 118                                                                               \
 119     __builtin_set_thread_pointer (_descr);                                    \
 120     NULL;                                                                     \
 121   })
 122
 123 /* Return the address of the dtv for the current thread.  */
 124 #  define THREAD_DTV() \
 125   (((tcbhead_t *) __builtin_thread_pointer ())->dtv)
 126
 127 # endif /* __ASSEMBLER__ */
 128
 129 #else   /* HAVE_TLS_SUPPORT && (FLOATING_STACKS || !IS_IN_libpthread) */
 130
 131 # ifndef __ASSEMBLER__
 132
 133 /* Get the thread descriptor definition.  */
 134 #  include <linuxthreads/descr.h>
 135
 136 #  define NONTLS_INIT_TP \
 137   do {                                                          \
 138     static const tcbhead_t nontls_init_tp                       \
 139       = { .multiple_threads = 0 };                              \
 140     INIT_THREAD_SELF (&nontls_init_tp, 0);                      \
 141   } while (0)
 142
 143 # endif /* __ASSEMBLER__ */
 144
 145 #endif  /* HAVE_TLS_SUPPORT && (FLOATING_STACKS || !IS_IN_libpthread) */
 146
 147 #endif  /* tls.h */