linuxthreads/sysdeps/alpha/tls.h

   1 /* Definitions for thread-local data handling.  linuxthreads/Alpha 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
  36 typedef struct
  37 {
  38   dtv_t *dtv;
  39
  40   /* Reserved for the thread implementation.  Unused in LinuxThreads.  */
  41   void *private;
  42 } tcbhead_t;
  43 #endif
  44
  45
  46 #ifdef HAVE_TLS_SUPPORT
  47
  48 /* Signal that TLS support is available.  */
  49 # define USE_TLS        1
  50
  51 # ifndef __ASSEMBLER__
  52 /* Get system call information.  */
  53 #  include <sysdep.h>
  54
  55 /* This is the size of the initial TCB.  */
  56 #  define TLS_INIT_TCB_SIZE     0
  57
  58 /* Alignment requirements for the initial TCB.  */
  59 #  define TLS_INIT_TCB_ALIGN    __alignof__ (struct _pthread_descr_struct)
  60
  61 /* This is the size of the TCB.  */
  62 #  define TLS_TCB_SIZE          0
  63
  64 /* Alignment requirements for the TCB.  */
  65 #  define TLS_TCB_ALIGN         __alignof__ (struct _pthread_descr_struct)
  66
  67 /* This is the size we need before TCB.  */
  68 #  ifndef IS_IN_rtld
  69 #   define TLS_PRE_TCB_SIZE \
  70   (sizeof (struct _pthread_descr_struct)                                \
  71    + ((sizeof (tcbhead_t) + TLS_TCB_ALIGN - 1) & ~(TLS_TCB_ALIGN - 1)))
  72 #  else
  73 #   include <nptl-struct-pthread.h>
  74 #   define TLS_PRE_TCB_SIZE \
  75   ((sizeof (struct _pthread_descr_struct) > NPTL_STRUCT_PTHREAD_SIZE    \
  76     ? sizeof (struct _pthread_descr_struct) : NPTL_STRUCT_PTHREAD_SIZE) \
  77    + ((sizeof (tcbhead_t) + TLS_TCB_ALIGN - 1) & ~(TLS_TCB_ALIGN - 1)))
  78 #  endif
  79
  80 /* The DTV is allocated at the TP; the TCB is placed elsewhere.  */
  81 #  define TLS_DTV_AT_TP 1
  82
  83 /* The following assumes that TP (R2 or R13) points to the end of the
  84    TCB + 0x7000 (per the ABI).  This implies that TCB address is
  85    TP - 0x7000.  As we define TLS_DTV_AT_TP we can
  86    assume that the pthread struct is allocated immediately ahead of the
  87    TCB.  This implies that the pthread_descr address is
  88    TP - (TLS_PRE_TCB_SIZE + 0x7000).  */
  89 /* ??? PPC uses offset 0x7000; seems like a good idea for alpha too,
  90    but binutils not yet changed to match.  */
  91 #  define TLS_TCB_OFFSET 0
  92
  93 /* Install the dtv pointer.  The pointer passed is to the element with
  94    index -1 which contain the length.  */
  95 #  define INSTALL_DTV(TCBP, DTVP) \
  96   (((tcbhead_t *) (TCBP))[-1].dtv = (DTVP) + 1)
  97
  98 /* Install new dtv for current thread.  */
  99 #  define INSTALL_NEW_DTV(DTV) \
 100   (THREAD_DTV() = (DTV))
 101
 102 /* Return dtv of given thread descriptor.  */
 103 #  define GET_DTV(TCBP) \
 104   (((tcbhead_t *) (TCBP))[-1].dtv)
 105
 106 /* Code to initially initialize the thread pointer.  This might need
 107    special attention since 'errno' is not yet available and if the
 108    operation can cause a failure 'errno' must not be touched.  */
 109 # define TLS_INIT_TP(TCBP, SECONDCALL) \
 110   (__builtin_set_thread_pointer ((void *) (TCBP) + TLS_TCB_OFFSET), NULL)
 111
 112 /* Return the address of the dtv for the current thread.  */
 113 #  define THREAD_DTV() \
 114   (((tcbhead_t *) (__builtin_thread_pointer () - TLS_TCB_OFFSET))[-1].dtv)
 115
 116 /* Return the thread descriptor for the current thread.  */
 117 #  undef THREAD_SELF
 118 #  define THREAD_SELF \
 119   ((pthread_descr) (__builtin_thread_pointer () \
 120                     - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
 121
 122 #  undef INIT_THREAD_SELF
 123 #  define INIT_THREAD_SELF(DESCR, NR) \
 124   __builtin_set_thread_pointer ((char *)(DESCR) \
 125                                 + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE)
 126
 127 /* Get the thread descriptor definition.  */
 128 #  include <linuxthreads/descr.h>
 129
 130 /* ??? Generic bits of LinuxThreads may call these macros with
 131    DESCR set to NULL.  We are expected to be able to reference
 132    the "current" value.
 133
 134    In our case, we'd really prefer to use DESCR, since lots of
 135    PAL_code calls would be expensive.  We can only trust that
 136    the compiler does its job and unifies the multiple
 137    __builtin_thread_pointer instances.  */
 138
 139 #define THREAD_GETMEM(descr, member) \
 140   ((void) sizeof (descr), THREAD_SELF->member)
 141 #define THREAD_GETMEM_NC(descr, member) \
 142   ((void) sizeof (descr), THREAD_SELF->member)
 143 #define THREAD_SETMEM(descr, member, value) \
 144   ((void) sizeof (descr), THREAD_SELF->member = (value))
 145 #define THREAD_SETMEM_NC(descr, member, value) \
 146   ((void) sizeof (descr), THREAD_SELF->member = (value))
 147
 148 # endif /* HAVE_TLS_SUPPORT */
 149 #endif /* __ASSEMBLER__ */
 150
 151 #endif  /* tls.h */