hurd/hurd/threadvar.h

   1 /* Internal per-thread variables for the Hurd.
   2    Copyright (C) 1994-2018 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _HURD_THREADVAR_H
  20 #define _HURD_THREADVAR_H
  21
  22 #include <features.h>
  23 #include <tls.h>
  24
  25 /* The per-thread variables are found by ANDing this mask
  26    with the value of the stack pointer and then adding this offset.
  27
  28    In the multi-threaded case, cthreads initialization sets
  29    __hurd_threadvar_stack_mask to ~(cthread_stack_size - 1), a mask which
  30    finds the base of the fixed-size cthreads stack; and
  31    __hurd_threadvar_stack_offset to a small offset that skips the data
  32    cthreads itself maintains at the base of each thread's stack.
  33
  34    In the single-threaded or libpthread case, __hurd_threadvar_stack_mask is
  35    zero, so the stack pointer is ignored. */
  36
  37 extern unsigned long int __hurd_threadvar_stack_mask;
  38 extern unsigned long int __hurd_threadvar_stack_offset;
  39
  40 /* The variables __hurd_sigthread_stack_base and
  41    __hurd_sigthread_stack_end define the bounds of the stack used by the
  42    signal thread, so that thread can always be specifically identified.  */
  43
  44 extern unsigned long int __hurd_sigthread_stack_base;
  45 extern unsigned long int __hurd_sigthread_stack_end;
  46
  47 /* Store the MiG reply port reply port until we enable TLS.  */
  48 extern mach_port_t __hurd_reply_port0;
  49
  50 /* This returns either the TLS reply port variable, or a single-thread variable
  51    when TLS is not initialized yet.  */
  52 #define __hurd_local_reply_port (*(__LIBC_NO_TLS () ? &__hurd_reply_port0 : &THREAD_SELF->reply_port))
  53
  54 #endif  /* hurd/threadvar.h */