1/* Internal per-thread variables for the Hurd.
2 Copyright (C) 1994-2022 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 <https://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
37extern unsigned long int __hurd_threadvar_stack_mask;
38extern 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
44extern unsigned long int __hurd_sigthread_stack_base;
45extern unsigned long int __hurd_sigthread_stack_end;
46
47/* Store the MiG reply port reply port until we enable TLS. */
48extern 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 */
55

source code of glibc/hurd/hurd/threadvar.h