2: * Abstraction layer for defining and using TLS variables
4: * Copyright (c) 2011 Red Hat, Inc
5: * Copyright (c) 2011 Linaro Limited
7: * Authors:
8: * Paolo Bonzini <email@example.com>
9: * Peter Maydell <firstname.lastname@example.org>
11: * This program is free software; you can redistribute it and/or
12: * modify it under the terms of the GNU General Public License as
13: * published by the Free Software Foundation; either version 2 of
14: * the License, or (at your option) any later version.
16: * This program is distributed in the hope that it will be useful,
17: * but WITHOUT ANY WARRANTY; without even the implied warranty of
18: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19: * GNU General Public License for more details.
21: * You should have received a copy of the GNU General Public License along
22: * with this program; if not, see <http://www.gnu.org/licenses/>.
25: #ifndef QEMU_TLS_H
26: #define QEMU_TLS_H
28: /* Per-thread variables. Note that we only have implementations
29: * which are really thread-local on Linux; the dummy implementations
30: * define plain global variables.
32: * This means that for the moment use should be restricted to
33: * per-VCPU variables, which are OK because:
34: * - the only -user mode supporting multiple VCPU threads is linux-user
35: * - TCG system mode is single-threaded regarding VCPUs
36: * - KVM system mode is multi-threaded but limited to Linux
38: * TODO: proper implementations via Win32 .tls sections and
39: * POSIX pthread_getspecific.
41: #ifdef __linux__
42: #define DECLARE_TLS(type, x) extern DEFINE_TLS(type, x)
43: #define DEFINE_TLS(type, x) __thread __typeof__(type) tls__##x
44: #define get_tls(x) tls__##x
46: /* Dummy implementations which define plain global variables */
47: #define DECLARE_TLS(type, x) extern DEFINE_TLS(type, x)
48: #define DEFINE_TLS(type, x) __typeof__(type) tls__##x
49: #define get_tls(x) tls__##x