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| -rw-r--r-- | qemu-tls.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/qemu-tls.h b/qemu-tls.h new file mode 100644 index 0000000000..5b70f10f8f --- /dev/null +++ b/qemu-tls.h @@ -0,0 +1,52 @@ +/* + * Abstraction layer for defining and using TLS variables + * + * Copyright (c) 2011 Red Hat, Inc + * Copyright (c) 2011 Linaro Limited + * + * Authors: + * Paolo Bonzini <pbonzini@redhat.com> + * Peter Maydell <peter.maydell@linaro.org> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef QEMU_TLS_H +#define QEMU_TLS_H + +/* Per-thread variables. Note that we only have implementations + * which are really thread-local on Linux; the dummy implementations + * define plain global variables. + * + * This means that for the moment use should be restricted to + * per-VCPU variables, which are OK because: + * - the only -user mode supporting multiple VCPU threads is linux-user + * - TCG system mode is single-threaded regarding VCPUs + * - KVM system mode is multi-threaded but limited to Linux + * + * TODO: proper implementations via Win32 .tls sections and + * POSIX pthread_getspecific. + */ +#ifdef __linux__ +#define DECLARE_TLS(type, x) extern DEFINE_TLS(type, x) +#define DEFINE_TLS(type, x) __thread __typeof__(type) tls__##x +#define get_tls(x) tls__##x +#else +/* Dummy implementations which define plain global variables */ +#define DECLARE_TLS(type, x) extern DEFINE_TLS(type, x) +#define DEFINE_TLS(type, x) __typeof__(type) tls__##x +#define get_tls(x) tls__##x +#endif + +#endif |