Annotation of qemu/qemu-tls.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Abstraction layer for defining and using TLS variables
        !             3:  *
        !             4:  * Copyright (c) 2011 Red Hat, Inc
        !             5:  * Copyright (c) 2011 Linaro Limited
        !             6:  *
        !             7:  * Authors:
        !             8:  *  Paolo Bonzini <pbonzini@redhat.com>
        !             9:  *  Peter Maydell <peter.maydell@linaro.org>
        !            10:  *
        !            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.
        !            15:  *
        !            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.
        !            20:  *
        !            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/>.
        !            23:  */
        !            24: 
        !            25: #ifndef QEMU_TLS_H
        !            26: #define QEMU_TLS_H
        !            27: 
        !            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.
        !            31:  *
        !            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
        !            37:  *
        !            38:  * TODO: proper implementations via Win32 .tls sections and
        !            39:  * POSIX pthread_getspecific.
        !            40:  */
        !            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
        !            45: #else
        !            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
        !            50: #endif
        !            51: 
        !            52: #endif

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