path: root/include/qemu/sys_membarrier.h

/*
 * Process-global memory barriers
 *
 * Copyright (c) 2018 Red Hat, Inc.
 *
 * Author: Paolo Bonzini <pbonzini@redhat.com>
 */

#ifndef QEMU_SYS_MEMBARRIER_H
#define QEMU_SYS_MEMBARRIER_H

#ifdef CONFIG_MEMBARRIER
/* Only block reordering at the compiler level in the performance-critical
 * side.  The slow side forces processor-level ordering on all other cores
 * through a system call.
 */
extern void smp_mb_global_init(void);
extern void smp_mb_global(void);
#define smp_mb_placeholder()       barrier()
#else
/* Keep it simple, execute a real memory barrier on both sides.  */
static inline void smp_mb_global_init(void) {}
#define smp_mb_global()            smp_mb()
#define smp_mb_placeholder()       smp_mb()
#endif

#endif