membarrier: introduce qemu/sys_membarrier.h

This new header file provides heavy-weight "global" memory barriers that
enforce memory ordering on each running thread belonging to the current
process.  For now, use a dummy implementation that issues memory barriers
on both sides (matching what QEMU has been doing so far).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2018-02-16 10:04:18 +01:00
parent 77a8b8462b
commit c8d3877e48
3 changed files with 26 additions and 7 deletions

View file

@ -0,0 +1,17 @@
/*
* 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 1
/* 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