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/*
* Process-global memory barriers
*
* Copyright (c) 2018 Red Hat, Inc.
*
* Author: Paolo Bonzini <pbonzini@redhat.com>
*/
#include "qemu/osdep.h"
#include "qemu/sys_membarrier.h"
#include "qemu/error-report.h"
#ifdef CONFIG_LINUX
#include <linux/membarrier.h>
#include <sys/syscall.h>
static int
membarrier(int cmd, int flags)
{
return syscall(__NR_membarrier, cmd, flags);
}
#endif
void smp_mb_global(void)
{
#if defined CONFIG_WIN32
FlushProcessWriteBuffers();
#elif defined CONFIG_LINUX
membarrier(MEMBARRIER_CMD_SHARED, 0);
#else
#error --enable-membarrier is not supported on this operating system.
#endif
}
void smp_mb_global_init(void)
{
#ifdef CONFIG_LINUX
int ret = membarrier(MEMBARRIER_CMD_QUERY, 0);
if (ret < 0) {
error_report("This QEMU binary requires the membarrier system call.");
error_report("Please upgrade your system to a newer version of Linux");
exit(1);
}
if (!(ret & MEMBARRIER_CMD_SHARED)) {
error_report("This QEMU binary requires MEMBARRIER_CMD_SHARED support.");
error_report("Please upgrade your system to a newer version of Linux");
exit(1);
}
#endif
}
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