qemu

FORK: QEMU emulator
git clone https://git.neptards.moe/neptards/qemu.git
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sys_membarrier.c (1178B)

      1 /*
      2  * Process-global memory barriers
      3  *
      4  * Copyright (c) 2018 Red Hat, Inc.
      5  *
      6  * Author: Paolo Bonzini <pbonzini@redhat.com>
      7  */
      8 
      9 #include "qemu/osdep.h"
     10 #include "qemu/sys_membarrier.h"
     11 #include "qemu/error-report.h"
     12 
     13 #ifdef CONFIG_LINUX
     14 #include <linux/membarrier.h>
     15 #include <sys/syscall.h>
     16 
     17 static int
     18 membarrier(int cmd, int flags)
     19 {
     20     return syscall(__NR_membarrier, cmd, flags);
     21 }
     22 #endif
     23 
     24 void smp_mb_global(void)
     25 {
     26 #if defined CONFIG_WIN32
     27     FlushProcessWriteBuffers();
     28 #elif defined CONFIG_LINUX
     29     membarrier(MEMBARRIER_CMD_SHARED, 0);
     30 #else
     31 #error --enable-membarrier is not supported on this operating system.
     32 #endif
     33 }
     34 
     35 void smp_mb_global_init(void)
     36 {
     37 #ifdef CONFIG_LINUX
     38     int ret = membarrier(MEMBARRIER_CMD_QUERY, 0);
     39     if (ret < 0) {
     40         error_report("This QEMU binary requires the membarrier system call.");
     41         error_report("Please upgrade your system to a newer version of Linux");
     42         exit(1);
     43     }
     44     if (!(ret & MEMBARRIER_CMD_SHARED)) {
     45         error_report("This QEMU binary requires MEMBARRIER_CMD_SHARED support.");
     46         error_report("Please upgrade your system to a newer version of Linux");
     47         exit(1);
     48     }
     49 #endif
     50 }