Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/tools/virtio/asm/barrier.h b/tools/virtio/asm/barrier.h
new file mode 100644
index 000000000..468435ed6
--- /dev/null
+++ b/tools/virtio/asm/barrier.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <stdlib.h>
+#if defined(__i386__) || defined(__x86_64__)
+#define barrier() asm volatile("" ::: "memory")
+#define virt_mb() __sync_synchronize()
+#define virt_rmb() barrier()
+#define virt_wmb() barrier()
+/* Atomic store should be enough, but gcc generates worse code in that case. */
+#define virt_store_mb(var, value)  do { \
+	typeof(var) virt_store_mb_value = (value); \
+	__atomic_exchange(&(var), &virt_store_mb_value, &virt_store_mb_value, \
+			  __ATOMIC_SEQ_CST); \
+	barrier(); \
+} while (0);
+/* Weak barriers should be used. If not - it's a bug */
+# define mb() abort()
+# define dma_rmb() abort()
+# define dma_wmb() abort()
+#elif defined(__aarch64__)
+#define dmb(opt) asm volatile("dmb " #opt : : : "memory")
+#define virt_mb() __sync_synchronize()
+#define virt_rmb() dmb(ishld)
+#define virt_wmb() dmb(ishst)
+#define virt_store_mb(var, value)  do { WRITE_ONCE(var, value); dmb(ish); } while (0)
+/* Weak barriers should be used. If not - it's a bug */
+# define mb() abort()
+# define dma_rmb() abort()
+# define dma_wmb() abort()
+#else
+#error Please fill in barrier macros
+#endif
+