diff options
Diffstat (limited to 'tools/virtio/asm')
| -rw-r--r-- | tools/virtio/asm/barrier.h | 32 |
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 + |