diff options
Diffstat (limited to 'src/barrier.h')
-rw-r--r-- | src/barrier.h | 87 |
1 files changed, 0 insertions, 87 deletions
diff --git a/src/barrier.h b/src/barrier.h deleted file mode 100644 index 98be9e5..0000000 --- a/src/barrier.h +++ /dev/null @@ -1,87 +0,0 @@ -#ifndef LIBURING_BARRIER_H -#define LIBURING_BARRIER_H - -/* -From the kernel documentation file refcount-vs-atomic.rst: - -A RELEASE memory ordering guarantees that all prior loads and -stores (all po-earlier instructions) on the same CPU are completed -before the operation. It also guarantees that all po-earlier -stores on the same CPU and all propagated stores from other CPUs -must propagate to all other CPUs before the release operation -(A-cumulative property). This is implemented using -:c:func:`smp_store_release`. - -An ACQUIRE memory ordering guarantees that all post loads and -stores (all po-later instructions) on the same CPU are -completed after the acquire operation. It also guarantees that all -po-later stores on the same CPU must propagate to all other CPUs -after the acquire operation executes. This is implemented using -:c:func:`smp_acquire__after_ctrl_dep`. -*/ - -/* From tools/include/linux/compiler.h */ -/* Optimization barrier */ -/* The "volatile" is due to gcc bugs */ -#define barrier() __asm__ __volatile__("": : :"memory") - -/* From tools/virtio/linux/compiler.h */ -#define WRITE_ONCE(var, val) \ - (*((volatile __typeof(val) *)(&(var))) = (val)) -#define READ_ONCE(var) (*((volatile __typeof(var) *)(&(var)))) - - -#if defined(__x86_64__) || defined(__i386__) -/* Adapted from arch/x86/include/asm/barrier.h */ -#define mb() asm volatile("mfence" ::: "memory") -#define rmb() asm volatile("lfence" ::: "memory") -#define wmb() asm volatile("sfence" ::: "memory") -#define smp_rmb() barrier() -#define smp_wmb() barrier() -#if defined(__i386__) -#define smp_mb() asm volatile("lock; addl $0,0(%%esp)" ::: "memory", "cc") -#else -#define smp_mb() asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc") -#endif - -#define smp_store_release(p, v) \ -do { \ - barrier(); \ - WRITE_ONCE(*(p), (v)); \ -} while (0) - -#define smp_load_acquire(p) \ -({ \ - __typeof(*p) ___p1 = READ_ONCE(*(p)); \ - barrier(); \ - ___p1; \ -}) -#else /* defined(__x86_64__) || defined(__i386__) */ -/* - * Add arch appropriate definitions. Be safe and use full barriers for - * archs we don't have support for. - */ -#define smp_rmb() __sync_synchronize() -#define smp_wmb() __sync_synchronize() -#endif /* defined(__x86_64__) || defined(__i386__) */ - -/* From tools/include/asm/barrier.h */ - -#ifndef smp_store_release -# define smp_store_release(p, v) \ -do { \ - smp_mb(); \ - WRITE_ONCE(*p, v); \ -} while (0) -#endif - -#ifndef smp_load_acquire -# define smp_load_acquire(p) \ -({ \ - __typeof(*p) ___p1 = READ_ONCE(*p); \ - smp_mb(); \ - ___p1; \ -}) -#endif - -#endif /* defined(LIBURING_BARRIER_H) */ |