Add more atomic_swap_* functions.

Obtained from:	ABT Systems Ltd
Sponsored by:	The FreeBSD Foundation

diff --git a/sys/arm64/include/atomic.h b/sys/arm64/include/atomic.h
index 4c9d7188e735d246f85a2d23f5b60aad0d2544d1..12ce4a1dcb8651e4b9f9b22844770586effc2e7f 100644 (file)
--- a/sys/arm64/include/atomic.h
+++ b/sys/arm64/include/atomic.h
@@ -153,6 +153,22 @@ atomic_set_32(volatile uint32_t *p, uint32_t val)
        );
 }
 
+static __inline uint32_t
+atomic_swap_32(volatile uint32_t *p, uint32_t val)
+{
+       uint32_t tmp;
+       int res;
+
+       __asm __volatile(
+           "1: ldxr    %w0, [%2]      \n"
+           "   stxr    %w1, %w3, [%2] \n"
+           "   cbnz    %w1, 1b        \n"
+           : "=&r"(tmp), "=&r"(res), "+r" (p), "+r" (val) : : "cc", "memory"
+       );
+
+       return (tmp);
+}
+
 static __inline void
 atomic_subtract_32(volatile uint32_t *p, uint32_t val)
 {
@@ -174,6 +190,7 @@ atomic_subtract_32(volatile uint32_t *p, uint32_t val)
 #define        atomic_fetchadd_int     atomic_fetchadd_32
 #define        atomic_readandclear_int atomic_readandclear_32
 #define        atomic_set_int          atomic_set_32
+#define        atomic_swap_int         atomic_swap_32
 #define        atomic_subtract_int     atomic_subtract_32
 
 static __inline void
@@ -515,6 +532,7 @@ atomic_swap_64(volatile uint64_t *p, uint64_t val)
 #define        atomic_fetchadd_long            atomic_fetchadd_64
 #define        atomic_readandclear_long        atomic_readandclear_64
 #define        atomic_set_long                 atomic_set_64
+#define        atomic_swap_long                atomic_swap_64
 #define        atomic_subtract_long            atomic_subtract_64
 
 #define        atomic_add_ptr                  atomic_add_64
@@ -523,6 +541,7 @@ atomic_swap_64(volatile uint64_t *p, uint64_t val)
 #define        atomic_fetchadd_ptr             atomic_fetchadd_64
 #define        atomic_readandclear_ptr         atomic_readandclear_64
 #define        atomic_set_ptr                  atomic_set_64
+#define        atomic_swap_ptr                 atomic_swap_64
 #define        atomic_subtract_ptr             atomic_subtract_64
 
 static __inline void