arm64: locks: introduce ticket-based spinlock implementation

This patch introduces a ticket lock implementation for arm64, along the
same lines as the implementation for arch/arm/.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/arch/arm64/include/asm/spinlock_types.h b/arch/arm64/include/asm/spinlock_types.h
index 9a494346efed..87692750ed94 100644
--- a/arch/arm64/include/asm/spinlock_types.h
+++ b/arch/arm64/include/asm/spinlock_types.h
@@ -20,14 +20,14 @@
 # error "please don't include this file directly"
 #endif
 
-/* We only require natural alignment for exclusive accesses. */
-#define __lock_aligned
+#define TICKET_SHIFT	16
 
 typedef struct {
-	volatile unsigned int lock;
-} arch_spinlock_t;
+	u16 owner;
+	u16 next;
+} __aligned(4) arch_spinlock_t;
 
-#define __ARCH_SPIN_LOCK_UNLOCKED	{ 0 }
+#define __ARCH_SPIN_LOCK_UNLOCKED	{ 0 , 0 }
 
 typedef struct {
 	volatile unsigned int lock;