1 files changed, 23 insertions, 0 deletions

diff --git a/arch/arm/include/asm/mcs_spinlock.h b/arch/arm/include/asm/mcs_spinlock.h
new file mode 100644
index 000000000000..f652ad65840a
--- /dev/null
+++ b/arch/arm/include/asm/mcs_spinlock.h
@@ -0,0 +1,23 @@
+#ifndef __ASM_MCS_LOCK_H
+#define __ASM_MCS_LOCK_H
+
+#ifdef CONFIG_SMP
+#include <asm/spinlock.h>
+
+/* MCS spin-locking. */
+#define arch_mcs_spin_lock_contended(lock)                              \
+do {                                                                    \
+        /* Ensure prior stores are observed before we enter wfe. */     \
+        smp_mb();                                                       \
+        while (!(smp_load_acquire(lock)))                               \
+                wfe();                                                  \
+} while (0)                                                             \
+
+#define arch_mcs_spin_unlock_contended(lock)                            \
+do {                                                                    \
+        smp_store_release(lock, 1);                                     \
+        dsb_sev();                                                      \
+} while (0)
+
+#endif  /* CONFIG_SMP */
+#endif  /* __ASM_MCS_LOCK_H */