Changeset 8df19af for libcfa

Timestamp:

Oct 23, 2023, 8:55:36 AM (6 months ago)

Author:

caparsons <caparson@…>

Branches:

master

Children:

2ad5e1d5

Parents:

3f0b062

Message:

added WO fences for mcs spin lock to fix failing arm test

File:

• libcfa/src/concurrency/locks.hfa (modified) (1 diff)

libcfa/src/concurrency/locks.hfa

@@ -182 +182 @@
 static inline void lock( mcs_spin_lock & l, mcs_spin_node & n ) {
     n.locked = true;
+
+        #if defined(__ARM_ARCH)
+        __asm__ __volatile__ ( "DMB ISH" ::: )
+        #endif
+
         mcs_spin_node * prev = __atomic_exchange_n(&l.queue.tail, &n, __ATOMIC_SEQ_CST);
         if( prev == 0p ) return;
         prev->next = &n;
+        
+        #if defined(__ARM_ARCH)
+        __asm__ __volatile__ ( "DMB ISH" ::: )
+        #endif
+
         while( __atomic_load_n(&n.locked, __ATOMIC_RELAXED) ) Pause();
+
+        #if defined(__ARM_ARCH)
+        __asm__ __volatile__ ( "DMB ISH" ::: )
+        #endif
 }
 
 static inline void unlock(mcs_spin_lock & l, mcs_spin_node & n) {
+        #if defined(__ARM_ARCH)
+        __asm__ __volatile__ ( "DMB ISH" ::: )
+        #endif
+
         mcs_spin_node * n_ptr = &n;
         if (__atomic_compare_exchange_n(&l.queue.tail, &n_ptr, 0p, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) return;
         while (__atomic_load_n(&n.next, __ATOMIC_RELAXED) == 0p) Pause();
+
+        #if defined(__ARM_ARCH)
+        __asm__ __volatile__ ( "DMB ISH" ::: )
+        #endif
+
         n.next->locked = false;
 }