From 777e3da31b198ff16b89a1b684904d5a2101960a Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Thu, 3 Jul 2025 18:22:48 -0400
Subject: kernel: synch: Use md_pause() in spinwait loop

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/kern/kern_synch.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index 0d36d7f..497aff7 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -35,6 +35,7 @@
 #include <sys/atomic.h>
 #include <sys/syslog.h>
 #include <sys/spinlock.h>
+#include <machine/cdefs.h>
 #include <dev/timer.h>
 #include <string.h>
 
@@ -83,7 +84,9 @@ spinlock_usleep(struct spinlock *lock, size_t usec_max)
 void
 spinlock_acquire(struct spinlock *lock)
 {
-    while (__atomic_test_and_set(&lock->lock, __ATOMIC_ACQUIRE));
+    while (__atomic_test_and_set(&lock->lock, __ATOMIC_ACQUIRE)) {
+        md_pause();
+    }
 }
 
 /*
-- 
cgit v1.2.3