From 9d9c9630befaea330c98a1be884688a09efd0547 Mon Sep 17 00:00:00 2001
From: ian <ian@FreeBSD.org>
Date: Fri, 1 Aug 2014 23:06:38 +0000
Subject: [PATCH] Use atomic_load/store_64() in the arm implementation of
 counter(9), and remove the XXX comments about non-atomic access to the
 counters.

---
 sys/arm/include/counter.h | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/sys/arm/include/counter.h b/sys/arm/include/counter.h
index a6dfa8ef875b..c4da91f7a14b 100644
--- a/sys/arm/include/counter.h
+++ b/sys/arm/include/counter.h
@@ -30,6 +30,7 @@
 #define __MACHINE_COUNTER_H__
 
 #include <sys/pcpu.h>
+#include <machine/atomic.h>
 #ifdef INVARIANTS
 #include <sys/proc.h>
 #endif
@@ -38,12 +39,13 @@
 #define	counter_exit()	critical_exit()
 
 #ifdef IN_SUBR_COUNTER_C
-/* XXXKIB non-atomic 64bit read */
+
 static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (atomic_load_64((uint64_t *)((char *)p + sizeof(struct pcpu) *
+	    cpu)));
 }
 
 static inline uint64_t
@@ -59,13 +61,12 @@ counter_u64_fetch_inline(uint64_t *p)
 	return (r);
 }
 
-/* XXXKIB non-atomic 64bit store, might interrupt increment */
 static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
-	    PCPU_GET(cpuid))) = 0;
+	atomic_store_64((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	    PCPU_GET(cpuid)), 0);
 }
 
 static inline void
@@ -79,7 +80,7 @@ counter_u64_zero_inline(counter_u64_t c)
 
 #define	counter_u64_add_protected(c, inc)	do {	\
 	CRITICAL_ASSERT(curthread);			\
-	*(uint64_t *)zpcpu_get(c) += (inc);		\
+	atomic_add_64((uint64_t *)zpcpu_get(c), (inc));	\
 } while (0)
 
 static inline void