diff --git a/common/lib/libc/arch/i386/atomic/atomic.S b/common/lib/libc/arch/i386/atomic/atomic.S
index 6313c8cd5c20..b208a52b7005 100644
--- a/common/lib/libc/arch/i386/atomic/atomic.S
+++ b/common/lib/libc/arch/i386/atomic/atomic.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: atomic.S,v 1.27 2020/04/26 13:59:44 maxv Exp $	*/
+/*	$NetBSD: atomic.S,v 1.28 2020/04/26 14:49:17 maxv Exp $	*/
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -45,11 +45,15 @@
 #ifdef _HARDKERNEL
 #include "opt_xen.h"
 #include <machine/frameasm.h>
-#define	LOCK		HOTPATCH(HP_NAME_NOLOCK, 1); lock
-#define	ENDLABEL(a)	_ALIGN_TEXT; LABEL(a)
+#define LOCK			HOTPATCH(HP_NAME_NOLOCK, 1); lock
+#define HOTPATCH_SSE2_LFENCE	HOTPATCH(HP_NAME_SSE2_LFENCE, 7);
+#define HOTPATCH_SSE2_MFENCE	HOTPATCH(HP_NAME_SSE2_MFENCE, 7);
+#define ENDLABEL(a)		_ALIGN_TEXT; LABEL(a)
 #else
-#define	LOCK		lock
-#define	ENDLABEL(a)	/* nothing */
+#define LOCK			lock
+#define HOTPATCH_SSE2_LFENCE	/* nothing */
+#define HOTPATCH_SSE2_MFENCE	/* nothing */
+#define ENDLABEL(a)		/* nothing */
 #endif
 
 	.text
@@ -177,11 +181,12 @@ ENTRY(_atomic_cas_32_ni)
 END(_atomic_cas_32_ni)
 
 ENTRY(_membar_consumer)
+	HOTPATCH_SSE2_LFENCE
+	/* 7 bytes of instructions */
 	LOCK
 	addl	$0, -4(%esp)
 	ret
 END(_membar_consumer)
-ENDLABEL(membar_consumer_end)
 
 ENTRY(_membar_producer)
 	/* A store is enough */
@@ -190,11 +195,12 @@ ENTRY(_membar_producer)
 END(_membar_producer)
 
 ENTRY(_membar_sync)
+	HOTPATCH_SSE2_MFENCE
+	/* 7 bytes of instructions */
 	LOCK
 	addl	$0, -4(%esp)
 	ret
 END(_membar_sync)
-ENDLABEL(membar_sync_end)
 
 #if defined(__HAVE_ATOMIC64_OPS) || defined(_KERNEL)
 #ifdef XENPV
@@ -257,20 +263,6 @@ END(_atomic_cas_cx8)
 ENDLABEL(_atomic_cas_cx8_end)
 #endif /* __HAVE_ATOMIC64_OPS || _KERNEL */
 
-#ifdef _HARDKERNEL
-ENTRY(sse2_lfence)
-	lfence
-	ret
-END(sse2_lfence)
-ENDLABEL(sse2_lfence_end)
-
-ENTRY(sse2_mfence)
-	mfence
-	ret
-END(sse2_mfence)
-ENDLABEL(sse2_mfence_end)
-#endif	/* _HARDKERNEL */
-
 ALIAS(atomic_add_32,_atomic_add_32)
 ALIAS(atomic_add_int,_atomic_add_32)
 ALIAS(atomic_add_long,_atomic_add_32)
@@ -402,3 +394,19 @@ STRONG_ALIAS(_atomic_cas_ptr_ni,_atomic_cas_32_ni)
 
 STRONG_ALIAS(_membar_enter,_membar_consumer)
 STRONG_ALIAS(_membar_exit,_membar_producer)
+
+#ifdef _HARDKERNEL
+	.section .rodata
+
+LABEL(sse2_lfence)
+	lfence
+	ret
+	nop; nop; nop;
+LABEL(sse2_lfence_end)
+
+LABEL(sse2_mfence)
+	mfence
+	ret
+	nop; nop; nop;
+LABEL(sse2_mfence_end)
+#endif	/* _HARDKERNEL */
diff --git a/common/lib/libc/arch/x86_64/atomic/atomic.S b/common/lib/libc/arch/x86_64/atomic/atomic.S
index 89fbffc32284..2b2d843cf3d8 100644
--- a/common/lib/libc/arch/x86_64/atomic/atomic.S
+++ b/common/lib/libc/arch/x86_64/atomic/atomic.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: atomic.S,v 1.21 2020/04/26 13:59:44 maxv Exp $	*/
+/*	$NetBSD: atomic.S,v 1.22 2020/04/26 14:49:17 maxv Exp $	*/
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -40,11 +40,13 @@
 
 #ifdef _HARDKERNEL
 #include <machine/frameasm.h>
-#define	LOCK		HOTPATCH(HP_NAME_NOLOCK, 1); lock
-#define	ENDLABEL(a)	_ALIGN_TEXT; LABEL(a)
+#define LOCK			HOTPATCH(HP_NAME_NOLOCK, 1); lock
+#define HOTPATCH_SSE2_LFENCE	HOTPATCH(HP_NAME_SSE2_LFENCE, 8);
+#define HOTPATCH_SSE2_MFENCE	HOTPATCH(HP_NAME_SSE2_MFENCE, 8);
 #else
-#define	LOCK		lock
-#define	ENDLABEL(a)	/* nothing */
+#define LOCK			lock
+#define HOTPATCH_SSE2_LFENCE	/* nothing */
+#define HOTPATCH_SSE2_MFENCE	/* nothing */
 #endif
 
 	.text
@@ -254,11 +256,12 @@ END(_atomic_cas_64_ni)
 /* memory barriers */
 
 ENTRY(_membar_consumer)
+	HOTPATCH_SSE2_LFENCE
+	/* 8 bytes of instructions */
 	LOCK
 	addq	$0, -8(%rsp)
 	ret
 END(_membar_consumer)
-ENDLABEL(membar_consumer_end)
 
 ENTRY(_membar_producer)
 	/* A store is enough */
@@ -267,25 +270,12 @@ ENTRY(_membar_producer)
 END(_membar_producer)
 
 ENTRY(_membar_sync)
+	HOTPATCH_SSE2_MFENCE
+	/* 8 bytes of instructions */
 	LOCK
 	addq	$0, -8(%rsp)
 	ret
 END(_membar_sync)
-ENDLABEL(membar_sync_end)
-
-#ifdef _HARDKERNEL
-ENTRY(sse2_lfence)
-	lfence
-	ret
-END(sse2_lfence)
-ENDLABEL(sse2_lfence_end)
-
-ENTRY(sse2_mfence)
-	mfence
-	ret
-END(sse2_mfence)
-ENDLABEL(sse2_mfence_end)
-#endif	/* _HARDKERNEL */
 
 ALIAS(atomic_add_32,_atomic_add_32)
 ALIAS(atomic_add_64,_atomic_add_64)
@@ -425,3 +415,19 @@ STRONG_ALIAS(_atomic_cas_ptr_ni,_atomic_cas_64_ni)
 
 STRONG_ALIAS(_membar_enter,_membar_consumer)
 STRONG_ALIAS(_membar_exit,_membar_producer)
+
+#ifdef _HARDKERNEL
+	.section .rodata
+
+LABEL(sse2_lfence)
+	lfence
+	ret
+	nop; nop; nop; nop;
+LABEL(sse2_lfence_end)
+
+LABEL(sse2_mfence)
+	mfence
+	ret
+	nop; nop; nop; nop;
+LABEL(sse2_mfence_end)
+#endif	/* _HARDKERNEL */
diff --git a/sys/arch/amd64/include/frameasm.h b/sys/arch/amd64/include/frameasm.h
index fc8db59446ae..f17c68146c4a 100644
--- a/sys/arch/amd64/include/frameasm.h
+++ b/sys/arch/amd64/include/frameasm.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: frameasm.h,v 1.48 2020/04/25 15:26:16 bouyer Exp $	*/
+/*	$NetBSD: frameasm.h,v 1.49 2020/04/26 14:49:17 maxv Exp $	*/
 
 #ifndef _AMD64_MACHINE_FRAMEASM_H
 #define _AMD64_MACHINE_FRAMEASM_H
@@ -63,6 +63,8 @@
 #define HP_NAME_SVS_ENTER_NMI	11
 #define HP_NAME_SVS_LEAVE_NMI	12
 #define HP_NAME_MDS_LEAVE	13
+#define HP_NAME_SSE2_LFENCE	14
+#define HP_NAME_SSE2_MFENCE	15
 
 #define HOTPATCH(name, size) \
 123:						; \
diff --git a/sys/arch/i386/include/frameasm.h b/sys/arch/i386/include/frameasm.h
index 1e4a0b4b8722..1fffb4539bd4 100644
--- a/sys/arch/i386/include/frameasm.h
+++ b/sys/arch/i386/include/frameasm.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: frameasm.h,v 1.30 2020/04/25 15:26:17 bouyer Exp $	*/
+/*	$NetBSD: frameasm.h,v 1.31 2020/04/26 14:49:17 maxv Exp $	*/
 
 #ifndef _I386_FRAMEASM_H_
 #define _I386_FRAMEASM_H_
@@ -48,6 +48,8 @@
 #define HP_NAME_STAC		2
 #define HP_NAME_NOLOCK		3
 #define HP_NAME_RETFENCE	4
+#define HP_NAME_SSE2_LFENCE	5
+#define HP_NAME_SSE2_MFENCE	6
 
 #define HOTPATCH(name, size) \
 123:						; \
diff --git a/sys/arch/x86/x86/patch.c b/sys/arch/x86/x86/patch.c
index 009cf863554e..2e626ad276ac 100644
--- a/sys/arch/x86/x86/patch.c
+++ b/sys/arch/x86/x86/patch.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: patch.c,v 1.41 2020/04/26 13:37:14 maxv Exp $	*/
+/*	$NetBSD: patch.c,v 1.42 2020/04/26 14:49:17 maxv Exp $	*/
 
 /*-
  * Copyright (c) 2007, 2008, 2009 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.41 2020/04/26 13:37:14 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.42 2020/04/26 14:49:17 maxv Exp $");
 
 #include "opt_lockdebug.h"
 #ifdef i386
@@ -69,15 +69,6 @@ void	i686_mutex_spin_exit(int);
 void	i686_mutex_spin_exit_end(void);
 void	i686_mutex_spin_exit_patch(void);
 
-void	membar_consumer(void);
-void	membar_consumer_end(void);
-void	membar_sync(void);
-void	membar_sync_end(void);
-void	sse2_lfence(void);
-void	sse2_lfence_end(void);
-void	sse2_mfence(void);
-void	sse2_mfence_end(void);
-
 void	_atomic_cas_64(void);
 void	_atomic_cas_64_end(void);
 void	_atomic_cas_cx8(void);
@@ -219,16 +210,18 @@ x86_patch(bool early)
 		 * ordinary non-temporal stores are always issued in
 		 * program order to main memory and to other CPUs.
 		 */
-		patchfunc(
-		    sse2_lfence, sse2_lfence_end,
-		    membar_consumer, membar_consumer_end,
-		    NULL
-		);
-		patchfunc(
-		    sse2_mfence, sse2_mfence_end,
-		    membar_sync, membar_sync_end,
-		    NULL
-		);
+		extern uint8_t sse2_lfence, sse2_lfence_end;
+		extern uint8_t sse2_mfence, sse2_mfence_end;
+		uint8_t *bytes;
+		size_t size;
+
+		bytes = &sse2_lfence;
+		size = (size_t)&sse2_lfence_end - (size_t)&sse2_lfence;
+		x86_hotpatch(HP_NAME_SSE2_LFENCE, bytes, size);
+
+		bytes = &sse2_mfence;
+		size = (size_t)&sse2_mfence_end - (size_t)&sse2_mfence;
+		x86_hotpatch(HP_NAME_SSE2_MFENCE, bytes, size);
 	}
 
 #ifdef i386