diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S
index e61de03bb06..a8217f31aab 100644
--- a/sys/amd64/amd64/cpu_switch.S
+++ b/sys/amd64/amd64/cpu_switch.S
@@ -108,7 +108,7 @@ ENTRY(cpu_switch)
 	movl	%fs,%eax
 	cmpl	$KUF32SEL,%eax
 	jne	1f
-	rdfsbaseq %rax
+	rdfsbase %rax
 	movq	%rax,PCB_FSBASE(%r8)
 1:	movl	%gs,%eax
 	cmpl	$KUG32SEL,%eax
diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S
index 9b60f749ba8..d3c11082958 100644
--- a/sys/amd64/amd64/exception.S
+++ b/sys/amd64/amd64/exception.S
@@ -340,10 +340,10 @@ prot_addrf:
 	jz	2f
 	cmpw	$KUF32SEL,TF_FS(%rsp)
 	jne	1f
-	rdfsbaseq %rax
+	rdfsbase %rax
 1:	cmpw	$KUG32SEL,TF_GS(%rsp)
 	jne	2f
-	rdgsbaseq %rdx
+	rdgsbase %rdx
 2:	swapgs
 	movq	PCPU(CURPCB),%rdi
 	testb	$CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip)
@@ -533,7 +533,7 @@ nmi_fromuserspace:
 	jz	2f
 	cmpw	$KUF32SEL,TF_FS(%rsp)
 	jne	1f
-	rdfsbaseq %rax
+	rdfsbase %rax
 	movq	%rax,PCB_FSBASE(%rdi)
 1:	cmpw	$KUG32SEL,TF_GS(%rsp)
 	jne	2f