Index: sys/amd64/amd64/support.S
===================================================================
--- sys/amd64/amd64/support.S
+++ sys/amd64/amd64/support.S
@@ -1556,3 +1556,9 @@
 	ret
 #undef	L1D_FLUSH_SIZE
 END(flush_l1d_sw)
+
+/* Return the current thread. */
+ENTRY(__curthread)
+	movq	PCPU(CURTHREAD),%rax
+	ret
+END(__curthread)
Index: sys/amd64/include/pcpu.h
===================================================================
--- sys/amd64/include/pcpu.h
+++ sys/amd64/include/pcpu.h
@@ -218,22 +218,7 @@
 #define	PCPU_SET(member, val)	__PCPU_SET(pc_ ## member, val)
 
 #define	OFFSETOF_CURTHREAD	0
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wnull-dereference"
-#endif
-static __inline __pure2 struct thread *
-__curthread(void)
-{
-	struct thread *td;
-
-	__asm("movq %%gs:%1,%0" : "=r" (td)
-	    : "m" (*(char *)OFFSETOF_CURTHREAD));
-	return (td);
-}
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
+struct thread * __curthread(void) __pure2 __attribute__((no_caller_saved_registers));
 #define	curthread		(__curthread())
 
 #define	OFFSETOF_CURPCB		32