diff --git a/sys/amd64/include/pcpu.h b/sys/amd64/include/pcpu.h
index a55627fc1df5..c4b0c440c7df 100644
--- a/sys/amd64/include/pcpu.h
+++ b/sys/amd64/include/pcpu.h
@@ -216,12 +216,12 @@ extern struct pcpu *pcpup;
 #define	PCPU_PTR(member)	__PCPU_PTR(pc_ ## member)
 #define	PCPU_SET(member, val)	__PCPU_SET(pc_ ## member, val)
 
-static __inline struct thread *
+static __inline __pure2 struct thread *
 __curthread(void)
 {
 	struct thread *td;
 
-	__asm __volatile("movq %%gs:0,%0" : "=r" (td));
+	__asm("movq %%gs:0,%0" : "=r" (td));
 	return (td);
 }
 #define	curthread		(__curthread())
diff --git a/sys/i386/include/pcpu.h b/sys/i386/include/pcpu.h
index d80f8e16ac2c..8906eda38cda 100644
--- a/sys/i386/include/pcpu.h
+++ b/sys/i386/include/pcpu.h
@@ -223,12 +223,12 @@ extern struct pcpu *pcpup;
 #define	PCPU_PTR(member)	__PCPU_PTR(pc_ ## member)
 #define	PCPU_SET(member, val)	__PCPU_SET(pc_ ## member, val)
 
-static __inline struct thread *
+static __inline __pure2 struct thread *
 __curthread(void)
 {
 	struct thread *td;
 
-	__asm __volatile("movl %%fs:0,%0" : "=r" (td));
+	__asm("movl %%fs:0,%0" : "=r" (td));
 	return (td);
 }
 #define	curthread		(__curthread())
diff --git a/sys/ia64/include/pcpu.h b/sys/ia64/include/pcpu.h
index 3c6e6a762af5..58403aad5871 100644
--- a/sys/ia64/include/pcpu.h
+++ b/sys/ia64/include/pcpu.h
@@ -70,12 +70,12 @@ struct pcpu;
 
 register struct pcpu *pcpup __asm__("r13");
 
-static __inline struct thread *
+static __inline __pure2 struct thread *
 __curthread(void)
 {
 	struct thread *td;
 
-	__asm __volatile("ld8.acq %0=[r13]" : "=r"(td));
+	__asm("ld8.acq %0=[r13]" : "=r"(td));
 	return (td);
 }
 #define	curthread	(__curthread())