diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index d2b5adf46512f20feb7fc27a14d39bc37c10e3e4..8ec575249aa9f42b64ec57c8cc6595c14163c2aa 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -109,7 +109,7 @@ typedef unsigned int addr_t;
 static inline u8 rdfs8(addr_t addr)
 {
 	u8 v;
-	asm volatile("movb %%fs:%1,%0" : "=r" (v) : "m" (*(u8 *)addr));
+	asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
 	return v;
 }
 static inline u16 rdfs16(addr_t addr)
@@ -127,21 +127,21 @@ static inline u32 rdfs32(addr_t addr)
 
 static inline void wrfs8(u8 v, addr_t addr)
 {
-	asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "r" (v));
+	asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
 }
 static inline void wrfs16(u16 v, addr_t addr)
 {
-	asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "r" (v));
+	asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
 }
 static inline void wrfs32(u32 v, addr_t addr)
 {
-	asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "r" (v));
+	asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
 }
 
 static inline u8 rdgs8(addr_t addr)
 {
 	u8 v;
-	asm volatile("movb %%gs:%1,%0" : "=r" (v) : "m" (*(u8 *)addr));
+	asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
 	return v;
 }
 static inline u16 rdgs16(addr_t addr)
@@ -159,15 +159,15 @@ static inline u32 rdgs32(addr_t addr)
 
 static inline void wrgs8(u8 v, addr_t addr)
 {
-	asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "r" (v));
+	asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
 }
 static inline void wrgs16(u16 v, addr_t addr)
 {
-	asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "r" (v));
+	asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
 }
 static inline void wrgs32(u32 v, addr_t addr)
 {
-	asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "r" (v));
+	asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
 }
 
 /* Note: these only return true/false, not a signed return value! */