s390/page: Add memory clobber to page_set_storage_key()

Add memory clobbers to the page_set_storage_key() inline assemblies. This
allows for data dependencies from other code, which is important to prevent
the compiler from reordering instructions if required.

Note that this doesn't fix a bug in existing code; this is just a
prerequisite for upcoming code changes.

Reviewed-by: Claudio Imbrenda <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>

Author: hcahca

arch/s390/include/asm/page.h

@@ -134,12 +134,14 @@ static inline void page_set_storage_key(unsigned long addr,
 		asm volatile(
 			"	.insn	rrf,0xb22b0000,%[skey],%[addr],8,0"
 			:
-			: [skey] "d" (skey), [addr] "a" (addr));
+			: [skey] "d" (skey), [addr] "a" (addr)
+			: "memory");
 	} else {
 		asm volatile(
 			"	sske	 %[skey],%[addr]"
 			:
-			: [skey] "d" (skey), [addr] "a" (addr));
+			: [skey] "d" (skey), [addr] "a" (addr)
+			: "memory");
 	}
 }