s390/pfault: do not use stack buffers for hardware data

With CONFIG_VMAP_STACK=y the stack is allocated from the vmalloc space.
Data structures passed to a hardware or a hypervisor interface that
requires V=R can not be allocated on the stack anymore.

Make the init and fini pfault parameter blocks static variables.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/fault.c

@@ -636,17 +636,19 @@ struct pfault_refbk {
 	u64 reserved;
 } __attribute__ ((packed, aligned(8)));
 
+static struct pfault_refbk pfault_init_refbk = {
+	.refdiagc = 0x258,
+	.reffcode = 0,
+	.refdwlen = 5,
+	.refversn = 2,
+	.refgaddr = __LC_LPP,
+	.refselmk = 1ULL << 48,
+	.refcmpmk = 1ULL << 48,
+	.reserved = __PF_RES_FIELD
+};
+
 int pfault_init(void)
 {
-	struct pfault_refbk refbk = {
-		.refdiagc = 0x258,
-		.reffcode = 0,
-		.refdwlen = 5,
-		.refversn = 2,
-		.refgaddr = __LC_LPP,
-		.refselmk = 1ULL << 48,
-		.refcmpmk = 1ULL << 48,
-		.reserved = __PF_RES_FIELD };
         int rc;
 
 	if (pfault_disable)
@@ -658,18 +660,20 @@ int pfault_init(void)
 		"1:	la	%0,8\n"
 		"2:\n"
 		EX_TABLE(0b,1b)
-		: "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc");
+		: "=d" (rc)
+		: "a" (&pfault_init_refbk), "m" (pfault_init_refbk) : "cc");
         return rc;
 }
 
+static struct pfault_refbk pfault_fini_refbk = {
+	.refdiagc = 0x258,
+	.reffcode = 1,
+	.refdwlen = 5,
+	.refversn = 2,
+};
+
 void pfault_fini(void)
 {
-	struct pfault_refbk refbk = {
-		.refdiagc = 0x258,
-		.reffcode = 1,
-		.refdwlen = 5,
-		.refversn = 2,
-	};
 
 	if (pfault_disable)
 		return;
@@ -678,7 +682,7 @@ void pfault_fini(void)
 		"	diag	%0,0,0x258\n"
 		"0:	nopr	%%r7\n"
 		EX_TABLE(0b,0b)
-		: : "a" (&refbk), "m" (refbk) : "cc");
+		: : "a" (&pfault_fini_refbk), "m" (pfault_fini_refbk) : "cc");
 }
 
 static DEFINE_SPINLOCK(pfault_lock);