s390/boot: Convert __diag308() to extable

Shorten __diag308() and use regular EX_TABLE program check handling.

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: hcahca

arch/s390/boot/ipl_parm.c

@@ -35,29 +35,14 @@ int vmalloc_size_set;
 
 static inline int __diag308(unsigned long subcode, void *addr)
 {
-	unsigned long reg1, reg2;
-	union register_pair r1;
-	psw_t old;
+	union register_pair r1 = { .even = (unsigned long)addr, .odd = 0 };
 
-	r1.even = (unsigned long) addr;
-	r1.odd	= 0;
 	asm volatile(
-		"	mvc	0(16,%[psw_old]),0(%[psw_pgm])\n"
-		"	epsw	%[reg1],%[reg2]\n"
-		"	st	%[reg1],0(%[psw_pgm])\n"
-		"	st	%[reg2],4(%[psw_pgm])\n"
-		"	larl	%[reg1],1f\n"
-		"	stg	%[reg1],8(%[psw_pgm])\n"
 		"	diag	%[r1],%[subcode],0x308\n"
-		"1:	mvc	0(16,%[psw_pgm]),0(%[psw_old])\n"
-		: [r1] "+&d" (r1.pair),
-		  [reg1] "=&d" (reg1),
-		  [reg2] "=&a" (reg2),
-		  "+Q" (get_lowcore()->program_new_psw),
-		  "=Q" (old)
-		: [subcode] "d" (subcode),
-		  [psw_old] "a" (&old),
-		  [psw_pgm] "a" (&get_lowcore()->program_new_psw)
+		"0:\n"
+		EX_TABLE(0b, 0b)
+		: [r1] "+d" (r1.pair)
+		: [subcode] "d" (subcode)
 		: "cc", "memory");
 	return r1.odd;
 }