[S390] Use copy_to_absolute_zero() instead of "stura/sturg"

Use the new copy_to_absolute_zero() function instead of manual "stura"
and "sturg" to make the code shorter and more readable.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/ipl.c

@@ -1498,30 +1498,12 @@ static struct shutdown_action __refdata dump_action = {
 
 static void dump_reipl_run(struct shutdown_trigger *trigger)
 {
-	preempt_disable();
-	/*
-	 * Bypass dynamic address translation (DAT) when storing IPL parameter
-	 * information block address and checksum into the prefix area
-	 * (corresponding to absolute addresses 0-8191).
-	 * When enhanced DAT applies and the STE format control in one,
-	 * the absolute address is formed without prefixing. In this case a
-	 * normal store (stg/st) into the prefix area would no more match to
-	 * absolute addresses 0-8191.
-	 */
-#ifdef CONFIG_64BIT
-	asm volatile("sturg %0,%1"
-		:: "a" ((unsigned long) reipl_block_actual),
-		"a" (&lowcore_ptr[smp_processor_id()]->ipib));
-#else
-	asm volatile("stura %0,%1"
-		:: "a" ((unsigned long) reipl_block_actual),
-		"a" (&lowcore_ptr[smp_processor_id()]->ipib));
-#endif
-	asm volatile("stura %0,%1"
-		:: "a" (csum_partial(reipl_block_actual,
-				     reipl_block_actual->hdr.len, 0)),
-		"a" (&lowcore_ptr[smp_processor_id()]->ipib_checksum));
-	preempt_enable();
+	u32 csum;
+
+	csum = csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);
+	copy_to_absolute_zero(&S390_lowcore.ipib_checksum, &csum, sizeof(csum));
+	copy_to_absolute_zero(&S390_lowcore.ipib, &reipl_block_actual,
+			      sizeof(reipl_block_actual));
 	dump_run(trigger);
 }