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Commit 52499d93 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/maccess: reduce stnsm instructions 



When fixing the DAT off bug ("s390: fix DAT off memory access, e.g.
on kdump") both Christian and I missed that we can save an additional
stnsm instruction.

This saves us a couple of cycles which could improve the speed of
memcpy_real.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f6c9b160

arch/s390/mm/maccess.c

+6 −4
Original line number Diff line number Diff line
@@ -93,15 +93,17 @@ static int __memcpy_real(void *dest, void *src, size_t count) 
 */

int memcpy_real(void *dest, void *src, size_t count)

{

	int irqs_disabled, rc;

	unsigned long flags;

	int rc;



	if (!count)

		return 0;

	local_irq_save(flags);

	__arch_local_irq_stnsm(0xfbUL);

	flags = __arch_local_irq_stnsm(0xf8UL);

	irqs_disabled = arch_irqs_disabled_flags(flags);

	if (!irqs_disabled)

		trace_hardirqs_off();

	rc = __memcpy_real(dest, src, count);

	if (!arch_irqs_disabled_flags(flags))

	if (!irqs_disabled)

		trace_hardirqs_on();

	__arch_local_irq_ssm(flags);

	return rc;