tree 805f6c767221ddf0813be23a9b05829429ec60bc
parent a9d7ab97812cf2cf9fd7c980205ae35f58c52cf5
author Christian Borntraeger <borntraeger@de.ibm.com> 1452500238 +0100
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1453202041 +0100

s390/irqflags: optimize irq restore

The ssm instruction takes longer that stnsm/stosm as it is often
used to modify DAT and PER. We know that irqsave/irqrestore only
deals with external and I/O interrupts and we know that irqrestore
can transition only from disabled->disabled or disabled->enabled,
so we can use the faster stosm.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>