s390/irqflags: optimize irq restore
authorChristian Borntraeger <borntraeger@de.ibm.com>
Mon, 11 Jan 2016 08:17:18 +0000 (09:17 +0100)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Tue, 19 Jan 2016 11:14:01 +0000 (12:14 +0100)
commit204ee2c5643199a25181ec04ea645d00709c2a5a
tree805f6c767221ddf0813be23a9b05829429ec60bc
parenta9d7ab97812cf2cf9fd7c980205ae35f58c52cf5
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>
arch/s390/include/asm/irqflags.h
arch/s390/mm/init.c