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authorChristian Borntraeger <borntraeger@de.ibm.com>2016-01-11 09:17:18 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-01-19 12:14:01 +0100
commit204ee2c5643199a25181ec04ea645d00709c2a5a (patch)
tree805f6c767221ddf0813be23a9b05829429ec60bc /arch/s390
parenta9d7ab97812cf2cf9fd7c980205ae35f58c52cf5 (diff)
downloadlinux-204ee2c5643199a25181ec04ea645d00709c2a5a.tar.bz2
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>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/irqflags.h9
-rw-r--r--arch/s390/mm/init.c2
2 files changed, 8 insertions, 3 deletions
diff --git a/arch/s390/include/asm/irqflags.h b/arch/s390/include/asm/irqflags.h
index 16aa0c779e07..595a275c36f8 100644
--- a/arch/s390/include/asm/irqflags.h
+++ b/arch/s390/include/asm/irqflags.h
@@ -8,6 +8,8 @@
#include <linux/types.h>
+#define ARCH_IRQ_ENABLED (3UL << (BITS_PER_LONG - 8))
+
/* store then OR system mask. */
#define __arch_local_irq_stosm(__or) \
({ \
@@ -54,14 +56,17 @@ static inline notrace void arch_local_irq_enable(void)
__arch_local_irq_stosm(0x03);
}
+/* This only restores external and I/O interrupt state */
static inline notrace void arch_local_irq_restore(unsigned long flags)
{
- __arch_local_irq_ssm(flags);
+ /* only disabled->disabled and disabled->enabled is valid */
+ if (flags & ARCH_IRQ_ENABLED)
+ arch_local_irq_enable();
}
static inline notrace bool arch_irqs_disabled_flags(unsigned long flags)
{
- return !(flags & (3UL << (BITS_PER_LONG - 8)));
+ return !(flags & ARCH_IRQ_ENABLED);
}
static inline notrace bool arch_irqs_disabled(void)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index c722400c7697..73e290337092 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -98,7 +98,7 @@ void __init paging_init(void)
__ctl_load(S390_lowcore.kernel_asce, 1, 1);
__ctl_load(S390_lowcore.kernel_asce, 7, 7);
__ctl_load(S390_lowcore.kernel_asce, 13, 13);
- arch_local_irq_restore(4UL << (BITS_PER_LONG - 8));
+ __arch_local_irq_stosm(0x04);
sparse_memory_present_with_active_regions(MAX_NUMNODES);
sparse_init();