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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2016-01-11 09:17:18 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-01-19 12:14:01 +0100 |
| commit | 204ee2c5643199a25181ec04ea645d00709c2a5a (patch) | |
| tree | 805f6c767221ddf0813be23a9b05829429ec60bc /arch/s390 | |
| parent | a9d7ab97812cf2cf9fd7c980205ae35f58c52cf5 (diff) | |
| download | linux-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.h | 9 | ||||
| -rw-r--r-- | arch/s390/mm/init.c | 2 |
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(); |