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s390/irqflags: optimize irq restore

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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>
This commit is contained in:
Christian Borntraeger 2016-01-11 09:17:18 +01:00 committed by Martin Schwidefsky
parent a9d7ab9781
commit 204ee2c564
2 changed files with 8 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
arch/s390/include/asm/irqflags.h
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@ -8,6 +8,8 @@
#include <linux/types.h> #include <linux/types.h>
#define ARCH_IRQ_ENABLED (3UL << (BITS_PER_LONG - 8))
/* store then OR system mask. */ /* store then OR system mask. */
#define __arch_local_irq_stosm(__or) \ #define __arch_local_irq_stosm(__or) \
({ \ ({ \
@ -54,14 +56,17 @@ static inline notrace void arch_local_irq_enable(void)
__arch_local_irq_stosm(0x03); __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) 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) 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) static inline notrace bool arch_irqs_disabled(void)

2
arch/s390/mm/init.c
View file

@ -98,7 +98,7 @@ void __init paging_init(void)
__ctl_load(S390_lowcore.kernel_asce, 1, 1); __ctl_load(S390_lowcore.kernel_asce, 1, 1);
__ctl_load(S390_lowcore.kernel_asce, 7, 7); __ctl_load(S390_lowcore.kernel_asce, 7, 7);
__ctl_load(S390_lowcore.kernel_asce, 13, 13); __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_memory_present_with_active_regions(MAX_NUMNODES);
sparse_init(); sparse_init();