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Commit 204ee2c5 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
Browse files

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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent a9d7ab97

arch/s390/include/asm/irqflags.h

+7 −2
Original line number Diff line number Diff line
@@ -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)

arch/s390/mm/init.c

+1 −1
Original line number Diff line number Diff line
@@ -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();