From 204ee2c5643199a25181ec04ea645d00709c2a5a Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Mon, 11 Jan 2016 09:17:18 +0100 Subject: [PATCH] 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 --- arch/s390/include/asm/irqflags.h | 9 +++++++-- 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 +#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(); -- 2.20.1