From 204ee2c5643199a25181ec04ea645d00709c2a5a Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Mon, 11 Jan 2016 09:17:18 +0100 Subject: 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 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'arch/s390/include/asm/irqflags.h') 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) -- cgit v1.2.3-55-g7522