[PATCH] powerpc: Make hard_irq_disable() do the right thing vs. irq tracing
tiejun.chen
tiejun.chen at windriver.com
Tue May 7 17:15:57 EST 2013
On 05/07/2013 03:04 PM, Benjamin Herrenschmidt wrote:
> If hard_irq_disable() is called while interrupts are already soft-disabled
> (which is the most common case) all is already well.
>
> However you can (and in some cases want) to call it while everything is
> enabled (to make sure you don't get a lazy even, for example before entry
> into KVM guests) and in this case we need to inform the irq tracer that
> the irqs are going off.
>
> We have to change the inline into a macro to avoid an include circular
> dependency hell hole.
>
> Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> ---
>
> Tested on pseries, Scott, I don't expect a problem with that patch especially
> since most callers already are soft disabled, so I'll merge it now along with
> my other pending stuff and you can simplify your KVM one.
>
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index e45c494..d615b28 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -95,15 +95,13 @@ static inline bool arch_irqs_disabled(void)
> #define __hard_irq_disable() __mtmsrd(local_paca->kernel_msr, 1)
> #endif
>
> -static inline void hard_irq_disable(void)
> -{
> - __hard_irq_disable();
> - get_paca()->soft_enabled = 0;
> - get_paca()->irq_happened |= PACA_IRQ_HARD_DIS;
> -}
> -
> -/* include/linux/interrupt.h needs hard_irq_disable to be a macro */
> -#define hard_irq_disable hard_irq_disable
> +#define hard_irq_disable() do { \
> + __hard_irq_disable(); \
> + if (local_paca->soft_enabled) \
> + trace_hardirqs_off(); \
> + get_paca()->soft_enabled = 0; \
Could we simplify this as follows:
+#define hard_irq_disable() do { \
+ __hard_irq_disable(); \
+ if (get_paca()->soft_enabled) { \
+ trace_hardirqs_off(); \
+ get_paca()->soft_enabled = 0; \
+ } \
+ get_paca()->irq_happened |= PACA_IRQ_HARD_DIS; \
+} while(0)
Tiejun
> + get_paca()->irq_happened |= PACA_IRQ_HARD_DIS; \
> +} while(0)
>
> static inline bool lazy_irq_pending(void)
> {
>
>
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