Subject: Re: [PATCH v2 1/4] powerpc: hard_irq_disable(): Call trace_hardirqs_off after disabling

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 10 May 2013 17:00:45 +1000

On Thu, 2013-05-09 at 22:09 -0500, Scott Wood wrote:
> lockdep.c has this:
>         /*
>          * So we're supposed to get called after you mask local IRQs,
>          * but for some reason the hardware doesn't quite think you did
>          * a proper job.
>          */
> 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
> 		return;
> 
> Since irqs_disabled() is based on soft_enabled(), that (not just the
> hard EE bit) needs to be 0 before we call trace_hardirqs_off.
> 
> Signed-off-by: Scott Wood <[email-masked]>

Oops ;-)

I'll apply that to my tree and will send it to Linus right after -rc1,
the rest will go the normal way for KVM patches.

Cheers,
Ben.

> ---
>  arch/powerpc/include/asm/hw_irq.h |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index d615b28..ba713f1 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -96,11 +96,12 @@ static inline bool arch_irqs_disabled(void)
>  #endif
>  
>  #define hard_irq_disable()	do {			\
> +	u8 _was_enabled = get_paca()->soft_enabled;	\
>  	__hard_irq_disable();				\
> -	if (local_paca->soft_enabled)			\
> -		trace_hardirqs_off();			\
>  	get_paca()->soft_enabled = 0;			\
>  	get_paca()->irq_happened |= PACA_IRQ_HARD_DIS;	\
> +	if (_was_enabled)				\
> +		trace_hardirqs_off();			\
>  } while(0)
>  
>  static inline bool lazy_irq_pending(void)