[PATCH 04/13] powerpc: Use soft_enabled_set api to update paca->soft_enabled

[Nicholas Piggin]

On Thu, 15 Sep 2016 18:31:54 +0530
Madhavan Srinivasan <maddy at linux.vnet.ibm.com> wrote:

> Force use of soft_enabled_set() wrapper to update paca-soft_enabled
> wherever possisble. Also add a new wrapper function, soft_enabled_set_return(),
> added to force the paca->soft_enabled updates.
> 
> Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/hw_irq.h  | 14 ++++++++++++++
>  arch/powerpc/include/asm/kvm_ppc.h |  2 +-
>  arch/powerpc/kernel/irq.c          |  2 +-
>  arch/powerpc/kernel/setup_64.c     |  4 ++--
>  arch/powerpc/kernel/time.c         |  6 +++---
>  5 files changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index 8fad8c24760b..f828b8f8df02 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -53,6 +53,20 @@ static inline notrace void soft_enabled_set(unsigned long enable)
>  	: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
>  }
>  
> +static inline notrace unsigned long soft_enabled_set_return(unsigned long enable)
> +{
> +	unsigned long flags;
> +
> +	asm volatile(
> +		"lbz %0,%1(13); stb %2,%1(13)"
> +		: "=r" (flags)
> +		: "i" (offsetof(struct paca_struct, soft_enabled)),\
> +		  "r" (enable)
> +		: "memory");
> +
> +	return flags;
> +}

Why do you have the "memory" clobber here while soft_enabled_set() does not?

Thanks,
Nick