[RFC PATCH] EDAC: Cleanup atomic_scrub mess

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Thu, May 21, 2015 at 08:11:57PM +0200, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
> 
> So first of all, this atomic_scrub() function's naming is bad. It looks
> like an atomic_t helper. Change it to edac_atomic_scrub().
> 
> The bigger problem is that this function is arch-specific and every new
> arch which doesn't necessarily need that functionality still needs to
> define it, otherwise EDAC doesn't compile.
> 
> So instead of doing that and including arch-specific headers, have each
> arch define an EDAC_ATOMIC_SCRUB symbol which can be used in edac_mc.c
> for ifdeffery. Much cleaner.
> 
> We already are doing this with another symbol - EDAC_SUPPORT. This is
> also much cleaner than having CONFIG_EDAC explicitly depend on all the
> arches which need/have EDAC support and drivers.
> 
> This way I can kill the useless edac.h header in tile too.
> 
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Russell King <linux@arm.linux.org.uk>

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>

> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 45df48ba0b12..325d6f3a596a 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -15,6 +15,8 @@ config ARM
>  	select CLONE_BACKWARDS
>  	select CPU_PM if (SUSPEND || CPU_IDLE)
>  	select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS
> +	select EDAC_SUPPORT
> +	select EDAC_ATOMIC_SCRUB

I wonder if it would make sense to conditionalise EDAC_SUPPORT on...
		if CPU_32v6 || CPU_32v7

since presumably its not useful for older architectures (certainly
edac_atomic_scrub() is a no-op for earlier arches.)

>  	select GENERIC_ALLOCATOR
>  	select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
>  	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> diff --git a/arch/arm/include/asm/edac.h b/arch/arm/include/asm/edac.h
> index 0df7a2c1fc3d..5189fa819b60 100644
> --- a/arch/arm/include/asm/edac.h
> +++ b/arch/arm/include/asm/edac.h
> @@ -18,11 +18,12 @@
>  #define ASM_EDAC_H
>  /*
>   * ECC atomic, DMA, SMP and interrupt safe scrub function.
> - * Implements the per arch atomic_scrub() that EDAC use for software
> + * Implements the per arch edac_atomic_scrub() that EDAC use for software
>   * ECC scrubbing.  It reads memory and then writes back the original
>   * value, allowing the hardware to detect and correct memory errors.
>   */
> -static inline void atomic_scrub(void *va, u32 size)
> +
> +static inline void edac_atomic_scrub(void *va, u32 size)
>  {
>  #if __LINUX_ARM_ARCH__ >= 6
>  	unsigned int *virt_addr = va;

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