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 for <linuxppc-dev@lists.ozlabs.org>; Wed, 29 Oct 2014 17:39:57 +1100 (AEDT)
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To: Christoph Lameter <cl@linux.com>,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>
From: Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: powerpc: Replace __get_cpu_var uses
Message-Id: <20141029063957.76C6014008E@ozlabs.org>
Date: Wed, 29 Oct 2014 17:39:57 +1100 (AEDT)
Cc: linuxppc-dev@ozlabs.org
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On Tue, 2014-21-10 at 20:23:25 UTC, Christoph Lameter wrote:
> This still has not been merged and now powerpc is the only arch that does
> not have this change. Sorry about missing linuxppc-dev before.
> 
> --- linux.orig/arch/powerpc/include/asm/hardirq.h
> +++ linux/arch/powerpc/include/asm/hardirq.h
> @@ -21,7 +21,9 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpust
> 
>  #define __ARCH_IRQ_STAT
> 
> -#define local_softirq_pending()	__get_cpu_var(irq_stat).__softirq_pending
> +#define local_softirq_pending()	__this_cpu_read(irq_stat.__softirq_pending)
> +#define set_softirq_pending(x) __this_cpu_write(irq_stat._softirq_pending, (x))
> +#define or_softirq_pending(x) __this_cpu_or(irq_stat._softirq_pending, (x))

This breaks the build, because we also get the version of set_ and or_ from
include/linux/interrupt.h, and then because it's __softirq_pending.

Fixed by adding:

#define __ARCH_SET_SOFTIRQ_PENDING

And fixing the typo.

> --- linux.orig/arch/powerpc/kernel/process.c
> +++ linux/arch/powerpc/kernel/process.c
> @@ -499,7 +499,7 @@ static inline int set_dawr(struct arch_h
> 
>  void __set_breakpoint(struct arch_hw_breakpoint *brk)
>  {
> -	__get_cpu_var(current_brk) = *brk;
> +	__this_cpu_write(current_brk, *brk);

This breaks the build because we're trying to do a structure assignment but
__this_cpu_write() only supports certain sizes.

I replaced it with this which I think is right?

	memcpy(this_cpu_ptr(&current_brk), brk, sizeof(*brk));


cheers