Re: [RFC] Add implicit barriers to irqsave/restore class of functions

From: Peter Zijlstra <peterz@infradead.org>
To: Christian Ruppert <christian.ruppert@abilis.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Pierrick Hascoet <pierrick.hascoet@abilis.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC] Add implicit barriers to irqsave/restore class of functions
Date: Thu, 04 Apr 2013 18:13:02 +0200	[thread overview]
Message-ID: <1365091982.2609.97.camel@laptop> (raw)
In-Reply-To: <1364994622-14110-1-git-send-email-christian.ruppert@abilis.com>

On Wed, 2013-04-03 at 15:10 +0200, Christian Ruppert wrote:
> This patch adds implicit memory barriers to irqsave/restore functions
> of
> the ARC architecture port in line with what is done in other
> architectures.

> diff --git a/arch/arc/include/asm/irqflags.h
> b/arch/arc/include/asm/irqflags.h
> index ccd8480..c8147d1 100644
> --- a/arch/arc/include/asm/irqflags.h
> +++ b/arch/arc/include/asm/irqflags.h
> @@ -39,7 +39,7 @@ static inline long arch_local_irq_save(void)
>         "       flag.nz %0              \n"
>         : "=r"(temp), "=r"(flags)
>         : "n"((STATUS_E1_MASK | STATUS_E2_MASK))
> -       : "cc");
> +       : "memory", "cc");

That's not a memory barrier, that a memory clobber, aka a compiler
barrier.