From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v3 01/22] arm64: Add macros to read/write system registers
Date: Mon, 7 Dec 2015 17:45:38 +0000
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Cc: Marc Zyngier <marc.zyngier@arm.com>,
	Christoffer Dall <christoffer.dall@linaro.org>,
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To: Catalin Marinas <catalin.marinas@arm.com>
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On Mon, Dec 07, 2015 at 05:35:20PM +0000, Catalin Marinas wrote:
> On Mon, Dec 07, 2015 at 10:53:17AM +0000, Marc Zyngier wrote:
> > From: Mark Rutland <mark.rutland@arm.com>
> > 
> > Rather than crafting custom macros for reading/writing each system
> > register provide generics accessors, read_sysreg and write_sysreg, for
> > this purpose.
> > 
> > Unlike read_cpuid, calls to read_exception_reg are never expected
> > to be optimized away or replaced with synthetic values.
> 
> What's read_exception_reg? Is it a macro somewhere?

That was what read_sysreg used to be called on a local branch of mine. I
didn't spot that when reworking the patch.

So s/read_exception_reg/read_sysreg/ here.

> > +#define read_sysreg(r) ({					\
> > +	u64 __val;						\
> > +	asm volatile("mrs %0, " __stringify(r) : "=r" (__val));	\
> > +	__val;							\
> > +})
> 
> And maybe a comment here on why this is always volatile.

Makes sense to me.

Marc, are you happy to turn the last sentence from the commit message
into a comment here (with the substitution)?

Thanks,
Mark.

From mboxrd@z Thu Jan  1 00:00:00 1970
From: mark.rutland@arm.com (Mark Rutland)
Date: Mon, 7 Dec 2015 17:45:38 +0000
Subject: [PATCH v3 01/22] arm64: Add macros to read/write system registers
In-Reply-To: <20151207173520.GJ7083@e104818-lin.cambridge.arm.com>
References: <1449485618-9443-1-git-send-email-marc.zyngier@arm.com>
 <1449485618-9443-2-git-send-email-marc.zyngier@arm.com>
 <20151207173520.GJ7083@e104818-lin.cambridge.arm.com>
Message-ID: <20151207174537.GD28024@leverpostej>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Dec 07, 2015 at 05:35:20PM +0000, Catalin Marinas wrote:
> On Mon, Dec 07, 2015 at 10:53:17AM +0000, Marc Zyngier wrote:
> > From: Mark Rutland <mark.rutland@arm.com>
> > 
> > Rather than crafting custom macros for reading/writing each system
> > register provide generics accessors, read_sysreg and write_sysreg, for
> > this purpose.
> > 
> > Unlike read_cpuid, calls to read_exception_reg are never expected
> > to be optimized away or replaced with synthetic values.
> 
> What's read_exception_reg? Is it a macro somewhere?

That was what read_sysreg used to be called on a local branch of mine. I
didn't spot that when reworking the patch.

So s/read_exception_reg/read_sysreg/ here.

> > +#define read_sysreg(r) ({					\
> > +	u64 __val;						\
> > +	asm volatile("mrs %0, " __stringify(r) : "=r" (__val));	\
> > +	__val;							\
> > +})
> 
> And maybe a comment here on why this is always volatile.

Makes sense to me.

Marc, are you happy to turn the last sentence from the commit message
into a comment here (with the substitution)?

Thanks,
Mark.