From mboxrd@z Thu Jan  1 00:00:00 1970
From: mark.rutland@arm.com (Mark Rutland)
Date: Thu, 19 Jun 2014 13:33:19 +0100
Subject: [PATCHv2 4/4] arm64: add runtime system sanity checks
In-Reply-To: <20140618172036.GH17851@arm.com>
References: <1403024674-25108-1-git-send-email-mark.rutland@arm.com>
 <1403024674-25108-5-git-send-email-mark.rutland@arm.com>
 <20140618172036.GH17851@arm.com>
Message-ID: <20140619123319.GD22217@leverpostej>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Jun 18, 2014 at 06:20:36PM +0100, Will Deacon wrote:
> On Tue, Jun 17, 2014 at 06:04:34PM +0100, Mark Rutland wrote:
> > Unexpected variation in certain system register values across CPUs is an
> > indicator of potential problems with a system. The kernel expects CPUs
> > to be mostly identical in terms of supported features, even in systems
> > with heterogeneous CPUs, with uniform instruction set support being
> > critical for the correct operation of userspace.
> > 
> > To help detect issues early where hardware violates the expectations of
> > the kernel, this patch adds simple runtime sanity checks on important ID
> > registers in the bring up path of each CPU.
> > 
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> 
> [...]
> 
> > +/*
> > + * Verify that CPUs don't have unexpected differences that will cause problems.
> > + */
> > +void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur)
> > +{
> > +	struct cpuinfo_arm64 *boot = &per_cpu(cpu_data, 0);
> > +	int cpu = smp_processor_id();
> 
> You could just as easily pass in the cpu number here, like you do for
> cpuinfo_detect_icache_policy.

Sure; done.

Mark.