linux-kernel - Re: [PATCH] irqchip: gic: Don't complain in gic_get

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Message-ID: <20130712111322.GC3213@e102654-lin.cambridge.arm.com>
Date:	Fri, 12 Jul 2013 12:13:22 +0100
From:	Javi Merino <javi.merino@....com>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Russell King <rmk+kernel@....linux.org.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Nicolas Pitre <nico@...aro.org>
Subject: Re: [PATCH] irqchip: gic: Don't complain in gic_get_cpumask() if UP
 system

On Sat, Jul 06, 2013 at 12:39:33AM +0100, Stephen Boyd wrote:
> In a uniprocessor implementation the interrupt processor targets
> registers are read-as-zero/write-ignored (RAZ/WI). Unfortunately
> gic_get_cpumask() will print a critical message saying
> 
>  GIC CPU mask not found - kernel will fail to boot.
> 
> if these registers all read as zero, but there won't actually be
> a problem on uniprocessor systems and the kernel will boot just
> fine. Skip this check if we're running a UP kernel or if we
> detect that the hardware only supports a single processor.
> 
> Cc: Nicolas Pitre <nico@...aro.org>
> Cc: Russell King <rmk+kernel@....linux.org.uk>
> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
> ---
> 
> Maybe we should just drop the check entirely? It looks like it may
> just be debug code that won't ever trigger in practice, even on the
> 11MPCore that caused this code to be introduced.

I agree, we should drop the check.  It's annoying in uniprocessors and
unlikely to be found in the real world unless your gic entry in the dt
is wrong.

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