[RFC PATCH 0/5] Fix Thumb-2 undef handling for mixed-arch kernels

From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 0/5] Fix Thumb-2 undef handling for mixed-arch kernels
Date: Tue, 16 Aug 2011 10:04:22 +0100	[thread overview]
Message-ID: <20110816090422.GA1993@arm.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1108151910030.20358@xanadu.home>

On Mon, Aug 15, 2011 at 07:13:35PM -0400, Nicolas Pitre wrote:
> On Thu, 11 Aug 2011, Dave Martin wrote:
> 
> > On Wed, Aug 10, 2011 at 12:31:37PM +0100, Tixy wrote:
> > > An alternative to defend against this is to make cpu_architecture() an
> > > inline function returning the value of the global variable like:
> > > 
> > > inline int cpu_architecture(void)
> > > {
> > > 	BUG_ON(the_cpu_architecture == CPU_ARCH_UNKNOWN);
> > > 	return the_cpu_architecture;
> > > }
> > > 
> > > This has the bonus of not needing to change users of the the function.
> > 
> > Sounds like a good idea.  I got rid of the function because I didn't like
> > calling a function from the undef handler entry code, but an inline
> > function which just reads the variable seems like the best of both worlds.
> 
> While at it, you could mark the function with __attribute__((pure)).

Hmmm, I don't know what exact impact that has for an inline function, but it
would certainly do no harm.  Maybe it will eliminate some calls to BUG_ON().
I will add it anyway -- I don't see a reason not to.

Cheers
---Dave