linux-kernel - Re: SDIV / UDIV Question

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Message-ID: <20131009105357.GC6564@mudshark.cambridge.arm.com>
Date:	Wed, 9 Oct 2013 11:53:57 +0100
From:	Will Deacon <will.deacon@....com>
To:	"Wang, Yalin" <Yalin.Wang@...ymobile.com>
Cc:	"'linux-arm-msm-owner@...r.kernel.org'" 
	<linux-arm-msm-owner@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: SDIV / UDIV  Question

On Wed, Oct 09, 2013 at 08:08:05AM +0100, Wang, Yalin wrote:
> I have a question about sdiv/ udiv  instructions :
> In  armv7 A/R  TRM, it said sdiv/udiv will cause 
> Divide by zero as undefined exception or just return zero
> (decided by implementation) .
> 
> So  in kernel ,  should we need register a undef hook to 
> Get this undef exception and send SIGFPE to user space
> Process ?  

As far as I can see, this can only happen for R-class cores,
based on SCTLR.DZ.

Will
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