Re: SDIV / UDIV Question

[Will Deacon]

[Adding Jonny]

On Thu, Oct 10, 2013 at 06:04:41AM +0100, Wang, Yalin wrote:
> Oh ,  I see ,
> Thanks for your clarification !
> So R-class cores will not run linux ?

R-class cores can run Linux, but I don't reckon we touch SCTLR.DZ. I've
added Jonny, so he can clarify the behaviour here. (I'm also not sure which
cores have these instructions either).

Will

> -----Original Message-----
> From: Will Deacon [mailto:will.deacon@xxxxxxx] 
> Sent: Wednesday, October 09, 2013 6:54 PM
> To: Wang, Yalin
> Cc: 'linux-arm-msm-owner@xxxxxxxxxxxxxxx'; linux-kernel@xxxxxxxxxxxxxxx
> 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
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/