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To: Anton Blanchard <anton@ozlabs.org>, benh@kernel.crashing.org,
 paulus@samba.org
From: Michael Ellerman <patch-notifications@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: powerpc: Avoid panic during boot due to divide by zero in
 init_cache_info()
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Date: Wed,  8 Mar 2017 18:25:58 +1100 (AEDT)
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On Sat, 2017-03-04 at 23:54:34 UTC, Anton Blanchard wrote:
> From: Anton Blanchard <anton@samba.org>
> 
> I see a panic in early boot when building with a recent gcc toolchain.
> The issue is a divide by zero, which is undefined. Older toolchains
> let us get away with it:
> 
> int foo(int a) { return a / 0; }
> 
> foo:
> 	li 9,0
> 	divw 3,3,9
> 	extsw 3,3
> 	blr
> 
> But newer ones catch it:
> 
> foo:
> 	trap
> 
> Add a check to avoid the divide by zero.
> 
> Fixes: bd067f83b084 ("powerpc/64: Fix naming of cache block vs. cache line")
> Signed-off-by: Anton Blanchard <anton@samba.org>
> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/6ba422c75facb1b1e0e206c464ee12

cheers