powerpc: Avoid panic during boot due to divide by zero in init_cache_info()

[Michael Ellerman]

On Sat, 2017-03-04 at 23:54:34 UTC, Anton Blanchard wrote:
> From: Anton Blanchard <anton at 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 at samba.org>
> Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>

Applied to powerpc fixes, thanks.

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

cheers