On Sun, 2017-03-05 at 10:54 +1100, Anton Blanchard wrote:
> From: Anton Blanchard <an...@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:
Maybe we should panic though ... not having a valid cache block size is
going to be fatal in other areas...
> 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 <an...@samba.org>
> ---
> arch/powerpc/kernel/setup_64.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kernel/setup_64.c
> b/arch/powerpc/kernel/setup_64.c
> index adf2084..afd1c26 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -408,7 +408,8 @@ static void init_cache_info(struct ppc_cache_info
> *info, u32 size, u32 lsize,
> info->line_size = lsize;
> info->block_size = bsize;
> info->log_block_size = __ilog2(bsize);
> - info->blocks_per_page = PAGE_SIZE / bsize;
> + if (bsize)
> + info->blocks_per_page = PAGE_SIZE / bsize;
>
> if (sets == 0)
> info->assoc = 0xffff;
