From patchwork Sat Mar 4 23:54:34 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 735358 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3vbNGX206zz9s7k for ; Sun, 5 Mar 2017 10:55:32 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3vbNGX10kszDqb0 for ; Sun, 5 Mar 2017 10:55:32 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vbNFT28lrzDqBV for ; Sun, 5 Mar 2017 10:54:37 +1100 (AEDT) Received: by ozlabs.org (Postfix, from userid 1010) id 3vbNFT11jBz9s7t; Sun, 5 Mar 2017 10:54:37 +1100 (AEDT) From: Anton Blanchard To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au Subject: [PATCH] powerpc: Avoid panic during boot due to divide by zero in init_cache_info() Date: Sun, 5 Mar 2017 10:54:34 +1100 Message-Id: <1488671674-20833-1-git-send-email-anton@ozlabs.org> X-Mailer: git-send-email 2.7.4 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Anton Blanchard 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 Acked-by: Benjamin Herrenschmidt --- 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;