From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934136AbcCHAH5 (ORCPT ); Mon, 7 Mar 2016 19:07:57 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:44923 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933972AbcCHAEd (ORCPT ); Mon, 7 Mar 2016 19:04:33 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Govindraj Raja , Paul Burton , James Hogan , Ralf Baechle , James Hartley , linux-mips@linux-mips.org Subject: [PATCH 4.4 62/74] MIPS: scache: Fix scache init with invalid line size. Date: Mon, 7 Mar 2016 16:03:27 -0800 Message-Id: <20160308000317.270430835@linuxfoundation.org> X-Mailer: git-send-email 2.7.2 In-Reply-To: <20160308000315.294406921@linuxfoundation.org> References: <20160308000315.294406921@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Govindraj Raja commit 56fa81fc9a5445938f3aa2e63d15ab63dc938ad6 upstream. In current scache init cache line_size is determined from cpu config register, however if there there no scache then mips_sc_probe_cm3 function populates a invalid line_size of 2. The invalid line_size can cause a NULL pointer deference during r4k_dma_cache_inv as r4k_blast_scache is populated based on line_size. Scache line_size of 2 is invalid option in r4k_blast_scache_setup. This issue was faced during a MIPS I6400 based virtual platform bring up where scache was not available in virtual platform model. Signed-off-by: Govindraj Raja Fixes: 7d53e9c4cd21("MIPS: CM3: Add support for CM3 L2 cache.") Cc: Paul Burton Cc: James Hogan Cc: Ralf Baechle Cc: James Hartley Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12710/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman --- arch/mips/mm/sc-mips.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/arch/mips/mm/sc-mips.c +++ b/arch/mips/mm/sc-mips.c @@ -164,11 +164,13 @@ static int __init mips_sc_probe_cm3(void sets = cfg & CM_GCR_L2_CONFIG_SET_SIZE_MSK; sets >>= CM_GCR_L2_CONFIG_SET_SIZE_SHF; - c->scache.sets = 64 << sets; + if (sets) + c->scache.sets = 64 << sets; line_sz = cfg & CM_GCR_L2_CONFIG_LINE_SIZE_MSK; line_sz >>= CM_GCR_L2_CONFIG_LINE_SIZE_SHF; - c->scache.linesz = 2 << line_sz; + if (line_sz) + c->scache.linesz = 2 << line_sz; assoc = cfg & CM_GCR_L2_CONFIG_ASSOC_MSK; assoc >>= CM_GCR_L2_CONFIG_ASSOC_SHF; @@ -176,9 +178,12 @@ static int __init mips_sc_probe_cm3(void c->scache.waysize = c->scache.sets * c->scache.linesz; c->scache.waybit = __ffs(c->scache.waysize); - c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT; + if (c->scache.linesz) { + c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT; + return 1; + } - return 1; + return 0; } void __weak platform_early_l2_init(void)