Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966475AbcJFIzc (ORCPT ); Thu, 6 Oct 2016 04:55:32 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48863 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966141AbcJFIza (ORCPT ); Thu, 6 Oct 2016 04:55:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Russell King , Robin Murphy , Russell King Subject: [PATCH 4.4 09/93] ARM: 8616/1: dt: Respect property size when parsing CPUs Date: Thu, 6 Oct 2016 10:28:39 +0200 Message-Id: <20161006074731.533656155@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161006074731.150212126@linuxfoundation.org> References: <20161006074731.150212126@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 Content-Length: 2176 Lines: 67 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Robin Murphy commit ba6dea4f7cedb4b1c17e36f4087675d817c2e24b upstream. Whilst MPIDR values themselves are less than 32 bits, it is still perfectly valid for a DT to have #address-cells > 1 in the CPUs node, resulting in the "reg" property having leading zero cell(s). In that situation, the big-endian nature of the data conspires with the current behaviour of only reading the first cell to cause the kernel to think all CPUs have ID 0, and become resoundingly unhappy as a consequence. Take the full property length into account when parsing CPUs so as to be correct under any circumstances. Cc: Russell King Signed-off-by: Robin Murphy Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- arch/arm/kernel/devtree.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -87,6 +87,8 @@ void __init arm_dt_init_cpu_maps(void) return; for_each_child_of_node(cpus, cpu) { + const __be32 *cell; + int prop_bytes; u32 hwid; if (of_node_cmp(cpu->type, "cpu")) @@ -98,7 +100,8 @@ void __init arm_dt_init_cpu_maps(void) * properties is considered invalid to build the * cpu_logical_map. */ - if (of_property_read_u32(cpu, "reg", &hwid)) { + cell = of_get_property(cpu, "reg", &prop_bytes); + if (!cell || prop_bytes < sizeof(*cell)) { pr_debug(" * %s missing reg property\n", cpu->full_name); of_node_put(cpu); @@ -106,10 +109,15 @@ void __init arm_dt_init_cpu_maps(void) } /* - * 8 MSBs must be set to 0 in the DT since the reg property + * Bits n:24 must be set to 0 in the DT since the reg property * defines the MPIDR[23:0]. */ - if (hwid & ~MPIDR_HWID_BITMASK) { + do { + hwid = be32_to_cpu(*cell++); + prop_bytes -= sizeof(*cell); + } while (!hwid && prop_bytes > 0); + + if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) { of_node_put(cpu); return; }