Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756187AbbGFXVC (ORCPT ); Mon, 6 Jul 2015 19:21:02 -0400 Received: from mail-wg0-f42.google.com ([74.125.82.42]:35793 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754742AbbGFXUx (ORCPT ); Mon, 6 Jul 2015 19:20:53 -0400 MIME-Version: 1.0 In-Reply-To: <1436224608-27754-1-git-send-email-al.stone@linaro.org> References: <1436224608-27754-1-git-send-email-al.stone@linaro.org> Date: Tue, 7 Jul 2015 01:20:51 +0200 X-Google-Sender-Auth: GEqwlSLpDge-vU7p9sk1mKFODTs Message-ID: Subject: Re: [PATCH v4 0/2] Correct for ACPI 5.1->6.0 spec changes in MADT GICC entries From: "Rafael J. Wysocki" To: Al Stone Cc: ACPI Devel Maling List , "linux-arm-kernel@lists.infradead.org" , "Rafael J. Wysocki" , Len Brown , Catalin Marinas , Will Deacon , Thomas Gleixner , Jason Cooper , Linux Kernel Mailing List , "linaro-acpi@lists.linaro.org" , Lists linaro-kernel , "patches@linaro.org" 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: 1856 Lines: 37 Hi Al, On Tue, Jul 7, 2015 at 1:16 AM, Al Stone wrote: > In the ACPI 5.1 version of the spec, the struct for the GICC subtable > (struct acpi_madt_generic_interrupt) of the MADT is 76 bytes long; in > ACPI 6.0, the struct is 80 bytes long. But, there is only one definition > in ACPICA for this struct -- and that is the 6.0 version. Hence, when > BAD_MADT_ENTRY() compares the struct size to the length in the GICC > subtable, it fails if 5.1 structs are in use, and there are systems in > the wild that have them. > > Note that this was found in linux-next and these patches apply against > that tree and the arm64 kernel tree; 4.1 does not appear to have this > problem since it still has the 5.1 struct definition. > > Though there is precedent in ia64 code for ignoring the changes in size, > this patch set instead verifies correctness. The first patch adds the > BAD_MADT_GICC_ENTRY() macro to check the GICC subtable only, accounting > for the difference in specification versions that are possible. The > second patch replaces BAD_MADT_ENTRY usage with the BAD_MADT_GICC_ENTRY > macro in arm64 code, which is currently the only architecture affected. > The BAD_MADT_ENTRY() will continue to work as is for all other MADT > subtables. > > I have tested these patches on an APM Mustang with version 1.15 firmware, > where the problem was found, and they fix the problem -- i.e., the system > will boot with either Linux 4.1 or linux-next kernels using the same ACPI > 5.1 compatible firmware. ACK for the series, but I guess it's better to let it go via ARM64, right? Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/