Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753552AbbHVJYf (ORCPT ); Sat, 22 Aug 2015 05:24:35 -0400 Received: from mail-wi0-f180.google.com ([209.85.212.180]:35502 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753253AbbHVJYd (ORCPT ); Sat, 22 Aug 2015 05:24:33 -0400 Date: Sat, 22 Aug 2015 11:24:29 +0200 From: Ingo Molnar To: "Jonathan (Zhixiong) Zhang" Cc: Will Deacon , Thomas Gleixner , "H . Peter Anvin" , "linux-kernel @ vger . kernel . org" , "linux-efi @ vger . kernel . org" , Matt Fleming , Borislav Petkov , Ard Biesheuvel , Catalin Marinas , Matt Fleming Subject: Re: [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory Message-ID: <20150822092429.GB18233@gmail.com> References: <1439591850-29002-1-git-send-email-zjzhang@codeaurora.org> <1439591850-29002-2-git-send-email-zjzhang@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1439591850-29002-2-git-send-email-zjzhang@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 33 * Jonathan (Zhixiong) Zhang wrote: > From: "Jonathan (Zhixiong) Zhang" > > With ACPI APEI firmware first handling, generic hardware error > record is updated by firmware in GHES memory region. On an arm64 > platform, firmware updates GHES memory region with uncached > access attribute, and then Linux reads stale data from cache. This paragraph *still* doesn't parse for me. It's not any English I can recognize: what is a 'With ACPI APEI firmware first handling'? > With current code, GHES memory region is mapped with PAGE_KERNEL > based on the assumption that cache coherency of GHES memory region > is maintained by firmware on all platforms. This assumption is > not true for above mentioned arm64 platform. > > Instead GHES memory region should be mapped with page protection type > according to what is returned from arch_apei_get_mem_attribute(). ... plus what this changelog still doesn't mention is the most important part of any bug fix description: how does the user notice this in practice and why does he care? Thanks, Ingo -- 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/