From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 720A0C433E1 for ; Fri, 21 Aug 2020 12:15:22 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4044420724 for ; Fri, 21 Aug 2020 12:15:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="y12YLDjY"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ox5cTwPb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4044420724 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Message-ID:Subject:To:From: Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References:List-Owner; bh=FO4z2b25rIQqtFny+stXkzupGj7mcs/EbkAF09NdwAE=; b=y12YLDjYW/rsuZeyqG/4/tcbY OE6q4ISh2UyzWABRdqPHtYHkcTqL3uwVdovXmtQwzaR0u4dHQOgN3Mn1tCdW3S3/M+z0ZNwrc01b0 /Q+teN85zqQkOmEbjVFdLf5dACyfdwult64VrLK5PFVIZe6u+oehZCXl4Js7ydeQ9PP4KHX9pFJt1 KdWEi3LGbSpYRMH6V/P4NPaO6Z+Dj1Q2K2piSG6fBRebmPGORdJoKWTcOPXWqGLBOc/2mamYzuBeK i9CFRFJSvWBjoL+Po64hcIc9xfGSoxWF0Cmot1mcl3JhxtSpsUmxXlH6CRc1yLBm/G5yd/ud2tHmU /tNtc/fYg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k95vm-0005cX-4a; Fri, 21 Aug 2020 12:14:02 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k95vj-0005bg-Bu for linux-arm-kernel@lists.infradead.org; Fri, 21 Aug 2020 12:14:00 +0000 Received: from localhost (104.sub-72-107-126.myvzw.com [72.107.126.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B1E0D2078D; Fri, 21 Aug 2020 12:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598012038; bh=uVOgG9JFL4Fi6p0po8bQ65Th7wRBuNvR5zhzLTPFR5k=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=ox5cTwPbjAUMDQ3PBaEQj29JiEe+7IH6AXVS6NxjULgL51ySfWOkFhBpDTJzVedaY /UuJysTOHbBMdbgEM7N7gU5gumkTHskOHzhwVjf+hvwlVhTurv/GZKKfyOQ8zI5AmJ zAPVwHcdFODduuOfyQXQDv1dwLqxCHq47/KNa/tk= Date: Fri, 21 Aug 2020 07:13:56 -0500 From: Bjorn Helgaas To: Jonathan Cameron Subject: Re: [PATCH v9 4/6] ACPI: HMAT: Fix handling of changes from ACPI 6.2 to ACPI 6.3 Message-ID: <20200821121356.GA1616281@bjorn-Precision-5520> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200821094258.00007925@Huawei.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200821_081359_545942_ED0F7D44 X-CRM114-Status: GOOD ( 26.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: rafael@kernel.org, Lorenzo Pieralisi , linux-acpi@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com, Keith Busch , linux-mm@kvack.org, Ingo Molnar , Brice Goglin , Bjorn Helgaas , Thomas Gleixner , Dan Williams , linux-arm-kernel@lists.infradead.org, Sean V Kelley Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org [+cc Keith, author of 3accf7ae37a9 ("acpi/hmat: Parse and report heterogeneous memory")] On Fri, Aug 21, 2020 at 09:42:58AM +0100, Jonathan Cameron wrote: > On Thu, 20 Aug 2020 17:21:29 -0500 > Bjorn Helgaas wrote: > > > On Wed, Aug 19, 2020 at 10:51:09PM +0800, Jonathan Cameron wrote: > > > In ACPI 6.3, the Memory Proximity Domain Attributes Structure > > > changed substantially. One of those changes was that the flag > > > for "Memory Proximity Domain field is valid" was deprecated. > > > > > > This was because the field "Proximity Domain for the Memory" > > > became a required field and hence having a validity flag makes > > > no sense. > > > > > > So the correct logic is to always assume the field is there. > > > Current code assumes it never is. > > > > > > Signed-off-by: Jonathan Cameron > > > --- > > > drivers/acpi/numa/hmat.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c > > > index 2c32cfb72370..07cfe50136e0 100644 > > > --- a/drivers/acpi/numa/hmat.c > > > +++ b/drivers/acpi/numa/hmat.c > > > @@ -424,7 +424,7 @@ static int __init hmat_parse_proximity_domain(union acpi_subtable_headers *heade > > > pr_info("HMAT: Memory Flags:%04x Processor Domain:%u Memory Domain:%u\n", > > > p->flags, p->processor_PD, p->memory_PD); > > > > > > - if (p->flags & ACPI_HMAT_MEMORY_PD_VALID && hmat_revision == 1) { > > > + if ((p->flags & ACPI_HMAT_MEMORY_PD_VALID && hmat_revision == 1) || hmat_revision == 2) { > > > > I hope/assume the spec is written in such a way that p->memory_PD is > > required for any revision > 1? So maybe this should be: > > > > if ((p->flags & ACPI_HMAT_MEMORY_PD_VALID && hmat_revision == 1) || > > hmat_revision > 1) { I should have said simply: if (hmat_revision == 1 && p->flags & ACPI_HMAT_MEMORY_PD_VALID) We shouldn't even test p->flags for ACPI_HMAT_MEMORY_PD_VALID unless we already know it's revision 1. And unless there was a revision 0 of HMAT, there's no need to look for hmat_revison > 1. > Good point. We have existing protections elsewhere against > hmat_revision being anything other than 1 or 2, so we should aim to > keep that in only one place. I think the "Ignoring HMAT: Unknown revision" test in hmat_init(), added by 3accf7ae37a9 ("acpi/hmat: Parse and report heterogeneous memory"), is a mistake. And I think hmat_normalize() has a similar mistake in that it tests explicitly for hmat_revision == 2 when it should accept 2 AND anything later. We should assume that future spec revisions will be backwards compatible. Otherwise we're forced to make kernel changes when we otherwise would not have to. Bjorn _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel