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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 070DFC001DB for ; Fri, 11 Aug 2023 10:25:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234836AbjHKKZ4 (ORCPT ); Fri, 11 Aug 2023 06:25:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234209AbjHKKZx (ORCPT ); Fri, 11 Aug 2023 06:25:53 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 76D78CE for ; Fri, 11 Aug 2023 03:25:52 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9B37ED75; Fri, 11 Aug 2023 03:26:34 -0700 (PDT) Received: from [10.163.54.13] (unknown [10.163.54.13]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 70A453F6C4; Fri, 11 Aug 2023 03:25:46 -0700 (PDT) Message-ID: <7920ce3b-15ee-c8d8-a7c0-59009620073c@arm.com> Date: Fri, 11 Aug 2023 15:55:43 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH V4 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device() Content-Language: en-US To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, suzuki.poulose@arm.com, yangyicong@huawei.com, Sami Mujawar , Catalin Marinas , Mark Rutland , Mike Leach , Leo Yan , Alexander Shishkin , James Clark , coresight@lists.linaro.org, linux-kernel@vger.kernel.org References: <20230808082247.383405-1-anshuman.khandual@arm.com> <20230808082247.383405-2-anshuman.khandual@arm.com> <9d22520a-3450-0e75-59a2-035209f239e6@arm.com> <20230811101201.GA6827@willie-the-truck> From: Anshuman Khandual In-Reply-To: <20230811101201.GA6827@willie-the-truck> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/11/23 15:42, Will Deacon wrote: > On Fri, Aug 11, 2023 at 02:13:42PM +0530, Anshuman Khandual wrote: >> On 8/8/23 13:52, Anshuman Khandual wrote: >>> + /* >>> + * Sanity check all the GICC tables for the same interrupt >>> + * number. For now, only support homogeneous ACPI machines. >>> + */ >>> + for_each_possible_cpu(cpu) { >>> + struct acpi_madt_generic_interrupt *gicc; >>> + >>> + gicc = acpi_cpu_get_madt_gicc(cpu); >>> + if (gicc->header.length < len) >>> + return gsi ? -ENXIO : 0; >>> + >>> + this_gsi = parse_gsi(gicc); >>> + if (!this_gsi) >>> + return gsi ? -ENXIO : 0; >>> + >>> + this_hetid = find_acpi_cpu_topology_hetero_id(cpu); >>> + if (!gsi) { >>> + hetid = this_hetid; >>> + gsi = this_gsi; >>> + } else if (hetid != this_hetid || gsi != this_gsi) { >>> + pr_warn("ACPI: %s: must be homogeneous\n", pdev->name); >>> + return -ENXIO; >>> + } >>> + } >> >> As discussed on the previous version i.e V3 thread, will move the >> 'this_gsi' check after parse_gsi(), inside if (!gsi) conditional >> block. This will treat subsequent cpu parse_gsi()'s failure as a >> mismatch thus triggering the pr_warn() message. >> >> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c >> index 845683ca7c64..6eae772d6298 100644 >> --- a/drivers/perf/arm_pmu_acpi.c >> +++ b/drivers/perf/arm_pmu_acpi.c >> @@ -98,11 +98,11 @@ arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len, >> return gsi ? -ENXIO : 0; >> >> this_gsi = parse_gsi(gicc); >> - if (!this_gsi) >> - return gsi ? -ENXIO : 0; >> - >> this_hetid = find_acpi_cpu_topology_hetero_id(cpu); >> if (!gsi) { >> + if (!this_gsi) >> + return 0; > > Why do you need this hunk? Otherwise '0' gsi on all cpus would just clear the above homogeneity test, and end up in acpi_register_gsi() making it fail, but with the following warning before returning with -ENXIO. irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH); if (irq < 0) { pr_warn("ACPI: %s Unable to register interrupt: %d\n", pdev->name, gsi); return -ENXIO; } Is this behaviour better than returning 0 after detecting '0' gsi in the first cpu to avoid the above mentioned scenario ? Although 0 gsi followed by non-zero ones will still end up warning about a mismatch.