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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 03923C0015E for ; Wed, 9 Aug 2023 12:55:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=knetP2M5y2J3QAUycY4bwjbvP27JHcdl0PWi5tDSVR4=; b=mY5ADs+zk/cesR ZRKXkOvn2dEuq3Jmf17zB1nlsc5rJlf0IJSUXYorTHcQhsZkX+bjysMLipHzL5zHaLhhmmb0HgY/T 84usmmZ5+Ctd/w+eBI2oSrEpBjReLnXYr1E6WXYbMYVGSqO+8/rgktfjsEBow2xFNZsCOhBijt4+H qqTv+GFyvdDk+c3HTx+FM0Bmp375jIoUi7fx1MEZnEi+4BLa9YA8V5GR7h2/9sufuEV9TH9Nwi3Yw 2FRLVoMf+TFyuVWj7luHlF7eg6ImnyVbutQDkYVBBX8fTIyVlsttWVu/4wtJhITnKWyLdca4PICJw 3JF1dBbmsKUKpI0afX7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qTiiT-004wFS-2F; Wed, 09 Aug 2023 12:55:09 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qTiiQ-004wCJ-16 for linux-arm-kernel@lists.infradead.org; Wed, 09 Aug 2023 12:55:08 +0000 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 4E3DBD75; Wed, 9 Aug 2023 05:55:41 -0700 (PDT) Received: from [10.57.90.239] (unknown [10.57.90.239]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 123383F6C4; Wed, 9 Aug 2023 05:54:56 -0700 (PDT) Message-ID: Date: Wed, 9 Aug 2023 13:54:55 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH V4 1/4] arm_pmu: acpi: Refactor arm_spe_acpi_register_device() To: Will Deacon Cc: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, 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> <8bef9c5a-eede-f78f-4418-da10c99a5bef@arm.com> <20230808131634.GA2369@willie-the-truck> From: Suzuki K Poulose In-Reply-To: <20230808131634.GA2369@willie-the-truck> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230809_055506_477657_D868D40C X-CRM114-Status: GOOD ( 28.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 08/08/2023 14:16, Will Deacon wrote: > On Tue, Aug 08, 2023 at 09:48:16AM +0100, Suzuki K Poulose wrote: >> On 08/08/2023 09:22, Anshuman Khandual wrote: >>> Sanity checking all the GICC tables for same interrupt number, and ensuring >>> a homogeneous ACPI based machine, could be used for other platform devices >>> as well. Hence this refactors arm_spe_acpi_register_device() into a common >>> helper arm_acpi_register_pmu_device(). >>> >>> Cc: Catalin Marinas >>> Cc: Will Deacon >>> Cc: Mark Rutland >>> Cc: linux-arm-kernel@lists.infradead.org >>> Cc: linux-kernel@vger.kernel.org >>> Co-developed-by: Will Deacon >>> Signed-off-by: Will Deacon >>> Signed-off-by: Anshuman Khandual >>> --- >>> drivers/perf/arm_pmu_acpi.c | 105 ++++++++++++++++++++++-------------- >>> 1 file changed, 65 insertions(+), 40 deletions(-) >>> >>> diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c >>> index 90815ad762eb..72454bef2a70 100644 >>> --- a/drivers/perf/arm_pmu_acpi.c >>> +++ b/drivers/perf/arm_pmu_acpi.c >>> @@ -69,6 +69,63 @@ static void arm_pmu_acpi_unregister_irq(int cpu) >>> acpi_unregister_gsi(gsi); >>> } >>> +static int __maybe_unused >>> +arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len, >>> + u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *)) >>> +{ >>> + int cpu, this_hetid, hetid, irq, ret; >>> + u16 this_gsi, gsi = 0; >>> + >>> + /* >>> + * Ensure that platform device must have IORESOURCE_IRQ >>> + * resource to hold gsi interrupt. >>> + */ >>> + if (pdev->num_resources != 1) >>> + return -ENXIO; >>> + >>> + if (pdev->resource[0].flags != IORESOURCE_IRQ) >>> + return -ENXIO; >>> + >>> + /* >>> + * 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; >>> + } >>> + } >>> + >>> + 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; >>> + } >>> + >>> + pdev->resource[0].start = irq; >>> + ret = platform_device_register(pdev); >>> + if (ret < 0) { >>> + pr_warn("ACPI: %s: Unable to register device\n", pdev->name); >>> + acpi_unregister_gsi(gsi); >>> + } >>> + return ret; >> >> A postivie return value here could confuse the caller. Also, with my comment >> below, we don't really need to return something from here. > > How does this return a positive value? Right now, there aren't. My point is this function returns a "return value" of another function. And the caller of this function doesn't really follow the "check" it needs. e.g.: ret = foo(); if (ret < 0) error; return ret; And the caller only checks for if (ret) error; This seems fragile. > >>> + int ret = arm_acpi_register_pmu_device(&spe_dev, ACPI_MADT_GICC_SPE, >>> + arm_spe_parse_gsi); >>> + if (ret) >>> pr_warn("ACPI: SPE: Unable to register device\n"); >> >> With this change, a system without SPE interrupt description always >> generates the above message. Is this intended ? > > If there are no irqs, why doesn't this return 0? Apologies, I missed that. > arm_acpi_register_pmu_device() should only fail if either: > > - The static resources passed in are broken > - The tables are not homogeneous > - We fail to register the interrupt > > so something is amiss. Agreed. We don't need duplicate messages about an error ? i.e., one in arm_acpi_register_pmu_device() and another one in the caller ? (Of course adding any missing error msgs). > >> Could we not drop the above message as all the other possible error >> scenarios are reported. We could simply make the above helper void, see my >> comment above. > > I disagree. If the ACPI tables are borked, we should print a message saying > so. Ok, fair point. Suzuki > > Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel