From patchwork Mon Oct 5 17:02:10 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 7329621 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 1425D9F302 for ; Mon, 5 Oct 2015 17:09:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1C37C206A0 for ; Mon, 5 Oct 2015 17:09:39 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2ADB7206A4 for ; Mon, 5 Oct 2015 17:09:38 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zj9Dw-0001wT-V8; Mon, 05 Oct 2015 17:06:52 +0000 Received: from eu-smtp-delivery-143.mimecast.com ([207.82.80.143]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zj9Ab-0004lz-I3 for linux-arm-kernel@lists.infradead.org; Mon, 05 Oct 2015 17:03:29 +0000 Received: from cam-owa2.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.140]) by eu-smtp-1.mimecast.com with ESMTP id uk-mta-8-75XNncm2Qdyv1augPblnhA-11; Mon, 05 Oct 2015 18:02:38 +0100 Received: from e106634-lin.cambridge.arm.com ([10.1.2.79]) by cam-owa2.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Mon, 5 Oct 2015 18:02:34 +0100 From: "Suzuki K. Poulose" To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 21/22] arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs Date: Mon, 5 Oct 2015 18:02:10 +0100 Message-Id: <1444064531-25607-22-git-send-email-suzuki.poulose@arm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1444064531-25607-1-git-send-email-suzuki.poulose@arm.com> References: <1444064531-25607-1-git-send-email-suzuki.poulose@arm.com> X-OriginalArrivalTime: 05 Oct 2015 17:02:34.0146 (UTC) FILETIME=[A111F820:01D0FF8F] X-MC-Unique: 75XNncm2Qdyv1augPblnhA-11 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151005_100326_120594_E1C9E30D X-CRM114-Status: GOOD ( 10.28 ) X-Spam-Score: -4.2 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, Vladimir.Murzin@arm.com, steve.capper@linaro.org, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, catalin.marinas@arm.com, "Suzuki K. Poulose" , will.deacon@arm.com, linux-kernel@vger.kernel.org, edward.nevill@linaro.org, aph@redhat.com, james.morse@arm.com, andre.przywara@arm.com, dave.martin@arm.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Steve Capper It can be useful for JIT software to be aware of MIDR_EL1 and REVIDR_EL1 to ascertain the presence of any core errata that could affect codegen. This patch exposes these registers through sysfs: /sys/devices/system/cpu/cpu$ID/identification/midr /sys/devices/system/cpu/cpu$ID/identification/revidr where $ID is the cpu number. For big.LITTLE systems, one can have a mixture of cores (e.g. Cortex A53 and Cortex A57), thus all CPUs need to be enumerated. If the kernel does not have valid information to populate these entries with, an empty string is returned to userspace. Signed-off-by: Steve Capper Signed-off-by: Suzuki K. Poulose --- arch/arm64/include/asm/cpu.h | 1 + arch/arm64/kernel/cpuinfo.c | 48 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h index b5e9cee..bb1b0cf 100644 --- a/arch/arm64/include/asm/cpu.h +++ b/arch/arm64/include/asm/cpu.h @@ -29,6 +29,7 @@ struct cpuinfo_arm64 { u32 reg_cntfrq; u32 reg_dczid; u32 reg_midr; + u32 reg_revidr; u64 reg_id_aa64dfr0; u64 reg_id_aa64dfr1; diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 52331ff..93e0488 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -199,6 +199,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) info->reg_ctr = read_cpuid_cachetype(); info->reg_dczid = read_cpuid(DCZID_EL0); info->reg_midr = read_cpuid_id(); + info->reg_revidr = read_cpuid(REVIDR_EL1); info->reg_id_aa64dfr0 = read_cpuid(ID_AA64DFR0_EL1); info->reg_id_aa64dfr1 = read_cpuid(ID_AA64DFR1_EL1); @@ -247,3 +248,50 @@ void __init cpuinfo_store_boot_cpu(void) boot_cpu_data = *info; init_cpu_features(&boot_cpu_data); } + +#define CPUINFO_ATTR_RO(_name) \ + static ssize_t show_##_name (struct device *dev, \ + struct device_attribute *attr, char *buf) \ + { \ + struct cpuinfo_arm64 *info = &per_cpu(cpu_data, dev->id); \ + \ + if (info->reg_midr) \ + return sprintf(buf, "0x%016x\n", info->reg_##_name); \ + else \ + return 0; \ + } \ + static DEVICE_ATTR(_name, 0444, show_##_name, NULL) + +CPUINFO_ATTR_RO(midr); +CPUINFO_ATTR_RO(revidr); + +static struct attribute *cpuregs_attrs[] = { + &dev_attr_midr.attr, + &dev_attr_revidr.attr, + NULL +}; + +static struct attribute_group cpuregs_attr_group = { + .attrs = cpuregs_attrs, + .name = "identification" +}; + +static int __init cpuinfo_regs_init(void) +{ + int cpu, ret; + + for_each_present_cpu(cpu) { + struct device *dev = get_cpu_device(cpu); + + if (!dev) + return -1; + + ret = sysfs_create_group(&dev->kobj, &cpuregs_attr_group); + if (ret) + return ret; + } + + return 0; +} + +device_initcall(cpuinfo_regs_init);