From patchwork Fri Oct 7 14:12:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiaxun Yang X-Patchwork-Id: 13001168 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 B7CF7C433F5 for ; Fri, 7 Oct 2022 14:12:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229513AbiJGOM2 (ORCPT ); Fri, 7 Oct 2022 10:12:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229672AbiJGOM1 (ORCPT ); Fri, 7 Oct 2022 10:12:27 -0400 Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F5AC118761; Fri, 7 Oct 2022 07:12:26 -0700 (PDT) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id D6EA35C0048; Fri, 7 Oct 2022 10:12:24 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Fri, 07 Oct 2022 10:12:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=flygoat.com; h= cc:cc:content-transfer-encoding:date:date:from:from:in-reply-to :message-id:mime-version:reply-to:sender:subject:subject:to:to; s=fm1; t=1665151944; x=1665238344; bh=mk4xjf3gmZg3rzLSnxLhmfT3y ziNUMfMLAV+9Oi1eds=; b=n1BFPXmJcwb4kUmZrtfB+TUTQRvUeyj5uWNA3RYwN YxqF9/PwBvgnp7leC8fp5I6TQhQ15ou/JfH3Wx7+FUT7hm3CCo7eXN+yW9/AFPFa nNSecqBAs7onGwvd1ecC4pTTcVLtpbhVBW4lndNtRKj7AnrUT+9cMANRawpr1FHS 7O+VABmLND+tSNzT00guyhXJ9TDBPL8G6IUsJHL2hEfpG4FYJlupwMwijj8Ip/Rf 5SQYRh2Uktm5Eqqtvfol2EhSNyxB1CKWjHstEXbk0j806bg86NgWY3wNLkAG/4PI zWLc/ANyxQXWgw5MP8pdr8rSkYl5U0k7PcLQOIU65mDqg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding:date:date :feedback-id:feedback-id:from:from:in-reply-to:message-id :mime-version:reply-to:sender:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t= 1665151944; x=1665238344; bh=mk4xjf3gmZg3rzLSnxLhmfT3yziNUMfMLAV +9Oi1eds=; b=ncZgtoLt619jJWNh8598q3GzjEWw+jItyFuYDNESy/79gZwivSp 1WjcWpmhGIAlsDdiWMamqXjREwt+BKOLaFu3aVyE0bs6wyDH8G2zpu5JSNCDu2yh OkCee7RcuounucErps2dXd2cQw7rqYlzakFs3V+miI2FV4/WSNZXWhxavoU2NFmB dQ9xo4d0TPcijUcJjxup9P6Js34dyZbkTXlzBBB7RYOtXBHi8wzGhyJ4kU7Cpnlc bTAa9lLWJVOe5pYDB9fSngBmYS/fMdA7Fcn1Ba3BeatzhMBxMTd3r5pemyd/1nD0 XcyYE3LTKlCuAGhUSizwNQysIL+U6ntjGzw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvfedrfeeijedgjeegucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhvfevufffkffoggfgsedtkeertd ertddtnecuhfhrohhmpeflihgrgihunhcujggrnhhguceojhhirgiguhhnrdihrghnghes fhhlhihgohgrthdrtghomheqnecuggftrfgrthhtvghrnhephfetuddtudevieeljeejte ffheeujeduhefgffejudfhueelleduffefgfffveeknecuvehluhhsthgvrhfuihiivgep tdenucfrrghrrghmpehmrghilhhfrhhomhepjhhirgiguhhnrdihrghnghesfhhlhihgoh grthdrtghomh X-ME-Proxy: Feedback-ID: ifd894703:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 7 Oct 2022 10:12:22 -0400 (EDT) From: Jiaxun Yang To: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org, tsbogend@alpha.franken.de, linux-api@vger.kernel.org, greg@kroah.com, f.fainelli@gmail.com, Jiaxun Yang Subject: [PATCH v5] MIPS: Expose prid and globalnumber to sysfs Date: Fri, 7 Oct 2022 15:12:07 +0100 Message-Id: <20221007141207.30635-1-jiaxun.yang@flygoat.com> X-Mailer: git-send-email 2.37.0 (Apple Git-136) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Some application would like to know precise model and rev of processor to do errata workaround or optimization. Expose them in sysfs as: /sys/devices/system/cpu/cpuX/regs/identification/prid /sys/devices/system/cpu/cpuX/regs/identification/globalnumber Reusing AArch64 CPU registers directory. Signed-off-by: Jiaxun Yang --- v2: Drop static qualifier for kobj (gregkh) v3: Use kzalloc to allocate struct cpuregs. note: When Greg mentioned about static I was thinking about static qualifier of percpu variable. After reading documents again it turns out kobjs should be allocated at runtime. Arm64's cpuinfo kobj is also on a percpu variable... I guess that was a intentional use? v4: Properly handle err of kobj creation. (gregkh) v5: Drop invalid kfree --- .../ABI/testing/sysfs-devices-system-cpu | 11 +++ arch/mips/kernel/topology.c | 99 +++++++++++++++++++ 2 files changed, 110 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 5bf61881f012..9fdfe2de0f76 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -512,6 +512,17 @@ Description: information about CPUs heterogeneity. cpu_capacity: capacity of cpuX. +What: /sys/devices/system/cpu/cpuX/regs/ + /sys/devices/system/cpu/cpuX/regs/identification/ + /sys/devices/system/cpu/cpuX/regs/identification/prid + /sys/devices/system/cpu/cpuX/regs/identification/globalnumber +Date: October 2022 +Contact: Linux MIPS Kernel Mailing list +Description: MIPS CPU registers + + 'identification' directory exposes the Processor ID and Global Number + registers for identifying model and revision of the CPU. + What: /sys/devices/system/cpu/vulnerabilities /sys/devices/system/cpu/vulnerabilities/meltdown /sys/devices/system/cpu/vulnerabilities/spectre_v1 diff --git a/arch/mips/kernel/topology.c b/arch/mips/kernel/topology.c index 9429d85a4703..80aaaca3cfbc 100644 --- a/arch/mips/kernel/topology.c +++ b/arch/mips/kernel/topology.c @@ -5,6 +5,8 @@ #include #include #include +#include +#include static DEFINE_PER_CPU(struct cpu, cpu_devices); @@ -26,3 +28,100 @@ static int __init topology_init(void) } subsys_initcall(topology_init); + +static struct kobj_type cpuregs_kobj_type = { + .sysfs_ops = &kobj_sysfs_ops, +}; + +struct cpureg { + struct kobject kobj; + struct cpuinfo_mips *info; +}; +static DEFINE_PER_CPU(struct cpureg *, cpuregs); + +#define kobj_to_cpureg(kobj) container_of(kobj, struct cpureg, kobj) +#define CPUREGS_ATTR_RO(_name, _field) \ + static ssize_t _name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + struct cpuinfo_mips *info = kobj_to_cpureg(kobj)->info; \ + \ + return sprintf(buf, "0x%08x\n", info->_field); \ + } \ + static struct kobj_attribute cpuregs_attr_##_name = __ATTR_RO(_name) + +CPUREGS_ATTR_RO(prid, processor_id); +CPUREGS_ATTR_RO(globalnumber, globalnumber); + +static struct attribute *cpuregs_id_attrs[] = { + &cpuregs_attr_prid.attr, + &cpuregs_attr_globalnumber.attr, + NULL +}; + +static const struct attribute_group cpuregs_attr_group = { + .attrs = cpuregs_id_attrs, + .name = "identification" +}; + +static int cpuregs_cpu_online(unsigned int cpu) +{ + int rc; + struct device *dev; + struct cpureg *reg; + + dev = get_cpu_device(cpu); + if (!dev) { + rc = -ENODEV; + goto out; + } + reg = kzalloc(sizeof(struct cpureg), GFP_KERNEL); + if (!reg) { + rc = -ENOMEM; + goto out; + } + rc = kobject_init_and_add(®->kobj, &cpuregs_kobj_type, + &dev->kobj, "regs"); + if (rc) + goto out_kobj; + rc = sysfs_create_group(®->kobj, &cpuregs_attr_group); + if (rc) + goto out_kobj; + + return 0; +out_kobj: + kobject_put(®->kobj); +out: + return rc; +} + +static int cpuregs_cpu_offline(unsigned int cpu) +{ + struct device *dev; + struct cpureg *reg = per_cpu(cpuregs, cpu); + + dev = get_cpu_device(cpu); + if (!dev || !reg) + return -ENODEV; + if (reg->kobj.parent) { + sysfs_remove_group(®->kobj, &cpuregs_attr_group); + kobject_put(®->kobj); + } + + return 0; +} + +static int __init cpuinfo_regs_init(void) +{ + int ret; + + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mips/topology:online", + cpuregs_cpu_online, cpuregs_cpu_offline); + if (ret < 0) { + pr_err("cpuinfo: failed to register hotplug callbacks.\n"); + return ret; + } + return 0; +} + +device_initcall(cpuinfo_regs_init);