Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754756AbeAGVtl (ORCPT + 1 other); Sun, 7 Jan 2018 16:49:41 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:47889 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754693AbeAGVtj (ORCPT ); Sun, 7 Jan 2018 16:49:39 -0500 Message-Id: <20180107214913.096657732@linutronix.de> User-Agent: quilt/0.63-1 Date: Sun, 07 Jan 2018 22:48:00 +0100 From: Thomas Gleixner To: LKML Cc: Linus Torvalds , Greg Kroah-Hartman , Ingo Molnar , Peter Zijlstra , Borislav Petkov , David Woodhouse , Dave Hansen , Will Deacon Subject: [patch V2 1/2] sysfs/cpu: Add vulnerability folder References: <20180107214759.387300853@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=sysfs-cpu--Add-vulnerability-folder.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: As the meltdown/spectre problem affects several CPU architectures, it makes sense to have common way to express whether a system is affected by a particular vulnerability or not. If affected the way to express the mitigation should be common as well. Create /sys/devices/system/cpu/vulnerabilities folder and files for meltdown, spectre_v1 and spectre_v2. Allow architectures to override the show function. Signed-off-by: Thomas Gleixner --- Documentation/ABI/testing/sysfs-devices-system-cpu | 16 +++++++ drivers/base/Kconfig | 3 + drivers/base/cpu.c | 48 +++++++++++++++++++++ include/linux/cpu.h | 7 +++ 4 files changed, 74 insertions(+) --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -373,3 +373,19 @@ Contact: Linux kernel mailing list +Description: Information about CPU vulnerabilities + + The files are named after the code names of CPU + vulnerabilities. The output of those files reflects the + state of the CPUs in the system. Possible output values: + + "Not affected" CPU is not affected by the vulnerability + "Vulnerable" CPU is affected and no mitigation in effect + "Mitigation: $M" CPU is affetcted and mitigation $M is in effect --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -235,6 +235,9 @@ config GENERIC_CPU_DEVICES config GENERIC_CPU_AUTOPROBE bool +config GENERIC_CPU_VULNERABILITIES + bool + config SOC_BUS bool select GLOB --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -501,10 +501,58 @@ static void __init cpu_dev_register_gene #endif } +#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES + +ssize_t __weak cpu_show_meltdown(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "Not affected\n"); +} + +ssize_t __weak cpu_show_spectre_v1(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "Not affected\n"); +} + +ssize_t __weak cpu_show_spectre_v2(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "Not affected\n"); +} + +static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL); +static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL); +static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL); + +static struct attribute *cpu_root_vulnerabilities_attrs[] = { + &dev_attr_meltdown.attr, + &dev_attr_spectre_v1.attr, + &dev_attr_spectre_v2.attr, + NULL +}; + +static const struct attribute_group cpu_root_vulnerabilities_group = { + .name = "vulnerabilities", + .attrs = cpu_root_vulnerabilities_attrs, +}; + +static void __init cpu_register_vulnerabilities(void) +{ + if (sysfs_create_group(&cpu_subsys.dev_root->kobj, + &cpu_root_vulnerabilities_group)) + pr_err("Unable to register CPU vulnerabilities\n"); +} + +#else +static inline void cpu_register_vulnerabilities(void) { } +#endif + void __init cpu_dev_init(void) { if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups)) panic("Failed to register CPU subsystem"); cpu_dev_register_generic(); + cpu_register_vulnerabilities(); } --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -47,6 +47,13 @@ extern void cpu_remove_dev_attr(struct d extern int cpu_add_dev_attr_group(struct attribute_group *attrs); extern void cpu_remove_dev_attr_group(struct attribute_group *attrs); +extern ssize_t cpu_show_meltdown(struct device *dev, + struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_spectre_v1(struct device *dev, + struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_spectre_v2(struct device *dev, + struct device_attribute *attr, char *buf); + extern __printf(4, 5) struct device *cpu_device_create(struct device *parent, void *drvdata, const struct attribute_group **groups,