| From 87590ce6e373d1a5401f6539f0c59ef92dd924a9 Mon Sep 17 00:00:00 2001 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Sun, 7 Jan 2018 22:48:00 +0100 |
| Subject: sysfs/cpu: Add vulnerability folder |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit 87590ce6e373d1a5401f6539f0c59ef92dd924a9 upstream. |
| |
| 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 <tglx@linutronix.de> |
| Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Will Deacon <will.deacon@arm.com> |
| Cc: Dave Hansen <dave.hansen@intel.com> |
| Cc: Linus Torvalds <torvalds@linuxfoundation.org> |
| Cc: Borislav Petkov <bp@alien8.de> |
| Cc: David Woodhouse <dwmw@amazon.co.uk> |
| Link: https://lkml.kernel.org/r/20180107214913.096657732@linutronix.de |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| 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 |
| @@ -350,3 +350,19 @@ Contact: Linux ARM Kernel Mailing list < |
| Description: AArch64 CPU registers |
| 'identification' directory exposes the CPU ID 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 |
| + /sys/devices/system/cpu/vulnerabilities/spectre_v2 |
| +Date: Januar 2018 |
| +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| +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 |
| |
| --- a/drivers/base/cpu.c |
| +++ b/drivers/base/cpu.c |
| @@ -499,10 +499,58 @@ 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 |
| @@ -44,6 +44,13 @@ 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, |