This is a note to let you know that I've just added the patch titled
sysfs/cpu: Add vulnerability folder
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: sysfs-cpu-add-vulnerability-folder.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
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 @@ -271,3 +271,19 @@ Description: Parameters for the CPU cach - WriteBack: data is written only to the cache line and the modified cache line is written to main memory only when it is replaced + +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 @@ -223,6 +223,9 @@ 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 @@ -498,10 +498,58 @@ 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 @@ -40,6 +40,13 @@ 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,
Patches currently in stable-queue which might be from tglx@linutronix.de are
queue-4.4/x86-mm-pat-dev-mem-remove-superfluous-error-message.patch queue-4.4/x86-microcode-intel-extend-bdw-late-loading-with-a-revision-check.patch queue-4.4/locking-mutex-allow-next-waiter-lockless-wakeup.patch queue-4.4/x86-vsdo-fix-build-on-paravirt_clock-y-kvm_guest-n.patch queue-4.4/x86-pti-efi-broken-conversion-from-efi-to-kernel-page-table.patch queue-4.4/x86-documentation-add-pti-description.patch queue-4.4/x86-acpi-handle-sci-interrupts-above-legacy-space-gracefully.patch queue-4.4/futex-replace-barrier-in-unqueue_me-with-read_once.patch queue-4.4/sysfs-cpu-add-vulnerability-folder.patch queue-4.4/x86-acpi-reduce-code-duplication-in-mp_override_legacy_irq.patch