From 6608b45ac5ecb56f9e171252229c39580cc85f0f Mon Sep 17 00:00:00 2001 From: Pawan Gupta Date: Wed, 23 Oct 2019 12:19:51 +0200 Subject: x86/speculation/taa: Add sysfs reporting for TSX Async Abort Add the sysfs reporting file for TSX Async Abort. It exposes the vulnerability and the mitigation state similar to the existing files for the other hardware vulnerabilities. Sysfs file path is: /sys/devices/system/cpu/vulnerabilities/tsx_async_abort Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Neelima Krishnan Reviewed-by: Mark Gross Reviewed-by: Tony Luck Reviewed-by: Greg Kroah-Hartman Reviewed-by: Josh Poimboeuf --- include/linux/cpu.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/cpu.h') diff --git a/include/linux/cpu.h b/include/linux/cpu.h index d0633ebdaa9c..f35369f79771 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -59,6 +59,9 @@ extern ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf); extern ssize_t cpu_show_mds(struct device *dev, struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_tsx_async_abort(struct device *dev, + struct device_attribute *attr, + char *buf); extern __printf(4, 5) struct device *cpu_device_create(struct device *parent, void *drvdata, -- cgit v1.2.3 From db4d30fbb71b47e4ecb11c4efa5d8aad4b03dfae Mon Sep 17 00:00:00 2001 From: Vineela Tummalapalli Date: Mon, 4 Nov 2019 12:22:01 +0100 Subject: x86/bugs: Add ITLB_MULTIHIT bug infrastructure Some processors may incur a machine check error possibly resulting in an unrecoverable CPU lockup when an instruction fetch encounters a TLB multi-hit in the instruction TLB. This can occur when the page size is changed along with either the physical address or cache type. The relevant erratum can be found here: https://bugzilla.kernel.org/show_bug.cgi?id=205195 There are other processors affected for which the erratum does not fully disclose the impact. This issue affects both bare-metal x86 page tables and EPT. It can be mitigated by either eliminating the use of large pages or by using careful TLB invalidations when changing the page size in the page tables. Just like Spectre, Meltdown, L1TF and MDS, a new bit has been allocated in MSR_IA32_ARCH_CAPABILITIES (PSCHANGE_MC_NO) and will be set on CPUs which are mitigated against this issue. Signed-off-by: Vineela Tummalapalli Co-developed-by: Pawan Gupta Signed-off-by: Pawan Gupta Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner --- include/linux/cpu.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/cpu.h') diff --git a/include/linux/cpu.h b/include/linux/cpu.h index f35369f79771..2a093434e975 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -62,6 +62,8 @@ extern ssize_t cpu_show_mds(struct device *dev, extern ssize_t cpu_show_tsx_async_abort(struct device *dev, struct device_attribute *attr, char *buf); +extern ssize_t cpu_show_itlb_multihit(struct device *dev, + struct device_attribute *attr, char *buf); extern __printf(4, 5) struct device *cpu_device_create(struct device *parent, void *drvdata, -- cgit v1.2.3 From 731dc9df975a5da21237a18c3384f811a7a41cc6 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Mon, 4 Nov 2019 12:22:02 +0100 Subject: cpu/speculation: Uninline and export CPU mitigations helpers A kernel module may need to check the value of the "mitigations=" kernel command line parameter as part of its setup when the module needs to perform software mitigations for a CPU flaw. Uninline and export the helper functions surrounding the cpu_mitigations enum to allow for their usage from a module. Lastly, privatize the enum and cpu_mitigations variable since the value of cpu_mitigations can be checked with the exported helper functions. Signed-off-by: Tyler Hicks Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner --- include/linux/cpu.h | 25 ++----------------------- 1 file changed, 2 insertions(+), 23 deletions(-) (limited to 'include/linux/cpu.h') diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 2a093434e975..bc6c879bd110 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -218,28 +218,7 @@ static inline int cpuhp_smt_enable(void) { return 0; } static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; } #endif -/* - * These are used for a global "mitigations=" cmdline option for toggling - * optional CPU mitigations. - */ -enum cpu_mitigations { - CPU_MITIGATIONS_OFF, - CPU_MITIGATIONS_AUTO, - CPU_MITIGATIONS_AUTO_NOSMT, -}; - -extern enum cpu_mitigations cpu_mitigations; - -/* mitigations=off */ -static inline bool cpu_mitigations_off(void) -{ - return cpu_mitigations == CPU_MITIGATIONS_OFF; -} - -/* mitigations=auto,nosmt */ -static inline bool cpu_mitigations_auto_nosmt(void) -{ - return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; -} +extern bool cpu_mitigations_off(void); +extern bool cpu_mitigations_auto_nosmt(void); #endif /* _LINUX_CPU_H_ */ -- cgit v1.2.3