[patch 2/2] x86/cpu: Implement CPU vulnerabilites sysfs functions

From: Thomas Gleixner
Date: Sun Jan 07 2018 - 16:08:10 EST


Implement the CPU vulnerabilty show functions for meltdown, spectre_v1 and
spectre_v2.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/cpu/bugs.c | 29 +++++++++++++++++++++++++++++
2 files changed, 30 insertions(+)

--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -89,6 +89,7 @@ config X86
select GENERIC_CLOCKEVENTS_MIN_ADJUST
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
+ select GENERIC_CPU_VULNERABILITIES
select GENERIC_EARLY_IOREMAP
select GENERIC_FIND_FIRST_BIT
select GENERIC_IOMAP
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -10,6 +10,7 @@
*/
#include <linux/init.h>
#include <linux/utsname.h>
+#include <linux/cpu.h>
#include <asm/bugs.h>
#include <asm/processor.h>
#include <asm/processor-flags.h>
@@ -60,3 +61,31 @@ void __init check_bugs(void)
set_memory_4k((unsigned long)__va(0), 1);
#endif
}
+
+#ifdef CONFIG_SYSFS
+ssize_t cpu_show_meltdown(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
+ return snprintf(buf, PAGE_SIZE - 2, "Not affected\n");
+ if (boot_cpu_has(X86_FEATURE_PTI))
+ return snprintf(buf, PAGE_SIZE - 2, "Mitigation: PTI\n");
+ return snprintf(buf, PAGE_SIZE - 2, "Vulnerable\n");
+}
+
+ssize_t cpu_show_spectre_v1(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1))
+ return snprintf(buf, PAGE_SIZE - 2, "Not affected\n");
+ return snprintf(buf, PAGE_SIZE - 2, "Vulnerable\n");
+}
+
+ssize_t cpu_show_spectre_v2(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
+ return snprintf(buf, PAGE_SIZE - 2, "Not affected\n");
+ return snprintf(buf, PAGE_SIZE - 2, "Vulnerable\n");
+}
+#endif