x86/cpu: Implement CPU vulnerabilites sysfs functions

commit 61dc0f555b5c761cdafb0ba5bd41ecf22d68a4c4 upstream.

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

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/20180107214913.177414879@linutronix.de
[bwh: Backported to 3.16:
 - Meltdown mitigation feature flag is KAISER
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ea6a3fb6a411154e6c2d6ecac80c2a685c9d3449..f2ae1b1427599721a682b88f1e16aef5a019d722 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -130,6 +130,7 @@ config X86
        select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
        select HAVE_CC_STACKPROTECTOR
        select GENERIC_CPU_AUTOPROBE
+       select GENERIC_CPU_VULNERABILITIES
        select HAVE_ARCH_AUDITSYSCALL
        select ARCH_SUPPORTS_ATOMIC_RMW
 

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index da0780f3f9cbe63a25f33cd19afba8e8cbef1465..d7c5df63593ead7fc95eed3e54d0dbaa6f9d40ff 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -9,6 +9,7 @@
  */
 #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>
@@ -122,3 +123,31 @@ 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 sprintf(buf, "Not affected\n");
+       if (boot_cpu_has(X86_FEATURE_KAISER))
+               return sprintf(buf, "Mitigation: PTI\n");
+       return sprintf(buf, "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 sprintf(buf, "Not affected\n");
+       return sprintf(buf, "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 sprintf(buf, "Not affected\n");
+       return sprintf(buf, "Vulnerable\n");
+}
+#endif