[PATCH v2 1/7] sysfs/cpu: Add "Unknown" vulnerability state

From: Jeremy Linton
Date: Wed Jan 02 2019 - 19:49:33 EST

There is a lot of variation in the Arm ecosystem. Because of this,
there exist possible cases where the kernel cannot authoritatively
determine if a machine is vulnerable.

Rather than guess the vulnerability status in cases where
the mitigation is disabled or the firmware isn't responding
correctly, we need to display an "Unknown" state.

Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: David Woodhouse <dwmw@xxxxxxxxxxxx>
Documentation/ABI/testing/sysfs-devices-system-cpu | 1 +
1 file changed, 1 insertion(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 9605dbd4b5b5..876103fddfa4 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -495,6 +495,7 @@ Description: Information about CPU vulnerabilities
"Not affected" CPU is not affected by the vulnerability
"Vulnerable" CPU is affected and no mitigation in effect
"Mitigation: $M" CPU is affected and mitigation $M is in effect
+ "Unknown" The kernel is unable to make a determination

Details about the l1tf file can be found in