Documentation: Document arm64 kpti control

commit de19055564c8f8f9d366f8db3395836da0b2176c upstream.

For a while Arm64 has been capable of force enabling
or disabling the kpti mitigations. Lets make sure the
documentation reflects that.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
[florian: patch the correct file]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1bc12619bedd8d078f25f8c9bd35410fab70d1ad..b2d2f4539a3fe32cd141c6fadf3902e07574345f 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1965,6 +1965,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        kmemcheck=2 (one-shot mode)
                        Default: 2 (one-shot mode)
 
+       kpti=           [ARM64] Control page table isolation of user
+                       and kernel address spaces.
+                       Default: enabled on cores which need mitigation.
+                       0: force disabled
+                       1: force enabled
+
        kstack=N        [X86] Print N words from the kernel stack
                        in oops dumps.