Documentation: Document arm64 kpti control

BugLink: https://bugs.launchpad.net/bugs/1864261
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 18cd251f77ee9961ff85784aa7157c986b49ec42..d824cfb1a1a57ca0d7d158cf7e8859bfa192562f 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1885,6 +1885,12 @@
                        Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
                        the default is off.
 
+       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
+
        kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
                        Default is 0 (don't ignore, but inject #GP)