From: Jeremy Linton <jeremy.linton@arm.com>
Date: Fri, 25 Jan 2019 18:07:00 +0000 (-0600)
Subject: Documentation: Document arm64 kpti control
X-Git-Tag: v4.9.212~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8973a61e77444907ff2ea7feb53f9f5edcdc7296;p=thirdparty%2Fkernel%2Fstable.git

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 1bc12619bedd8..b2d2f4539a3fe 100644
--- 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.