x86, kaslr: boot-time selectable with hibernation

Changes kASLR from being compile-time selectable (blocked by
CONFIG_HIBERNATION), to being boot-time selectable (with hibernation
available by default) via the "kaslr" kernel command line.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f8f0466b8b1d..884904975d0b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1474,6 +1474,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         js=             [HW,JOY] Analog joystick
                         See Documentation/input/joystick.txt.
 
+        kaslr/nokaslr   [X86]
+                        Enable/disable kernel and module base offset ASLR
+                        (Address Space Layout Randomization) if built into
+                        the kernel. When CONFIG_HIBERNATION is selected,
+                        kASLR is disabled by default. When kASLR is enabled,
+                        hibernation will be disabled.
+
         keepinitrd      [HW,ARM]
 
         kernelcore=nn[KMG]      [KNL,X86,IA-64,PPC] This parameter
@@ -2110,10 +2117,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         noapic          [SMP,APIC] Tells the kernel to not make use of any
                         IOAPICs that may be present in the system.
 
-        nokaslr         [X86]
-                        Disable kernel and module base offset ASLR (Address
-                        Space Layout Randomization) if built into the kernel.
-
         noautogroup     Disable scheduler automatic task group creation.
 
         nobats          [PPC] Do not use BATs for mapping kernel lowmem