x86/KASLR, x86/power: Remove x86 hibernation restrictions

With the following fix:

  70595b479ce1 ("x86/power/64: Fix crash whan the hibernation code passes control to the image kernel")

... there is no longer a problem with hibernation resuming a
KASLR-booted kernel image, so remove the restriction.

Signed-off-by: Kees Cook <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Linux PM list <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephen Smalley <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: kees

Documentation/kernel-parameters.txt

@@ -1803,12 +1803,10 @@ 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.
+	nokaslr		[KNL]
+			When CONFIG_RANDOMIZE_BASE is set, this disables
+			kernel and module base offset ASLR (Address Space
+			Layout Randomization).
 
 	keepinitrd	[HW,ARM]
 

arch/x86/boot/compressed/kaslr.c

@@ -471,17 +471,10 @@ unsigned char *choose_random_location(unsigned long input,
 	unsigned long choice = output;
 	unsigned long random_addr;
 
-#ifdef CONFIG_HIBERNATION
-	if (!cmdline_find_option_bool("kaslr")) {
-		warn("KASLR disabled: 'kaslr' not on cmdline (hibernation selected).");
-		goto out;
-	}
-#else
 	if (cmdline_find_option_bool("nokaslr")) {
 		warn("KASLR disabled: 'nokaslr' on cmdline.");
 		goto out;
 	}
-#endif
 
 	boot_params->hdr.loadflags |= KASLR_FLAG;
 

kernel/power/hibernate.c

@@ -1154,11 +1154,6 @@ static int __init nohibernate_setup(char *str)
 	return 1;
 }
 
-static int __init kaslr_nohibernate_setup(char *str)
-{
-	return nohibernate_setup(str);
-}
-
 static int __init page_poison_nohibernate_setup(char *str)
 {
 #ifdef CONFIG_PAGE_POISONING_ZERO
@@ -1182,5 +1177,4 @@ __setup("hibernate=", hibernate_setup);
 __setup("resumewait", resumewait_setup);
 __setup("resumedelay=", resumedelay_setup);
 __setup("nohibernate", nohibernate_setup);
-__setup("kaslr", kaslr_nohibernate_setup);
 __setup("page_poison=", page_poison_nohibernate_setup);