x86/boot: Comment what finalize_identity_maps() does

So it is not really obvious that finalize_identity_maps() doesn't do any
finalization but it *actually* writes CR3 with the ident PGD. Comment
that at the call site.

Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index f82975b0f9d6..f5a138c3fe96 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -437,6 +437,8 @@ unsigned char *choose_random_location(unsigned long input,
 	choice = random_addr;
 
 	add_identity_map(choice, output_size);
+
+	/* This actually loads the identity pagetable on x86_64. */
 	finalize_identity_maps();
 out:
 	return (unsigned char *)choice;