From d319bb79afa4039bda6f85661d6bf0c13299ce93 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@mit.edu>
Date: Sun, 5 Jun 2011 13:50:21 -0400
Subject: x86-64: Map the HPET NX

Currently the HPET mapping is a user-accessible syscall
instruction at a fixed address some of the time.

A sufficiently determined hacker might be able to guess when.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/ab41b525a4ca346b1ca1145d16fb8d181861a8aa.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/hpet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'arch/x86/kernel')

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 6781765b3a0..e9f5605e474 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -71,7 +71,7 @@ static inline void hpet_set_mapping(void)
 {
 	hpet_virt_address = ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
 #ifdef CONFIG_X86_64
-	__set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
+	__set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VVAR_NOCACHE);
 #endif
 }
 
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