x86: Default to vsyscall=emulate

This essentially reverts:

  2b666859ec32: x86: Default to vsyscall=native for now

The ABI breakage should now be fixed by:

 commit 48c4206f5b02f28c4c78a1f5b491d3772fb64fb9
 Author: Andy Lutomirski <luto@mit.edu>
 Date:   Thu Oct 20 08:48:19 2011 -0700

    x86-64: Set siginfo and context on vsyscall emulation faults

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/93154af3b2b6d208906ae02d80d92cf60c6fa94f.1320712291.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 4 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a0c5c5f4fce6..ce7fc8b3e2c0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2750,11 +2750,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         functions are at fixed addresses, they make nice
                         targets for exploits that can control RIP.
 
-                        emulate     Vsyscalls turn into traps and are emulated
-                                    reasonably safely.
+                        emulate     [default] Vsyscalls turn into traps and are
+                                    emulated reasonably safely.
 
-                        native      [default] Vsyscalls are native syscall
-                                    instructions.
+                        native      Vsyscalls are native syscall instructions.
                                     This is a little bit faster than trapping
                                     and makes a few dynamic recompilers work
                                     better than they would in emulation mode.