x86/vsyscall: Change the default vsyscall mode to xonly

The use case for full emulation over xonly is very esoteric, e.g. magic
instrumentation tools.

Change the default to the safer xonly mode.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/30539f8072d2376b9c9efcc07e6ed0d6bf20e882.1561610354.git.luto@kernel.org
This commit is contained in:
Andy Lutomirski 2019-06-26 21:45:07 -07:00 • committed by Thomas Gleixner
commit 625b7b7f79