[PATCH 5/5] x86/vsyscall: Change the default vsyscall mode to xonly

[Andy Lutomirski]

The use case for full emulation over xonly is very esoteric.  Let's
change the default to the safer xonly mode.

Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Kernel Hardening <kernel-hardening@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
 arch/x86/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 054033cc4b1b..e56f33e6b045 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2280,7 +2280,7 @@ config COMPAT_VDSO
 choice
 	prompt "vsyscall table for legacy applications"
 	depends on X86_64
-	default LEGACY_VSYSCALL_EMULATE
+	default LEGACY_VSYSCALL_XONLY
 	help
 	  Legacy user code that does not know how to find the vDSO expects
 	  to be able to issue three syscalls by calling fixed addresses in
-- 
2.21.0