x86: Centaur Isaiah processor to use sysenter in 64-bit compatibility mode rather than syscall

Upcoming 64 bit processors from Centaur can use sysenter.

Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Jesse Ahrens <jahrens@centtech.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index f7e78d84fc01..e2af8eee80e3 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -210,8 +210,12 @@ static int use_sysenter __read_mostly = -1;
 /* May not be __init: called during resume */
 void syscall32_cpu_init(void)
 {
-        if (use_sysenter < 0)
-                use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL);
+        if (use_sysenter < 0) {
+                if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+                        use_sysenter = 1;
+                if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR)
+                        use_sysenter = 1;
+        }
 
         /* Load these always in case some future AMD CPU supports
            SYSENTER from compat mode too. */