+#ifdef CONFIG_XEN
+ if (boot_cpu_has(X86_FEATURE_SEP)) {
+ struct callback_register sysenter = {
+ .type = CALLBACKTYPE_sysenter,
+ .address = { __KERNEL_CS, (unsigned long)sysenter_entry },
+ };
+
+ if (HYPERVISOR_callback_op(CALLBACKOP_register, &sysenter) < 0)
+ clear_bit(X86_FEATURE_SEP, boot_cpu_data.x86_capability);
+ }
+#endif
+
+ if (boot_cpu_has(X86_FEATURE_SEP)) {