um: start switching the references to host mcontext_t to its userland type

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/arch/um/sys-x86/shared/sysdep/sigcontext_64.h b/arch/um/sys-x86/shared/sysdep/sigcontext_64.h
index 60d89a2..5c4a6a3 100644
--- a/arch/um/sys-x86/shared/sysdep/sigcontext_64.h
+++ b/arch/um/sys-x86/shared/sysdep/sigcontext_64.h
@@ -22,4 +22,11 @@
 		(fi).trap_no = SC_TRAPNO(sc); \
 	}
 
+#define GET_FAULTINFO_FROM_MC(fi, mc) \
+	{ \
+		(fi).cr2 = (mc)->gregs[REG_CR2]; \
+		(fi).error_code = (mc)->gregs[REG_ERR]; \
+		(fi).trap_no = (mc)->gregs[REG_TRAPNO]; \
+	}
+
 #endif