v4.19.13 snapshot.
diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h
new file mode 100644
index 0000000..b7b838b
--- /dev/null
+++ b/arch/arm/kernel/signal.h
@@ -0,0 +1,11 @@
+#include <asm/ucontext.h>
+
+struct sigframe {
+	struct ucontext uc;
+	unsigned long retcode[4];
+};
+
+struct rt_sigframe {
+	struct siginfo info;
+	struct sigframe sig;
+};