unicore32 core architecture: signals handling

This patch implements signals.
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>

arch/unicore32/include/asm/sigcontext.h

+/*
+ * linux/arch/unicore32/include/asm/sigcontext.h
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __UNICORE_SIGCONTEXT_H__
+#define __UNICORE_SIGCONTEXT_H__
+
+#include <asm/ptrace.h>
+/*
+ * Signal context structure - contains all info to do with the state
+ * before the signal handler was invoked.  Note: only add new entries
+ * to the end of the structure.
+ */
+struct sigcontext {
+	unsigned long trap_no;
+	unsigned long error_code;
+	unsigned long oldmask;
+	unsigned long fault_address;
+	struct pt_regs regs;
+};
+
+#endif