csky: Debug and Ptrace GDB

This patch adds arch ptrace implementation, stack dump and bug.h.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

arch/csky/include/asm/bug.h

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_BUG_H
+#define __ASM_CSKY_BUG_H
+
+#include <linux/compiler.h>
+#include <linux/const.h>
+#include <linux/types.h>
+
+#define BUG()				\
+do {					\
+	asm volatile ("bkpt\n");	\
+	unreachable();			\
+} while (0)
+
+#define HAVE_ARCH_BUG
+
+#include <asm-generic/bug.h>
+
+struct pt_regs;
+
+void die_if_kernel(char *str, struct pt_regs *regs, int nr);
+void show_regs(struct pt_regs *regs);
+
+#endif /* __ASM_CSKY_BUG_H */