xtensa: add trap_set_handler function

/*

 * arch/xtensa/include/asm/traps.h

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 2012 Tensilica Inc.

 */

#ifndef _XTENSA_TRAPS_H

#define _XTENSA_TRAPS_H

#include <asm/ptrace.h>

/*

 * handler must be either of the following:

 *  void (*)(struct pt_regs *regs);

 *  void (*)(struct pt_regs *regs, unsigned long exccause);

 */

extern void * __init trap_set_handler(int cause, void *handler);

extern void do_unhandled(struct pt_regs *regs, unsigned long exccause);

#endif /* _XTENSA_TRAPS_H */

}

/* Set exception C handler - for temporary use when probing exceptions */

void * __init trap_set_handler(int cause, void *handler)

{

	unsigned long *entry = &exc_table[EXC_TABLE_DEFAULT / 4 + cause];

	void *previous = (void *)*entry;

	*entry = (unsigned long)handler;

	return previous;

}

/*

 * Initialize dispatch tables.

 *