1. 根目录:
2. arch
3. xtensa
4. include
5. asm
6. ftrace.h

/*
 * arch/xtensa/include/asm/ftrace.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) 2013 Tensilica Inc.
 */
#ifndef _XTENSA_FTRACE_H
#define _XTENSA_FTRACE_H

#include <asm/processor.h>

#define HAVE_ARCH_CALLER_ADDR
#define CALLER_ADDR0 ({ unsigned long a0, a1; \
		__asm__ __volatile__ ( \
			"mov %0, a0\n" \
			"mov %1, a1\n" \
			: "=r"(a0), "=r"(a1) : : ); \
		MAKE_PC_FROM_RA(a0, a1); })
#ifdef CONFIG_FRAME_POINTER
extern unsigned long return_address(unsigned level);
#define CALLER_ADDR1 return_address(1)
#define CALLER_ADDR2 return_address(2)
#define CALLER_ADDR3 return_address(3)
#else
#define CALLER_ADDR1 (0)
#define CALLER_ADDR2 (0)
#define CALLER_ADDR3 (0)
#endif

#endif /* _XTENSA_FTRACE_H */