/*

 * Copyright (c) 2013-2017, Intel Corporation

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *  * Neither the name of Intel Corporation nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef PT_RETSTACK_H

#define PT_RETSTACK_H

#include <stdint.h>

/* The size of the call/return stack in number of entries. */

enum {

	pt_retstack_size	= 64

};

/* A stack of return addresses used for return compression. */

struct pt_retstack {

	/* The stack of return addresses.

	 *

	 * We use one additional entry in order to distinguish a full from

	 * an empty stack.

	 */

	uint64_t stack[pt_retstack_size + 1];

	/* The top of the stack. */

	uint8_t top;

	/* The bottom of the stack. */

	uint8_t bottom;

};

/* Initialize (or reset) a call/return stack. */

extern void pt_retstack_init(struct pt_retstack *);

/* Test a call/return stack for emptiness.

 *

 * Returns zero if @retstack contains at least one element.

 * Returns a positive integer if @retstack is empty.

 * Returns -pte_invalid if @retstack is NULL.

 */

extern int pt_retstack_is_empty(const struct pt_retstack *retstack);

/* Pop and return the topmost IP.

 *

 * If @ip is not NULL, provides the topmost return address on success.

 * If @retstack is not empty, pops the topmost return address on success.

 *

 * Returns zero on success.

 * Returns -pte_invalid if @retstack is NULL.

 * Returns -pte_noip if @retstack is empty.

 */

extern int pt_retstack_pop(struct pt_retstack *retstack, uint64_t *ip);

/* Push a return address onto the stack.

 *

 * Pushes @ip onto @retstack.

 * If @retstack is full, drops the oldest return address.

 *

 * Returns zero on success.

 */

extern int pt_retstack_push(struct pt_retstack *retstack, uint64_t ip);

#endif /* PT_RETSTACK_H */