1/*
2 * Copyright (c) 2013-2019, Intel Corporation
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 *  * Redistributions of source code must retain the above copyright notice,
8 *    this list of conditions and the following disclaimer.
9 *  * Redistributions in binary form must reproduce the above copyright notice,
10 *    this list of conditions and the following disclaimer in the documentation
11 *    and/or other materials provided with the distribution.
12 *  * Neither the name of Intel Corporation nor the names of its contributors
13 *    may be used to endorse or promote products derived from this software
14 *    without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "pt_retstack.h"
30
31#include "intel-pt.h"
32
33
34void pt_retstack_init(struct pt_retstack *retstack)
35{
36	if (!retstack)
37		return;
38
39	retstack->top = 0;
40	retstack->bottom = 0;
41}
42
43int pt_retstack_is_empty(const struct pt_retstack *retstack)
44{
45	if (!retstack)
46		return -pte_invalid;
47
48	return (retstack->top == retstack->bottom ? 1 : 0);
49}
50
51int pt_retstack_pop(struct pt_retstack *retstack, uint64_t *ip)
52{
53	uint8_t top;
54
55	if (!retstack)
56		return -pte_invalid;
57
58	top = retstack->top;
59
60	if (top == retstack->bottom)
61		return -pte_retstack_empty;
62
63	top = (!top ? pt_retstack_size : top - 1);
64
65	retstack->top = top;
66
67	if (ip)
68		*ip = retstack->stack[top];
69
70	return 0;
71}
72
73int pt_retstack_push(struct pt_retstack *retstack, uint64_t ip)
74{
75	uint8_t top, bottom;
76
77	if (!retstack)
78		return -pte_invalid;
79
80	top = retstack->top;
81	bottom = retstack->bottom;
82
83	retstack->stack[top] = ip;
84
85	top = (top == pt_retstack_size ? 0 : top + 1);
86
87	if (bottom == top)
88		bottom = (bottom == pt_retstack_size ? 0 : bottom + 1);
89
90	retstack->top = top;
91	retstack->bottom = bottom;
92
93	return 0;
94}
95