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 34 void pt_retstack_init(struct pt_retstack *retstack) 35 { 36 if (!retstack) 37 return; 38 39 retstack->top = 0; 40 retstack->bottom = 0; 41 } 42 43 int 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 51 int 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 73 int 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