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 #ifndef PT_RETSTACK_H 30 #define PT_RETSTACK_H 31 32 #include <stdint.h> 33 34 35 /* The size of the call/return stack in number of entries. */ 36 enum { 37 pt_retstack_size = 64 38 }; 39 40 /* A stack of return addresses used for return compression. */ 41 struct pt_retstack { 42 /* The stack of return addresses. 43 * 44 * We use one additional entry in order to distinguish a full from 45 * an empty stack. 46 */ 47 uint64_t stack[pt_retstack_size + 1]; 48 49 /* The top of the stack. */ 50 uint8_t top; 51 52 /* The bottom of the stack. */ 53 uint8_t bottom; 54 }; 55 56 /* Initialize (or reset) a call/return stack. */ 57 extern void pt_retstack_init(struct pt_retstack *); 58 59 /* Test a call/return stack for emptiness. 60 * 61 * Returns zero if @retstack contains at least one element. 62 * Returns a positive integer if @retstack is empty. 63 * Returns -pte_invalid if @retstack is NULL. 64 */ 65 extern int pt_retstack_is_empty(const struct pt_retstack *retstack); 66 67 /* Pop and return the topmost IP. 68 * 69 * If @ip is not NULL, provides the topmost return address on success. 70 * If @retstack is not empty, pops the topmost return address on success. 71 * 72 * Returns zero on success. 73 * Returns -pte_invalid if @retstack is NULL. 74 * Returns -pte_noip if @retstack is empty. 75 */ 76 extern int pt_retstack_pop(struct pt_retstack *retstack, uint64_t *ip); 77 78 /* Push a return address onto the stack. 79 * 80 * Pushes @ip onto @retstack. 81 * If @retstack is full, drops the oldest return address. 82 * 83 * Returns zero on success. 84 */ 85 extern int pt_retstack_push(struct pt_retstack *retstack, uint64_t ip); 86 87 #endif /* PT_RETSTACK_H */ 88