| Peter Collingbourne | e949195 | 2019-10-28 10:57:26 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2019 The Android Open Source Project |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * * Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * * Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in |
| 12 | * the documentation and/or other materials provided with the |
| 13 | * distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 16 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 17 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| 18 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| 19 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| 21 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| 22 | * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| 23 | * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| 24 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| 25 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 26 | * SUCH DAMAGE. |
| 27 | */ |
| 28 | |
| 29 | #pragma once |
| 30 | |
| 31 | #include <sys/cdefs.h> |
| 32 | |
| 33 | /** |
| 34 | * @file sys/ifunc.h |
| 35 | * @brief Declarations used for ifunc resolvers. Currently only meaningful for arm64. |
| 36 | */ |
| 37 | |
| 38 | __BEGIN_DECLS |
| 39 | |
| 40 | #if defined(__aarch64__) |
| 41 | |
| 42 | /** |
| 43 | * Provides information about hardware capabilities to ifunc resolvers. |
| 44 | * |
| 45 | * Starting with API level 30, ifunc resolvers on arm64 are passed two arguments. The first is a |
| 46 | * uint64_t whose value is equal to getauxval(AT_HWCAP) | _IFUNC_ARG_HWCAP. The second is a pointer |
| 47 | * to a data structure of this type. Prior to API level 30, no arguments are passed to ifunc |
| 48 | * resolvers. Code that wishes to be compatible with prior API levels should not accept any |
| 49 | * arguments in the resolver. |
| 50 | */ |
| 51 | typedef struct __ifunc_arg_t { |
| 52 | /** Set to sizeof(__ifunc_arg_t). */ |
| 53 | unsigned long _size; |
| 54 | |
| 55 | /** Set to getauxval(AT_HWCAP). */ |
| 56 | unsigned long _hwcap; |
| 57 | |
| 58 | /** Set to getauxval(AT_HWCAP2). */ |
| 59 | unsigned long _hwcap2; |
| 60 | } __ifunc_arg_t; |
| 61 | |
| 62 | /** |
| 63 | * If this bit is set in the first argument to an ifunc resolver, indicates that the second argument |
| 64 | * is a pointer to a data structure of type __ifunc_arg_t. This bit is always set on Android |
| 65 | * starting with API level 30. |
| 66 | */ |
| 67 | #define _IFUNC_ARG_HWCAP (1ULL << 62) |
| 68 | |
| 69 | #endif |
| 70 | |
| 71 | __END_DECLS |