/* * Copyright (C) 2019 The Android Open Source Project * All rights reserved. * * 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. * * 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. */ #pragma once #include /** * @file sys/ifunc.h * @brief Declarations used for ifunc resolvers. Currently only meaningful for arm64. */ __BEGIN_DECLS #if defined(__aarch64__) /** * Provides information about hardware capabilities to arm64 ifunc resolvers. * * Prior to API level 30, arm64 ifunc resolvers are passed no arguments. * * Starting with API level 30, arm64 ifunc resolvers are passed two arguments. * The first is a uint64_t whose value is equal to getauxval(AT_HWCAP) | _IFUNC_ARG_HWCAP. * The second is a pointer to a data structure of this type. * * Code that wishes to be compatible with API levels before 30 must call getauxval() itself. */ typedef struct __ifunc_arg_t { /** Set to sizeof(__ifunc_arg_t). */ unsigned long _size; /** Set to getauxval(AT_HWCAP). */ unsigned long _hwcap; /** Set to getauxval(AT_HWCAP2). */ unsigned long _hwcap2; } __ifunc_arg_t; /** * If this bit is set in the first argument to an ifunc resolver, the second argument * is a pointer to a data structure of type __ifunc_arg_t. * * This bit is always set on Android starting with API level 30. * This bit is meaningless before API level 30 because ifunc resolvers are not passed any arguments. * This bit has no real use on Android, but is included for glibc source compatibility; * glibc used this bit to distinguish the case where the ifunc resolver received a single argument, * which was an evolutionary stage Android never went through. */ #define _IFUNC_ARG_HWCAP (1ULL << 62) #endif __END_DECLS