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/*
* 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 <sys/cdefs.h>
/**
* @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 ifunc resolvers.
*
* Starting with API level 30, ifunc resolvers on arm64 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. Prior to API level 30, no arguments are passed to ifunc
* resolvers. Code that wishes to be compatible with prior API levels should not accept any
* arguments in the resolver.
*/
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, indicates that 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.
*/
#define _IFUNC_ARG_HWCAP (1ULL << 62)
#endif
__END_DECLS