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/*
* Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef OSSL_INTERNAL_REFCOUNT_H
# define OSSL_INTERNAL_REFCOUNT_H
# pragma once
# include <openssl/e_os2.h>
# include <openssl/trace.h>
# ifndef OPENSSL_DEV_NO_ATOMICS
# if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
&& !defined(__STDC_NO_ATOMICS__)
# include <stdatomic.h>
# define HAVE_C11_ATOMICS
# endif
# if defined(HAVE_C11_ATOMICS) && defined(ATOMIC_INT_LOCK_FREE) \
&& ATOMIC_INT_LOCK_FREE > 0
# define HAVE_ATOMICS 1
typedef _Atomic int CRYPTO_REF_COUNT;
static inline int CRYPTO_UP_REF(_Atomic int *val, int *ret,
ossl_unused void *lock)
{
*ret = atomic_fetch_add_explicit(val, 1, memory_order_relaxed) + 1;
return 1;
}
/*
* Changes to shared structure other than reference counter have to be
* serialized. And any kind of serialization implies a release fence. This
* means that by the time reference counter is decremented all other
* changes are visible on all processors. Hence decrement itself can be
* relaxed. In case it hits zero, object will be destructed. Since it's
* last use of the object, destructor programmer might reason that access
* to mutable members doesn't have to be serialized anymore, which would
* otherwise imply an acquire fence. Hence conditional acquire fence...
*/
static inline int CRYPTO_DOWN_REF(_Atomic int *val, int *ret,
ossl_unused void *lock)
{
*ret = atomic_fetch_sub_explicit(val, 1, memory_order_relaxed) - 1;
if (*ret == 0)
atomic_thread_fence(memory_order_acquire);
return 1;
}
# elif defined(__GNUC__) && defined(__ATOMIC_RELAXED) && __GCC_ATOMIC_INT_LOCK_FREE > 0
# define HAVE_ATOMICS 1
typedef int CRYPTO_REF_COUNT;
static __inline__ int CRYPTO_UP_REF(int *val, int *ret, ossl_unused void *lock)
{
*ret = __atomic_fetch_add(val, 1, __ATOMIC_RELAXED) + 1;
return 1;
}
static __inline__ int CRYPTO_DOWN_REF(int *val, int *ret,
ossl_unused void *lock)
{
*ret = __atomic_fetch_sub(val, 1, __ATOMIC_RELAXED) - 1;
if (*ret == 0)
__atomic_thread_fence(__ATOMIC_ACQUIRE);
return 1;
}
# elif defined(__ICL) && defined(_WIN32)
# define HAVE_ATOMICS 1
typedef volatile int CRYPTO_REF_COUNT;
static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
ossl_unused void *lock)
{
*ret = _InterlockedExchangeAdd((void *)val, 1) + 1;
return 1;
}
static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
ossl_unused void *lock)
{
*ret = _InterlockedExchangeAdd((void *)val, -1) - 1;
return 1;
}
# elif defined(_MSC_VER) && _MSC_VER>=1200
# define HAVE_ATOMICS 1
typedef volatile int CRYPTO_REF_COUNT;
# if (defined(_M_ARM) && _M_ARM>=7 && !defined(_WIN32_WCE)) || defined(_M_ARM64)
# include <intrin.h>
# if defined(_M_ARM64) && !defined(_ARM_BARRIER_ISH)
# define _ARM_BARRIER_ISH _ARM64_BARRIER_ISH
# endif
static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
ossl_unused void *lock)
{
*ret = _InterlockedExchangeAdd_nf(val, 1) + 1;
return 1;
}
static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
ossl_unused void *lock)
{
*ret = _InterlockedExchangeAdd_nf(val, -1) - 1;
if (*ret == 0)
__dmb(_ARM_BARRIER_ISH);
return 1;
}
# else
# if !defined(_WIN32_WCE)
# pragma intrinsic(_InterlockedExchangeAdd)
# else
# if _WIN32_WCE >= 0x600
extern long __cdecl _InterlockedExchangeAdd(long volatile*, long);
# else
/* under Windows CE we still have old-style Interlocked* functions */
extern long __cdecl InterlockedExchangeAdd(long volatile*, long);
# define _InterlockedExchangeAdd InterlockedExchangeAdd
# endif
# endif
static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
ossl_unused void *lock)
{
*ret = _InterlockedExchangeAdd(val, 1) + 1;
return 1;
}
static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
ossl_unused void *lock)
{
*ret = _InterlockedExchangeAdd(val, -1) - 1;
return 1;
}
# endif
# endif
# endif /* !OPENSSL_DEV_NO_ATOMICS */
/*
* All the refcounting implementations above define HAVE_ATOMICS, so if it's
* still undefined here (such as when OPENSSL_DEV_NO_ATOMICS is defined), it
* means we need to implement a fallback. This fallback uses locks.
*/
# ifndef HAVE_ATOMICS
typedef int CRYPTO_REF_COUNT;
# define CRYPTO_UP_REF(val, ret, lock) CRYPTO_atomic_add(val, 1, ret, lock)
# define CRYPTO_DOWN_REF(val, ret, lock) CRYPTO_atomic_add(val, -1, ret, lock)
# endif
# if !defined(NDEBUG) && !defined(OPENSSL_NO_STDIO)
# define REF_ASSERT_ISNT(test) \
(void)((test) ? (OPENSSL_die("refcount error", __FILE__, __LINE__), 1) : 0)
# else
# define REF_ASSERT_ISNT(i)
# endif
# define REF_PRINT_EX(text, count, object) \
OSSL_TRACE3(REF_COUNT, "%p:%4d:%s\n", (object), (count), (text));
# define REF_PRINT_COUNT(text, object) \
REF_PRINT_EX(text, object->references, (void *)object)
#endif
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