2 * Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
9 #ifndef OSSL_INTERNAL_REFCOUNT_H
10 # define OSSL_INTERNAL_REFCOUNT_H
13 # include <openssl/e_os2.h>
14 # include <openssl/trace.h>
16 # if defined(OPENSSL_THREADS) && !defined(OPENSSL_DEV_NO_ATOMICS)
17 # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
18 && !defined(__STDC_NO_ATOMICS__)
19 # include <stdatomic.h>
20 # define HAVE_C11_ATOMICS
23 # if defined(HAVE_C11_ATOMICS) && defined(ATOMIC_INT_LOCK_FREE) \
24 && ATOMIC_INT_LOCK_FREE > 0
26 # define HAVE_ATOMICS 1
28 typedef _Atomic int CRYPTO_REF_COUNT;
30 static inline int CRYPTO_UP_REF(_Atomic int *val, int *ret,
31 ossl_unused void *lock)
33 *ret = atomic_fetch_add_explicit(val, 1, memory_order_relaxed) + 1;
38 * Changes to shared structure other than reference counter have to be
39 * serialized. And any kind of serialization implies a release fence. This
40 * means that by the time reference counter is decremented all other
41 * changes are visible on all processors. Hence decrement itself can be
42 * relaxed. In case it hits zero, object will be destructed. Since it's
43 * last use of the object, destructor programmer might reason that access
44 * to mutable members doesn't have to be serialized anymore, which would
45 * otherwise imply an acquire fence. Hence conditional acquire fence...
47 static inline int CRYPTO_DOWN_REF(_Atomic int *val, int *ret,
48 ossl_unused void *lock)
50 *ret = atomic_fetch_sub_explicit(val, 1, memory_order_relaxed) - 1;
52 atomic_thread_fence(memory_order_acquire);
56 static inline int CRYPTO_GET_REF(_Atomic int *val, int *ret,
57 ossl_unused void *lock)
59 *ret = atomic_load_explicit(val, memory_order_relaxed);
63 # elif defined(__GNUC__) && defined(__ATOMIC_RELAXED) && __GCC_ATOMIC_INT_LOCK_FREE > 0
65 # define HAVE_ATOMICS 1
67 typedef int CRYPTO_REF_COUNT;
69 static __inline__ int CRYPTO_UP_REF(int *val, int *ret, ossl_unused void *lock)
71 *ret = __atomic_fetch_add(val, 1, __ATOMIC_RELAXED) + 1;
75 static __inline__ int CRYPTO_DOWN_REF(int *val, int *ret,
76 ossl_unused void *lock)
78 *ret = __atomic_fetch_sub(val, 1, __ATOMIC_RELAXED) - 1;
80 __atomic_thread_fence(__ATOMIC_ACQUIRE);
84 static __inline__ int CRYPTO_GET_REF(int *val, int *ret, ossl_unused void *lock)
86 *ret = __atomic_load_n(val, __ATOMIC_RELAXED);
90 # elif defined(__ICL) && defined(_WIN32)
91 # define HAVE_ATOMICS 1
92 typedef volatile int CRYPTO_REF_COUNT;
94 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
95 ossl_unused void *lock)
97 *ret = _InterlockedExchangeAdd((void *)val, 1) + 1;
101 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
102 ossl_unused void *lock)
104 *ret = _InterlockedExchangeAdd((void *)val, -1) - 1;
108 static __inline int CRYPTO_GET_REF(volatile int *val, int *ret,
109 ossl_unused void *lock)
111 *ret = _InterlockedOr((void *)val, 0);
115 # elif defined(_MSC_VER) && _MSC_VER>=1200
117 # define HAVE_ATOMICS 1
119 typedef volatile int CRYPTO_REF_COUNT;
121 # if (defined(_M_ARM) && _M_ARM>=7 && !defined(_WIN32_WCE)) || defined(_M_ARM64)
123 # if defined(_M_ARM64) && !defined(_ARM_BARRIER_ISH)
124 # define _ARM_BARRIER_ISH _ARM64_BARRIER_ISH
127 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
128 ossl_unused void *lock)
130 *ret = _InterlockedExchangeAdd_nf(val, 1) + 1;
134 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
135 ossl_unused void *lock)
137 *ret = _InterlockedExchangeAdd_nf(val, -1) - 1;
139 __dmb(_ARM_BARRIER_ISH);
143 static __inline int CRYPTO_GET_REF(volatile int *val, int *ret,
144 ossl_unused void *lock)
146 *ret = _InterlockedOr_nf((void *)val, 0);
151 # if !defined(_WIN32_WCE)
152 # pragma intrinsic(_InterlockedExchangeAdd)
154 # if _WIN32_WCE >= 0x600
155 extern long __cdecl _InterlockedExchangeAdd(long volatile*, long);
157 /* under Windows CE we still have old-style Interlocked* functions */
158 extern long __cdecl InterlockedExchangeAdd(long volatile*, long);
159 # define _InterlockedExchangeAdd InterlockedExchangeAdd
163 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
164 ossl_unused void *lock)
166 *ret = _InterlockedExchangeAdd(val, 1) + 1;
170 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
171 ossl_unused void *lock)
173 *ret = _InterlockedExchangeAdd(val, -1) - 1;
177 static __inline int CRYPTO_GET_REF(volatile int *val, int *ret,
178 ossl_unused void *lock)
180 *ret = _InterlockedExchangeAdd(val, 0);
187 # endif /* !OPENSSL_DEV_NO_ATOMICS */
190 * All the refcounting implementations above define HAVE_ATOMICS, so if it's
191 * still undefined here (such as when OPENSSL_DEV_NO_ATOMICS is defined), it
192 * means we need to implement a fallback. This fallback uses locks.
194 # ifndef HAVE_ATOMICS
196 typedef int CRYPTO_REF_COUNT;
198 # define CRYPTO_UP_REF(val, ret, lock) CRYPTO_atomic_add(val, 1, ret, lock)
199 # define CRYPTO_DOWN_REF(val, ret, lock) CRYPTO_atomic_add(val, -1, ret, lock)
203 # if !defined(NDEBUG) && !defined(OPENSSL_NO_STDIO)
204 # define REF_ASSERT_ISNT(test) \
205 (void)((test) ? (OPENSSL_die("refcount error", __FILE__, __LINE__), 1) : 0)
207 # define REF_ASSERT_ISNT(i)
210 # define REF_PRINT_EX(text, count, object) \
211 OSSL_TRACE3(REF_COUNT, "%p:%4d:%s\n", (object), (count), (text));
212 # define REF_PRINT_COUNT(text, object) \
213 REF_PRINT_EX(text, object->references, (void *)object)