1 /*
2 * Copyright 2016-2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9 #ifndef OSSL_INTERNAL_REFCOUNT_H
10 # define OSSL_INTERNAL_REFCOUNT_H
11 # pragma once
12
13 # include <openssl/e_os2.h>
14 # include <openssl/trace.h>
15
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
21 # endif
22
23 # if defined(HAVE_C11_ATOMICS) && defined(ATOMIC_INT_LOCK_FREE) \
24 && ATOMIC_INT_LOCK_FREE > 0
25
26 # define HAVE_ATOMICS 1
27
28 typedef _Atomic int CRYPTO_REF_COUNT;
29
CRYPTO_UP_REF(_Atomic int * val,int * ret,ossl_unused void * lock)30 static inline int CRYPTO_UP_REF(_Atomic int *val, int *ret,
31 ossl_unused void *lock)
32 {
33 *ret = atomic_fetch_add_explicit(val, 1, memory_order_relaxed) + 1;
34 return 1;
35 }
36
37 /*
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...
46 */
CRYPTO_DOWN_REF(_Atomic int * val,int * ret,ossl_unused void * lock)47 static inline int CRYPTO_DOWN_REF(_Atomic int *val, int *ret,
48 ossl_unused void *lock)
49 {
50 *ret = atomic_fetch_sub_explicit(val, 1, memory_order_relaxed) - 1;
51 if (*ret == 0)
52 atomic_thread_fence(memory_order_acquire);
53 return 1;
54 }
55
56 # elif defined(__GNUC__) && defined(__ATOMIC_RELAXED) && __GCC_ATOMIC_INT_LOCK_FREE > 0
57
58 # define HAVE_ATOMICS 1
59
60 typedef int CRYPTO_REF_COUNT;
61
CRYPTO_UP_REF(int * val,int * ret,ossl_unused void * lock)62 static __inline__ int CRYPTO_UP_REF(int *val, int *ret, ossl_unused void *lock)
63 {
64 *ret = __atomic_fetch_add(val, 1, __ATOMIC_RELAXED) + 1;
65 return 1;
66 }
67
CRYPTO_DOWN_REF(int * val,int * ret,ossl_unused void * lock)68 static __inline__ int CRYPTO_DOWN_REF(int *val, int *ret,
69 ossl_unused void *lock)
70 {
71 *ret = __atomic_fetch_sub(val, 1, __ATOMIC_RELAXED) - 1;
72 if (*ret == 0)
73 __atomic_thread_fence(__ATOMIC_ACQUIRE);
74 return 1;
75 }
76 # elif defined(__ICL) && defined(_WIN32)
77 # define HAVE_ATOMICS 1
78 typedef volatile int CRYPTO_REF_COUNT;
79
CRYPTO_UP_REF(volatile int * val,int * ret,ossl_unused void * lock)80 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
81 ossl_unused void *lock)
82 {
83 *ret = _InterlockedExchangeAdd((void *)val, 1) + 1;
84 return 1;
85 }
86
CRYPTO_DOWN_REF(volatile int * val,int * ret,ossl_unused void * lock)87 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
88 ossl_unused void *lock)
89 {
90 *ret = _InterlockedExchangeAdd((void *)val, -1) - 1;
91 return 1;
92 }
93
94 # elif defined(_MSC_VER) && _MSC_VER>=1200
95
96 # define HAVE_ATOMICS 1
97
98 typedef volatile int CRYPTO_REF_COUNT;
99
100 # if (defined(_M_ARM) && _M_ARM>=7 && !defined(_WIN32_WCE)) || defined(_M_ARM64)
101 # include <intrin.h>
102 # if defined(_M_ARM64) && !defined(_ARM_BARRIER_ISH)
103 # define _ARM_BARRIER_ISH _ARM64_BARRIER_ISH
104 # endif
105
CRYPTO_UP_REF(volatile int * val,int * ret,ossl_unused void * lock)106 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
107 ossl_unused void *lock)
108 {
109 *ret = _InterlockedExchangeAdd_nf(val, 1) + 1;
110 return 1;
111 }
112
CRYPTO_DOWN_REF(volatile int * val,int * ret,ossl_unused void * lock)113 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
114 ossl_unused void *lock)
115 {
116 *ret = _InterlockedExchangeAdd_nf(val, -1) - 1;
117 if (*ret == 0)
118 __dmb(_ARM_BARRIER_ISH);
119 return 1;
120 }
121 # else
122 # if !defined(_WIN32_WCE)
123 # pragma intrinsic(_InterlockedExchangeAdd)
124 # else
125 # if _WIN32_WCE >= 0x600
126 extern long __cdecl _InterlockedExchangeAdd(long volatile*, long);
127 # else
128 /* under Windows CE we still have old-style Interlocked* functions */
129 extern long __cdecl InterlockedExchangeAdd(long volatile*, long);
130 # define _InterlockedExchangeAdd InterlockedExchangeAdd
131 # endif
132 # endif
133
CRYPTO_UP_REF(volatile int * val,int * ret,ossl_unused void * lock)134 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret,
135 ossl_unused void *lock)
136 {
137 *ret = _InterlockedExchangeAdd((long volatile *)val, 1) + 1;
138 return 1;
139 }
140
CRYPTO_DOWN_REF(volatile int * val,int * ret,ossl_unused void * lock)141 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret,
142 ossl_unused void *lock)
143 {
144 *ret = _InterlockedExchangeAdd((long volatile *)val, -1) - 1;
145 return 1;
146 }
147 # endif
148
149 # endif
150 # endif /* !OPENSSL_DEV_NO_ATOMICS */
151
152 /*
153 * All the refcounting implementations above define HAVE_ATOMICS, so if it's
154 * still undefined here (such as when OPENSSL_DEV_NO_ATOMICS is defined), it
155 * means we need to implement a fallback. This fallback uses locks.
156 */
157 # ifndef HAVE_ATOMICS
158
159 typedef int CRYPTO_REF_COUNT;
160
161 # define CRYPTO_UP_REF(val, ret, lock) CRYPTO_atomic_add(val, 1, ret, lock)
162 # define CRYPTO_DOWN_REF(val, ret, lock) CRYPTO_atomic_add(val, -1, ret, lock)
163
164 # endif
165
166 # if !defined(NDEBUG) && !defined(OPENSSL_NO_STDIO)
167 # define REF_ASSERT_ISNT(test) \
168 (void)((test) ? (OPENSSL_die("refcount error", __FILE__, __LINE__), 1) : 0)
169 # else
170 # define REF_ASSERT_ISNT(i)
171 # endif
172
173 # define REF_PRINT_EX(text, count, object) \
174 OSSL_TRACE3(REF_COUNT, "%p:%4d:%s\n", (object), (count), (text));
175 # define REF_PRINT_COUNT(text, object) \
176 REF_PRINT_EX(text, object->references, (void *)object)
177
178 #endif
179