1 /*
2 * Copyright 2016-2019 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (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
12 /* Used to checking reference counts, most while doing perl5 stuff :-) */
13 # if defined(OPENSSL_NO_STDIO)
14 # if defined(REF_PRINT)
15 # error "REF_PRINT requires stdio"
16 # endif
17 # endif
18
19 # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
20 && !defined(__STDC_NO_ATOMICS__)
21 # include <stdatomic.h>
22 # define HAVE_C11_ATOMICS
23 # endif
24
25 # if defined(HAVE_C11_ATOMICS) && defined(ATOMIC_INT_LOCK_FREE) \
26 && ATOMIC_INT_LOCK_FREE > 0
27
28 # define HAVE_ATOMICS 1
29
30 typedef _Atomic int CRYPTO_REF_COUNT;
31
CRYPTO_UP_REF(_Atomic int *val, int *ret, void *lock)32 static inline int CRYPTO_UP_REF(_Atomic int *val, int *ret, void *lock)
33 {
34 *ret = atomic_fetch_add_explicit(val, 1, memory_order_relaxed) + 1;
35 return 1;
36 }
37
38 /*
39 * Changes to shared structure other than reference counter have to be
40 * serialized. And any kind of serialization implies a release fence. This
41 * means that by the time reference counter is decremented all other
42 * changes are visible on all processors. Hence decrement itself can be
43 * relaxed. In case it hits zero, object will be destructed. Since it's
44 * last use of the object, destructor programmer might reason that access
45 * to mutable members doesn't have to be serialized anymore, which would
46 * otherwise imply an acquire fence. Hence conditional acquire fence...
47 */
CRYPTO_DOWN_REF(_Atomic int *val, int *ret, void *lock)48 static inline int CRYPTO_DOWN_REF(_Atomic int *val, int *ret, 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, void *lock)62 static __inline__ int CRYPTO_UP_REF(int *val, int *ret, 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, void *lock)68 static __inline__ int CRYPTO_DOWN_REF(int *val, int *ret, void *lock)
69 {
70 *ret = __atomic_fetch_sub(val, 1, __ATOMIC_RELAXED) - 1;
71 if (*ret == 0)
72 __atomic_thread_fence(__ATOMIC_ACQUIRE);
73 return 1;
74 }
75
76 # elif defined(_MSC_VER) && _MSC_VER>=1200
77
78 # define HAVE_ATOMICS 1
79
80 typedef volatile int CRYPTO_REF_COUNT;
81
82 # if (defined(_M_ARM) && _M_ARM>=7 && !defined(_WIN32_WCE)) || defined(_M_ARM64)
83 # include <intrin.h>
84 # if defined(_M_ARM64) && !defined(_ARM_BARRIER_ISH)
85 # define _ARM_BARRIER_ISH _ARM64_BARRIER_ISH
86 # endif
87
CRYPTO_UP_REF(volatile int *val, int *ret, void *lock)88 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret, void *lock)
89 {
90 *ret = _InterlockedExchangeAdd_nf(val, 1) + 1;
91 return 1;
92 }
93
CRYPTO_DOWN_REF(volatile int *val, int *ret, void *lock)94 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret, void *lock)
95 {
96 *ret = _InterlockedExchangeAdd_nf(val, -1) - 1;
97 if (*ret == 0)
98 __dmb(_ARM_BARRIER_ISH);
99 return 1;
100 }
101 # else
102 # if !defined(_WIN32_WCE)
103 # pragma intrinsic(_InterlockedExchangeAdd)
104 # else
105 # if _WIN32_WCE >= 0x600
106 extern long __cdecl _InterlockedExchangeAdd(long volatile*, long);
107 # else
108 /* under Windows CE we still have old-style Interlocked* functions */
109 extern long __cdecl InterlockedExchangeAdd(long volatile*, long);
110 # define _InterlockedExchangeAdd InterlockedExchangeAdd
111 # endif
112 # endif
113
CRYPTO_UP_REF(volatile int *val, int *ret, void *lock)114 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret, void *lock)
115 {
116 *ret = _InterlockedExchangeAdd(val, 1) + 1;
117 return 1;
118 }
119
CRYPTO_DOWN_REF(volatile int *val, int *ret, void *lock)120 static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret, void *lock)
121 {
122 *ret = _InterlockedExchangeAdd(val, -1) - 1;
123 return 1;
124 }
125 # endif
126
127 # else
128
129 typedef int CRYPTO_REF_COUNT;
130
131 # define CRYPTO_UP_REF(val, ret, lock) CRYPTO_atomic_add(val, 1, ret, lock)
132 # define CRYPTO_DOWN_REF(val, ret, lock) CRYPTO_atomic_add(val, -1, ret, lock)
133
134 # endif
135
136 # if !defined(NDEBUG) && !defined(OPENSSL_NO_STDIO)
137 # define REF_ASSERT_ISNT(test) \
138 (void)((test) ? (OPENSSL_die("refcount error", __FILE__, __LINE__), 1) : 0)
139 # else
140 # define REF_ASSERT_ISNT(i)
141 # endif
142
143 # ifdef REF_PRINT
144 # define REF_PRINT_COUNT(a, b) \
145 fprintf(stderr, "%p:%4d:%s\n", b, b->references, a)
146 # else
147 # define REF_PRINT_COUNT(a, b)
148 # endif
149
150 #endif
151