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 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 */ 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 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 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 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 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 113 114 static __inline int CRYPTO_UP_REF(volatile int *val, int *ret, void *lock) 115 { 116 *ret = _InterlockedExchangeAdd(val, 1) + 1; 117 return 1; 118 } 119 120 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