/* * Copyright 2016-2018 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 HEADER_INTERNAL_REFCOUNT_H # define HEADER_INTERNAL_REFCOUNT_H /* Used to checking reference counts, most while doing perl5 stuff :-) */ # if defined(OPENSSL_NO_STDIO) # if defined(REF_PRINT) # error "REF_PRINT requires stdio" # endif # endif # ifndef OPENSSL_DEV_NO_ATOMICS # if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \ && !defined(__STDC_NO_ATOMICS__) # include # 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, 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, 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, void *lock) { *ret = __atomic_fetch_add(val, 1, __ATOMIC_RELAXED) + 1; return 1; } static __inline__ int CRYPTO_DOWN_REF(int *val, int *ret, void *lock) { *ret = __atomic_fetch_sub(val, 1, __ATOMIC_RELAXED) - 1; if (*ret == 0) __atomic_thread_fence(__ATOMIC_ACQUIRE); 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 # 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, void *lock) { *ret = _InterlockedExchangeAdd_nf(val, 1) + 1; return 1; } static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret, 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, void *lock) { *ret = _InterlockedExchangeAdd(val, 1) + 1; return 1; } static __inline int CRYPTO_DOWN_REF(volatile int *val, int *ret, 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_ATMOICS 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 # ifdef REF_PRINT # define REF_PRINT_COUNT(a, b) \ fprintf(stderr, "%p:%4d:%s\n", b, b->references, a) # else # define REF_PRINT_COUNT(a, b) # endif #endif