/* * Copyright (c) 2017 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef included_clib_lock_h #define included_clib_lock_h #include <vppinfra/clib.h> #if __x86_64__ #define CLIB_PAUSE() __builtin_ia32_pause () #else #define CLIB_PAUSE() #endif #if CLIB_DEBUG > 1 #define CLIB_LOCK_DBG(_p) \ do { \ (*_p)->frame_address = __builtin_frame_address (0); \ (*_p)->pid = getpid (); \ (*_p)->thread_index = os_get_thread_index (); \ } while (0) #define CLIB_LOCK_DBG_CLEAR(_p) \ do { \ (*_p)->frame_address = 0; \ (*_p)->pid = 0; \ (*_p)->thread_index = 0; \ } while (0) #else #define CLIB_LOCK_DBG(_p) #define CLIB_LOCK_DBG_CLEAR(_p) #endif typedef struct { CLIB_CACHE_LINE_ALIGN_MARK (cacheline0); u32 lock; #if CLIB_DEBUG > 0 pid_t pid; uword thread_index; void *frame_address; #endif } *clib_spinlock_t; static inline void clib_spinlock_init (clib_spinlock_t * p) { *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES); clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES); } static inline void clib_spinlock_free (clib_spinlock_t * p) { if (*p) { clib_mem_free ((void *) *p); *p = 0; } } static_always_inline void clib_spinlock_lock (clib_spinlock_t * p) { while (clib_atomic_test_and_set (&(*p)->lock)) CLIB_PAUSE (); CLIB_LOCK_DBG (p); } static_always_inline void clib_spinlock_lock_if_init (clib_spinlock_t * p) { if (PREDICT_FALSE (*p != 0)) clib_spinlock_lock (p); } static_always_inline void clib_spinlock_unlock (clib_spinlock_t * p) { CLIB_LOCK_DBG_CLEAR (p); /* Make sure all writes are complete before releasing the lock */ CLIB_MEMORY_BARRIER (); (*p)->lock = 0; } static_always_inline void clib_spinlock_unlock_if_init (clib_spinlock_t * p) { if (PREDICT_FALSE (*p != 0)) clib_spinlock_unlock (p); } /* * Readers-Writer Lock */ typedef struct clib_rw_lock_ { CLIB_CACHE_LINE_ALIGN_MARK (cacheline0); volatile u32 n_readers; volatile u32 n_readers_lock; volatile u32 writer_lock; #if CLIB_DEBUG > 0 pid_t pid; uword thread_index; void *frame_address; #endif } *clib_rwlock_t; always_inline void clib_rwlock_init (clib_rwlock_t * p) { *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES); clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES); } always_inline void clib_rwlock_free (clib_rwlock_t * p) { if (*p) { clib_mem_free ((void *) *p); *p = 0; } } always_inline void clib_rwlock_reader_lock (clib_rwlock_t * p) { while (clib_atomic_test_and_set (&(*p)->n_readers_lock)) CLIB_PAUSE (); (*p)->n_readers += 1; if ((*p)->n_readers == 1) { while (clib_atomic_test_and_set (&(*p)->writer_lock)) CLIB_PAUSE (); } CLIB_MEMORY_BARRIER (); (*p)->n_readers_lock = 0; CLIB_LOCK_DBG (p); } always_inline void clib_rwlock_reader_unlock (clib_rwlock_t * p) { ASSERT ((*p)->n_readers > 0); CLIB_LOCK_DBG_CLEAR (p); while (clib_atomic_test_and_set (&(*p)->n_readers_lock)) CLIB_PAUSE (); (*p)->n_readers -= 1; if ((*p)->n_readers == 0) { CLIB_MEMORY_BARRIER (); (*p)->writer_lock = 0; } CLIB_MEMORY_BARRIER (); (*p)->n_readers_lock = 0; } always_inline void clib_rwlock_writer_lock (clib_rwlock_t * p) { while (clib_atomic_test_and_set (&(*p)->writer_lock)) CLIB_PAUSE (); CLIB_LOCK_DBG (p); } always_inline void clib_rwlock_writer_unlock (clib_rwlock_t * p) { CLIB_LOCK_DBG_CLEAR (p); CLIB_MEMORY_BARRIER (); (*p)->writer_lock = 0; } #endif /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */