src/vppinfra/lock.h

   1 /*
   2  * Copyright (c) 2017 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #ifndef included_clib_lock_h
  17 #define included_clib_lock_h
  18
  19 #include <vppinfra/clib.h>
  20
  21 #if __x86_64__
  22 #define CLIB_PAUSE() __builtin_ia32_pause ()
  23 #else
  24 #define CLIB_PAUSE()
  25 #endif
  26
  27 #if CLIB_DEBUG > 1
  28 #define CLIB_LOCK_DBG(_p)                               \
  29 do {                                                    \
  30     (*_p)->frame_address = __builtin_frame_address (0); \
  31     (*_p)->pid = getpid ();                             \
  32     (*_p)->thread_index = os_get_thread_index ();       \
  33 } while (0)
  34 #define CLIB_LOCK_DBG_CLEAR(_p)                         \
  35 do {                                                    \
  36     (*_p)->frame_address = 0;                           \
  37     (*_p)->pid = 0;                                     \
  38     (*_p)->thread_index = 0;                            \
  39 } while (0)
  40 #else
  41 #define CLIB_LOCK_DBG(_p)
  42 #define CLIB_LOCK_DBG_CLEAR(_p)
  43 #endif
  44
  45 typedef struct
  46 {
  47   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  48   u32 lock;
  49 #if CLIB_DEBUG > 0
  50   pid_t pid;
  51   uword thread_index;
  52   void *frame_address;
  53 #endif
  54 } *clib_spinlock_t;
  55
  56 static inline void
  57 clib_spinlock_init (clib_spinlock_t * p)
  58 {
  59   *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
  60   clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
  61 }
  62
  63 static inline void
  64 clib_spinlock_free (clib_spinlock_t * p)
  65 {
  66   if (*p)
  67     {
  68       clib_mem_free ((void *) *p);
  69       *p = 0;
  70     }
  71 }
  72
  73 static_always_inline void
  74 clib_spinlock_lock (clib_spinlock_t * p)
  75 {
  76   while (clib_atomic_test_and_set (&(*p)->lock))
  77     CLIB_PAUSE ();
  78   CLIB_LOCK_DBG (p);
  79 }
  80
  81 static_always_inline void
  82 clib_spinlock_lock_if_init (clib_spinlock_t * p)
  83 {
  84   if (PREDICT_FALSE (*p != 0))
  85     clib_spinlock_lock (p);
  86 }
  87
  88 static_always_inline void
  89 clib_spinlock_unlock (clib_spinlock_t * p)
  90 {
  91   CLIB_LOCK_DBG_CLEAR (p);
  92   /* Make sure all reads/writes are complete before releasing the lock */
  93   clib_atomic_release (&(*p)->lock);
  94 }
  95
  96 static_always_inline void
  97 clib_spinlock_unlock_if_init (clib_spinlock_t * p)
  98 {
  99   if (PREDICT_FALSE (*p != 0))
 100     clib_spinlock_unlock (p);
 101 }
 102
 103 /*
 104  * Readers-Writer Lock
 105  */
 106
 107 typedef struct clib_rw_lock_
 108 {
 109   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
 110   volatile u32 n_readers;
 111   volatile u32 n_readers_lock;
 112   volatile u32 writer_lock;
 113 #if CLIB_DEBUG > 0
 114   pid_t pid;
 115   uword thread_index;
 116   void *frame_address;
 117 #endif
 118 } *clib_rwlock_t;
 119
 120 always_inline void
 121 clib_rwlock_init (clib_rwlock_t * p)
 122 {
 123   *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
 124   clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
 125 }
 126
 127 always_inline void
 128 clib_rwlock_free (clib_rwlock_t * p)
 129 {
 130   if (*p)
 131     {
 132       clib_mem_free ((void *) *p);
 133       *p = 0;
 134     }
 135 }
 136
 137 always_inline void
 138 clib_rwlock_reader_lock (clib_rwlock_t * p)
 139 {
 140   while (clib_atomic_test_and_set (&(*p)->n_readers_lock))
 141     CLIB_PAUSE ();
 142
 143   (*p)->n_readers += 1;
 144   if ((*p)->n_readers == 1)
 145     {
 146       while (clib_atomic_test_and_set (&(*p)->writer_lock))
 147         CLIB_PAUSE ();
 148     }
 149   clib_atomic_release (&(*p)->n_readers_lock);
 150   CLIB_LOCK_DBG (p);
 151 }
 152
 153 always_inline void
 154 clib_rwlock_reader_unlock (clib_rwlock_t * p)
 155 {
 156   ASSERT ((*p)->n_readers > 0);
 157   CLIB_LOCK_DBG_CLEAR (p);
 158
 159   while (clib_atomic_test_and_set (&(*p)->n_readers_lock))
 160     CLIB_PAUSE ();
 161
 162   (*p)->n_readers -= 1;
 163   if ((*p)->n_readers == 0)
 164     {
 165       clib_atomic_release (&(*p)->writer_lock);
 166     }
 167   clib_atomic_release (&(*p)->n_readers_lock);
 168 }
 169
 170 always_inline void
 171 clib_rwlock_writer_lock (clib_rwlock_t * p)
 172 {
 173   while (clib_atomic_test_and_set (&(*p)->writer_lock))
 174     CLIB_PAUSE ();
 175   CLIB_LOCK_DBG (p);
 176 }
 177
 178 always_inline void
 179 clib_rwlock_writer_unlock (clib_rwlock_t * p)
 180 {
 181   CLIB_LOCK_DBG_CLEAR (p);
 182   clib_atomic_release (&(*p)->writer_lock);
 183 }
 184
 185 #endif
 186
 187 /*
 188  * fd.io coding-style-patch-verification: ON
 189  *
 190  * Local Variables:
 191  * eval: (c-set-style "gnu")
 192  * End:
 193  */