malloc/thread-m.h

   1 /* Basic platform-independent macro definitions for mutexes and
   2    thread-specific data.
   3    Copyright (C) 1996,1997,1998,2000,2001,2002 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Wolfram Gloger <wg@malloc.de>, 2001.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 /* $Id$
  23    One out of _LIBC, USE_PTHREADS, USE_THR or USE_SPROC should be
  24    defined, otherwise the token NO_THREADS and dummy implementations
  25    of the macros will be defined.  */
  26
  27 #ifndef _THREAD_M_H
  28 #define _THREAD_M_H
  29
  30 #undef thread_atfork_static
  31
  32 #if defined(_LIBC) /* The GNU C library, a special case of Posix threads */
  33
  34 #include <bits/libc-lock.h>
  35
  36 #ifdef PTHREAD_MUTEX_INITIALIZER
  37
  38 typedef pthread_t thread_id;
  39
  40 /* mutex */
  41 typedef pthread_mutex_t mutex_t;
  42
  43 #define MUTEX_INITIALIZER       PTHREAD_MUTEX_INITIALIZER
  44
  45 /* Even if not linking with libpthread, ensure usability of mutex as
  46    an `in use' flag, see also the NO_THREADS case below.  Assume
  47    pthread_mutex_t is at least one int wide.  */
  48
  49 #define mutex_init(m)           \
  50    (__pthread_mutex_init != NULL \
  51     ? __pthread_mutex_init (m, NULL) : (*(int *)(m) = 0))
  52 #define mutex_lock(m)           \
  53    (__pthread_mutex_lock != NULL \
  54     ? __pthread_mutex_lock (m) : ((*(int *)(m) = 1), 0))
  55 #define mutex_trylock(m)        \
  56    (__pthread_mutex_trylock != NULL \
  57     ? __pthread_mutex_trylock (m) : (*(int *)(m) ? 1 : ((*(int *)(m) = 1), 0)))
  58 #define mutex_unlock(m)         \
  59    (__pthread_mutex_unlock != NULL \
  60     ? __pthread_mutex_unlock (m) : (*(int*)(m) = 0))
  61
  62 #define thread_atfork(prepare, parent, child) \
  63    (__pthread_atfork != NULL ? __pthread_atfork(prepare, parent, child) : 0)
  64
  65 #elif defined(MUTEX_INITIALIZER)
  66 /* Assume hurd, with cthreads */
  67
  68 /* Cthreads `mutex_t' is a pointer to a mutex, and malloc wants just the
  69    mutex itself.  */
  70 #undef mutex_t
  71 #define mutex_t struct mutex
  72
  73 #undef mutex_init
  74 #define mutex_init(m) (__mutex_init(m), 0)
  75
  76 #undef mutex_lock
  77 #define mutex_lock(m) (__mutex_lock(m), 0)
  78
  79 #undef mutex_unlock
  80 #define mutex_unlock(m) (__mutex_unlock(m), 0)
  81
  82 #define mutex_trylock(m) (!__mutex_trylock(m))
  83
  84 #define thread_atfork(prepare, parent, child) do {} while(0)
  85 #define thread_atfork_static(prepare, parent, child) \
  86  text_set_element(_hurd_fork_prepare_hook, prepare); \
  87  text_set_element(_hurd_fork_parent_hook, parent); \
  88  text_set_element(_hurd_fork_child_hook, child);
  89
  90 /* No we're *not* using pthreads.  */
  91 #define __pthread_initialize ((void (*)(void))0)
  92
  93 #else
  94
  95 #define NO_THREADS
  96
  97 #endif /* MUTEX_INITIALIZER && PTHREAD_MUTEX_INITIALIZER */
  98
  99 #ifndef NO_THREADS
 100
 101 /* thread specific data for glibc */
 102
 103 #include <bits/libc-tsd.h>
 104
 105 typedef int tsd_key_t[1];       /* no key data structure, libc magic does it */
 106 __libc_tsd_define (static, MALLOC)      /* declaration/common definition */
 107 #define tsd_key_create(key, destr)      ((void) (key))
 108 #define tsd_setspecific(key, data)      __libc_tsd_set (MALLOC, (data))
 109 #define tsd_getspecific(key, vptr)      ((vptr) = __libc_tsd_get (MALLOC))
 110
 111 #endif
 112
 113 #elif defined(USE_PTHREADS) /* Posix threads */
 114
 115 #include <pthread.h>
 116
 117 typedef pthread_t thread_id;
 118
 119 /* mutex */
 120 #if (defined __i386__ || defined __x86_64__) && defined __GNUC__ && \
 121     !defined USE_NO_SPINLOCKS
 122
 123 #include <time.h>
 124
 125 /* Use fast inline spinlocks.  */
 126 typedef struct {
 127   volatile unsigned int lock;
 128   int pad0_;
 129 } mutex_t;
 130
 131 #define MUTEX_INITIALIZER          { 0 }
 132 #define mutex_init(m)              ((m)->lock = 0)
 133 static inline int mutex_lock(mutex_t *m) {
 134   int cnt = 0, r;
 135   struct timespec tm;
 136
 137   for(;;) {
 138     __asm__ __volatile__
 139       ("xchgl %0, %1"
 140        : "=r"(r), "=m"(m->lock)
 141        : "0"(1), "m"(m->lock)
 142        : "memory");
 143     if(!r)
 144       return 0;
 145     if(cnt < 50) {
 146       sched_yield();
 147       cnt++;
 148     } else {
 149       tm.tv_sec = 0;
 150       tm.tv_nsec = 2000001;
 151       nanosleep(&tm, NULL);
 152       cnt = 0;
 153     }
 154   }
 155 }
 156 static inline int mutex_trylock(mutex_t *m) {
 157   int r;
 158
 159   __asm__ __volatile__
 160     ("xchgl %0, %1"
 161      : "=r"(r), "=m"(m->lock)
 162      : "0"(1), "m"(m->lock)
 163      : "memory");
 164   return r;
 165 }
 166 static inline int mutex_unlock(mutex_t *m) {
 167   m->lock = 0;
 168   __asm __volatile ("" : "=m" (m->lock) : "0" (m->lock));
 169   return 0;
 170 }
 171
 172 #else
 173
 174 /* Normal pthread mutex.  */
 175 typedef pthread_mutex_t mutex_t;
 176
 177 #define MUTEX_INITIALIZER          PTHREAD_MUTEX_INITIALIZER
 178 #define mutex_init(m)              pthread_mutex_init(m, NULL)
 179 #define mutex_lock(m)              pthread_mutex_lock(m)
 180 #define mutex_trylock(m)           pthread_mutex_trylock(m)
 181 #define mutex_unlock(m)            pthread_mutex_unlock(m)
 182
 183 #endif /* (__i386__ || __x86_64__) && __GNUC__ && !USE_NO_SPINLOCKS */
 184
 185 /* thread specific data */
 186 #if defined(__sgi) || defined(USE_TSD_DATA_HACK)
 187
 188 /* Hack for thread-specific data, e.g. on Irix 6.x.  We can't use
 189    pthread_setspecific because that function calls malloc() itself.
 190    The hack only works when pthread_t can be converted to an integral
 191    type. */
 192
 193 typedef void *tsd_key_t[256];
 194 #define tsd_key_create(key, destr) do { \
 195   int i; \
 196   for(i=0; i<256; i++) (*key)[i] = 0; \
 197 } while(0)
 198 #define tsd_setspecific(key, data) \
 199  (key[(unsigned)pthread_self() % 256] = (data))
 200 #define tsd_getspecific(key, vptr) \
 201  (vptr = key[(unsigned)pthread_self() % 256])
 202
 203 #else
 204
 205 typedef pthread_key_t tsd_key_t;
 206
 207 #define tsd_key_create(key, destr) pthread_key_create(key, destr)
 208 #define tsd_setspecific(key, data) pthread_setspecific(key, data)
 209 #define tsd_getspecific(key, vptr) (vptr = pthread_getspecific(key))
 210
 211 #endif
 212
 213 /* at fork */
 214 #define thread_atfork(prepare, parent, child) \
 215                                    pthread_atfork(prepare, parent, child)
 216
 217 #elif USE_THR /* Solaris threads */
 218
 219 #include <thread.h>
 220
 221 typedef thread_t thread_id;
 222
 223 #define MUTEX_INITIALIZER          { 0 }
 224 #define mutex_init(m)              mutex_init(m, USYNC_THREAD, NULL)
 225
 226 /*
 227  * Hack for thread-specific data on Solaris.  We can't use thr_setspecific
 228  * because that function calls malloc() itself.
 229  */
 230 typedef void *tsd_key_t[256];
 231 #define tsd_key_create(key, destr) do { \
 232   int i; \
 233   for(i=0; i<256; i++) (*key)[i] = 0; \
 234 } while(0)
 235 #define tsd_setspecific(key, data) (key[(unsigned)thr_self() % 256] = (data))
 236 #define tsd_getspecific(key, vptr) (vptr = key[(unsigned)thr_self() % 256])
 237
 238 #define thread_atfork(prepare, parent, child) do {} while(0)
 239
 240 #elif USE_SPROC /* SGI sproc() threads */
 241
 242 #include <sys/wait.h>
 243 #include <sys/types.h>
 244 #include <sys/prctl.h>
 245 #include <abi_mutex.h>
 246
 247 typedef int thread_id;
 248
 249 typedef abilock_t mutex_t;
 250
 251 #define MUTEX_INITIALIZER          { 0 }
 252 #define mutex_init(m)              init_lock(m)
 253 #define mutex_lock(m)              (spin_lock(m), 0)
 254 #define mutex_trylock(m)           acquire_lock(m)
 255 #define mutex_unlock(m)            release_lock(m)
 256
 257 typedef int tsd_key_t;
 258 int tsd_key_next;
 259 #define tsd_key_create(key, destr) ((*key) = tsd_key_next++)
 260 #define tsd_setspecific(key, data) (((void **)(&PRDA->usr_prda))[key] = data)
 261 #define tsd_getspecific(key, vptr) (vptr = ((void **)(&PRDA->usr_prda))[key])
 262
 263 #define thread_atfork(prepare, parent, child) do {} while(0)
 264
 265 #else /* no _LIBC or USE_... are defined */
 266
 267 #define NO_THREADS
 268
 269 #endif /* defined(_LIBC) */
 270
 271 #ifdef NO_THREADS /* No threads, provide dummy macros */
 272
 273 typedef int thread_id;
 274
 275 /* The mutex functions used to do absolutely nothing, i.e. lock,
 276    trylock and unlock would always just return 0.  However, even
 277    without any concurrently active threads, a mutex can be used
 278    legitimately as an `in use' flag.  To make the code that is
 279    protected by a mutex async-signal safe, these macros would have to
 280    be based on atomic test-and-set operations, for example. */
 281 typedef int mutex_t;
 282
 283 #define MUTEX_INITIALIZER          0
 284 #define mutex_init(m)              (*(m) = 0)
 285 #define mutex_lock(m)              ((*(m) = 1), 0)
 286 #define mutex_trylock(m)           (*(m) ? 1 : ((*(m) = 1), 0))
 287 #define mutex_unlock(m)            (*(m) = 0)
 288
 289 typedef void *tsd_key_t;
 290 #define tsd_key_create(key, destr) do {} while(0)
 291 #define tsd_setspecific(key, data) ((key) = (data))
 292 #define tsd_getspecific(key, vptr) (vptr = (key))
 293
 294 #define thread_atfork(prepare, parent, child) do {} while(0)
 295
 296 #endif /* defined(NO_THREADS) */
 297
 298 #endif /* !defined(_THREAD_M_H) */