initial import of latest linuxthreads

1 files changed, 218 insertions, 0 deletions

diff --git a/libpthread/linuxthreads/spinlock.h b/libpthread/linuxthreads/spinlock.h
new file mode 100644
index 000000000..ff96fc336
--- /dev/null
+++ b/libpthread/linuxthreads/spinlock.h
@@ -0,0 +1,218 @@
+/* Linuxthreads - a simple clone()-based implementation of Posix        */
+/* threads for Linux.                                                   */
+/* Copyright (C) 1998 Xavier Leroy (Xavier.Leroy@inria.fr)              */
+/*                                                                      */
+/* This program is free software; you can redistribute it and/or        */
+/* modify it under the terms of the GNU Library General Public License  */
+/* as published by the Free Software Foundation; either version 2       */
+/* of the License, or (at your option) any later version.               */
+/*                                                                      */
+/* This program is distributed in the hope that it will be useful,      */
+/* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
+/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
+/* GNU Library General Public License for more details.                 */
+
+#include <bits/initspin.h>
+
+
+/* There are 2 compare and swap synchronization primitives with
+   different semantics:
+
+	1. compare_and_swap, which has acquire semantics (i.e. it
+	completes befor subsequent writes.)
+	2. compare_and_swap_with_release_semantics, which has release
+	semantics (it completes after previous writes.)
+
+   For those platforms on which they are the same. HAS_COMPARE_AND_SWAP
+   should be defined. For those platforms on which they are different,
+   HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS has to be defined.  */
+
+#ifndef HAS_COMPARE_AND_SWAP
+#ifdef HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS
+#define HAS_COMPARE_AND_SWAP
+#endif
+#endif
+
+#if defined(TEST_FOR_COMPARE_AND_SWAP)
+
+extern int __pthread_has_cas;
+extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval,
+                                      int * spinlock);
+
+static inline int compare_and_swap(long * ptr, long oldval, long newval,
+                                   int * spinlock)
+{
+  if (__builtin_expect (__pthread_has_cas, 1))
+    return __compare_and_swap(ptr, oldval, newval);
+  else
+    return __pthread_compare_and_swap(ptr, oldval, newval, spinlock);
+}
+
+#elif defined(HAS_COMPARE_AND_SWAP)
+
+#ifdef IMPLEMENT_TAS_WITH_CAS
+#define testandset(p) !__compare_and_swap((long int *) p, 0, 1)
+#endif
+
+#ifdef HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS
+
+static inline int
+compare_and_swap_with_release_semantics (long * ptr, long oldval,
+					 long newval, int * spinlock)
+{
+  return __compare_and_swap_with_release_semantics (ptr, oldval,
+						    newval);
+}
+
+#endif
+
+static inline int compare_and_swap(long * ptr, long oldval, long newval,
+                                   int * spinlock)
+{
+  return __compare_and_swap(ptr, oldval, newval);
+}
+
+#else
+
+extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval,
+                                      int * spinlock);
+
+static inline int compare_and_swap(long * ptr, long oldval, long newval,
+                                   int * spinlock)
+{
+  return __pthread_compare_and_swap(ptr, oldval, newval, spinlock);
+}
+
+#endif
+
+#ifndef HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS
+#define compare_and_swap_with_release_semantics compare_and_swap
+#define __compare_and_swap_with_release_semantics __compare_and_swap
+#endif
+
+/* Internal locks */
+
+extern void internal_function __pthread_lock(struct _pthread_fastlock * lock,
+					     pthread_descr self);
+extern int __pthread_unlock(struct _pthread_fastlock *lock);
+
+static inline void __pthread_init_lock(struct _pthread_fastlock * lock)
+{
+  lock->__status = 0;
+  lock->__spinlock = __LT_SPINLOCK_INIT;
+}
+
+static inline int __pthread_trylock (struct _pthread_fastlock * lock)
+{
+#if defined TEST_FOR_COMPARE_AND_SWAP
+  if (!__pthread_has_cas)
+#endif
+#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
+  {
+    return (testandset(&lock->__spinlock) ? EBUSY : 0);
+  }
+#endif
+
+#if defined HAS_COMPARE_AND_SWAP
+  do {
+    if (lock->__status != 0) return EBUSY;
+  } while(! __compare_and_swap(&lock->__status, 0, 1));
+  return 0;
+#endif
+}
+
+/* Variation of internal lock used for pthread_mutex_t, supporting
+   timed-out waits.  Warning: do not mix these operations with the above ones
+   over the same lock object! */
+
+extern void __pthread_alt_lock(struct _pthread_fastlock * lock,
+			       pthread_descr self);
+
+extern int __pthread_alt_timedlock(struct _pthread_fastlock * lock,
+			       pthread_descr self, const struct timespec *abstime);
+
+extern void __pthread_alt_unlock(struct _pthread_fastlock *lock);
+
+static inline void __pthread_alt_init_lock(struct _pthread_fastlock * lock)
+{
+  lock->__status = 0;
+  lock->__spinlock = __LT_SPINLOCK_INIT;
+}
+
+static inline int __pthread_alt_trylock (struct _pthread_fastlock * lock)
+{
+#if defined TEST_FOR_COMPARE_AND_SWAP
+  if (!__pthread_has_cas)
+#endif
+#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
+  {
+    int res = EBUSY;
+
+    if (testandset(&lock->__spinlock) == 0)
+      {
+	if (lock->__status == 0)
+	  {
+	    lock->__status = 1;
+	    WRITE_MEMORY_BARRIER();
+	    res = 0;
+	  }
+	lock->__spinlock = __LT_SPINLOCK_INIT;
+      }
+    return res;
+  }
+#endif
+
+#if defined HAS_COMPARE_AND_SWAP
+  do {
+    if (lock->__status != 0) return EBUSY;
+  } while(! compare_and_swap(&lock->__status, 0, 1, &lock->__spinlock));
+  return 0;
+#endif
+}
+
+/* Operations on pthread_atomic, which is defined in internals.h */
+
+static inline long atomic_increment(struct pthread_atomic *pa)
+{
+    long oldval;
+
+    do {
+	oldval = pa->p_count;
+    } while (!compare_and_swap(&pa->p_count, oldval, oldval + 1, &pa->p_spinlock));
+
+    return oldval;
+}
+
+
+static inline long atomic_decrement(struct pthread_atomic *pa)
+{
+    long oldval;
+
+    do {
+	oldval = pa->p_count;
+    } while (!compare_and_swap(&pa->p_count, oldval, oldval - 1, &pa->p_spinlock));
+
+    return oldval;
+}
+
+
+static inline __attribute__((always_inline)) void
+__pthread_set_own_extricate_if (pthread_descr self, pthread_extricate_if *peif)
+{
+  /* Only store a non-null peif if the thread has cancellation enabled.
+     Otherwise pthread_cancel will unconditionally call the extricate handler,
+     and restart the thread giving rise to forbidden spurious wakeups. */
+  if (peif == NULL
+      || THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)
+    {
+      /* If we are removing the extricate interface, we need to synchronize
+	 against pthread_cancel so that it does not continue with a pointer
+         to a deallocated pthread_extricate_if struct! The thread lock
+         is (ab)used for this synchronization purpose. */
+      if (peif == NULL)
+	__pthread_lock (THREAD_GETMEM(self, p_lock), self);
+      THREAD_SETMEM(self, p_extricate, peif);
+      if (peif == NULL)
+	__pthread_unlock (THREAD_GETMEM(self, p_lock));
+    }
+}