update

[l4.git] / l4 / pkg / uclibc / lib / contrib / uclibc / libpthread / nptl / sysdeps / unix / sysv / linux / metag / pthread_once.c

diff --git a/l4/pkg/uclibc/lib/contrib/uclibc/libpthread/nptl/sysdeps/unix/sysv/linux/metag/pthread_once.c b/l4/pkg/uclibc/lib/contrib/uclibc/libpthread/nptl/sysdeps/unix/sysv/linux/metag/pthread_once.c
new file mode 100644 (file)
index 0000000..e977a7d
--- /dev/null
+++ b/l4/pkg/uclibc/lib/contrib/uclibc/libpthread/nptl/sysdeps/unix/sysv/linux/metag/pthread_once.c
@@ -0,0 +1,100 @@
+/* Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include "pthreadP.h"
+#include <lowlevellock.h>
+
+unsigned long int __fork_generation attribute_hidden;
+
+static void
+clear_once_control (void *arg)
+{
+  pthread_once_t *once_control = (pthread_once_t *) arg;
+
+  *once_control = 0;
+  lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
+}
+
+int
+attribute_protected
+__pthread_once (pthread_once_t *once_control, void (*init_routine) (void))
+{
+  for (;;)
+    {
+      int oldval;
+      int newval;
+
+      /* Pseudo code:
+        newval = __fork_generation | 1;
+        oldval = *once_control;
+        if ((oldval & 2) == 0)
+          *once_control = newval;
+        Do this atomically.
+      */
+      do
+       {
+         newval = __fork_generation | 1;
+         oldval = *once_control;
+         if (oldval & 2)
+           break;
+       } while (atomic_compare_and_exchange_val_acq (once_control, newval, oldval) != oldval);
+
+      /* Check if the initializer has already been done.  */
+      if ((oldval & 2) != 0)
+       return 0;
+
+      /* Check if another thread already runs the initializer. */
+      if ((oldval & 1) == 0)
+       break;
+
+      /* Check whether the initializer execution was interrupted by a fork.  */
+      if (oldval != newval)
+       break;
+
+      /* Same generation, some other thread was faster. Wait.  */
+      lll_futex_wait (once_control, oldval, LLL_PRIVATE);
+    }
+
+  /* This thread is the first here.  Do the initialization.
+     Register a cleanup handler so that in case the thread gets
+     interrupted the initialization can be restarted.  */
+  pthread_cleanup_push (clear_once_control, once_control);
+
+  init_routine ();
+
+  pthread_cleanup_pop (0);
+
+  /* Say that the initialisation is done.  */
+  *once_control = __fork_generation | 2;
+
+  /* Wake up all other threads.  */
+  lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
+
+  return 0;
+}
+weak_alias (__pthread_once, pthread_once)
+strong_alias (__pthread_once, __pthread_once_internal)
+
+#if defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__PIC__)
+/* When statically linked, if pthread_create is used, this file
+   will be brought in.  The exception handling code in GCC assumes
+   that if pthread_create is available, so are these.  */
+const void *include_pthread_getspecific attribute_hidden = pthread_getspecific;
+const void *include_pthread_setspecific attribute_hidden = pthread_setspecific;
+const void *include_pthread_key_create attribute_hidden = pthread_key_create;
+#endif