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authorDavid S. Miller <davem@davemloft.net>2015-01-31 18:59:40 -0800
committerDavid S. Miller <davem@davemloft.net>2015-01-31 23:39:50 -0800
commitd4abeca50400747402a5a33f3a8aa0941be076d5 (patch)
tree0af10d77c2be123e4592654038d4bc3ac7a5dab5 /sysdeps/sparc/sparc32/sem_waitcommon.c
parent5f3d0b78e011d2a72f9e88b0e9ef5bc081d18f97 (diff)
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Fix sparc semaphore implementation after recent changes.
	* sysdeps/sparc/nptl/sem_init.c: Delete.
	* sysdeps/sparc/nptl/sem_post.c: Delete.
	* sysdeps/sparc/nptl/sem_timedwait.c: Delete.
	* sysdeps/sparc/nptl/sem_wait.c: Delete.
	* sysdeps/sparc/sparc32/sem_init.c: New file.
	* sysdeps/sparc/sparc32/sem_waitcommon.c: New file.
	* sysdeps/sparc/sparc32/sem_open.c: Generic nptl version with
	padding explicitly initialized.
	* sysdeps/sparc/sparc32/sem_post.c: Generic nptl version using
	padding for in-semaphore spinlock.
	* sysdeps/sparc/sparc32/sem_wait.c: Likewise.
	* sysdeps/sparc/sparc32/sem_trywait.c: Delete.
	* sysdeps/sparc/sparc32/sem_timedwait.c: Delete.
	* sysdeps/sparc/sparc32/sparcv9/sem_init.c: New file.
	* sysdeps/sparc/sparc32/sparcv9/sem_open.c: New file.
	* sysdeps/sparc/sparc32/sparcv9/sem_post.c: New file.
	* sysdeps/sparc/sparc32/sparcv9/sem_waitcommon.c: New file.
	* sysdeps/sparc/sparc32/sparcv9/sem_wait.c: Redirect to nptl
	version.
	* sysdeps/sparc/sparc32/sparcv9/sem_timedwait.c: Delete.
	* sysdeps/sparc/sparc32/sparcv9/sem_trywait.c: Delete.
Diffstat (limited to 'sysdeps/sparc/sparc32/sem_waitcommon.c')
-rw-r--r--sysdeps/sparc/sparc32/sem_waitcommon.c245
1 files changed, 245 insertions, 0 deletions
diff --git a/sysdeps/sparc/sparc32/sem_waitcommon.c b/sysdeps/sparc/sparc32/sem_waitcommon.c
new file mode 100644
index 0000000000..9c1c6a5af7
--- /dev/null
+++ b/sysdeps/sparc/sparc32/sem_waitcommon.c
@@ -0,0 +1,245 @@
+/* sem_waitcommon -- wait on a semaphore, shared code.
+   Copyright (C) 2003-2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
+
+   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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <lowlevellock.h>
+#include <internaltypes.h>
+#include <semaphore.h>
+#include <sys/time.h>
+
+#include <pthreadP.h>
+#include <shlib-compat.h>
+#include <atomic.h>
+
+/* Wrapper for lll_futex_wait with absolute timeout and error checking.
+   TODO Remove when cleaning up the futex API throughout glibc.  */
+static __always_inline int
+futex_abstimed_wait (unsigned int* futex, unsigned int expected,
+		     const struct timespec* abstime, int private, bool cancel)
+{
+  int err, oldtype;
+  if (abstime == NULL)
+    {
+      if (cancel)
+	oldtype = __pthread_enable_asynccancel ();
+      err = lll_futex_wait (futex, expected, private);
+      if (cancel)
+	__pthread_disable_asynccancel (oldtype);
+    }
+  else
+    {
+      struct timeval tv;
+      struct timespec rt;
+      int sec, nsec;
+
+      /* Get the current time.  */
+      __gettimeofday (&tv, NULL);
+
+      /* Compute relative timeout.  */
+      sec = abstime->tv_sec - tv.tv_sec;
+      nsec = abstime->tv_nsec - tv.tv_usec * 1000;
+      if (nsec < 0)
+        {
+          nsec += 1000000000;
+          --sec;
+        }
+
+      /* Already timed out?  */
+      if (sec < 0)
+        return ETIMEDOUT;
+
+      /* Do wait.  */
+      rt.tv_sec = sec;
+      rt.tv_nsec = nsec;
+      if (cancel)
+	oldtype = __pthread_enable_asynccancel ();
+      err = lll_futex_timed_wait (futex, expected, &rt, private);
+      if (cancel)
+	__pthread_disable_asynccancel (oldtype);
+    }
+  switch (err)
+    {
+    case 0:
+    case -EAGAIN:
+    case -EINTR:
+    case -ETIMEDOUT:
+      return -err;
+
+    case -EFAULT: /* Must have been caused by a glibc or application bug.  */
+    case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+		     being normalized.  Must have been caused by a glibc or
+		     application bug.  */
+    case -ENOSYS: /* Must have been caused by a glibc bug.  */
+    /* No other errors are documented at this time.  */
+    default:
+      abort ();
+    }
+}
+
+/* Wrapper for lll_futex_wake, with error checking.
+   TODO Remove when cleaning up the futex API throughout glibc.  */
+static __always_inline void
+futex_wake (unsigned int* futex, int processes_to_wake, int private)
+{
+  int res = lll_futex_wake (futex, processes_to_wake, private);
+  /* No error.  Ignore the number of woken processes.  */
+  if (res >= 0)
+    return;
+  switch (res)
+    {
+    case -EFAULT: /* Could have happened due to memory reuse.  */
+    case -EINVAL: /* Could be either due to incorrect alignment (a bug in
+		     glibc or in the application) or due to memory being
+		     reused for a PI futex.  We cannot distinguish between the
+		     two causes, and one of them is correct use, so we do not
+		     act in this case.  */
+      return;
+    case -ENOSYS: /* Must have been caused by a glibc bug.  */
+    /* No other errors are documented at this time.  */
+    default:
+      abort ();
+    }
+}
+
+
+/* Set this to true if you assume that, in contrast to current Linux futex
+   documentation, lll_futex_wake can return -EINTR only if interrupted by a
+   signal, not spuriously due to some other reason.
+   TODO Discuss EINTR conditions with the Linux kernel community.  For
+   now, we set this to true to not change behavior of semaphores compared
+   to previous glibc builds.  */
+static const int sem_assume_only_signals_cause_futex_EINTR = 1;
+
+static void
+__sem_wait_32_finish (struct new_sem *sem);
+
+static void
+__sem_wait_cleanup (void *arg)
+{
+  struct new_sem *sem = (struct new_sem *) arg;
+
+  __sem_wait_32_finish (sem);
+}
+
+/* Wait until at least one token is available, possibly with a timeout.
+   This is in a separate function in order to make sure gcc
+   puts the call site into an exception region, and thus the
+   cleanups get properly run.  TODO still necessary?  Other futex_wait
+   users don't seem to need it.  */
+static int
+__attribute__ ((noinline))
+do_futex_wait (struct new_sem *sem, const struct timespec *abstime)
+{
+  int err;
+
+  err = futex_abstimed_wait (&sem->value, SEM_NWAITERS_MASK, abstime,
+			     sem->private, true);
+
+  return err;
+}
+
+/* Fast path: Try to grab a token without blocking.  */
+static int
+__new_sem_wait_fast (struct new_sem *sem, int definitive_result)
+{
+  unsigned int v;
+  int ret = 0;
+
+  __sparc32_atomic_do_lock24(&sem->pad);
+
+  v = sem->value;
+  if ((v >> SEM_VALUE_SHIFT) == 0)
+    ret = -1;
+  else
+    sem->value = v - (1 << SEM_VALUE_SHIFT);
+
+  __sparc32_atomic_do_unlock24(&sem->pad);
+
+  return ret;
+}
+
+/* Slow path that blocks.  */
+static int
+__attribute__ ((noinline))
+__new_sem_wait_slow (struct new_sem *sem, const struct timespec *abstime)
+{
+  unsigned int v;
+  int err = 0;
+
+  __sparc32_atomic_do_lock24(&sem->pad);
+
+  sem->nwaiters++;
+
+  pthread_cleanup_push (__sem_wait_cleanup, sem);
+
+  /* Wait for a token to be available.  Retry until we can grab one.  */
+  v = sem->value;
+  do
+    {
+      if (!(v & SEM_NWAITERS_MASK))
+	sem->value = v | SEM_NWAITERS_MASK;
+
+      /* If there is no token, wait.  */
+      if ((v >> SEM_VALUE_SHIFT) == 0)
+	{
+	  __sparc32_atomic_do_unlock24(&sem->pad);
+
+	  err = do_futex_wait(sem, abstime);
+	  if (err == ETIMEDOUT ||
+	      (err == EINTR && sem_assume_only_signals_cause_futex_EINTR))
+	    {
+	      __set_errno (err);
+	      err = -1;
+	      goto error;
+	    }
+	  err = 0;
+
+	  __sparc32_atomic_do_lock24(&sem->pad);
+
+	  /* We blocked, so there might be a token now.  */
+	  v = sem->value;
+	}
+    }
+  /* If there is no token, we must not try to grab one.  */
+  while ((v >> SEM_VALUE_SHIFT) == 0);
+
+  sem->value = v - (1 << SEM_VALUE_SHIFT);
+
+  __sparc32_atomic_do_unlock24(&sem->pad);
+
+error:
+  pthread_cleanup_pop (0);
+
+  __sem_wait_32_finish (sem);
+
+  return err;
+}
+
+/* Stop being a registered waiter (non-64b-atomics code only).  */
+static void
+__sem_wait_32_finish (struct new_sem *sem)
+{
+  __sparc32_atomic_do_lock24(&sem->pad);
+
+  if (--sem->nwaiters == 0)
+    sem->value &= ~SEM_NWAITERS_MASK;
+
+  __sparc32_atomic_do_unlock24(&sem->pad);
+}