From: Roland McGrath <roland@hack.frob.com>
Date: Wed, 12 Nov 2014 22:29:17 +0000 (-0800)
Subject: Use basic futex ops.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=668e4ca1618ea7a4f577376789668ce9ac039b85;p=thirdparty%2Fglibc.git

Use basic futex ops.
---

diff --git a/sysdeps/nacl/lowlevellock-futex.h b/sysdeps/nacl/lowlevellock-futex.h
new file mode 100644
index 00000000000..85fd9b4299e
--- /dev/null
+++ b/sysdeps/nacl/lowlevellock-futex.h
@@ -0,0 +1,82 @@
+/* Low-level locking access to futex facilities.  Stub version.
+   Copyright (C) 2014 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _LOWLEVELLOCK_FUTEX_H
+#define _LOWLEVELLOCK_FUTEX_H   1
+
+#include <nacl-interfaces.h>
+#include <time.h>
+
+
+/* Values for 'private' parameter of locking macros.  Note pthreadP.h
+   optimizes for these exact values, though they are not required.  */
+#define LLL_PRIVATE     0
+#define LLL_SHARED      128
+
+
+/* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP.  */
+#define lll_futex_wait(futexp, val, private) \
+  (- __nacl_irt_futex.futex_wait_abs (futexp, val, NULL))
+
+/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses.  */
+#define lll_futex_timed_wait(futexp, val, timeout, private)             \
+  ({                                                                    \
+    /* This timeout is relative, but the IRT call wants it absolute.  */ \
+    const struct timespec *_to = (timeout);                             \
+    struct timespec _ts;                                                \
+    int _err = 0;                                                       \
+    if (_to != NULL                                                     \
+        && __glibc_likely ((_err = __nacl_irt_clock.clock_gettime	\
+                            (CLOCK_REALTIME, &_ts)) == 0))		\
+      {                                                                 \
+        _ts.tv_sec -= _to->tv_sec;                                      \
+        _ts.tv_nsec -= _to->tv_nsec;                                    \
+        while (_ts.tv_nsec < 0)                                         \
+          {                                                             \
+            _ts.tv_nsec += 1000000000;                                  \
+            --_ts.tv_sec;                                               \
+          }                                                             \
+        _to = &_ts;                                                     \
+      }                                                                 \
+    if (_err == 0)                                                      \
+      _err = __nacl_irt_futex.futex_wait_abs (futexp, val, _to);        \
+    -_err;                                                              \
+  })
+
+/* Wake up up to NR waiters on FUTEXP.  */
+#define lll_futex_wake(futexp, nr, private)                     \
+  ({                                                            \
+    int _woken;                                                 \
+    - __nacl_irt_futex.futex_wake (futexp, nr, &_woken);	\
+  })
+
+/* NaCl does not support the requeue operation.  The only use of this is in
+   pthread_cond_broadcast, which handles an error return by falling back to
+   plain lll_futex_wake.  */
+#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
+  ((futexp), (nr_wake), (nr_move), (mutex), (val), (private), -ENOSYS)
+
+/* NaCl does not support the special wake-unlock operation.  The only use
+   of this is in pthread_cond_signal, which handles an error return by
+   falling back to plain lll_futex_wake.  */
+/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2.  */
+#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
+  ((futexp), (nr_wake), (nr_wake2), (futexp2), (private), -ENOSYS)
+
+
+#endif  /* lowlevellock-futex.h */