Separate Linuxisms from lowlevellock.h, make a generic one

2 files changed, 273 insertions, 0 deletions

diff --git a/sysdeps/nptl/lowlevellock-futex.h b/sysdeps/nptl/lowlevellock-futex.h
new file mode 100644
index 0000000..12f3876
--- /dev/null
+++ b/sysdeps/nptl/lowlevellock-futex.h
@@ -0,0 +1,86 @@
+/* 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 <errno.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
+
+
+/* For most of these macros, the return value is never really used.
+   Nevertheless, the protocol is that each one returns a negated errno
+   code for failure or zero for success.  (Note that the corresponding
+   Linux system calls can sometimes return positive values for success
+   cases too.  We never use those values.)  */
+
+
+/* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP.  */
+#define lll_futex_wait(futexp, val, private) \
+  lll_futex_timed_wait (futexp, val, NULL, private)
+
+/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses.  */
+#define lll_futex_timed_wait(futexp, val, timeout, private)             \
+  -ENOSYS
+
+/* This macro should be defined only if FUTEX_CLOCK_REALTIME is also defined.
+   If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
+   If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
+   TIMEOUT is counted by CLOCK_REALTIME rather than CLOCK_MONOTONIC.  */
+#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
+  -ENOSYS
+
+/* Wake up up to NR waiters on FUTEXP.  */
+#define lll_futex_wake(futexp, nr, private)                             \
+  -ENOSYS
+
+/* Wake up up to NR_WAKE waiters on FUTEXP.  Move up to NR_MOVE of the
+   rest from waiting on FUTEXP to waiting on MUTEX (a different futex).  */
+#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
+  -ENOSYS
+
+/* 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) \
+  -ENOSYS
+
+
+/* Like lll_futex_wait (FUTEXP, VAL, PRIVATE) but with the expectation
+   that lll_futex_cmp_requeue_pi (FUTEXP, _, _, MUTEX, _, PRIVATE) will
+   be used to do the wakeup.  Confers priority-inheritance behavior on
+   the waiter.  */
+#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
+  lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
+
+/* Like lll_futex_wait_requeue_pi, but with a timeout.  */
+#define lll_futex_timed_wait_requeue_pi(futexp, val, timeout, clockbit, \
+                                        mutex, private)                 \
+  -ENOSYS
+
+/* Like lll_futex_requeue, but pairs with lll_futex_wait_requeue_pi
+   and inherits priority from the waiter.  */
+#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex,       \
+                                 val, private)                          \
+  -ENOSYS
+
+
+#endif  /* lowlevellock-futex.h */
diff --git a/sysdeps/nptl/lowlevellock.h b/sysdeps/nptl/lowlevellock.h
new file mode 100644
index 0000000..548a9c8
--- /dev/null
+++ b/sysdeps/nptl/lowlevellock.h
@@ -0,0 +1,187 @@
+/* Low-level lock implementation.  Generic futex-based version.
+   Copyright (C) 2005-2014 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_H
+#define _LOWLEVELLOCK_H	1
+
+#include <atomic.h>
+#include <lowlevellock-futex.h>
+
+#define lll_trylock(lock)	\
+  atomic_compare_and_exchange_bool_acq (&(lock), 1, 0)
+
+#define lll_cond_trylock(lock)	\
+  atomic_compare_and_exchange_bool_acq (&(lock), 2, 0)
+
+extern void __lll_lock_wait_private (int *futex) attribute_hidden;
+extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
+extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
+
+/* This is an expression rather than a statement even though its value is
+   void, so that it can be used in a comma expression or as an expression
+   that's cast to void.  */
+#define __lll_lock(futex, private)                                      \
+  ((void)                                                               \
+   ({                                                                   \
+     int *__futex = (futex);                                            \
+     if (__glibc_unlikely                                               \
+         (atomic_compare_and_exchange_bool_acq (__futex, 1, 0)))        \
+       {                                                                \
+         if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
+           __lll_lock_wait_private (__futex);                           \
+         else                                                           \
+           __lll_lock_wait (__futex, private);                          \
+       }                                                                \
+   }))
+#define lll_lock(futex, private)	\
+  __lll_lock (&(futex), private)
+
+
+#define __lll_robust_lock(futex, id, private)                           \
+  ({                                                                    \
+    int *__futex = (futex);                                             \
+    int __val = 0;                                                      \
+                                                                        \
+    if (__glibc_unlikely                                                \
+        (atomic_compare_and_exchange_bool_acq (__futex, id, 0)))        \
+      __val = __lll_robust_lock_wait (__futex, private);                \
+    __val;                                                              \
+  })
+#define lll_robust_lock(futex, id, private)     \
+  __lll_robust_lock (&(futex), id, private)
+
+
+/* This is an expression rather than a statement even though its value is
+   void, so that it can be used in a comma expression or as an expression
+   that's cast to void.  */
+#define __lll_cond_lock(futex, private)                                 \
+  ((void)                                                               \
+   ({                                                                   \
+     int *__futex = (futex);                                            \
+     if (__glibc_unlikely (atomic_exchange_acq (__futex, 2) != 0))      \
+       __lll_lock_wait (__futex, private);                              \
+   }))
+#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
+
+
+#define lll_robust_cond_lock(futex, id, private)	\
+  __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
+
+
+extern int __lll_timedlock_wait (int *futex, const struct timespec *,
+				 int private) attribute_hidden;
+extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
+					int private) attribute_hidden;
+
+#define __lll_timedlock(futex, abstime, private)                \
+  ({                                                            \
+    int *__futex = (futex);                                     \
+    int __val = 0;                                              \
+                                                                \
+    if (__glibc_unlikely (atomic_exchange_acq (__futex, 1)))    \
+      __val = __lll_timedlock_wait (__futex, abstime, private); \
+    __val;                                                      \
+  })
+#define lll_timedlock(futex, abstime, private)  \
+  __lll_timedlock (&(futex), abstime, private)
+
+
+#define __lll_robust_timedlock(futex, abstime, id, private)             \
+  ({                                                                    \
+    int *__futex = (futex);                                             \
+    int __val = 0;                                                      \
+                                                                        \
+    if (__glibc_unlikely                                                \
+        (atomic_compare_and_exchange_bool_acq (__futex, id, 0)))        \
+      __val = __lll_robust_timedlock_wait (__futex, abstime, private);  \
+    __val;                                                              \
+  })
+#define lll_robust_timedlock(futex, abstime, id, private)       \
+  __lll_robust_timedlock (&(futex), abstime, id, private)
+
+
+/* This is an expression rather than a statement even though its value is
+   void, so that it can be used in a comma expression or as an expression
+   that's cast to void.  */
+#define __lll_unlock(futex, private)                    \
+  ((void)                                               \
+   ({                                                   \
+     int *__futex = (futex);                            \
+     int __oldval = atomic_exchange_rel (__futex, 0);   \
+     if (__glibc_unlikely (__oldval > 1))               \
+       lll_futex_wake (__futex, 1, private);            \
+   }))
+#define lll_unlock(futex, private)	\
+  __lll_unlock (&(futex), private)
+
+
+/* This is an expression rather than a statement even though its value is
+   void, so that it can be used in a comma expression or as an expression
+   that's cast to void.  */
+#define __lll_robust_unlock(futex, private)             \
+  ((void)                                               \
+   ({                                                   \
+     int *__futex = (futex);                            \
+     int __oldval = atomic_exchange_rel (__futex, 0);   \
+     if (__glibc_unlikely (__oldval & FUTEX_WAITERS))	\
+       lll_futex_wake (__futex, 1, private);            \
+   }))
+#define lll_robust_unlock(futex, private)       \
+  __lll_robust_unlock (&(futex), private)
+
+
+#define lll_islocked(futex) \
+  ((futex) != LLL_LOCK_INITIALIZER)
+
+
+/* Our internal lock implementation is identical to the binary-compatible
+   mutex implementation. */
+
+/* Initializers for lock.  */
+#define LLL_LOCK_INITIALIZER		(0)
+#define LLL_LOCK_INITIALIZER_LOCKED	(1)
+
+/* The states of a lock are:
+    0  -  untaken
+    1  -  taken by one user
+   >1  -  taken by more users */
+
+/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
+   wakeup when the clone terminates.  The memory location contains the
+   thread ID while the clone is running and is reset to zero
+   afterwards.	*/
+#define lll_wait_tid(tid) \
+  do {					\
+    __typeof (tid) __tid;		\
+    while ((__tid = (tid)) != 0)	\
+      lll_futex_wait (&(tid), __tid, LLL_SHARED);\
+  } while (0)
+
+extern int __lll_timedwait_tid (int *, const struct timespec *)
+     attribute_hidden;
+
+#define lll_timedwait_tid(tid, abstime) \
+  ({							\
+    int __res = 0;					\
+    if ((tid) != 0)					\
+      __res = __lll_timedwait_tid (&(tid), (abstime));	\
+    __res;						\
+  })
+
+
+#endif	/* lowlevellock.h */