This patch provides minimal non-stub implementations for libgomp
mutex/ptrlock/semaphore, using atomic ops and busy waiting. The goal here is
to at least provide stub struct declarations necessary to unbreak libgomp.h.
Atomics with busy waiting seems to be the only way to provide such primitives
for inter-team synchronizations, but for intra-team ops a more efficient
implementation may be possible.
(all functionality is unused since consumers are stubbed out in config/nvptx)
* config/nvptx/mutex.h: New file.
* config/nvptx/ptrlock.h: New file.
* config/nvptx/sem.h: New file.
---
libgomp/config/nvptx/mutex.h | 67 ++++++++++++++++++++++++++++++++++++++
libgomp/config/nvptx/ptrlock.h | 73 ++++++++++++++++++++++++++++++++++++++++++
libgomp/config/nvptx/sem.h | 65 +++++++++++++++++++++++++++++++++++++
3 files changed, 205 insertions(+)
create mode 100644 libgomp/config/nvptx/mutex.h
create mode 100644 libgomp/config/nvptx/ptrlock.h
create mode 100644 libgomp/config/nvptx/sem.h
diff --git a/libgomp/config/nvptx/mutex.h b/libgomp/config/nvptx/mutex.h
new file mode 100644
index 0000000..a98d5a9
--- /dev/null
+++ b/libgomp/config/nvptx/mutex.h
@@ -0,0 +1,67 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+ Contributed by Alexander Monakov <amona...@ispras.ru>
+
+ This file is part of the GNU Offloading and Multi Processing Library
+ (libgomp).
+
+ Libgomp is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ Libgomp 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* This is an NVPTX specific implementation of a mutex synchronization
+ mechanism for libgomp. This type is private to the library. This
+ implementation uses atomic instructions and busy waiting. */
+
+#ifndef GOMP_MUTEX_H
+#define GOMP_MUTEX_H 1
+
+typedef int gomp_mutex_t;
+
+#define GOMP_MUTEX_INIT_0 1
+
+static inline void
+gomp_mutex_init (gomp_mutex_t *mutex)
+{
+ *mutex = 0;
+}
+
+static inline void
+gomp_mutex_destroy (gomp_mutex_t *mutex)
+{
+}
+
+static inline void
+gomp_mutex_lock (gomp_mutex_t *mutex)
+{
+ int value = __atomic_load_n (mutex, MEMMODEL_ACQUIRE);
+ for (;;)
+ {
+ while (value == 0)
+ value = __atomic_load_n (mutex, MEMMODEL_ACQUIRE);
+ if (__atomic_compare_exchange_n (mutex, &value, 1, false,
+ MEMMODEL_ACQUIRE, MEMMODEL_RELAXED))
+ return;
+ }
+}
+
+static inline void
+gomp_mutex_unlock (gomp_mutex_t *mutex)
+{
+ __atomic_store_n (mutex, 0, MEMMODEL_RELEASE);
+}
+#endif /* GOMP_MUTEX_H */
diff --git a/libgomp/config/nvptx/ptrlock.h b/libgomp/config/nvptx/ptrlock.h
new file mode 100644
index 0000000..c4ff033
--- /dev/null
+++ b/libgomp/config/nvptx/ptrlock.h
@@ -0,0 +1,73 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+ Contributed by Alexander Monakov <amona...@ispras.ru>
+
+ This file is part of the GNU Offloading and Multi Processing Library
+ (libgomp).
+
+ Libgomp is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ Libgomp 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* This is an NVPTX specific implementation of a mutex synchronization
+ mechanism for libgomp. This type is private to the library. This
+ implementation uses atomic instructions and busy waiting.
+
+ A ptrlock has four states:
+ 0/NULL Initial
+ 1 Owned by me, I get to write a pointer to ptrlock.
+ 2 Some thread is waiting on the ptrlock.
+ >2 Ptrlock contains a valid pointer.
+ It is not valid to gain the ptrlock and then write a NULL to it. */
+
+#ifndef GOMP_PTRLOCK_H
+#define GOMP_PTRLOCK_H 1
+
+typedef void *gomp_ptrlock_t;
+
+static inline void gomp_ptrlock_init (gomp_ptrlock_t *ptrlock, void *ptr)
+{
+ *ptrlock = ptr;
+}
+
+static inline void *gomp_ptrlock_get (gomp_ptrlock_t *ptrlock)
+{
+ uintptr_t v = (uintptr_t) __atomic_load_n (ptrlock, MEMMODEL_ACQUIRE);
+ if (v > 2)
+ return (void *) v;
+
+ if (v == 0
+ && __atomic_compare_exchange_n (ptrlock, &v, 1, false,
+ MEMMODEL_ACQUIRE, MEMMODEL_ACQUIRE))
+ return NULL;
+
+ while (v == 1)
+ v = (uintptr_t) __atomic_load_n (ptrlock, MEMMODEL_ACQUIRE);
+
+ return (void *) v;
+}
+
+static inline void gomp_ptrlock_set (gomp_ptrlock_t *ptrlock, void *ptr)
+{
+ __atomic_store_n (ptrlock, ptr, MEMMODEL_RELEASE);
+}
+
+static inline void gomp_ptrlock_destroy (gomp_ptrlock_t *ptrlock)
+{
+}
+
+#endif /* GOMP_PTRLOCK_H */
diff --git a/libgomp/config/nvptx/sem.h b/libgomp/config/nvptx/sem.h
new file mode 100644
index 0000000..c29ebac
--- /dev/null
+++ b/libgomp/config/nvptx/sem.h
@@ -0,0 +1,65 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+ Contributed by Alexander Monakov <amona...@ispras.ru>
+
+ This file is part of the GNU Offloading and Multi Processing Library
+ (libgomp).
+
+ Libgomp is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ Libgomp 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 General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* This is an NVPTX specific implementation of a semaphore synchronization
+ mechanism for libgomp. This type is private to the library. This
+ semaphore implementation uses atomic instructions and busy waiting. */
+
+#ifndef GOMP_SEM_H
+#define GOMP_SEM_H 1
+
+typedef int gomp_sem_t;
+
+static inline void
+gomp_sem_init (gomp_sem_t *sem, int value)
+{
+ *sem = value;
+}
+
+static inline void
+gomp_sem_destroy (gomp_sem_t *sem)
+{
+}
+
+static inline void
+gomp_sem_wait (gomp_sem_t *sem)
+{
+ int count = __atomic_load_n (sem, MEMMODEL_ACQUIRE);
+ for (;;)
+ {
+ while (count == 0)
+ count = __atomic_load_n (sem, MEMMODEL_ACQUIRE);
+ if (__atomic_compare_exchange_n (sem, &count, count - 1, false,
+ MEMMODEL_ACQUIRE, MEMMODEL_RELAXED))
+ return;
+ }
+}
+
+static inline void
+gomp_sem_post (gomp_sem_t *sem)
+{
+ (void) __atomic_add_fetch (sem, 1, MEMMODEL_RELEASE);
+}
+#endif /* GOMP_SEM_H */
