1 files changed, 279 insertions, 0 deletions
diff --git a/core/arch/arm/kernel/mutex.c b/core/arch/arm/kernel/mutex.c
new file mode 100644
index 0000000..0e1b836
--- /dev/null
+++ b/core/arch/arm/kernel/mutex.c
@@ -0,0 +1,279 @@
+/*
+ * Copyright (c) 2015, Linaro Limited
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <kernel/mutex.h>
+#include <kernel/panic.h>
+#include <kernel/spinlock.h>
+#include <kernel/thread.h>
+#include <trace.h>
+
+void mutex_init(struct mutex *m)
+{
+	*m = (struct mutex)MUTEX_INITIALIZER;
+}
+
+static void __mutex_lock(struct mutex *m, const char *fname, int lineno)
+{
+	assert_have_no_spinlock();
+	assert(thread_get_id_may_fail() != -1);
+
+	while (true) {
+		uint32_t old_itr_status;
+		enum mutex_value old_value;
+		struct wait_queue_elem wqe;
+
+		/*
+		 * If the mutex is locked we need to initialize the wqe
+		 * before releasing the spinlock to guarantee that we don't
+		 * miss the wakeup from mutex_unlock().
+		 *
+		 * If the mutex is unlocked we don't need to use the wqe at
+		 * all.
+		 */
+
+		old_itr_status = thread_mask_exceptions(THREAD_EXCP_ALL);
+		cpu_spin_lock(&m->spin_lock);
+
+		old_value = m->value;
+		if (old_value == MUTEX_VALUE_LOCKED) {
+			wq_wait_init(&m->wq, &wqe);
+		} else {
+			m->value = MUTEX_VALUE_LOCKED;
+			thread_add_mutex(m);
+		}
+
+		cpu_spin_unlock(&m->spin_lock);
+		thread_unmask_exceptions(old_itr_status);
+
+		if (old_value == MUTEX_VALUE_LOCKED) {
+			/*
+			 * Someone else is holding the lock, wait in normal
+			 * world for the lock to become available.
+			 */
+			wq_wait_final(&m->wq, &wqe, m, fname, lineno);
+		} else
+			return;
+	}
+}
+
+static void __mutex_unlock(struct mutex *m, const char *fname, int lineno)
+{
+	uint32_t old_itr_status;
+
+	assert_have_no_spinlock();
+	assert(thread_get_id_may_fail() != -1);
+
+	old_itr_status = thread_mask_exceptions(THREAD_EXCP_ALL);
+	cpu_spin_lock(&m->spin_lock);
+
+	if (m->value != MUTEX_VALUE_LOCKED)
+		panic();
+
+	thread_rem_mutex(m);
+	m->value = MUTEX_VALUE_UNLOCKED;
+
+	cpu_spin_unlock(&m->spin_lock);
+	thread_unmask_exceptions(old_itr_status);
+
+	wq_wake_one(&m->wq, m, fname, lineno);
+}
+
+static bool __mutex_trylock(struct mutex *m, const char *fname __unused,
+			int lineno __unused)
+{
+	uint32_t old_itr_status;
+	enum mutex_value old_value;
+
+	assert_have_no_spinlock();
+	assert(thread_get_id_may_fail() != -1);
+
+	old_itr_status = thread_mask_exceptions(THREAD_EXCP_ALL);
+	cpu_spin_lock(&m->spin_lock);
+
+	old_value = m->value;
+	if (old_value == MUTEX_VALUE_UNLOCKED) {
+		m->value = MUTEX_VALUE_LOCKED;
+		thread_add_mutex(m);
+	}
+
+	cpu_spin_unlock(&m->spin_lock);
+	thread_unmask_exceptions(old_itr_status);
+
+	return old_value == MUTEX_VALUE_UNLOCKED;
+}
+
+#ifdef CFG_MUTEX_DEBUG
+void mutex_unlock_debug(struct mutex *m, const char *fname, int lineno)
+{
+	__mutex_unlock(m, fname, lineno);
+}
+
+void mutex_lock_debug(struct mutex *m, const char *fname, int lineno)
+{
+	__mutex_lock(m, fname, lineno);
+}
+
+bool mutex_trylock_debug(struct mutex *m, const char *fname, int lineno)
+{
+	return __mutex_trylock(m, fname, lineno);
+}
+#else
+void mutex_unlock(struct mutex *m)
+{
+	__mutex_unlock(m, NULL, -1);
+}
+
+void mutex_lock(struct mutex *m)
+{
+	__mutex_lock(m, NULL, -1);
+}
+
+bool mutex_trylock(struct mutex *m)
+{
+	return __mutex_trylock(m, NULL, -1);
+}
+#endif
+
+
+
+void mutex_destroy(struct mutex *m)
+{
+	/*
+	 * Caller guarantees that no one will try to take the mutex so
+	 * there's no need to take the spinlock before accessing it.
+	 */
+	if (m->value != MUTEX_VALUE_UNLOCKED)
+		panic();
+	if (!wq_is_empty(&m->wq))
+		panic("waitqueue not empty");
+}
+
+void condvar_init(struct condvar *cv)
+{
+	*cv = (struct condvar)CONDVAR_INITIALIZER;
+}
+
+void condvar_destroy(struct condvar *cv)
+{
+	if (cv->m && wq_have_condvar(&cv->m->wq, cv))
+		panic();
+
+	condvar_init(cv);
+}
+
+static void cv_signal(struct condvar *cv, bool only_one, const char *fname,
+			int lineno)
+{
+	uint32_t old_itr_status;
+	struct mutex *m;
+
+	old_itr_status = thread_mask_exceptions(THREAD_EXCP_ALL);
+	cpu_spin_lock(&cv->spin_lock);
+	m = cv->m;
+	cpu_spin_unlock(&cv->spin_lock);
+	thread_unmask_exceptions(old_itr_status);
+
+	if (m)
+		wq_promote_condvar(&m->wq, cv, only_one, m, fname, lineno);
+
+}
+
+#ifdef CFG_MUTEX_DEBUG
+void condvar_signal_debug(struct condvar *cv, const char *fname, int lineno)
+{
+	cv_signal(cv, true /* only one */, fname, lineno);
+}
+
+void condvar_broadcast_debug(struct condvar *cv, const char *fname, int lineno)
+{
+	cv_signal(cv, false /* all */, fname, lineno);
+}
+
+#else
+void condvar_signal(struct condvar *cv)
+{
+	cv_signal(cv, true /* only one */, NULL, -1);
+}
+
+void condvar_broadcast(struct condvar *cv)
+{
+	cv_signal(cv, false /* all */, NULL, -1);
+}
+#endif /*CFG_MUTEX_DEBUG*/
+
+static void __condvar_wait(struct condvar *cv, struct mutex *m,
+			const char *fname, int lineno)
+{
+	uint32_t old_itr_status;
+	struct wait_queue_elem wqe;
+
+	old_itr_status = thread_mask_exceptions(THREAD_EXCP_ALL);
+
+	/* Link this condvar to this mutex until reinitialized */
+	cpu_spin_lock(&cv->spin_lock);
+	if (cv->m && cv->m != m)
+		panic("invalid mutex");
+
+	cv->m = m;
+	cpu_spin_unlock(&cv->spin_lock);
+
+	cpu_spin_lock(&m->spin_lock);
+
+	/* Add to mutex wait queue as a condvar waiter */
+	wq_wait_init_condvar(&m->wq, &wqe, cv);
+
+	/* Unlock the mutex */
+	if (m->value != MUTEX_VALUE_LOCKED)
+		panic();
+
+	thread_rem_mutex(m);
+	m->value = MUTEX_VALUE_UNLOCKED;
+
+	cpu_spin_unlock(&m->spin_lock);
+
+	thread_unmask_exceptions(old_itr_status);
+
+	/* Wake eventual waiters */
+	wq_wake_one(&m->wq, m, fname, lineno);
+
+	wq_wait_final(&m->wq, &wqe, m, fname, lineno);
+
+	mutex_lock(m);
+}
+
+#ifdef CFG_MUTEX_DEBUG
+void condvar_wait_debug(struct condvar *cv, struct mutex *m,
+			const char *fname, int lineno)
+{
+	__condvar_wait(cv, m, fname, lineno);
+}
+#else
+void condvar_wait(struct condvar *cv, struct mutex *m)
+{
+	__condvar_wait(cv, m, NULL, -1);
+}
+#endif