Initial Spring 2016 commit.

kern/include/spinlock.h

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
+ *	The President and Fellows of Harvard College.
+ *
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY 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 UNIVERSITY 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.
+ */
+
+#ifndef _SPINLOCK_H_
+#define _SPINLOCK_H_
+
+/*
+ * Spinlocks. While the guts are machine-dependent, the structure and the
+ * basic functions are supposed to be the same across all machines.
+ */
+
+#include <cdefs.h>
+
+/* Inlining support - for making sure an out-of-line copy gets built */
+#ifndef SPINLOCK_INLINE
+#define SPINLOCK_INLINE INLINE
+#endif
+
+/* Get the machine-dependent bits. */
+#include <machine/spinlock.h>
+
+/*
+ * Basic spinlock.
+ *
+ * Note that spinlocks are held by CPUs, not by threads.
+ *
+ * This structure is made public so spinlocks do not have to be
+ * malloc'd; however, code that uses spinlocks should not look inside
+ * the structure directly but always use the spinlock API functions.
+ */
+struct spinlock {
+	volatile spinlock_data_t splk_lock; /* Memory word where we spin. */
+	struct cpu *splk_holder;	    /* CPU holding this lock. */
+};
+
+/*
+ * Initializer for cases where a spinlock needs to be static or global.
+ */
+#define SPINLOCK_INITIALIZER	{ SPINLOCK_DATA_INITIALIZER, NULL }
+
+/*
+ * Spinlock functions.
+ *
+ * init		Initialize the contents of a spinlock.
+ * cleanup	Opposite of init. Lock must be unlocked.
+ *
+ * acquire	Get the lock, spinning as necessary. Also disables interrupts.
+ * release	Release the lock. May re-enable interrupts.
+ *
+ * do_i_hold	Check if the current CPU holds the lock.
+ */
+
+void spinlock_init(struct spinlock *lk);
+void spinlock_cleanup(struct spinlock *lk);
+
+void spinlock_acquire(struct spinlock *lk);
+void spinlock_release(struct spinlock *lk);
+
+bool spinlock_do_i_hold(struct spinlock *lk);
+
+
+#endif /* _SPINLOCK_H_ */