Hang detection additions.

kern/include/cpu.h

@@ -87,6 +87,11 @@ struct cpu {
 	struct tlbshootdown c_shootdown[TLBSHOOTDOWN_MAX];
 	unsigned c_numshootdown;
 	struct spinlock c_ipi_lock;
+
+	/*
+	 * Accessed by other cpus. Protected inside hangman.c.
+	 */
+	HANGMAN_ACTOR(c_hangman);
 };
 
 /*

kern/include/hangman.h

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2015
+ *	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 HANGMAN_H
+#define HANGMAN_H
+
+/*
+ * Simple deadlock detector. Enable with "options hangman" in the
+ * kernel config.
+ */
+
+#include "opt-hangman.h"
+
+#if OPT_HANGMAN
+
+struct hangman_actor {
+	const char *a_name;
+	const struct hangman_lockable *a_waiting;
+};
+
+struct hangman_lockable {
+	const char *l_name;
+	const struct hangman_actor *l_holding;
+};
+
+void hangman_wait(struct hangman_actor *a, struct hangman_lockable *l);
+void hangman_acquire(struct hangman_actor *a, struct hangman_lockable *l);
+void hangman_release(struct hangman_actor *a, struct hangman_lockable *l);
+
+#define HANGMAN_ACTOR(sym)	struct hangman_actor sym
+#define HANGMAN_LOCKABLE(sym)	struct hangman_lockable sym
+
+#define HANGMAN_ACTORINIT(a, n)	    ((a)->a_name = (n), (a)->a_waiting = NULL)
+#define HANGMAN_LOCKABLEINIT(l, n)  ((l)->l_name = (n), (l)->l_holding = NULL)
+
+#define HANGMAN_LOCKABLE_INITIALIZER	{ "spinlock", NULL }
+
+#define HANGMAN_WAIT(a, l)	hangman_wait(a, l)
+#define HANGMAN_ACQUIRE(a, l)	hangman_acquire(a, l)
+#define HANGMAN_RELEASE(a, l)	hangman_release(a, l)
+
+#else
+
+#define HANGMAN_ACTOR(sym)
+#define HANGMAN_LOCKABLE(sym)
+
+#define HANGMAN_ACTORINIT(a, name)
+#define HANGMAN_LOCKABLEINIT(a, name)
+
+#define HANGMAN_LOCKABLE_INITIALIZER
+
+#define HANGMAN_WAIT(a, l)
+#define HANGMAN_ACQUIRE(a, l)
+#define HANGMAN_RELEASE(a, l)
+
+#endif
+
+#endif /* HANGMAN_H */

kern/include/lib.h

@@ -192,7 +192,7 @@ void kprintf_bootstrap(void);
  */
 
 #define DIVROUNDUP(a,b) (((a)+(b)-1)/(b))
-#define ROUNDUP(a,b)    (DIVROUNDUP(a,b)*b)
+#define ROUNDUP(a,b)    (DIVROUNDUP(a,b)*(b))
 
 
 #endif /* _LIB_H_ */

kern/include/mainbus.h

@@ -55,6 +55,9 @@ size_t mainbus_ramsize(void);
 /* Switch on an inter-processor interrupt. (Low-level.) */
 void mainbus_send_ipi(struct cpu *target);
 
+/* Request breaking into the debugger, where available. */
+void mainbus_debugger(void);
+
 /*
  * The various ways to shut down the system. (These are very low-level
  * and should generally not be called directly - md_poweroff, for

kern/include/spinlock.h

@@ -36,6 +36,7 @@
  */
 
 #include <cdefs.h>
+#include <hangman.h>
 
 /* Inlining support - for making sure an out-of-line copy gets built */
 #ifndef SPINLOCK_INLINE
@@ -57,12 +58,18 @@
 struct spinlock {
 	volatile spinlock_data_t splk_lock; /* Memory word where we spin. */
 	struct cpu *splk_holder;	    /* CPU holding this lock. */
+	HANGMAN_LOCKABLE(splk_hangman);     /* Deadlock detector hook. */
 };
 
 /*
  * Initializer for cases where a spinlock needs to be static or global.
  */
+#ifdef OPT_HANGMAN
+#define SPINLOCK_INITIALIZER	{ SPINLOCK_DATA_INITIALIZER, NULL, \
+				  HANGMAN_LOCKABLE_INITIALIZER }
+#else
 #define SPINLOCK_INITIALIZER	{ SPINLOCK_DATA_INITIALIZER, NULL }
+#endif
 
 /*
  * Spinlock functions.

kern/include/synch.h

@@ -74,6 +74,7 @@ void V(struct semaphore *);
  */
 struct lock {
         char *lk_name;
+        HANGMAN_LOCKABLE(lk_hangman);   /* Deadlock detector hook. */
         // add what you need here
         // (don't forget to mark things volatile as needed)
 };

kern/include/thread.h

@@ -83,6 +83,7 @@ struct thread {
 	struct switchframe *t_context;	/* Saved register context (on stack) */
 	struct cpu *t_cpu;		/* CPU thread runs on */
 	struct proc *t_proc;		/* Process thread belongs to */
+	HANGMAN_ACTOR(t_hangman);	/* Deadlock detector hook */
 
 	/*
 	 * Interrupt state fields.

kern/include/version.h

@@ -34,7 +34,7 @@
  * Leave this alone, so we can tell what version of the OS/161 base
  * code we gave you.
  */
-#define BASE_VERSION    "2.0.2"
+#define BASE_VERSION    "2.0.3"
 
 /*
  * Change this as you see fit in the course of hacking the system.