From ca86693be28e7194ad1cf3f628004f98c872ec26 Mon Sep 17 00:00:00 2001
From: uebayasi <uebayasi@openbsd.org>
Date: Sun, 13 Jul 2014 15:46:21 +0000
Subject: [PATCH] KERNEL_ASSERT_LOCKED(9): Assertion for kernel lock (Rev. 3)

This adds a new assertion macro, KERNEL_ASSERT_LOCKED(), to assert that
kernel_lock is held.  In the long process of removing kernel_lock, there will
be a lot (hundreds or thousands) of use of this; virtually almost all functions
in !MP-safe subsystems should have this assertion.  Thus this assertion should
have a short, good name.

Not only that "KERNEL_ASSERT_LOCKED" is consistent with other KERNEL_* and
SCHED_ASSERT_LOCKED() macros.

Input from dlg@ guenther@ kettenis@.

OK dlg@ guenther@
---
 sys/kern/kern_fork.c   |  4 ++--
 sys/kern/kern_ktrace.c |  6 ++----
 sys/kern/kern_lock.c   |  8 +++++++-
 sys/kern/kern_sig.c    | 10 +++-------
 sys/sys/systm.h        |  7 ++++++-
 5 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 2e035f17ab2..3efa176192b 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_fork.c,v 1.172 2014/07/12 18:43:32 tedu Exp $	*/
+/*	$OpenBSD: kern_fork.c,v 1.173 2014/07/13 15:46:21 uebayasi Exp $	*/
 /*	$NetBSD: kern_fork.c,v 1.29 1996/02/09 18:59:34 christos Exp $	*/
 
 /*
@@ -614,7 +614,7 @@ proc_trampoline_mp(void)
 	__mp_unlock(&sched_lock);
 	spl0();
 	SCHED_ASSERT_UNLOCKED();
-	KASSERT(__mp_lock_held(&kernel_lock) == 0);
+	KERNEL_ASSERT_UNLOCKED();
 
 	KERNEL_LOCK();
 }
diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
index d0f68be1153..7c3f1d4762d 100644
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_ktrace.c,v 1.68 2014/07/13 15:00:40 tedu Exp $	*/
+/*	$OpenBSD: kern_ktrace.c,v 1.69 2014/07/13 15:46:21 uebayasi Exp $	*/
 /*	$NetBSD: kern_ktrace.c,v 1.23 1996/02/09 18:59:36 christos Exp $	*/
 
 /*
@@ -332,9 +332,7 @@ ktrstruct(struct proc *p, const char *name, const void *data, size_t datalen)
 	void *buf;
 	size_t buflen;
 
-#ifdef MULTIPROCESSOR
-	KASSERT(__mp_lock_held(&kernel_lock) > 0);
-#endif
+	KERNEL_ASSERT_LOCKED();
 	atomic_setbits_int(&p->p_flag, P_INKTR);
 	ktrinitheader(&kth, p, KTR_STRUCT);
 	
diff --git a/sys/kern/kern_lock.c b/sys/kern/kern_lock.c
index 946fd17e3b3..a9eb9574cd3 100644
--- a/sys/kern/kern_lock.c
+++ b/sys/kern/kern_lock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_lock.c,v 1.44 2014/07/09 13:32:00 guenther Exp $	*/
+/*	$OpenBSD: kern_lock.c,v 1.45 2014/07/13 15:46:21 uebayasi Exp $	*/
 
 /* 
  * Copyright (c) 1995
@@ -134,4 +134,10 @@ _kernel_unlock(void)
 {
 	__mp_unlock(&kernel_lock);
 }
+
+int
+_kernel_lock_held(void)
+{
+	return (__mp_lock_held(&kernel_lock));
+}
 #endif /* MULTIPROCESSOR */
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 28ebd811904..970507f28b6 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sig.c,v 1.171 2014/07/12 21:21:19 matthew Exp $	*/
+/*	$OpenBSD: kern_sig.c,v 1.172 2014/07/13 15:46:21 uebayasi Exp $	*/
 /*	$NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $	*/
 
 /*
@@ -1897,9 +1897,7 @@ single_thread_set(struct proc *p, enum single_thread_mode mode, int deep)
 	struct proc *q;
 	int error;
 
-#ifdef MULTIPROCESSOR
-	KASSERT(__mp_lock_held(&kernel_lock));
-#endif
+	KERNEL_ASSERT_LOCKED();
 
 	if ((error = single_thread_check(p, deep)))
 		return error;
@@ -1996,9 +1994,7 @@ single_thread_clear(struct proc *p, int flag)
 	struct proc *q;
 
 	KASSERT(pr->ps_single == p);
-#ifdef MULTIPROCESSOR
-	KASSERT(__mp_lock_held(&kernel_lock));
-#endif
+	KERNEL_ASSERT_LOCKED();
 
 	pr->ps_single = NULL;
 	atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT);
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 96386d4d081..a3929a0eda8 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: systm.h,v 1.100 2013/06/11 18:15:54 deraadt Exp $	*/
+/*	$OpenBSD: systm.h,v 1.101 2014/07/13 15:46:21 uebayasi Exp $	*/
 /*	$NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $	*/
 
 /*-
@@ -340,16 +340,21 @@ void	user_config(void);
 void	_kernel_lock_init(void);
 void	_kernel_lock(void);
 void	_kernel_unlock(void);
+int	_kernel_lock_held(void);
 
 #define	KERNEL_LOCK_INIT()		_kernel_lock_init()
 #define	KERNEL_LOCK()			_kernel_lock()
 #define	KERNEL_UNLOCK()			_kernel_unlock()
+#define	KERNEL_ASSERT_LOCKED()		KASSERT(_kernel_lock_held())
+#define	KERNEL_ASSERT_UNLOCKED()	KASSERT(!_kernel_lock_held())
 
 #else /* ! MULTIPROCESSOR */
 
 #define	KERNEL_LOCK_INIT()		/* nothing */
 #define	KERNEL_LOCK()			/* nothing */
 #define	KERNEL_UNLOCK()			/* nothing */
+#define	KERNEL_ASSERT_LOCKED()		/* nothing */
+#define	KERNEL_ASSERT_UNLOCKED()	/* nothing */
 
 #endif /* MULTIPROCESSOR */
 
-- 
2.20.1