Implement splassert() for sparc - a tool for finding problems related to

spl handling (already found 3 problems).

Man page in a few seconds.
deraadt@ ok.

6 files changed, 79 insertions, 15 deletions

diff --git a/sys/arch/sparc/include/psl.h b/sys/arch/sparc/include/psl.h
index 556559353f9..a673d5fa37e 100644
--- a/sys/arch/sparc/include/psl.h
+++ b/sys/arch/sparc/include/psl.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: psl.h,v 1.12 2002/04/30 01:03:04 art Exp $	*/
+/*	$OpenBSD: psl.h,v 1.13 2002/05/15 23:17:54 art Exp $	*/
 /*	$NetBSD: psl.h,v 1.12 1997/03/10 21:49:11 pk Exp $ */
 
 /*
@@ -107,13 +107,11 @@ static __inline int splhigh(void);
 static __inline void splx(int);
 static __inline int getmid(void);
 
-/* SPL asserts */
-#define	splassert(wantipl)	/* nothing */
-
 /*
  * GCC pseudo-functions for manipulating PSR (primarily PIL field).
  */
-static __inline int getpsr()
+static __inline int
+getpsr()
 {
 	int psr;
 
@@ -121,7 +119,8 @@ static __inline int getpsr()
 	return (psr);
 }
 
-static __inline int getmid()
+static __inline int
+getmid()
 {
 	int mid;
 
@@ -129,7 +128,8 @@ static __inline int getmid()
 	return ((mid >> 20) & 0x3);
 }
 
-static __inline void setpsr(newpsr)
+static __inline void
+setpsr(newpsr)
 	int newpsr;
 {
 	__asm __volatile("wr %0,0,%%psr" : : "r" (newpsr));
@@ -138,7 +138,8 @@ static __inline void setpsr(newpsr)
 	__asm __volatile("nop");
 }
 
-static __inline int spl0()
+static __inline int
+spl0()
 {
 	int psr, oldipl;
 
@@ -159,6 +160,23 @@ static __inline int spl0()
 	return (oldipl);
 }
 
+#ifdef DIAGNOSTIC
+/*
+ * Although this function is implemented in MI code, it must be in this MD
+ * header because we don't want this header to include MI includes.
+ */
+void splassert_fail(int, int, const char *);
+extern int splassert_ctl;
+void splassert_check(int, const char *);
+#define splassert(__wantipl) do {			\
+	if (__predict_false(splassert_ctl > 0)) {	\
+		splassert_check(__wantipl, __func__);	\
+	}						\
+} while (0)
+#else
+#define splassert(wantipl) do { /* nada */ } while (0)
+#endif
+
 /*
  * PIL 1 through 14 can use this macro.
  * (spl0 and splhigh are special since they put all 0s or all 1s
@@ -166,7 +184,7 @@ static __inline int spl0()
  */
 #define	SPL(name, newipl) \
 static __inline int name(void); \
- static __inline int name() \
+static __inline int name() \
 { \
 	int psr, oldipl; \
 	__asm __volatile("rd %%psr,%0" : "=r" (psr)); \
diff --git a/sys/arch/sparc/sparc/intr.c b/sys/arch/sparc/sparc/intr.c
index 24e92b62f38..1dc8a42a81c 100644
--- a/sys/arch/sparc/sparc/intr.c
+++ b/sys/arch/sparc/sparc/intr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: intr.c,v 1.19 2002/04/30 01:12:28 art Exp $ */
+/*	$OpenBSD: intr.c,v 1.20 2002/05/15 23:17:54 art Exp $ */
 /*	$NetBSD: intr.c,v 1.20 1997/07/29 09:42:03 fair Exp $ */
 
 /*
@@ -365,3 +365,18 @@ intr_fasttrap(level, vec)
 		pmap_writetext(tvp, *instrp);
 	splx(s);
 }
+
+void
+splassert_check(int wantipl, const char *func)
+{
+	int oldipl = (getpsr() & PSR_PIL) >> 8;
+
+	if (oldipl < wantipl) {
+		splassert_fail(wantipl, oldipl, func);
+		/*
+		 * If the splassert_ctl is set to not panic, raise the ipl
+		 * in a feeble attempt to reduce damage.
+		 */
+		setpsr((getpsr() & ~PSR_PIL) | wantipl << 8);
+	}
+}
diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index 99b50f6d300..d56f03df0f7 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sysctl.c,v 1.64 2002/03/14 20:31:31 mickey Exp $	*/
+/*	$OpenBSD: kern_sysctl.c,v 1.65 2002/05/15 23:17:53 art Exp $	*/
 /*	$NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $	*/
 
 /*-
@@ -433,6 +433,9 @@ kern_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
 		return (sysctl_int(oldp, oldlenp, newp, newlen,
 			    &cryptodevallowsoft));
 #endif
+	case KERN_SPLASSERT:
+		return (sysctl_int(oldp, oldlenp, newp, newlen,
+		    &splassert_ctl));
 	default:
 		return (EOPNOTSUPP);
 	}
diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index b15cb472739..2a20170da5e 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_prf.c,v 1.40 2002/03/15 18:19:52 millert Exp $	*/
+/*	$OpenBSD: subr_prf.c,v 1.41 2002/05/15 23:17:53 art Exp $	*/
 /*	$NetBSD: subr_prf.c,v 1.45 1997/10/24 18:14:25 chuck Exp $	*/
 
 /*-
@@ -131,6 +131,11 @@ int	db_console = 0;
 #endif
 
 /*
+ * panic on spl assertion failure?
+ */
+int splassert_ctl = 0;
+
+/*
  * v_putc: routine to putc on virtual console
  *
  * the v_putc pointer can be used to redirect the console cnputc elsewhere
@@ -219,6 +224,24 @@ panic(const char *fmt, ...)
 }
 
 /*
+ * We print only the function name. The file name is usually very long and
+ * would eat tons of space in the kernel.
+ */
+void
+splassert_fail(int wantipl, int haveipl, const char *func)
+{
+
+	printf("splassert: %s: want %d have %d\n", func, wantipl, haveipl);
+	if (splassert_ctl > 1) {
+		panic("spl assertion failure in %s", func);
+	} else {
+#ifdef DDB
+		/* Will print stack trace RSN. */
+#endif
+	}
+}
+
+/*
  * kernel logging functions: log, logpri, addlog
  */
 
diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index 12123791f10..f87efe46679 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sysctl.h,v 1.48 2002/03/14 19:42:54 mickey Exp $	*/
+/*	$OpenBSD: sysctl.h,v 1.49 2002/05/15 23:17:53 art Exp $	*/
 /*	$NetBSD: sysctl.h,v 1.16 1996/04/09 20:55:36 cgd Exp $	*/
 
 /*
@@ -167,7 +167,8 @@ struct ctlname {
 #define	KERN_SYSVIPC_INFO	51	/* struct: SysV sem/shm/msg info */
 #define KERN_USERCRYPTO		52	/* int: usercrypto */
 #define KERN_CRYPTODEVALLOWSOFT	53	/* int: cryptodevallowsoft */
-#define	KERN_MAXID		54	/* number of valid kern ids */
+#define KERN_SPLASSERT		54	/* int: splassert */
+#define	KERN_MAXID		55	/* number of valid kern ids */
 
 #define	CTL_KERN_NAMES { \
 	{ 0, 0 }, \
@@ -224,6 +225,7 @@ struct ctlname {
 	{ "sysvipc_info", CTLTYPE_INT }, \
 	{ "usercrypto", CTLTYPE_INT }, \
 	{ "cryptodevallowsoft", CTLTYPE_INT }, \
+	{ "splassert", CTLTYPE_INT }, \
 }
 
 /*
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index b78d46a638f..e46f17a0a99 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: systm.h,v 1.49 2002/03/14 20:31:31 mickey Exp $	*/
+/*	$OpenBSD: systm.h,v 1.50 2002/05/15 23:17:53 art Exp $	*/
 /*	$NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $	*/
 
 /*-
@@ -182,6 +182,9 @@ struct tty;
 void	ttyprintf(struct tty *, const char *, ...)
     __kprintf_attribute__((__format__(__kprintf__,2,3)));
 
+void	splassert_fail(int, int, const char *);
+extern	int splassert_ctl;
+
 void	tablefull(const char *);
 
 int	kcopy(const void *, void *, size_t);