From 1eb36d23fd67f0f6ddae37d8fa1f71c9565e540b Mon Sep 17 00:00:00 2001
From: thorpej <thorpej@NetBSD.org>
Date: Sun, 14 Jan 2001 00:10:28 +0000
Subject: [PATCH] - Make ast() loop around astpending; it's possible for a new 
  AST to be posted when delivering signals, or after a process   is preempted.
 - Move all signal posting to ast().  userret() is now a one-liner.

---
 sys/arch/mips/include/cpu.h     |  6 ++---
 sys/arch/mips/include/userret.h |  7 +----
 sys/arch/mips/mips/trap.c       | 45 ++++++++++++++++++++-------------
 3 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/sys/arch/mips/include/cpu.h b/sys/arch/mips/include/cpu.h
index 3f09bc303256..322f717e4051 100644
--- a/sys/arch/mips/include/cpu.h
+++ b/sys/arch/mips/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: cpu.h,v 1.48 2001/01/11 21:08:18 thorpej Exp $	*/
+/*	$NetBSD: cpu.h,v 1.49 2001/01/14 00:10:28 thorpej Exp $	*/
 
 /*-
  * Copyright (c) 1992, 1993
@@ -183,8 +183,8 @@ struct clockframe {
 
 #define aston()		(astpending = 1)
 
-extern int astpending;	/* need to trap before returning to user mode */
-extern int want_resched;	/* resched() was called */
+extern __volatile int astpending;	/* AST pending on return to user mode */
+extern int want_resched;		/* resched() was called */
 #ifdef MIPS3
 extern u_int	mips_L2CacheSize;
 extern int	mips_L2CacheIsSnooping; /* L2 cache snoops uncached writes ? */
diff --git a/sys/arch/mips/include/userret.h b/sys/arch/mips/include/userret.h
index cc8769338e97..52ac54a63c46 100644
--- a/sys/arch/mips/include/userret.h
+++ b/sys/arch/mips/include/userret.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: userret.h,v 1.1 2001/01/11 18:44:30 thorpej Exp $	*/
+/*	$NetBSD: userret.h,v 1.2 2001/01/14 00:10:28 thorpej Exp $	*/
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -48,11 +48,6 @@
 static __inline void
 userret(struct proc *p)
 {
-	int sig;
-
-	/* take pending signals */
-	while ((sig = CURSIG(p)) != 0)
-		postsig(sig);
 
 	curcpu()->ci_schedstate.spc_curpriority = p->p_priority = p->p_usrpri;
 }
diff --git a/sys/arch/mips/mips/trap.c b/sys/arch/mips/mips/trap.c
index 38ce3b3678a5..c7acb4179b83 100644
--- a/sys/arch/mips/mips/trap.c
+++ b/sys/arch/mips/mips/trap.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: trap.c,v 1.154 2001/01/11 18:44:29 thorpej Exp $	*/
+/*	$NetBSD: trap.c,v 1.155 2001/01/14 00:10:29 thorpej Exp $	*/
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -44,7 +44,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.154 2001/01/11 18:44:29 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.155 2001/01/14 00:10:29 thorpej Exp $");
 
 #include "opt_cputype.h"	/* which mips CPU levels do we support? */
 #include "opt_ktrace.h"
@@ -91,7 +91,7 @@ __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.154 2001/01/11 18:44:29 thorpej Exp $");
 #include <sys/kgdb.h>
 #endif
 
-int astpending;
+__volatile int astpending;
 int want_resched;
 
 const char *trap_type[] = {
@@ -691,23 +691,34 @@ ast(pc)
 	unsigned pc;		/* program counter where to continue */
 {
 	struct proc *p = curproc;
+	int sig;
 
-	uvmexp.softs++;
-	astpending = 0;
+	while (astpending) {
+		uvmexp.softs++;
+		astpending = 0;
 
-	if (p->p_flag & P_OWEUPC) {
-		p->p_flag &= ~P_OWEUPC;
-		ADDUPROF(p);
+		if (p->p_flag & P_OWEUPC) {
+			p->p_flag &= ~P_OWEUPC;
+			ADDUPROF(p);
+		}
+
+		/* Take pending signals. */
+		while ((sig = CURSIG(p)) != 0)
+			postsig(sig);
+
+		if (want_resched) {
+			/*
+			 * We are being preempted.
+			 */
+			preempt(NULL);
+
+			/* Running again; take any new pending signals. */
+			while ((sig = CURSIG(p)) != 0)
+				postsig(sig);
+		}
+
+		userret(p);
 	}
-
-	if (want_resched) {
-		/*
-		 * We are being preempted.
-		 */
-		preempt(NULL);
-	}
-
-	userret(p);
 }
 
 /*