From 90f6e3533941b1db7af8caf03641c3275d111a4f Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Fri, 26 Jul 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-07-26

---
 port/alarm.c   | 25 ++++++++++++-------------
 port/qlock.c   |  3 +++
 port/segment.c | 28 +++++++++++++++++-----------
 port/swap.c    |  2 ++
 power/fns.h    |  1 +
 power/l.s      |  5 +++++
 power/lock.c   | 12 +++++-------
 7 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/port/alarm.c b/port/alarm.c
index 23aa3f96f57326873f2616a1cdffbfa16631ce5d..a22e465921ca5518c80d25fd77c95b59a88f08d4 100644
--- a/port/alarm.c
+++ b/port/alarm.c
@@ -107,20 +107,19 @@ checkalarms(void)
 					(*f)(alist[i]);
 				alist[i]->busy = 0;
 			}
-		} else
+		}else
 			unlock(&m->alarmlock);
 	}
 
-	if(m == MACHP(0) && canqlock(&alarms)) {
+	if(m == MACHP(0) && canqlock(&alarms)){
 		now = MACHP(0)->ticks;
-		while((rp = alarms.head) && rp->alarm <= now) {
-			if(rp->alarm != 0L) {
-				if(canlock(&rp->debug)) {
+		while((rp = alarms.head) && rp->alarm <= now){
+			if(rp->alarm != 0L){
+				if(canlock(&rp->debug)){
 					postnote(rp, 0, "alarm", NUser);
 					unlock(&rp->debug);
 					rp->alarm = 0L;
-				}
-				else
+				}else
 					break;
 			}
 			alarms.head = rp->palarm;
@@ -137,7 +136,7 @@ procalarm(ulong time)
 
 	when = MS2TK(time);
 	old = u->p->alarm - MACHP(0)->ticks;
-	if(when == 0) {
+	if(when == 0){
 		u->p->alarm = 0;
 		return TK2MS(old);
 	}
@@ -146,8 +145,8 @@ procalarm(ulong time)
 
 	qlock(&alarms);
 	l = &alarms.head;
-	for(f = *l; f; f = f->palarm) {
-		if(u->p == f) {
+	for(f = *l; f; f = f->palarm){
+		if(u->p == f){
 			*l = f->palarm;
 			break;
 		}
@@ -155,10 +154,10 @@ procalarm(ulong time)
 	}
 
 	u->p->palarm = 0;
-	if(alarms.head) {
+	if(alarms.head){
 		l = &alarms.head;
-		for(f = *l; f; f = f->palarm) {
-			if(f->alarm > when) {
+		for(f = *l; f; f = f->palarm){
+			if(f->alarm > when){
 				u->p->palarm = f;
 				*l = u->p;
 				goto done;
diff --git a/port/qlock.c b/port/qlock.c
index 5dceace5faba4e34496d0e28f8e68b4e1b17867c..3596a991b5fc892ea2368915618347f95e766d67 100644
--- a/port/qlock.c
+++ b/port/qlock.c
@@ -53,7 +53,10 @@ qunlock(QLock *q)
 		unlock(&q->queue);
 		ready(p);
 	}else{
+		/* horrible botch because clock does a canqlock */
+		int s = splhi();
 		unlock(&q->use);
 		unlock(&q->queue);
+		splx(s);
 	}
 }
diff --git a/port/segment.c b/port/segment.c
index d3821698de89b87601f0d19692de60959cc9a812..00f8ba08410ff9a9f7b2aae033850ecee4ba3ccb 100644
--- a/port/segment.c
+++ b/port/segment.c
@@ -94,20 +94,26 @@ putseg(Segment *s)
 	Pte **pp, **emap;
 	Image *i;
 
-	if(s && decref(s) == 0) {
+	if(s == 0)
+		return;
+
+	i = s->image;
+	if(i && i->s == s && s->ref == 1){
+		lock(i);
+		if(s->ref == 1)
+			i->s = 0;
+		unlock(i);
+	}
+
+	if(decref(s) == 0) {
+		if(i)
+			putimage(i);
+
 		emap = &s->map[SEGMAPSIZE];
 		for(pp = s->map; pp < emap; pp++)
 			if(*pp)
 				freepte(s, *pp);
 
-		if(i = s->image) {
-			lock(i);
-			if(i->s == s)
-				i->s = 0;
-			unlock(i);
-			putimage(i);
-		}
-
 		lock(&segalloc);
 		s->next = segalloc.free;		
 		segalloc.free = s;
@@ -395,10 +401,10 @@ mfreeseg(Segment *s, ulong start, int pages)
 					goto done;
 				j++;
 			}
-			j = 0;
 		}
 		else
-			pages -= PTEMAPMEM/BY2PG;
+			pages -= PTEPERTAB-j;
+		j = 0;
 	}
 done:
 	flushmmu();
diff --git a/port/swap.c b/port/swap.c
index 96d467b01a0be9a2bc387aa94769024122002af4..cda70a5817c10f10fcb54e2bb0883d4a55fe521a 100644
--- a/port/swap.c
+++ b/port/swap.c
@@ -114,6 +114,8 @@ pager(void *junk)
 
 			sleep(&swapalloc.r, needpages, 0);
 
+			if(p->state == Dead || p->kp)
+				continue;
 			if(swapimage.c) {
 				for(i = 0; i < NSEG; i++)
 					if(s = p->seg[i]) {
diff --git a/power/fns.h b/power/fns.h
index fe510987b8d97bdb258ee5e56bcc0c3f9d66074b..babdeba88325b22475a0fd7f8e24de138355680a 100644
--- a/power/fns.h
+++ b/power/fns.h
@@ -26,6 +26,7 @@ void	flushmmu(void);
 void	gettlb(int, ulong*);
 ulong	gettlbvirt(int);
 void	gotopc(ulong);
+ulong	getcallerpc(void);
 void	icflush(void *, ulong);
 void	ioboardinit(void);
 void	intr(Ureg*);
diff --git a/power/l.s b/power/l.s
index bdf4e88568a20b94b89fa54314a1685837ced655..80777f92b1434f2d2d01d6b433debc55280376bc 100644
--- a/power/l.s
+++ b/power/l.s
@@ -146,6 +146,11 @@ TEXT	gotolabel(SB), $-4
 	MOVW	4(R2), R29
 	RET
 
+TEXT	getcallerpc(SB), $0
+
+	MOVW	(SP), R1
+	RET
+
 TEXT	gotopc(SB), $8
 
 	MOVW	$(64*1024), R1
diff --git a/power/lock.c b/power/lock.c
index 56121e54369008cac80f0db52037e2ad1a7a197a..7c2fca8664c54e22215d41a8a323d0c464f6fd9b 100644
--- a/power/lock.c
+++ b/power/lock.c
@@ -103,15 +103,12 @@ lkpgfree(Page *pg)
 	unlock(&semalloc.lock);
 }
 
-#define PCOFF -9
-
 /*
  * If l->sbsem is zero, allocate a hardware semaphore first.
  */
 void
-lock(Lock *ll)
+lock(Lock *l)
 {
-	Lock *l = ll;
 	int i;
 	ulong *sbsem;
 
@@ -133,16 +130,16 @@ lock(Lock *ll)
 	 * Try the fast grab first
 	 */
 	if((*sbsem&1) == 0){
-		l->pc = ((ulong*)&ll)[PCOFF];
+		l->pc = getcallerpc();
 		return;
 	}
 	for(i=0; i<10000000; i++)
     		if((*sbsem&1) == 0){
-			l->pc = ((ulong*)&ll)[PCOFF];
+			l->pc = getcallerpc();
 			return;
 	}
 	*sbsem = 0;
-	print("lock loop %lux pc %lux held by pc %lux\n", l, ((ulong*)&ll)[PCOFF], l->pc);
+	print("lock loop %lux pc %lux held by pc %lux\n", l, getcallerpc(), l->pc);
 	dumpstack();
 }
 
@@ -167,6 +164,7 @@ canlock(Lock *l)
 	}
 	if(*sbsem & 1)
 		return 0;
+	l->pc = getcallerpc();
 	return 1;
 }