Various debugging.
 [rsc] --rw-rw-r-- M 4315 glenda sys 6554 Nov  9 06:54 sys/src/9/pc/dat.h
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/dat.h:111,117 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/dat.h:111,119
	  	Page*	mmupdb;			/* page directory base */
	  	Page*	mmufree;		/* unused page table pages */
	  	Page*	mmuused;		/* used page table pages */
	+ 	Page*	kmaptable;		/* page table used by kmap */
	  	uint	lastkmap;		/* last entry used by kmap */
	+ 	int	nkmap;		/* number of current kmaps */
	  };
	  
	  /*
 [rsc] --rw-rw-r-- M 4315 glenda sys 23004 Nov  9 06:54 sys/src/9/port/devcons.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/devcons.c:227,236 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/devcons.c:227,258
	  	return n;
	  }
	  
	+ /*
	+  * Want to interlock iprints to avoid interlaced output on 
	+  * multiprocessor, but don't want to deadlock if one processor
	+  * dies during print and another has something important to say.
	+  * Make a good faith effort.
	+  */
	+ static Lock iprintlock;
	+ static int
	+ iprintcanlock(Lock *l)
	+ {
	+ 	int i;
	+ 	
	+ 	for(i=0; i<1000; i++){
	+ 		if(canlock(l))
	+ 			return 1;
	+ 		if(l->m == MACHP(m->machno))
	+ 			return 0;
	+ 		microdelay(100);
	+ 	}
	+ 	return 0;
	+ }
	+ 
	  int
	  iprint(char *fmt, ...)
	  {
	- 	int n, s;
	+ 	int n, s, locked;
	  	va_list arg;
	  	char buf[PRINTSIZE];
	  
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/devcons.c:238,246 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/devcons.c:260,271
	  	va_start(arg, fmt);
	  	n = vseprint(buf, buf+sizeof(buf), fmt, arg) - buf;
	  	va_end(arg);
	+ 	locked = iprintcanlock(&iprintlock);
	  	if(screenputs != nil && iprintscreenputs)
	  		screenputs(buf, n);
	  	uartputs(buf, n);
	+ 	if(locked)
	+ 		unlock(&iprintlock);
	  	splx(s);
	  
	  	return n;
 [rsc] --rw-rw-r-- M 4315 glenda sys 11124 Nov  9 06:54 sys/src/9/port/page.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/page.c:22,32 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/page.c:22,33
	  		pm = &palloc.mem[i];
	  		np += pm->npage;
	  	}
	- 	palloc.head = xalloc(np*sizeof(Page));
	- 	if(palloc.head == 0)
	+ 	palloc.pages = xalloc(np*sizeof(Page));
	+ 	if(palloc.pages == 0)
	  		panic("pageinit");
	  
	  	color = 0;
	+ 	palloc.head = palloc.pages;
	  	p = palloc.head;
	  	for(i=0; i<nelem(palloc.mem); i++){
	  		pm = &palloc.mem[i];
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/page.c:44,50 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/page.c:45,51
	  	palloc.head->prev = 0;
	  	palloc.tail->next = 0;
	  
	- 	palloc.user = p - palloc.head;
	+ 	palloc.user = p - palloc.pages;
	  	pkb = palloc.user*BY2PG/1024;
	  	vkb = pkb + (conf.nswap*BY2PG)/1024;
	  
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/page.c:323,329 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/page.c:324,340
	  
	  	pageunchain(np);
	  	pagechaintail(np);
	- 
	+ /*
	+ * XXX - here's a bug? - np is on the freelist but it's not really free.
	+ * when we unlock palloc someone else can come in, decide to
	+ * use np, and then try to lock it.  they succeed after we've 
	+ * run copypage and cachepage and unlock(np).  then what?
	+ * they call pageunchain before locking(np), so it's removed
	+ * from the freelist, but still in the cache because of
	+ * cachepage below.  if someone else looks in the cache
	+ * before they remove it, the page will have a nonzero ref
	+ * once they finally lock(np).
	+ */
	  	lock(np);
	  	unlock(&palloc);
	  
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/page.c:526,528 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/page.c:537,652
	  	}
	  	free(p);
	  }
	+ 
	+ ulong
	+ pagenumber(Page *p)
	+ {
	+ 	return p-palloc.pages;
	+ }
	+ 
	+ void
	+ checkpagerefs(void)
	+ {
	+ 	int s;
	+ 	ulong i, np, nwrong;
	+ 	ulong *ref;
	+ 	
	+ 	np = palloc.user;
	+ 	ref = malloc(np*sizeof ref[0]);
	+ 	if(ref == nil){
	+ 		print("checkpagerefs: out of memory\n");
	+ 		return;
	+ 	}
	+ 	
	+ 	/*
	+ 	 * This may not be exact if there are other processes
	+ 	 * holding refs to pages on their stacks.  The hope is
	+ 	 * that if you run it on a quiescent system it will still
	+ 	 * be useful.
	+ 	 */
	+ 	s = splhi();
	+ 	lock(&palloc);
	+ 	countpagerefs(ref, 0);
	+ 	portcountpagerefs(ref, 0);
	+ 	nwrong = 0;
	+ 	for(i=0; i<np; i++){
	+ 		if(palloc.pages[i].ref != ref[i]){
	+ 			iprint("page %#.8lux ref %d actual %lud\n", 
	+ 				palloc.pages[i].pa, palloc.pages[i].ref, ref[i]);
	+ 			ref[i] = 1;
	+ 			nwrong++;
	+ 		}else
	+ 			ref[i] = 0;
	+ 	}
	+ 	countpagerefs(ref, 1);
	+ 	portcountpagerefs(ref, 1);
	+ 	iprint("%lud mistakes found\n", nwrong);
	+ 	unlock(&palloc);
	+ 	splx(s);
	+ }
	+ 
	+ void
	+ portcountpagerefs(ulong *ref, int print)
	+ {
	+ 	ulong i, j, k, ns, n;
	+ 	Page **pg, *entry;
	+ 	Proc *p;
	+ 	Pte *pte;
	+ 	Segment *s;
	+ 
	+ 	/*
	+ 	 * Pages in segments.  s->mark avoids double-counting.
	+ 	 */
	+ 	n = 0;
	+ 	ns = 0;
	+ 	for(i=0; i<conf.nproc; i++){
	+ 		p = proctab(i);
	+ 		for(j=0; j<NSEG; j++){
	+ 			s = p->seg[j];
	+ 			if(s)
	+ 				s->mark = 0;
	+ 		}
	+ 	}
	+ 	for(i=0; i<conf.nproc; i++){
	+ 		p = proctab(i);
	+ 		for(j=0; j<NSEG; j++){
	+ 			s = p->seg[j];
	+ 			if(s == nil || s->mark++)
	+ 				continue;
	+ 			ns++;
	+ 			for(k=0; k<s->mapsize; k++){
	+ 				pte = s->map[k];
	+ 				if(pte == nil)
	+ 					continue;
	+ 				for(pg = pte->first; pg <= pte->last; pg++){
	+ 					entry = *pg;
	+ 					if(pagedout(entry))
	+ 						continue;
	+ 					if(print){
	+ 						if(ref[pagenumber(entry)])
	+ 							iprint("page %#.8lux in segment %#p\n", entry->pa, s);
	+ 						continue;
	+ 					}
	+ 					if(ref[pagenumber(entry)]++ == 0)
	+ 						n++;
	+ 				}
	+ 			}
	+ 		}
	+ 	}
	+ 	if(!print){
	+ 		iprint("%lud pages in %lud segments\n", n, ns);
	+ 		for(i=0; i<conf.nproc; i++){
	+ 			p = proctab(i);
	+ 			for(j=0; j<NSEG; j++){
	+ 				s = p->seg[j];
	+ 				if(s == nil)
	+ 					continue;
	+ 				if(s->ref != s->mark){
	+ 					iprint("segment %#.8lux (used by proc %lud pid %lud) has bad ref count %lud actual %lud\n",
	+ 						s, i, p->pid, s->ref, s->mark);
	+ 				}
	+ 			}
	+ 		}
	+ 	}
	+ }
	+ 
 [rsc] --rw-rw-r-- M 4315 glenda sys 22702 Nov  9 06:54 sys/src/9/port/portdat.h
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/portdat.h:416,421 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/portdat.h:416,422
	  	Pte	**map;
	  	int	mapsize;
	  	Pte	*ssegmap[SSEGMAPSIZE];
	+ 	ulong	mark;	/* portcountrefs */
	  };
	  
	  enum
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/portdat.h:494,499 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/portdat.h:495,501
	  	Page	*head;			/* most recently used */
	  	Page	*tail;			/* least recently used */
	  	ulong	freecount;		/* how many pages on free list now */
	+ 	Page	*pages;			/* array of all pages */
	  	ulong	user;			/* how many user pages */
	  	Page	*hash[PGHSIZE];
	  	Lock	hashlock;
 [rsc] --rw-rw-r-- M 4315 glenda sys 11022 Nov  9 06:54 sys/src/9/port/portfns.h
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/portfns.h:45,50 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/portfns.h:45,51
	  Block*		concatblock(Block*);
	  Block*		copyblock(Block*, int);
	  void		copypage(Page*, Page*);
	+ void		countpagerefs(ulong*, int);
	  int		cread(Chan*, uchar*, int, vlong);
	  void		cunmount(Chan*, Chan*);
	  void		cupdate(Chan*, uchar*, int, vlong);
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/portfns.h:204,209 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/portfns.h:205,211
	  Block*		padblock(Block*, int);
	  void		pagechainhead(Page*);
	  void		pageinit(void);
	+ ulong	pagenumber(Page*);
	  void		pagersummary(void);
	  void		panic(char*, ...);
	  Cmdbuf*		parsecmd(char *a, int n);
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/portfns.h:214,219 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/portfns.h:216,222
	  void		pgrpnote(ulong, char*, long, int);
	  void		pio(Segment *, ulong, ulong, Page **);
	  #define		poperror()		up->nerrlab--
	+ void		portcountpagerefs(ulong*, int);
	  int		postnote(Proc*, int, char*, int);
	  int		pprint(char*, ...);
	  int		preempted(void);
 [rsc] --rw-rw-r-- M 4315 glenda sys 15145 Nov  9 06:54 sys/src/9/port/sysproc.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/port/sysproc.c:12,25 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/port/sysproc.c:12,23
	  int	shargs(char*, int, char**);
	  
	  extern void checkpages(void);
	+ extern void checkpagerefs(void);
	  
	  long
	  sysr1(ulong*)
	  {
	- 	extern int chandebug;
	- 	
	- 	chandebug = !chandebug;
	- 	checkpages();
	+ 	checkpagerefs();
	  	return 0;
	  }
	  
 [rsc] --rw-rw-r-- M 4315 glenda sys 4981 Nov  9 07:14 sys/src/9/alphapc/mmu.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/alphapc/mmu.c:278,280 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/alphapc/mmu.c:278,284
	  {
	  }
	  
	+ void
	+ countpagerefs(ulong*, int)
	+ {
	+ }
 [rsc] --rw-rw-r-- M 4315 glenda bitsy 11298 Nov  9 07:14 sys/src/9/bitsy/mmu.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/bitsy/mmu.c:505,508 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/bitsy/mmu.c:505,516
	  	}
	  }
	  
	- void checkmmu(ulong, ulong) { }
	+ void
	+ checkmmu(ulong, ulong)
	+ {
	+ }
	+ 
	+ void
	+ countpagerefs(ulong*, int)
	+ {
	+ }
 [rsc] --rw-rw-r-- M 4315 glenda sys 4458 Nov  9 07:14 sys/src/9/mtx/mmu.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/mtx/mmu.c:231,234 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/mtx/mmu.c:231,242
	  	}
	  }
	  
	- void checkmmu(ulong, ulong) { }
	+ void
	+ checkmmu(ulong, ulong)
	+ {
	+ }
	+ 
	+ void
	+ countpagerefs(ulong*, int)
	+ {
	+ }
 [rsc] --rw-rw-r-- M 4315 glenda sys 17317 Nov  9 07:15 sys/src/9/pc/mp.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/mp.c:145,151 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/mp.c:145,151
	  	/*
	  	 * Map the I/O APIC.
	  	 */
	- 	if((va = vmap(p->addr, 1024)) == 0)
	+ 	if((va = vmap(p->addr, 1024)) == nil)
	  		return 0;
	  
	  	apic = &mpapic[p->apicno];
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/mp.c:152,157 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/mp.c:152,158
	  	apic->type = PcmpIOAPIC;
	  	apic->apicno = p->apicno;
	  	apic->addr = va;
	+ 	apic->paddr = p->addr;
	  	apic->flags = p->flags;
	  
	  	return apic;
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/mp.c:483,488 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/mp.c:484,490
	  	 */
	  	if((va = vmap(pcmp->lapicbase, 1024)) == nil)
	  		return;
	+ 	print("LAPIC: %.8lux %.8lux\n", pcmp->lapicbase, (ulong)va);
	  
	  	bpapic = nil;
	  
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/mp.c:514,519 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/mp.c:516,522
	  			 * first in the table before the others.
	  			 */
	  			apic->addr = va;
	+ 			apic->paddr = pcmp->lapicbase;
	  			if(apic->flags & PcmpBP)
	  				bpapic = apic;
	  		}
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/mp.c:667,672 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/mp.c:670,676
	  			vno = lo & 0xFF;
	  			n = mpintrinit(bus, aintr->intr, vno, v->irq);
	  			n |= ApicLOGICAL;
	+ 			lo &= ~(ApicRemoteIRR|ApicDELIVS);
	  			if(n != lo || !(n & ApicLEVEL)){
	  				print("mpintrenable: multiple botch irq%d, tbdf %uX, lo %8.8uX, n %8.8uX\n",
	  					v->irq, tbdf, lo, n);
 [rsc] --rw-rw-r-- M 4315 glenda sys 6652 Nov  9 07:15 sys/src/9/pc/mp.h
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/mp.h:157,162 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/mp.h:157,163
	  	int	type;
	  	int	apicno;
	  	ulong*	addr;			/* register base address */
	+ 	ulong	paddr;
	  	int	flags;			/* PcmpBP|PcmpEN */
	  
	  	Lock;				/* I/O APIC: register access */
 [rsc] --rw-rw-r-- M 4315 glenda sys 55207 Nov  9 07:14 sys/src/9/pc/sd53c8xx.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/sd53c8xx.c:2182,2188 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/sd53c8xx.c:2182,2188
	  		/*
	  		 * Because we don't yet have an abstraction for the
	  		 * addresses as seen from the controller side (and on
	- 		 * the 386 it doesn't matter), the follwong two lines
	+ 		 * the 386 it doesn't matter), the following two lines
	  		 * are different between the 386 and alpha copies of
	  		 * this driver.
	  		 */
 [rsc] --rw-rw-r-- M 4315 jmk sys 22616 Nov  9 07:16 sys/src/9/pc/ethervt6102.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/ethervt6102.c:948,953 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/ethervt6102.c:948,954
	  		default:
	  			continue;
	  		case (0x3065<<16)|0x1106:	/* Rhine II */
	+ 		case (0x3106<<16)|0x1106:	/* Rhine III */
	  			break;
	  		}
	  
 [rsc] --rw-rw-r-- M 4315 presotto sys 4934 Nov  9 07:14 sys/src/9/ppc/mmu.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/ppc/mmu.c:258,261 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/ppc/mmu.c:258,269
	  
	  }
	  
	- void checkmmu(ulong, ulong) { }
	+ void
	+ checkmmu(ulong, ulong)
	+ {
	+ }
	+ 
	+ void
	+ countpagerefs(ulong*, int)
	+ {
	+ }
 [rsc] --rw-rw-r-- M 4315 glenda sys 18191 Nov  9 16:55 sys/src/9/pc/memory.c
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/memory.c:633,639 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/memory.c:633,640
	  {
	  	int i;
	  	Ureg u;
	- 	ulong cont, base, last, len;
	+ 	ulong cont, base, len;
	+ 	uvlong last;
	  	Emap *e;
	  
	  	if(getconf("*norealmode") || getconf("*noe820scan"))
	/n/sourcesdump/2005/1109/plan9/sys/src/9/pc/memory.c:696,702 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/9/pc/memory.c:697,704
	  		else
	  			map(base, len, MemReserved);
	  	}
	- 	
	+ 	if(last < (1LL<<32))
	+ 		map(last, (u32int)-last, MemUPA);
	  	return 0;
	  }
	  

Snap mouse to border when grabbing to resize.
 [rsc] --rw-rw-r-- M 4315 glenda sys 22788 Nov  9 16:18 sys/src/cmd/rio/rio.c
	/n/sourcesdump/2005/1109/plan9/sys/src/cmd/rio/rio.c:887,892 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/cmd/rio/rio.c:887,924
	  	return ni;
	  }
	  
	+ Point
	+ cornerpt(Rectangle r, Point p, int which)
	+ {
	+ 	switch(which){
	+ 	case 0:	/* top left */
	+ 		p = Pt(r.min.x, r.min.y);
	+ 		break;
	+ 	case 2:	/* top right */
	+ 		p = Pt(r.max.x,r.min.y);
	+ 		break;
	+ 	case 6:	/* bottom left */
	+ 		p = Pt(r.min.x, r.max.y);
	+ 		break;
	+ 	case 8:	/* bottom right */
	+ 		p = Pt(r.max.x, r.max.y);
	+ 		break;
	+ 	case 1:	/* top edge */
	+ 		p = Pt(p.x,r.min.y);
	+ 		break;
	+ 	case 5:	/* right edge */
	+ 		p = Pt(r.max.x, p.y);
	+ 		break;
	+ 	case 7:	/* bottom edge */
	+ 		p = Pt(p.x, r.max.y);
	+ 		break;
	+ 	case 3:		/* left edge */
	+ 		p = Pt(r.min.x, p.y);
	+ 		break;
	+ 	}
	+ 	return p;
	+ }
	+ 
	  Rectangle
	  whichrect(Rectangle r, Point p, int which)
	  {
	/n/sourcesdump/2005/1109/plan9/sys/src/cmd/rio/rio.c:928,935 - 
	/n/sourcesdump/2005/1110/plan9/sys/src/cmd/rio/rio.c:960,970
	  	int which, but;
	  
	  	p = mouse->xy;
	- 	startp = p;
	+ 	
	  	which = whichcorner(w, p);
	+ 	startp = cornerpt(w->screenr, p, which);
	+ 	wmovemouse(w, startp);
	+ 	readmouse(mousectl);
	  	r = whichrect(w->screenr, p, which);
	  	drawborder(r, 1);
	  	or = r;