Various mmu cleanups.
 [rsc] --rw-rw-r-- M 208448 glenda sys 24152 Jan  3 19:54 sys/src/9/pc/mmu.c
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:211,216 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:211,217
	  	ulong *pdb;
	  
	  	s = splhi();
	+ 	m->pdballoc++;
	  	if(m->pdbpool == 0){
	  		spllo();
	  		page = newpage(0, 0, 0);
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:234,239 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:235,241
	  {
	  	if(islo())
	  		panic("mmupdbfree: islo");
	+ 	m->pdbfree++;
	  	if(m->pdbcnt >= 10){
	  		p->next = proc->mmufree;
	  		proc->mmufree = p;
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:240,245 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:242,248
	  	}else{
	  		p->next = m->pdbpool;
	  		m->pdbpool = p;
	+ 		m->pdbcnt++;
	  	}
	  }
	  
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:322,331 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:325,335
	  void
	  mmurelease(Proc* proc)
	  {
	- 	int s;
	  	Page *page, *next;
	  	ulong *pdb;
	  
	+ 	if(islo())
	+ 		panic("mmurelease: islo");
	  	taskswitch(PADDR(m->pdb), (ulong)m + BY2PG);
	  	if(proc->kmaptable){
	  		if(proc->mmupdb == nil)
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:337,343 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:341,346
	  		/*
	  		 * remove kmaptable from pdb before putting pdb up for reuse.
	  		 */
	- 		s = splhi();
	  		pdb = tmpmap(proc->mmupdb);
	  		if(PPN(pdb[PDX(KMAP)]) != proc->kmaptable->pa)
	  			panic("mmurelease: bad kmap pde %#.8lux kmap %#.8lux",
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:344,350 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:347,352
	  				pdb[PDX(KMAP)], proc->kmaptable->pa);
	  		pdb[PDX(KMAP)] = 0;
	  		tmpunmap(pdb);
	- 		splx(s);
	  		/*
	  		 * move kmaptable to free list.
	  		 */
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:383,389 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:385,392
	  	pdb[PDX(MACHADDR)] = m->pdb[PDX(MACHADDR)];
	  	tmpunmap(pdb);
	  	up->mmupdb = page;
	- 	mmuflushtlb(up->mmupdb->pa);
	+ //XXX should have this	m->tss->cr3 = up->mmupdb->pa;
	+ 	putcr3(up->mmupdb->pa);
	  	splx(s);
	  }
	  	
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:393,405 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:396,407
	  void
	  putmmu(ulong va, ulong pa, Page*)
	  {
	- 	int old, s;
	+ 	int old;
	  	Page *page;
	  
	  	if(up->mmupdb == nil)
	  		upallocpdb();
	  
	- 	s = splhi();
	  	if(!(vpd[PDX(va)]&PTEVALID)){
	  		if(up->mmufree == 0)
	  			page = newpage(0, 0, 0);
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:418,424 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:420,427
	  	vpt[VPTX(va)] = pa|PTEUSER|PTEVALID;
	  	if(old&PTEVALID)
	  		flushpg(va);
	- 	splx(s);
	+ 	if(getcr3() != up->mmupdb->pa)
	+ 		print("bad cr3 %.8lux %.8lux\n", getcr3(), up->mmupdb->pa);
	  }
	  
	  /*
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:572,578 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:575,581
	  		n = (size+4*MB-1) / (4*MB);
	  		if((o = findhole(vpdb, vpdbsize, n)) != -1)
	  			return VMAP + o*4*MB;
	- 		return VMAP + o;
	+ 		return 0;
	  	}
	  	n = (size+BY2PG-1) / BY2PG;
	  	for(i=0; i<vpdbsize; i++)
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/mmu.c:988,995 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/mmu.c:991,1002
	  					pg->pa, i);
	  		}
	  	}
	- 	if(!print)
	+ 	if(!print){
	  		iprint("%d pages in mach pdbpools\n", n);
	+ 		for(i=0; i<conf.nmach; i++)
	+ 			iprint("cpu%d: %d pdballoc, %d pdbfree\n",
	+ 				i, MACHP(i)->pdballoc, MACHP(i)->pdbfree);
	+ 	}
	  }
	  
	  void
 [rsc] --rw-rw-r-- M 208448 glenda sys 13971 Jan  3 19:54 sys/src/9/pc/screen.c
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/screen.c:511,516 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/screen.c:511,522
	  	npaddr = paddr-x;
	  	nsize = PGROUND(size+x);
	  
	+ 	/*
	+ 	 * Don't bother trying to map more than 4000x4000x32 = 64MB.
	+ 	 * We only have a 256MB window.
	+ 	 */
	+ 	if(nsize > 64*MB)
	+ 		nsize = 64*MB;
	  	scr->vaddr = vmap(npaddr, nsize);
	  	if(scr->vaddr == 0)
	  		error("cannot allocate vga frame buffer");
 [jmk] --rw-rw-r-- M 208448 glenda sys 6583 Jan  3 22:57 sys/src/9/pc/dat.h
	/n/sourcesdump/2006/0103/plan9/sys/src/9/pc/dat.h:214,219 - 
	/n/sourcesdump/2006/0104/plan9/sys/src/9/pc/dat.h:214,221
	  	int	havetsc;
	  	int	havepge;
	  	uvlong	tscticks;
	+ 	int	pdballoc;
	+ 	int	pdbfree;
	  
	  	vlong	mtrrcap;
	  	vlong	mtrrdef;