1991/0115/ss/mmu.c (diff list | history)

1991/0115/sys/src/9/ss/mmu.c:1,363 – 1991/01151/sys/src/9/ss/mmu.c:1,355 (short | long | prev | next)
1990/1223		#include "u.h" #include "lib.h" #include "mem.h" #include "dat.h" #include "fns.h"
1990/1226		#include "io.h"
1990/1223		struct { Lock; int init;
1990/1226		int lowpmeg;
1990/1223		KMap *free;
1990/1226		KMap arena[(IOEND-IOSEGM)/BY2PG];
1990/1223		}kmapalloc;
1991/0111		#define NKLUDGE 12
1991/0110
1990/1223		/*
1990/1226		* On SPARC, tlbpid i == context i-1 so that 0 means unallocated */ int newpid(Proc*); void purgepid(int);
1991/0110		int pidtime[NTLBPID]; /* should be per m */
1990/1226		/*
1990/1223		* Called splhi, not in Running state */ void mapstack(Proc *p) {
1990/1226		short tp; ulong tlbphys;
1990/1223
1990/1226		tp = p->pidonmach[m->machno]; if(tp == 0){ tp = newpid(p); p->pidonmach[m->machno] = tp; }
1990/1223		if(p->upage->va != (USERADDR|(p->pid&0xFFFF)))
1991/0110		panic("mapstack %s %d %lux 0x%lux 0x%lux", p->text, p->pid, p->upage, p->upage->pa, p->upage->va);
1990/1226		tlbphys = PPN(p->upage->pa)|PTEVALID|PTEWRITE|PTEKERNEL|PTEMAINMEM; putcontext(tp-1);
1990/1227		/*
1991/0110		* shouldn't need putpmeg because nothing has been mapped at * USERADDR in this context except this page. however, it crashes.
1990/1227		*/
1990/1226		putpmeg(USERADDR, tlbphys);
1990/1223		u = (User*)USERADDR;
1990/1226		}
1990/1223
1990/1226		/* * Process must be non-interruptible */ int newpid(Proc *p) {
1991/0109		int i, j, k;
1991/0110		ulong t;
1990/1226		Proc *sp;
1991/0110		t = ~0; i = 1+((m->ticks)&(NCONTEXT-1)); /* random guess */ for(j=1; j<NTLBPID; j++) if(pidtime[j] < t){ i = j; t = pidtime[j]; }
1990/1226		sp = m->pidproc[i];
1991/0115		if(sp)
1990/1226		sp->pidonmach[m->machno] = 0;
1991/0115		purgepid(i); /* also does putcontext */
1991/0110		pidtime[i] = m->ticks;
1990/1226		m->pidproc[i] = p; m->lastpid = i;
1991/0111
1990/1223		/*
1991/0112		* kludge: each context is allowed NKLUDGE pmegs. * NKLUDGE-1 for text & data and 1 for stack. * initialize by giving just a stack segment.
1990/1223		*/
1991/0112		i--; /* now i==context */ p->nmmuseg = 0;
1991/0110		for(j=0; j<NKLUDGE-1; j++)
1991/0112		putsegm(UZERO+j*BY2SEGM, INVALIDPMEG); putsegm(TSTKTOP-BY2SEGM, kmapalloc.lowpmeg+NKLUDGE*i+(NKLUDGE-1)); for(j=0; j<PG2SEGM; j++)
1990/1226		putpmeg((TSTKTOP-BY2SEGM)+j*BY2PG, INVALIDPTE);
1991/0112		return i+1;
1990/1226		}
1990/1223
1990/1226		void
1990/1231		putcontext(int c) { putcxreg(c); } void
1991/0110		flushcontext(void)
1990/1226		{
1991/0110		int i;
1990/1223
1991/0110		/* * Clear context from cache */ for(i=0; i<0x1000; i+=16) putwE16((i<<4), 0); } void purgepid(int pid) {
1990/1226		putcontext(pid-1);
1991/0110		flushcontext();
1990/1223		}
1990/1226
1990/1223		void
1990/1226		mmuinit(void)
1990/1223		{
1990/1226		ulong l, i, j, c, pte; /* * First map lots of memory as kernel addressable in all contexts */ i = 0; /* used */ for(c=0; c<NCONTEXT; c++) for(i=0; i<conf.maxialloc/BY2SEGM; i++) putcxsegm(c, KZERO+i*BY2SEGM, i); kmapalloc.lowpmeg = i; /* * Make sure cache is turned on for kernel */ pte = PTEVALID|PTEWRITE|PTEKERNEL|PTEMAINMEM; for(i=0; i<conf.maxialloc/BY2PG; i++) putpmeg(KZERO+i*BY2PG, pte+i); /* * Create invalid pmeg; use highest segment */ putsegm(INVALIDSEGM, INVALIDPMEG); for(i=0; i<PG2SEGM; i++) putpmeg(INVALIDSEGM+i*BY2PG, INVALIDPTE); for(c=0; c<NCONTEXT; c++){ putcontext(c); putsegm(INVALIDSEGM, INVALIDPMEG); /* * Invalidate user addresses */
1990/1227		for(l=UZERO; l<(KZERO&VAMASK); l+=BY2SEGM)
1990/1226		putsegm(l, INVALIDPMEG);
1990/1227
1991/0111		#ifdef doesntwork
1990/1226		/*
1991/0111		* Invalidate high kernel addresses */ for(l=conf.maxialloc; l<IOSEGM0; l+=BY2SEGM) putsegm(l, INVALIDPMEG); #endif                  /*
1990/1226		* One segment for screen */ putsegm(SCREENSEGM, SCREENPMEG); if(c == 0){ pte = PTEVALID|PTEWRITE|PTEKERNEL|PTENOCACHE| PTEIO|((DISPLAYRAM>>PGSHIFT)&0xFFFF); for(i=0; i<PG2SEGM; i++) putpmeg(SCREENSEGM+i*BY2PG, pte+i); } /* * First page of IO space includes ROM; be careful */ putsegm(IOSEGM0, IOPMEG0); /* IOSEGM == ROMSEGM */ if(c == 0){ pte = PTEVALID|PTEKERNEL|PTENOCACHE| PTEIO|((EPROM>>PGSHIFT)&0xFFFF); for(i=0; i<PG2ROM; i++) putpmeg(IOSEGM0+i*BY2PG, pte+i); for(; i<PG2SEGM; i++) putpmeg(IOSEGM0+i*BY2PG, INVALIDPTE); } /* * Remaining segments for IO and kmap */ for(j=1; j<NIOSEGM; j++){ putsegm(IOSEGM0+j*BY2SEGM, IOPMEG0+j); if(c == 0) for(i=0; i<PG2SEGM; i++) putpmeg(IOSEGM0+j*BY2SEGM+i*BY2PG, INVALIDPTE); } } putcontext(0);
1990/1223		} void putmmu(ulong tlbvirt, ulong tlbphys) {
1990/1226		short tp; Proc *p;
1991/0112		ulong seg, l; int j, k;
1990/1223
1990/1226		splhi(); p = u->p; tp = p->pidonmach[m->machno]; if(tp == 0){ tp = newpid(p); p->pidonmach[m->machno] = tp;
1990/1223		}
1990/1226		/* * kludge part 2: make sure we've got a valid segment */
1991/0112		if(TSTKTOP-BY2SEGM<=tlbvirt && tlbvirt<TSTKTOP) /* stack; easy */ goto put; /* UZERO is known to be zero here */ if(tlbvirt < UZERO+p->nmmuseg*BY2SEGM) /* in range; easy */ goto put; seg = tlbvirt/BY2SEGM; if(seg >= (UZERO/BY2SEGM)+(NKLUDGE-1)){ pprint("putmmu %lux\n", tlbvirt); print("putmmu %lux %d %s\n", tlbvirt, seg, p->text);
1991/0111		pexit("Suicide", 1);
1991/0110		}
1991/0112		/* * Prepare mmu up to this address */
1991/0115		tp = (tp-1)*NKLUDGE; /* now tp==base of pmeg area for this proc */
1991/0112		l = UZERO+p->nmmuseg*BY2SEGM; for(j=p->nmmuseg; j<=seg; j++){ putsegm(l, kmapalloc.lowpmeg+tp+j); for(k=0; k<PG2SEGM; k++,l+=BY2PG) putpmeg(l, INVALIDPTE); } p->nmmuseg = seg+1; put:
1990/1226		putpmeg(tlbvirt, tlbphys); spllo();
1990/1223		} void
1990/1227		putpmeg(ulong virt, ulong phys) { int i;
1990/1231		int tp;
1990/1227		virt &= VAMASK; virt &= ~(BY2PG-1); /* * Flush old entries from cache */
1991/0110		for(i=0; i<0x100; i+=16) putwD16(virt+(i<<4), 0);
1990/1227		putw4(virt, phys); } void
1990/1223		flushmmu(void) {
1991/0110		int tp;
1990/1226		splhi();
1991/0110		flushcontext(); tp = u->p->pidonmach[m->machno]; if(tp) pidtime[tp] = 0;
1990/1226		/* easiest is to forget what pid we had.... */ memset(u->p->pidonmach, 0, sizeof u->p->pidonmach); /* ....then get a new one by trying to map our stack */ mapstack(u->p); spllo();
1990/1223		} void
1990/1226		cacheinit(void)
1990/1223		{
1991/0110		int c, i;
1990/1226		/* * Initialize cache by clearing the valid bit * (along with the others) in all cache entries */
1991/0110		for(c=0; c<NCONTEXT; c++){ /* necessary? */ putcontext(c); for(i=0; i<0x1000; i++) putw2(CACHETAGS+(i<<4), 0); } putcontext(0);
1990/1226		/* * Turn cache on */ putb2(ENAB, getb2(ENAB)|ENABCACHE); /**/
1990/1223		} void kmapinit(void) { KMap *k;
1990/1226		int i;
1990/1223
1991/0110		print("low pmeg %d high pmeg %d\n", kmapalloc.lowpmeg, TOPPMEG);
1990/1223		kmapalloc.free = 0;
1990/1226		k = kmapalloc.arena; for(i=0; i<(IOEND-IOSEGM)/BY2PG; i++,k++){ k->va = IOSEGM+i*BY2PG;
1990/1223		kunmap(k); } } KMap*
1990/1227		kmappa(ulong pa, ulong flag)
1990/1223		{ KMap *k;
1991/0110		ulong s;
1990/1223		lock(&kmapalloc); k = kmapalloc.free; if(k == 0){ dumpstack(); panic("kmap"); } kmapalloc.free = k->next; unlock(&kmapalloc);
1990/1227		k->pa = pa;
1990/1226		/* * Cache is virtual and a pain to deal with. * Must avoid having the same entry in the cache twice, so * must use NOCACHE or else extreme cleverness elsewhere. */
1991/0110		s = splhi();
1990/1227		putpmeg(k->va, PPN(pa)|PTEVALID|PTEKERNEL|PTEWRITE|PTENOCACHE|flag);
1991/0110		splx(s);
1990/1223		return k; }
1990/1226		KMap* kmap(Page *pg) {
1990/1227		return kmappa(pg->pa, PTEMAINMEM);
1990/1226		}
1990/1223		void kunmap(KMap *k) {
1990/1226		ulong pte; int i;
1990/1223		k->pa = 0; lock(&kmapalloc); k->next = kmapalloc.free; kmapalloc.free = k;
1990/1226		putpmeg(k->va, INVALIDPTE);
1990/1223		unlock(&kmapalloc); } void invalidateu(void) {
1990/1226		putpmeg(USERADDR, INVALIDPTE);
1990/1223		}