2000/0924/bitsy/mmu.c (diff list | history)

2000/0923/sys/src/9/bitsy/mmu.c:94,155 – 2000/0924/sys/src/9/bitsy/mmu.c:94,158 (short | long | prev | next)
2000/0923		* map special space uncached, assume that the space isn't already mapped
2000/0907		*/ ulong*
2000/0923		mapspecmeg(ulong physaddr, int len) ulong*
2000/0909		mapspecial(ulong physaddr, int len)
2000/0924		mapspecial(ulong pa, int len)
2000/0907		{ ulong *t;
2000/0921		ulong virtaddr, i, base, end, off, entry, candidate;
2000/0924		ulong va, i, base, end, off; int livelarge; ulong* rv;
2000/0907
2000/0921		base = physaddr & ~(BY2PG-1); end = (physaddr+len-1) & ~(BY2PG-1); if(len > 128*1024) usemeg = 1; off = 0; candidate = 0;
2000/0924		rv = nil; livelarge = len >= 128*1024; if(livelarge){ base = pa & ~(OneMeg-1); end = (pa+len-1) & ~(OneMeg-1); } else { base = pa & ~(BY2PG-1); end = (pa+len-1) & ~(BY2PG-1); } off = pa - base;
2000/0921
2000/0907		/* first see if we've mapped it somewhere, the first hole means we're done */
2000/0909		for(virtaddr = REGZERO; virtaddr < REGTOP; virtaddr += OneMeg){ if((l1table[virtaddr>>20] & L1TypeMask) != L1PageTable){
2000/0907		/* create a page table and break */
2000/0924		for(va = REGZERO; va < REGTOP && base >= end; va += OneMeg){ if((l1table[va>>20] & L1TypeMask) != L1PageTable){ /* found unused entry on level 1 table */ if(livelarge){ if(rv == nil) rv = (ulong*)(va+i*BY2PG+off); l1table[va>>20] = L1Section | L1KernelRW | (base&L1SectBaseMask); base += OneMeg; continue; } /* create a page table and keep going */
2000/0907		t = xspanalloc(BY2PG, 1024, 0); memzero(t, BY2PG, 0);
2000/0921		l1table[virtaddr>>20] = L1PageTable | L1Domain0 |
2000/0924		l1table[va>>20] = L1PageTable | L1Domain0 |
2000/0921		(((ulong)t) & L1PTBaseMask);
2000/0907		break; }
2000/0909		t = (ulong*)(l1table[virtaddr>>20] & L1PTBaseMask);
2000/0924		t = (ulong*)(l1table[va>>20] & L1PTBaseMask);
2000/0907		for(i = 0; i < OneMeg; i += BY2PG){
2000/0921		entry = t[(virtaddr+i)>>20];
2000/0924		entry = t[i>>PGSHIFT];
2000/0921		/* first hole means nothing left, add map */ if((entry & L2TypeMask) != L2SmallPage)
2000/0907		break;
2000/0921		if(candidate == 0){ /* look for start of range */ if((entry & L2PageBaseMask) != base) continue; candidate = virtaddr+i; } else { /* look for contiunued range */
2000/0923		if((entry & L2PageBaseMask) != base + off){
2000/0921		candidate = 0; continue; }
2000/0924		/* found unused entry on level 2 table */ if((entry & L2TypeMask) != L2SmallPage){ if(rv == nil) rv = (ulong*)(va+i*BY2PG+off); t[i>>PGSHIFT] = L2SmallPage | L2KernelRW | (base & L2PageBaseMask); base += BY2PG; continue;
2000/0921		}                  /* if we're at the end of the range, area is already mapped */ if((entry & L2PageBaseMask) == end) return candidate + (physaddr-base);
2000/0907		} if(i < OneMeg){
2000/0909		virtaddr += i;
2000/0907		break; } }
2000/0909
2000/0920		/* we get here if no entry was found mapping this physical range */
2000/0924		/* didn't fit */ if(base <= end) return nil; return rv;
2000/0905		} void