2000/1002/bitsy/mmu.c (diff list | history)

bitsy/mmu.c on 2000/0902
2000/0902		#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "io.h" #include "ureg.h" #include "../port/error.h"
2000/0906		/* real protection bits */ enum {
2000/0907		/* level 1 descriptor bits */ L1TypeMask= (3<<0), L1Invalid= (0<<0), L1PageTable= (1<<0), L1Section= (2<<0), L1Cached= (1<<3), L1Buffered= (1<<2), L1Domain0= (0<<5), L1KernelRW= (0x1<<10), L1UserRO= (0x2<<10), L1UserRW= (0x3<<10), L1SectBaseMask= (0xFFF<<20), L1PTBaseMask= (0x3FFFFF<<10), /* level 2 descriptor bits */ L2TypeMask= (3<<0), L2SmallPage= (2<<0), L2LargePage= (1<<0), L2Cached= (1<<3), L2Buffered= (1<<2), L2KernelRW= (0x55<<4), L2UserRO= (0xAA<<4), L2UserRW= (0xFF<<4), L2PageBaseMask= (0xFFFFF<<12),
2000/0906		}; /* * table to map fault.c bits to physical bits */
2000/0907		static ulong phystrans[16] =
2000/0906		{
2000/0907		[PTEVALID] L2SmallPage|L2Cached|L2Buffered|L2UserRO, [PTEVALID|PTEWRITE] L2SmallPage|L2Cached|L2Buffered|L2UserRW, [PTEVALID|PTEUNCACHED] L2SmallPage|L2UserRO, [PTEVALID|PTEUNCACHED|PTEWRITE] L2SmallPage|L2UserRW, [PTEKERNEL|PTEVALID] L2SmallPage|L2Cached|L2Buffered|L2KernelRW, [PTEKERNEL|PTEVALID|PTEWRITE] L2SmallPage|L2Cached|L2Buffered|L2KernelRW, [PTEKERNEL|PTEVALID|PTEUNCACHED] L2SmallPage|L2KernelRW, [PTEKERNEL|PTEVALID|PTEUNCACHED|PTEWRITE] L2SmallPage|L2KernelRW,
2000/0906		};
2000/0907		ulong *l1table;
2000/0906		/* * We map all of memory, flash, and the zeros area with sections. * Special use space is mapped on the fly with regmap. */
2000/0902		void
2000/0905		mmuinit(void) {
2000/0906		ulong a, e;
2000/0929		ulong *t;
2000/0906		/* get a prototype level 1 page */
2000/0907		l1table = xspanalloc(BY2PG, 16*1024, 0); memset(l1table, 0, BY2PG);
2000/0906
2000/0907		/* direct map DRAM */
2000/0928		e = conf.base1 + BY2PG*conf.npage1;
2000/0907		for(a = PHYSDRAM0; a < e; a += OneMeg)
2000/0929		l1table[a>>20] = L1Section | L1KernelRW | (a&L1SectBaseMask) | L1Cached | L1Buffered;
2000/0907		/* direct map zeros area */ for(a = PHYSNULL0; a < PHYSNULL0 + 128 * OneMeg; a += OneMeg)
2000/0929		l1table[a>>20] = L1Section | L1KernelRW | (a&L1SectBaseMask);
2000/0907		/* direct map flash */
2000/0928		for(a = PHYSFLASH0; a < PHYSFLASH0 + 128 * OneMeg; a += OneMeg)
2000/0929		l1table[a>>20] = L1Section | L1KernelRW | (a&L1SectBaseMask) | L1Cached | L1Buffered;
2000/0907
2000/0929		/* map first page of DRAM also into 0xFFFF0000 for the interrupt vectors */ t = xspanalloc(BY2PG, 16*1024, 0); memset(t, 0, BY2PG); l1table[0xFFFF0000>>20] = L1PageTable | L1Domain0 | (((ulong)t) & L1PTBaseMask); t[0xF0000>>PGSHIFT] = L2SmallPage | L2KernelRW | PHYSDRAM0;
2000/0928		/* set up the domain register to cause all domains to obey pte access bits */ iprint("setting up domain access\n");
2000/0929		putdac(0xFFFFFFFF);
2000/0928		/* point to map */ iprint("setting tlb map %lux\n", (ulong)l1table); putttb((ulong)l1table);
2000/0929		/* map the uart so that we can continue using iprint */
2000/1002		uart3regs = mapspecial(UART3REGS, 64);
2000/0929		/* enable mmu, and make 0xFFFF0000 the virtual address of the exception vecs */ mmuenable(); iprint("uart3regs now at %lux\n", uart3regs);
2000/0907		} /*
2000/0923		* map special space uncached, assume that the space isn't already mapped
2000/0907		*/
2000/1002		void*
2000/0924		mapspecial(ulong pa, int len)
2000/0907		{ ulong *t;
2000/0928		ulong va, i, base, end, off, entry;
2000/0924		int livelarge; ulong* rv;
2000/0907
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
2000/0929		for(va = REGZERO; va < REGTOP && base <= end; va += OneMeg){ switch(l1table[va>>20] & L1TypeMask){ default:
2000/0924		/* found unused entry on level 1 table */ if(livelarge){ if(rv == nil)
2000/0929		rv = (ulong*)(va+off);
2000/0924		l1table[va>>20] = L1Section | L1KernelRW |
2000/0929		(base & L1SectBaseMask);
2000/0924		base += OneMeg; continue;
2000/0929		} else {
2000/0924
2000/0929		/* create an L2 page table and keep going */ t = xspanalloc(BY2PG, 1024, 0); memset(t, 0, BY2PG); l1table[va>>20] = L1PageTable | L1Domain0 | (((ulong)t) & L1PTBaseMask); } break; case L1Section: continue; case L1PageTable: if(livelarge) continue; break;
2000/0907		}
2000/0924
2000/0929		/* here if we're using page maps instead of sections */
2000/0924		t = (ulong*)(l1table[va>>20] & L1PTBaseMask);
2000/0907		for(i = 0; i < OneMeg; i += BY2PG){
2000/0924		entry = t[i>>PGSHIFT];
2000/0921
2000/0924		/* found unused entry on level 2 table */ if((entry & L2TypeMask) != L2SmallPage){ if(rv == nil)
2000/0929		rv = (ulong*)(va+i+off);
2000/0924		t[i>>PGSHIFT] = L2SmallPage | L2KernelRW | (base & L2PageBaseMask); base += BY2PG; continue;
2000/0921		}
2000/0907		} }
2000/0909
2000/0924		/* didn't fit */ if(base <= end) return nil; return rv;
2000/0905		} void
2000/0902		putmmu(ulong va, ulong pa, Page*) { USED(va, pa); } void mmurelease(Proc* proc) { USED(proc); } void mmuswitch(Proc* proc) { USED(proc); }