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- /*
- * Size memory and create the kernel page-tables on the fly while doing so.
- * Called from main(), this code should only be run by the bootstrap processor.
- */
- #include "u.h"
- #include "../port/lib.h"
- #include "mem.h"
- #include "dat.h"
- #include "fns.h"
- #include "io.h"
- #define MEMDEBUG 0
- enum {
- MemUPA = 0, /* unbacked physical address */
- MemRAM = 1, /* physical memory */
- MemUMB = 2, /* upper memory block (<16MB) */
- NMemType = 3,
- KB = 1024,
- MemMinMB = 4, /* minimum physical memory (<=4MB) */
- MemMaxMB = 768, /* maximum physical memory to check */
- NMemBase = 10,
- };
- typedef struct Map Map;
- struct Map {
- int size;
- ulong addr;
- };
- typedef struct RMap RMap;
- struct RMap {
- char* name;
- Map* map;
- Map* mapend;
- Lock;
- };
- static Map mapupa[16];
- static RMap rmapupa = {
- "unallocated unbacked physical memory",
- mapupa,
- &mapupa[nelem(mapupa)-1],
- };
- static Map xmapupa[16];
- static RMap xrmapupa = {
- "unbacked physical memory",
- xmapupa,
- &xmapupa[nelem(xmapupa)-1],
- };
- static Map mapram[16];
- static RMap rmapram = {
- "physical memory",
- mapram,
- &mapram[nelem(mapram)-1],
- };
- static Map mapumb[64];
- static RMap rmapumb = {
- "upper memory block",
- mapumb,
- &mapumb[nelem(mapumb)-1],
- };
- static Map mapumbrw[16];
- static RMap rmapumbrw = {
- "UMB device memory",
- mapumbrw,
- &mapumbrw[nelem(mapumbrw)-1],
- };
- void
- mapprint(RMap *rmap)
- {
- Map *mp;
- print("%s\n", rmap->name);
- for(mp = rmap->map; mp->size; mp++)
- print("\t%8.8luX %8.8uX %8.8luX\n", mp->addr, mp->size, mp->addr+mp->size);
- }
- void
- memdebug(void)
- {
- ulong maxpa, maxpa1, maxpa2;
- if(MEMDEBUG == 0)
- return;
- maxpa = (nvramread(0x18)<<8)|nvramread(0x17);
- maxpa1 = (nvramread(0x31)<<8)|nvramread(0x30);
- maxpa2 = (nvramread(0x16)<<8)|nvramread(0x15);
- print("maxpa = %luX -> %luX, maxpa1 = %luX maxpa2 = %luX\n",
- maxpa, MB+maxpa*KB, maxpa1, maxpa2);
- mapprint(&rmapram);
- mapprint(&rmapumb);
- mapprint(&rmapumbrw);
- mapprint(&rmapupa);
- }
- void
- mapfree(RMap* rmap, ulong addr, ulong size)
- {
- Map *mp;
- ulong t;
- if(size <= 0)
- return;
- lock(rmap);
- for(mp = rmap->map; mp->addr <= addr && mp->size; mp++)
- ;
- if(mp > rmap->map && (mp-1)->addr+(mp-1)->size == addr){
- (mp-1)->size += size;
- if(addr+size == mp->addr){
- (mp-1)->size += mp->size;
- while(mp->size){
- mp++;
- (mp-1)->addr = mp->addr;
- (mp-1)->size = mp->size;
- }
- }
- }
- else{
- if(addr+size == mp->addr && mp->size){
- mp->addr -= size;
- mp->size += size;
- }
- else do{
- if(mp >= rmap->mapend){
- print("mapfree: %s: losing 0x%luX, %ld\n",
- rmap->name, addr, size);
- break;
- }
- t = mp->addr;
- mp->addr = addr;
- addr = t;
- t = mp->size;
- mp->size = size;
- mp++;
- }while(size = t);
- }
- unlock(rmap);
- }
- ulong
- mapalloc(RMap* rmap, ulong addr, int size, int align)
- {
- Map *mp;
- ulong maddr, oaddr;
- lock(rmap);
- for(mp = rmap->map; mp->size; mp++){
- maddr = mp->addr;
- if(addr){
- /*
- * A specific address range has been given:
- * if the current map entry is greater then
- * the address is not in the map;
- * if the current map entry does not overlap
- * the beginning of the requested range then
- * continue on to the next map entry;
- * if the current map entry does not entirely
- * contain the requested range then the range
- * is not in the map.
- */
- if(maddr > addr)
- break;
- if(mp->size < addr - maddr) /* maddr+mp->size < addr, but no overflow */
- continue;
- if(addr - maddr > mp->size - size) /* addr+size > maddr+mp->size, but no overflow */
- break;
- maddr = addr;
- }
- if(align > 0)
- maddr = ((maddr+align-1)/align)*align;
- if(mp->addr+mp->size-maddr < size)
- continue;
- oaddr = mp->addr;
- mp->addr = maddr+size;
- mp->size -= maddr-oaddr+size;
- if(mp->size == 0){
- do{
- mp++;
- (mp-1)->addr = mp->addr;
- }while((mp-1)->size = mp->size);
- }
- unlock(rmap);
- if(oaddr != maddr)
- mapfree(rmap, oaddr, maddr-oaddr);
- return maddr;
- }
- unlock(rmap);
- return 0;
- }
- static void
- umbscan(void)
- {
- uchar *p;
- /*
- * Scan the Upper Memory Blocks (0xA0000->0xF0000) for pieces
- * which aren't used; they can be used later for devices which
- * want to allocate some virtual address space.
- * Check for two things:
- * 1) device BIOS ROM. This should start with a two-byte header
- * of 0x55 0xAA, followed by a byte giving the size of the ROM
- * in 512-byte chunks. These ROM's must start on a 2KB boundary.
- * 2) device memory. This is read-write.
- * There are some assumptions: there's VGA memory at 0xA0000 and
- * the VGA BIOS ROM is at 0xC0000. Also, if there's no ROM signature
- * at 0xE0000 then the whole 64KB up to 0xF0000 is theoretically up
- * for grabs; check anyway.
- */
- p = KADDR(0xD0000);
- while(p < (uchar*)KADDR(0xE0000)){
- /*
- * Test for 0x55 0xAA before poking obtrusively,
- * some machines (e.g. Thinkpad X20) seem to map
- * something dynamic here (cardbus?) causing weird
- * problems if it is changed.
- */
- if(p[0] == 0x55 && p[1] == 0xAA){
- p += p[2]*512;
- continue;
- }
- p[0] = 0xCC;
- p[2*KB-1] = 0xCC;
- if(p[0] != 0xCC || p[2*KB-1] != 0xCC){
- p[0] = 0x55;
- p[1] = 0xAA;
- p[2] = 4;
- if(p[0] == 0x55 && p[1] == 0xAA){
- p += p[2]*512;
- continue;
- }
- if(p[0] == 0xFF && p[1] == 0xFF)
- mapfree(&rmapumb, PADDR(p), 2*KB);
- }
- else
- mapfree(&rmapumbrw, PADDR(p), 2*KB);
- p += 2*KB;
- }
- p = KADDR(0xE0000);
- if(p[0] != 0x55 || p[1] != 0xAA){
- p[0] = 0xCC;
- p[64*KB-1] = 0xCC;
- if(p[0] != 0xCC && p[64*KB-1] != 0xCC)
- mapfree(&rmapumb, PADDR(p), 64*KB);
- }
- }
- static void
- ramscan(ulong maxmem)
- {
- ulong *k0, kzero, map, maxpa, pa, *pte, *table, *va, x, n;
- int nvalid[NMemType];
- uchar *bda;
- /*
- * The bootstrap code has has created a prototype page
- * table which maps the first MemMinMB of physical memory to KZERO.
- * The page directory is at m->pdb and the first page of
- * free memory is after the per-processor MMU information.
- */
- /*
- * Initialise the memory bank information for conventional memory
- * (i.e. less than 640KB). The base is the first location after the
- * bootstrap processor MMU information and the limit is obtained from
- * the BIOS data area.
- */
- x = PADDR(CPU0MACH+BY2PG);
- bda = (uchar*)KADDR(0x400);
- n = ((bda[0x14]<<8)|bda[0x13])*KB-x;
- mapfree(&rmapram, x, n);
- memset(KADDR(x), 0, n); /* keep us honest */
- x = PADDR(PGROUND((ulong)end));
- pa = MemMinMB*MB;
- mapfree(&rmapram, x, pa-x);
- memset(KADDR(x), 0, pa-x); /* keep us honest */
- /*
- * Check if the extended memory size can be obtained from the CMOS.
- * If it's 0 then it's either not known or >= 64MB. Always check
- * at least 24MB in case there's a memory gap (up to 8MB) below 16MB;
- * in this case the memory from the gap is remapped to the top of
- * memory.
- * The value in CMOS is supposed to be the number of KB above 1MB.
- */
- if(maxmem == 0){
- x = (nvramread(0x18)<<8)|nvramread(0x17);
- if(x == 0 || x >= (63*KB))
- maxpa = MemMaxMB*MB;
- else
- maxpa = MB+x*KB;
- if(maxpa < 24*MB)
- maxpa = 24*MB;
- maxmem = MemMaxMB*MB;
- }
- else
- maxpa = maxmem;
- /*
- * March up memory from MemMinMB to maxpa 1MB at a time,
- * mapping the first page and checking the page can
- * be written and read correctly. The page tables are created here
- * on the fly, allocating from low memory as necessary.
- */
- k0 = (ulong*)KADDR(0);
- kzero = *k0;
- map = 0;
- x = 0x12345678;
- memset(nvalid, 0, sizeof(nvalid));
- while(pa < maxpa){
- /*
- * Map the page. Use mapalloc(&rmapram, ...) to make
- * the page table if necessary, it will be returned to the
- * pool later if it isn't needed.
- */
- va = KADDR(pa);
- table = &m->pdb[PDX(va)];
- if(*table == 0){
- if(map == 0 && (map = mapalloc(&rmapram, 0, BY2PG, BY2PG)) == 0)
- break;
- memset(KADDR(map), 0, BY2PG);
- *table = map|PTEWRITE|PTEVALID;
- memset(nvalid, 0, sizeof(nvalid));
- }
- table = KADDR(PPN(*table));
- pte = &table[PTX(va)];
- *pte = pa|PTEWRITE|PTEUNCACHED|PTEVALID;
- mmuflushtlb(PADDR(m->pdb));
- /*
- * Write a pattern to the page and write a different
- * pattern to a possible mirror at KZER0. If the data
- * reads back correctly the chunk is some type of RAM (possibly
- * a linearly-mapped VGA framebuffer, for instance...) and
- * can be cleared and added to the memory pool. If not, the
- * chunk is marked uncached and added to the UMB pool if <16MB
- * or is marked invalid and added to the UPA pool.
- */
- *va = x;
- *k0 = ~x;
- if(*va == x){
- nvalid[MemRAM] += MB/BY2PG;
- mapfree(&rmapram, pa, MB);
- do{
- *pte++ = pa|PTEWRITE|PTEVALID;
- pa += BY2PG;
- }while(pa % MB);
- mmuflushtlb(PADDR(m->pdb));
- /* memset(va, 0, MB); so damn slow to memset all of memory */
- }
- else if(pa < 16*MB){
- nvalid[MemUMB] += MB/BY2PG;
- mapfree(&rmapumb, pa, MB);
- do{
- *pte++ = pa|PTEWRITE|PTEUNCACHED|PTEVALID;
- pa += BY2PG;
- }while(pa % MB);
- }
- else{
- nvalid[MemUPA] += MB/BY2PG;
- mapfree(&rmapupa, pa, MB);
- *pte = 0;
- pa += MB;
- }
- /*
- * Done with this 4MB chunk, review the options:
- * 1) not physical memory and >=16MB - invalidate the PDB entry;
- * 2) physical memory - use the 4MB page extension if possible;
- * 3) not physical memory and <16MB - use the 4MB page extension
- * if possible;
- * 4) mixed or no 4MB page extension - commit the already
- * initialised space for the page table.
- */
- if((pa % (4*MB)) == 0){
- table = &m->pdb[PDX(va)];
- if(nvalid[MemUPA] == (4*MB)/BY2PG)
- *table = 0;
- else if(nvalid[MemRAM] == (4*MB)/BY2PG && (m->cpuiddx & 0x08))
- *table = (pa - 4*MB)|PTESIZE|PTEWRITE|PTEVALID;
- else if(nvalid[MemUMB] == (4*MB)/BY2PG && (m->cpuiddx & 0x08))
- *table = (pa - 4*MB)|PTESIZE|PTEWRITE|PTEUNCACHED|PTEVALID;
- else
- map = 0;
- }
- mmuflushtlb(PADDR(m->pdb));
- x += 0x3141526;
- }
- /*
- * If we didn't reach the end of the 4MB chunk, that part won't
- * be mapped. Commit the already initialised space for the page table.
- */
- if(pa % (4*MB))
- map = 0;
- if(map)
- mapfree(&rmapram, map, BY2PG);
- if(pa < maxmem)
- mapfree(&rmapupa, pa, maxmem-pa);
- if(maxmem < 0xFFE00000)
- mapfree(&rmapupa, maxmem, 0x00000000-maxmem);
- if(MEMDEBUG)
- print("maxmem %luX %luX\n", maxmem, 0x00000000-maxmem);
- *k0 = kzero;
- }
- void
- meminit(void)
- {
- Map *mp, *xmp;
- ulong pa, *pte;
- ulong maxmem;
- char *p;
- if(p = getconf("*maxmem"))
- maxmem = strtoul(p, 0, 0);
- else
- maxmem = 0;
- /*
- * Set special attributes for memory between 640KB and 1MB:
- * VGA memory is writethrough;
- * BIOS ROM's/UMB's are uncached;
- * then scan for useful memory.
- */
- for(pa = 0xA0000; pa < 0xC0000; pa += BY2PG){
- pte = mmuwalk(m->pdb, (ulong)KADDR(pa), 2, 0);
- *pte |= PTEWT;
- }
- for(pa = 0xC0000; pa < 0x100000; pa += BY2PG){
- pte = mmuwalk(m->pdb, (ulong)KADDR(pa), 2, 0);
- *pte |= PTEUNCACHED;
- }
- mmuflushtlb(PADDR(m->pdb));
- umbscan();
- ramscan(maxmem);
- /*
- * Set the conf entries describing two banks of allocatable memory.
- * Grab the first and largest entries in rmapram as left by ramscan().
- *
- * It would be nice to have more than 2 memory banks describable in conf.
- */
- mp = rmapram.map;
- conf.base0 = mp->addr;
- conf.npage0 = mp->size/BY2PG;
- mp++;
- for(xmp = 0; mp->size; mp++){
- if(xmp == 0 || mp->size > xmp->size)
- xmp = mp;
- }
- if(xmp){
- conf.base1 = xmp->addr;
- conf.npage1 = xmp->size/BY2PG;
- }
- if(MEMDEBUG)
- memdebug();
- }
- ulong
- umbmalloc(ulong addr, int size, int align)
- {
- ulong a;
- if(a = mapalloc(&rmapumb, addr, size, align))
- return (ulong)KADDR(a);
- return 0;
- }
- void
- umbfree(ulong addr, int size)
- {
- mapfree(&rmapumb, PADDR(addr), size);
- }
- ulong
- umbrwmalloc(ulong addr, int size, int align)
- {
- ulong a;
- uchar *p;
- if(a = mapalloc(&rmapumbrw, addr, size, align))
- return(ulong)KADDR(a);
- /*
- * Perhaps the memory wasn't visible before
- * the interface is initialised, so try again.
- */
- if((a = umbmalloc(addr, size, align)) == 0)
- return 0;
- p = (uchar*)a;
- p[0] = 0xCC;
- p[size-1] = 0xCC;
- if(p[0] == 0xCC && p[size-1] == 0xCC)
- return a;
- umbfree(a, size);
- return 0;
- }
- void
- umbrwfree(ulong addr, int size)
- {
- mapfree(&rmapumbrw, PADDR(addr), size);
- }
- ulong
- upamalloc(ulong pa, int size, int align)
- {
- ulong a, ae;
- if(a = mapalloc(&xrmapupa, pa, size, align))
- return a;
- if((a = mapalloc(&rmapupa, pa, size, align)) == 0){
- memdebug();
- return 0;
- }
- /*
- * Upamalloc is a request to map a range of physical addresses.
- * Therefore, if pa is 0 mapalloc will choose the base address.
- * Note, however, mmukmap is always asked to give a 1-to-1 mapping
- * of va to pa.
- ae = mmukmap(a, a, size);
- * ...but for the moment go back to the old scheme for VLB cards.
- */
- ae = mmukmap(a, 0, size);
- /*
- * Should check here that it was all delivered
- * and put it back and barf if not.
- */
- USED(ae);
- /*
- * Be very careful this returns a PHYSICAL address
- * mapped 1-to-1 with the virtual address.
- * If a < KZERO it's probably not a good idea to
- * try KADDR(a)...
- */
- return a;
- }
- void
- upafree(ulong pa, int size)
- {
- mapfree(&xrmapupa, pa, size);
- }
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