/* * 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. * * MemMin is what the bootstrap code in l.s has already mapped; * MemMax is the limit of physical memory to scan. */#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h"#include "ureg.h" #define MEMDEBUG 0 enum { MemUPA = 0, /* unbacked physical address */ MemRAM = 1, /* physical memory */ MemUMB = 2, /* upper memory block (<16MB) */ MemReserved = 3, NMemType = 4, KB = 1024, /* * for a kernel to boot, we need MemMin > end+sizeof pagetables. */ MemMin = 8*MB, MemMax = (3*1024+768)*MB, /* maximum physical memory to check */}; typedef struct Map Map;struct Map { uintmem size; /* bytes */ uintmem addr;}; typedef struct RMap RMap;struct RMap { char* name; Map* map; Map* mapend; Lock;}; /* * Memory allocation tracking. */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],}; voidmapprint(RMap *rmap){ Map *mp; print("%s\n", rmap->name); for(mp = rmap->map; mp->size; mp++) print("\t%P %P (%llud)\n", mp->addr, mp->addr+mp->size, (uvlong)mp->size);} voidmemdebug(void){ uintmem maxpa, maxpa1, maxpa2; maxpa = (nvramread(0x18)<<8)|nvramread(0x17); maxpa1 = (nvramread(0x31)<<8)|nvramread(0x30); maxpa2 = (nvramread(0x16)<<8)|nvramread(0x15); print("maxpa = %#P -> %#P, maxpa1 = %#P maxpa2 = %#P\n", maxpa, MB+maxpa*KB, maxpa1, maxpa2); mapprint(&rmapram); mapprint(&rmapumb); mapprint(&rmapumbrw); mapprint(&rmapupa);} voidmapfree(RMap* rmap, uintmem addr, uintmem size){ Map *mp; uintmem 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 %#P, %P\n", rmap->name, addr, size); break; } t = mp->addr; mp->addr = addr; addr = t; t = mp->size; mp->size = size; mp++; size = t; }while(size != 0); } unlock(rmap);} uintmemmapalloc(RMap* rmap, uintmem addr, int size, int align){ Map *mp; uintmem 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; (mp-1)->size = mp->size; }while(mp->size); } unlock(rmap); if(oaddr != maddr) mapfree(rmap, oaddr, maddr-oaddr); return maddr; } unlock(rmap); return 0;} /* * Allocate from the ram map directly to make page tables. * Called by mmuwalk during e820scan. */void*rampage(void){ uintmem m; void *p; m = mapalloc(&rmapram, 0, BY2PG, BY2PG); if(m == 0 || (m & ~(uintmem)0xFFFFFFFF) != 0) return nil; p = KADDR(m); memset(p, 0, BY2PG); return p;} static voidumbexclude(char *p){ int size; ulong addr; char *op, *rptr; if(p == nil) return; while(p && *p != '\0' && *p != '\n'){ op = p; addr = strtoul(p, &rptr, 0); if(rptr == nil || rptr == p || *rptr != '-'){ print("umbexclude: invalid argument <%s>\n", op); break; } p = rptr+1; size = strtoul(p, &rptr, 0) - addr + 1; if(size <= 0){ print("umbexclude: bad range <%s>\n", op); break; } if(rptr != nil && *rptr == ',') *rptr++ = '\0'; p = rptr; mapalloc(&rmapumb, addr, size, 0); }} static voidumbscan(void){ char *s; uchar o[2], *p; s = getconf("*noumb"); if(s && strcmp(s, "0") != 0) umbexclude("0xd0000-0xfffff"); /* * 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)){ /* * Check for the ROM signature, skip if valid. */ if(p[0] == 0x55 && p[1] == 0xAA){ p += p[2]*512; continue; } /* * Is it writeable? If yes, then stick it in * the UMB device memory map. A floating bus will * return 0xff, so add that to the map of the * UMB space available for allocation. * If it is neither of those, ignore it. */ o[0] = p[0]; p[0] = 0xCC; o[1] = p[2*KB-1]; p[2*KB-1] = 0xCC; if(p[0] == 0xCC && p[2*KB-1] == 0xCC){ p[0] = o[0]; p[2*KB-1] = o[1]; mapfree(&rmapumbrw, PADDR(p), 2*KB); } else if(p[0] == 0xFF && p[1] == 0xFF) mapfree(&rmapumb, 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); } umbexclude(getconf("umbexclude"));} static voidlowraminit(void){ uintmem n, pa, x; uchar *bda; /* * 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(CPU0END); 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((uintptr)end)); pa = MemMin; if(x > pa) panic("kernel too big"); mapfree(&rmapram, x, pa-x); memset(KADDR(x), 0, pa-x); /* keep us honest */} static voidramscan(ulong maxmem){ uintptr *k0, kzero, map, *va, vbase, x; uintmem pa, maxpa, maxkpa; PTE *table, *pte; int nvalid[NMemType]; /* * The bootstrap code has has created a prototype page * table which maps the first MemMin 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. */ pa = MemMin; /* * 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 = MemMax; else maxpa = MB+x*KB; if(maxpa < 24*MB) maxpa = 24*MB; }else maxpa = maxmem; maxkpa = (u32int)-KZERO; /* 2^32 - KZERO */ /* * March up memory from MemMin 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)); /* * Can't map memory to KADDR(pa) when we're walking because * can only use KADDR for relatively low addresses. Instead, * map each 4MB we scan to the virtual address range 4MB-8MB * while we are scanning. */ vbase = MemMin; 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. Map in a fixed range (the second 4M) * because high physical addresses cannot be passed to KADDR. */ va = (void*)(vbase + pa%(4*MB)); table = &m->pdb[PDX(va)]; if(pa%(4*MB) == 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(); /* * Write a pattern to the page and write a different * pattern to a possible mirror at KZERO. 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(); /* 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 && pa >= 32*MB && nvalid[MemUPA] == (4*MB)/BY2PG){ /* * If we encounter a 4MB chunk of missing memory * at a sufficiently high offset, call it the end of * memory. Otherwise we run the risk of thinking * that video memory is real RAM. */ break; } if(pa <= maxkpa && pa%(4*MB) == 0){ table = &m->pdb[PDX(KADDR(pa - 4*MB))]; 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{ *table = map|PTEWRITE|PTEVALID;Lines 1–500 of 940. Load more
/* * 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. * * MemMin is what the bootstrap code in l.s has already mapped; * MemMax is the limit of physical memory to scan. */ #include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "io.h" #include "ureg.h" #define MEMDEBUG 0 enum { MemUPA = 0, /* unbacked physical address */ MemRAM = 1, /* physical memory */ MemUMB = 2, /* upper memory block (<16MB) */ MemReserved = 3, NMemType = 4, KB = 1024, /* * for a kernel to boot, we need MemMin > end+sizeof pagetables. */ MemMin = 8*MB, MemMax = (3*1024+768)*MB, /* maximum physical memory to check */ }; typedef struct Map Map; struct Map { uintmem size; /* bytes */ uintmem addr; }; typedef struct RMap RMap; struct RMap { char* name; Map* map; Map* mapend; Lock; }; /* * Memory allocation tracking. */ 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%P %P (%llud)\n", mp->addr, mp->addr+mp->size, (uvlong)mp->size); } void memdebug(void) { uintmem maxpa, maxpa1, maxpa2; maxpa = (nvramread(0x18)<<8)|nvramread(0x17); maxpa1 = (nvramread(0x31)<<8)|nvramread(0x30); maxpa2 = (nvramread(0x16)<<8)|nvramread(0x15); print("maxpa = %#P -> %#P, maxpa1 = %#P maxpa2 = %#P\n", maxpa, MB+maxpa*KB, maxpa1, maxpa2); mapprint(&rmapram); mapprint(&rmapumb); mapprint(&rmapumbrw); mapprint(&rmapupa); } void mapfree(RMap* rmap, uintmem addr, uintmem size) { Map *mp; uintmem 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 %#P, %P\n", rmap->name, addr, size); break; } t = mp->addr; mp->addr = addr; addr = t; t = mp->size; mp->size = size; mp++; size = t; }while(size != 0); } unlock(rmap); } uintmem mapalloc(RMap* rmap, uintmem addr, int size, int align) { Map *mp; uintmem 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; (mp-1)->size = mp->size; }while(mp->size); } unlock(rmap); if(oaddr != maddr) mapfree(rmap, oaddr, maddr-oaddr); return maddr; } unlock(rmap); return 0; } /* * Allocate from the ram map directly to make page tables. * Called by mmuwalk during e820scan. */ void* rampage(void) { uintmem m; void *p; m = mapalloc(&rmapram, 0, BY2PG, BY2PG); if(m == 0 || (m & ~(uintmem)0xFFFFFFFF) != 0) return nil; p = KADDR(m); memset(p, 0, BY2PG); return p; } static void umbexclude(char *p) { int size; ulong addr; char *op, *rptr; if(p == nil) return; while(p && *p != '\0' && *p != '\n'){ op = p; addr = strtoul(p, &rptr, 0); if(rptr == nil || rptr == p || *rptr != '-'){ print("umbexclude: invalid argument <%s>\n", op); break; } p = rptr+1; size = strtoul(p, &rptr, 0) - addr + 1; if(size <= 0){ print("umbexclude: bad range <%s>\n", op); break; } if(rptr != nil && *rptr == ',') *rptr++ = '\0'; p = rptr; mapalloc(&rmapumb, addr, size, 0); } } static void umbscan(void) { char *s; uchar o[2], *p; s = getconf("*noumb"); if(s && strcmp(s, "0") != 0) umbexclude("0xd0000-0xfffff"); /* * 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)){ /* * Check for the ROM signature, skip if valid. */ if(p[0] == 0x55 && p[1] == 0xAA){ p += p[2]*512; continue; } /* * Is it writeable? If yes, then stick it in * the UMB device memory map. A floating bus will * return 0xff, so add that to the map of the * UMB space available for allocation. * If it is neither of those, ignore it. */ o[0] = p[0]; p[0] = 0xCC; o[1] = p[2*KB-1]; p[2*KB-1] = 0xCC; if(p[0] == 0xCC && p[2*KB-1] == 0xCC){ p[0] = o[0]; p[2*KB-1] = o[1]; mapfree(&rmapumbrw, PADDR(p), 2*KB); } else if(p[0] == 0xFF && p[1] == 0xFF) mapfree(&rmapumb, 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); } umbexclude(getconf("umbexclude")); } static void lowraminit(void) { uintmem n, pa, x; uchar *bda; /* * 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(CPU0END); 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((uintptr)end)); pa = MemMin; if(x > pa) panic("kernel too big"); mapfree(&rmapram, x, pa-x); memset(KADDR(x), 0, pa-x); /* keep us honest */ } static void ramscan(ulong maxmem) { uintptr *k0, kzero, map, *va, vbase, x; uintmem pa, maxpa, maxkpa; PTE *table, *pte; int nvalid[NMemType]; /* * The bootstrap code has has created a prototype page * table which maps the first MemMin 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. */ pa = MemMin; /* * 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 = MemMax; else maxpa = MB+x*KB; if(maxpa < 24*MB) maxpa = 24*MB; }else maxpa = maxmem; maxkpa = (u32int)-KZERO; /* 2^32 - KZERO */ /* * March up memory from MemMin 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)); /* * Can't map memory to KADDR(pa) when we're walking because * can only use KADDR for relatively low addresses. Instead, * map each 4MB we scan to the virtual address range 4MB-8MB * while we are scanning. */ vbase = MemMin; 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. Map in a fixed range (the second 4M) * because high physical addresses cannot be passed to KADDR. */ va = (void*)(vbase + pa%(4*MB)); table = &m->pdb[PDX(va)]; if(pa%(4*MB) == 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(); /* * Write a pattern to the page and write a different * pattern to a possible mirror at KZERO. 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(); /* 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 && pa >= 32*MB && nvalid[MemUPA] == (4*MB)/BY2PG){ /* * If we encounter a 4MB chunk of missing memory * at a sufficiently high offset, call it the end of * memory. Otherwise we run the risk of thinking * that video memory is real RAM. */ break; } if(pa <= maxkpa && pa%(4*MB) == 0){ table = &m->pdb[PDX(KADDR(pa - 4*MB))]; 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{ *table = map|PTEWRITE|PTEVALID;