ref: dff1e3813fb0deb18ca790b7c28f6a1405720ff6
dir: /sys/src/9/pc/memory.c/
/* * 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 u32int MemMin = 8*MB; /* set in l.s */ enum { MemUPA = 0, /* unbacked physical address */ MemRAM = 1, /* physical memory */ MemUMB = 2, /* upper memory block (<16MB) */ MemReserved = 3, NMemType = 4, KB = 1024, MemMax = (3*1024+768)*MB, }; typedef struct Map Map; struct Map { ulong size; ulong 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 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 %8.8luX (%lud)\n", mp->addr, mp->addr+mp->size, mp->size); } void memdebug(void) { ulong maxpa, maxpa1, maxpa2; 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; } /* * Allocate from the ram map directly to make page tables. * Called by mmuwalk during e820scan. */ void* rampage(void) { ulong m; m = mapalloc(&rmapram, 0, BY2PG, BY2PG); if(m == 0) return nil; return KADDR(m); } static void umbexclude(void) { int size; ulong addr; char *op, *p, *rptr; if((p = getconf("umbexclude")) == 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) { 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); } umbexclude(); } int checksum(void *v, int n) { uchar *p, s; s = 0; p = v; while(n-- > 0) s += *p++; return s; } static void* sigscan(uchar* addr, int len, char* signature) { int sl; uchar *e, *p; e = addr+len; sl = strlen(signature); for(p = addr; p+sl < e; p += 16) if(memcmp(p, signature, sl) == 0) return p; return nil; } static uintptr convmemsize(void) { uintptr top; uchar *bda; bda = KADDR(0x400); top = ((bda[0x14]<<8) | bda[0x13])*KB; if(top < 64*KB || top > 640*KB) top = 640*KB; /* sanity */ /* reserved for bios tables (EBDA) */ top -= 1*KB; return top; } void* sigsearch(char* signature) { uintptr p; uchar *bda; void *r; /* * Search for the data structure: * 1) within the first KiB of the Extended BIOS Data Area (EBDA), or * 2) within the last KiB of system base memory if the EBDA segment * is undefined, or * 3) within the BIOS ROM address space between 0xf0000 and 0xfffff * (but will actually check 0xe0000 to 0xfffff). */ bda = KADDR(0x400); if(memcmp(KADDR(0xfffd9), "EISA", 4) == 0){ if((p = (bda[0x0f]<<8)|bda[0x0e]) != 0){ if((r = sigscan(KADDR(p<<4), 1024, signature)) != nil) return r; } } if((r = sigscan(KADDR(convmemsize()), 1024, signature)) != nil) return r; /* hack for virtualbox: look in KiB below 0xa0000 */ if((r = sigscan(KADDR(0xa0000-1024), 1024, signature)) != nil) return r; return sigscan(KADDR(0xe0000), 0x20000, signature); } static void lowraminit(void) { uintptr pa, x; /* * 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); pa = convmemsize(); if(x < pa){ mapfree(&rmapram, x, pa-x); memset(KADDR(x), 0, pa-x); /* 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) { ulong *k0, kzero, map, maxkpa, maxpa, pa, *pte, *table, *va, vbase, x; 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 * MemMin->MemMin+4MB 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(PADDR(m->pdb)); /* * 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(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 && 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 & Pse)) *table = (pa - 4*MB)|PTESIZE|PTEWRITE|PTEVALID; else if(nvalid[MemUMB] == (4*MB)/BY2PG && (m->cpuiddx & Pse)) *table = (pa - 4*MB)|PTESIZE|PTEWRITE|PTEUNCACHED|PTEVALID; else{ *table = map|PTEWRITE|PTEVALID; 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) && pa <= maxkpa){ m->pdb[PDX(KADDR(pa))] = map|PTEWRITE|PTEVALID; map = 0; } if(map) mapfree(&rmapram, map, BY2PG); m->pdb[PDX(vbase)] = 0; mmuflushtlb(PADDR(m->pdb)); mapfree(&rmapupa, pa, (u32int)-pa); *k0 = kzero; } typedef struct Emap Emap; struct Emap { int type; uvlong base; uvlong top; }; static Emap emap[128]; int nemap; static int emapcmp(const void *va, const void *vb) { Emap *a, *b; a = (Emap*)va; b = (Emap*)vb; if(a->top < b->top) return -1; if(a->top > b->top) return 1; if(a->base < b->base) return -1; if(a->base > b->base) return 1; return 0; } static void map(ulong base, ulong len, int type) { ulong e, n; ulong *table, flags, maxkpa; /* * Split any call crossing MemMin to make below simpler. */ if(base < MemMin && len > MemMin-base){ n = MemMin - base; map(base, n, type); map(MemMin, len-n, type); } /* * Let lowraminit and umbscan hash out the low MemMin. */ if(base < MemMin) return; /* * Any non-memory below 16*MB is used as upper mem blocks. */ if(type == MemUPA && base < 16*MB && len > 16*MB-base){ map(base, 16*MB-base, MemUMB); map(16*MB, len-(16*MB-base), MemUPA); return; } /* * Memory below CPU0END is reserved for the kernel * and already mapped. */ if(base < PADDR(CPU0END)){ n = PADDR(CPU0END) - base; if(len <= n) return; map(PADDR(CPU0END), len-n, type); return; } /* * Memory between KTZERO and end is the kernel itself * and is already mapped. */ if(base < PADDR(KTZERO) && len > PADDR(KTZERO)-base){ map(base, PADDR(KTZERO)-base, type); return; } if(PADDR(KTZERO) < base && base < PADDR(PGROUND((ulong)end))){ n = PADDR(PGROUND((ulong)end)); if(len <= n) return; map(PADDR(PGROUND((ulong)end)), len-n, type); return; } /* * Now we have a simple case. */ // print("map %.8lux %.8lux %d\n", base, base+len, type); switch(type){ case MemRAM: mapfree(&rmapram, base, len); flags = PTEWRITE|PTEVALID; break; case MemUMB: mapfree(&rmapumb, base, len); flags = PTEWRITE|PTEUNCACHED|PTEVALID; break; case MemUPA: mapfree(&rmapupa, base, len); flags = 0; break; default: case MemReserved: flags = 0; break; } /* * bottom MemMin is already mapped - just twiddle flags. * (not currently used - see above) */ if(base < MemMin){ table = KADDR(PPN(m->pdb[PDX(base)])); e = base+len; base = PPN(base); for(; base<e; base+=BY2PG) table[PTX(base)] |= flags; return; } /* * Only map from KZERO to 2^32. */ if(flags){ maxkpa = -KZERO; if(base >= maxkpa) return; if(len > maxkpa-base) len = maxkpa - base; pdbmap(m->pdb, base|flags, base+KZERO, len); } } static int e820scan(void) { ulong base, len, last; Emap *e; char *s; int i; /* passed by bootloader */ if((s = getconf("*e820")) == nil) if((s = getconf("e820")) == nil) return -1; nemap = 0; while(nemap < nelem(emap)){ while(*s == ' ') s++; if(*s == 0) break; e = emap + nemap; e->type = 1; if(s[1] == ' '){ /* new format */ e->type = s[0] - '0'; s += 2; } e->base = strtoull(s, &s, 16); if(*s != ' ') break; e->top = strtoull(s, &s, 16); if(*s != ' ' && *s != 0) break; if(e->base < e->top) nemap++; } if(nemap == 0) return -1; qsort(emap, nemap, sizeof emap[0], emapcmp); last = 0; for(i=0; i<nemap; i++){ e = &emap[i]; /* * pull out the info but only about the low 32 bits... */ if(e->base >= (1ULL<<32)) break; if(e->top <= last) continue; if(e->base < last) base = last; else base = e->base; if(e->top > (1ULL<<32)) len = -base; else len = e->top - base; /* * If the map skips addresses, mark them available. */ if(last < base) map(last, base-last, MemUPA); map(base, len, (e->type == 1) ? MemRAM : MemReserved); last = base + len; if(last == 0) break; } if(last != 0) map(last, -last, MemUPA); return 0; } void meminit(void) { int i; Map *mp; Confmem *cm; ulong pa, *pte; ulong maxmem, lost; 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(); lowraminit(); if(e820scan() < 0) ramscan(maxmem); /* * Set the conf entries describing banks of allocatable memory. */ for(i=0; i<nelem(mapram) && i<nelem(conf.mem); i++){ mp = &rmapram.map[i]; cm = &conf.mem[i]; cm->base = mp->addr; cm->npage = mp->size/BY2PG; } lost = 0; for(; i<nelem(mapram); i++) lost += rmapram.map[i].size; if(lost) print("meminit - lost %lud bytes\n", lost); if(MEMDEBUG) memdebug(); } /* * Allocate memory from the upper memory blocks. */ 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); } /* * Give out otherwise-unused physical address space * for use in configuring devices. Note that upaalloc * does not map the physical address into virtual memory. * Call vmap to do that. */ ulong upaalloc(int size, int align) { ulong a; a = mapalloc(&rmapupa, 0, size, align); if(a == 0){ print("out of physical address space allocating %d\n", size); mapprint(&rmapupa); } return a; } void upafree(ulong pa, int size) { mapfree(&rmapupa, pa, size); } void upareserve(ulong pa, int size) { ulong a; a = mapalloc(&rmapupa, pa, size, 0); if(a != pa){ /* * This can happen when we're using the E820 * map, which might have already reserved some * of the regions claimed by the pci devices. */ // print("upareserve: cannot reserve pa=%#.8lux size=%d\n", pa, size); if(a != 0) mapfree(&rmapupa, a, size); } } void memorysummary(void) { memdebug(); }