ref: 9ca327dd06c30341d984bff84727ea451b428db7
dir: /os/manga/mmu.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" /* * Small pages: * L1: 12-bit index -> 4096 descriptors -> 16Kb * L2: 8-bit index -> 256 descriptors -> 1Kb * Each L2 descriptor has access permissions for 4 1Kb sub-pages. * * TTB + L1Tx gives address of L1 descriptor * L1 descriptor gives PTBA * PTBA + L2Tx gives address of L2 descriptor * L2 descriptor gives PBA * * C & B are interpreted as follows: * C=0 B=0 uncached, unbuffered, stall until data access complete * C=0 B=1 uncached, buffered * C=1 B=0 write-through cachable * C=1 B=1 write-back cachable * and the i-cache uses only the C bit (cached if non-zero). */ #define TTB(pa) ((pa) & ~0x3FFF) /* translation table base */ #define L1x(pa) (((pa)>>20) & 0xFFF) /* L1 table index */ #define PTBA(pa) ((pa) & ~0x3FF) /* page table base address */ #define L2x(pa) (((pa)>>12) & 0xFF) /* L2 table index */ #define PBA(pa) ((pa) & ~0xFFF) /* page base address */ #define SBA(pa) ((pa) & ~0xFFFFF) /* section base address */ enum { /* sizes */ Section= 1<<20, LargePage= 1<<16, SmallPage= 1<<12, EsmallPage= 1<<10, SectionPages = Section/SmallPage, PtAlign = 1<<10, /* L1 descriptor format */ L1type= 3<<0, /* mask for type */ L1page= 1<<0, /* descriptor is for L2 pages */ L1section= 2<<0, /* descriptor is for section */ L1fpage= 3<<0, /* descriptor is for fine (1k) L2 pages */ L1buffered= 1<<2, L1cached= 1<<3, L1mbo= 1<<4, /* must be one */ /* L2 descriptor format for coarse page table */ L2type= 3<<0, /* mask for type */ L2invalid= 0<<0, L2large= 1<<0, /* large page */ L2small= 2<<0, /* small page */ L2esmall= 3<<0, /* extended small page */ L2buffered= 1<<2, L2cached= 1<<3, /* then access permissions */ L2smallX= 1<<6, L2largeX= 1<<12, /* domains */ Dnone= 0, Dclient= 1, Dmanager= 3, /* access permissions */ APsro= 0, /* supervisor ro if S|R */ APsrw= 1, /* supervisor rw */ APuro= 2, /* supervisor rw + user ro */ APurw= 3, /* supervisor rw + user rw */ }; #define L1dom(d) (((d) & 0xF)<<5) /* L1 domain */ #define AP(i, v) ((v)<<(((i)*2)+4)) /* access permissions */ #define L1AP(v) AP(3, (v)) #define L2AP(v) AP(3, (v))|AP(2, (v))|AP(1, (v))|AP(0, (v)) #define L1krw (L1AP(APsrw) | L1dom(0)) /* * return physical address corresponding to a given virtual address, * or 0 if there is no such address */ ulong va2pa(void *v) { int idx; ulong pte, ste, *ttb; idx = L1x((ulong)v); ttb = (ulong*)KTTB; ste = ttb[idx]; switch(ste & L1type) { case L1section: return SBA(ste)|((ulong)v & 0x000fffff); case L1page: pte = ((ulong *)PTBA(ste))[L2x((ulong)v)]; switch(pte & 3) { case L2large: return (pte & 0xffff0000)|((ulong)v & 0x0000ffff); case L2small: return (pte & 0xfffff000)|((ulong)v & 0x00000fff); } } return 0; } /* for debugging */ void prs(char *s) { serialputs(s, strlen(s)); } void pr16(ulong n) { int i, c; for(i=28; i>=0; i-=4){ c = (n>>i) & 0xF; if(c >= 0 && c <= 9) c += '0'; else c += 'A'-10; serialputc(c); } } void xdelay(int n) { int j; for(j=0; j<1000000/4; j++) n++; USED(n); } void* mmuphysmap(void *va, ulong pa, ulong nbytes) { ulong *ttb; ulong p, o; if(va == nil) va = KADDR(pa); p = (ulong)va; if((pa|p) & (Section-1)) panic("kmapphys"); ttb = (ulong*)KTTB; nbytes = (nbytes+Section-1)&~(Section-1); for(o = 0; o < nbytes; o += Section) ttb[L1x(p+o)] = (pa+o) | (1<<4) | L1krw | L1section; return va; } void* mmukaddr(ulong pa) { if(pa >= PHYSDRAM0 && pa < conf.topofmem) return (void*)(KZERO+(pa-PHYSDRAM0)); return (void*)pa; } /* * Set a 1-1 map of virtual to physical memory, except: * kernel is mapped to KZERO * doubly-map page0 at the alternative interrupt vector address, * doubly-map physical memory at KZERO+256*MB as uncached but buffered, * map flash to virtual space away from 0, * disable access to 0 (nil pointers). * * Other section maps are added later as required by mmuphysmap. */ void mmuinit(void) { int i; ulong *ttb, *ptable; ttb = (ulong*)KTTB; memset(ttb, 0, 16384); /* assume flash is first in special physical space */ for(i = L1x(PHYSFLASH0); i < 0x1000; i++) ttb[i] = (i<<20) | L1krw | (1<<4) | L1section; /* cached dram at normal kernel addresses */ for(i = 0; i < 32*MB; i += MB) ttb[L1x(KZERO+i)] = (PHYSDRAM0+i) | (1<<4) | L1krw | L1section | L1cached | L1buffered; /* aliases for uncached dram */ for(i = 0; i < 64*MB; i += MB) ttb[L1x(UCDRAMZERO+i)] = (PHYSDRAM0+i) | L1krw | (1<<4) | L1section; /* TO DO: make the text read only */ /* remap flash */ for(i=0; i<8*MB; i+=MB) ttb[L1x(FLASHMEM+i)] = (PHYSFLASH0+i) | L1krw | (1<<4) | L1section; /* we'll make flash uncached for now */ /* * build page table for alternative vector page, mapping trap vectors in *page0 */ ptable = xspanalloc(SectionPages*sizeof(*ptable), PtAlign, 0); ptable[L2x(AIVECADDR)] = PADDR(page0) | L2AP(APsrw) | L2cached | L2buffered | L2small; ttb[L1x(AIVECADDR)] = PADDR(ptable) | (1<<4) | L1page; mmuputttb(KTTB & ~KZERO); mmuputdac(Dclient); mmuputctl(mmugetctl() | CpCaltivec | CpCIcache | CpCsystem | CpCwpd | CpCDcache | CpCmmu); tlbinvalidateall(); } /* * flush data in a given address range to memory * and invalidate the region in the instruction cache. */ int segflush(void *a, ulong n) { dcflush(a, n); icflush(a, n); return 0; } /* * return an uncached alias for the memory at a */ void* mmucacheinhib(void *a, ulong nb) { ulong p; if(a == nil) return nil; p = PADDR(a); if(p & (CACHELINESZ-1)) panic("mmucacheinhib"); dcflush(a, nb); return (void*)(UCDRAMZERO|PADDR(a)); }