Import sources from 2011-03-30 iso image
This commit is contained in:
Taru Karttunen
commit
e5888a1ffd
7810 changed files with 2489717 additions and 0 deletions
407
sys/src/9/port/fault.c
Executable file
407
sys/src/9/port/fault.c
Executable file
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@ -0,0 +1,407 @@
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#include "u.h"
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#include "../port/lib.h"
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#include "mem.h"
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#include "dat.h"
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#include "fns.h"
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#include "../port/error.h"
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int
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fault(ulong addr, int read)
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{
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Segment *s;
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char *sps;
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if(up == nil)
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panic("fault: nil up");
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if(up->nlocks.ref)
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print("fault: nlocks %ld\n", up->nlocks.ref);
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sps = up->psstate;
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up->psstate = "Fault";
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spllo();
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m->pfault++;
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for(;;) {
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s = seg(up, addr, 1); /* leaves s->lk qlocked if seg != nil */
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if(s == 0) {
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up->psstate = sps;
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return -1;
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}
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if(!read && (s->type&SG_RONLY)) {
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qunlock(&s->lk);
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up->psstate = sps;
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return -1;
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}
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if(fixfault(s, addr, read, 1) == 0)
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break;
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}
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up->psstate = sps;
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return 0;
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}
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static void
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faulterror(char *s, Chan *c, int freemem)
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{
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char buf[ERRMAX];
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if(c && c->path){
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snprint(buf, sizeof buf, "%s accessing %s: %s", s, c->path->s, up->errstr);
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s = buf;
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}
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if(up->nerrlab) {
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postnote(up, 1, s, NDebug);
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error(s);
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}
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pexit(s, freemem);
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}
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void (*checkaddr)(ulong, Segment *, Page *);
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ulong addr2check;
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int
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fixfault(Segment *s, ulong addr, int read, int doputmmu)
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{
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int type;
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int ref;
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Pte **p, *etp;
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ulong mmuphys=0, soff;
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Page **pg, *lkp, *new;
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Page *(*fn)(Segment*, ulong);
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addr &= ~(BY2PG-1);
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soff = addr-s->base;
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p = &s->map[soff/PTEMAPMEM];
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if(*p == 0)
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*p = ptealloc();
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etp = *p;
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pg = &etp->pages[(soff&(PTEMAPMEM-1))/BY2PG];
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type = s->type&SG_TYPE;
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if(pg < etp->first)
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etp->first = pg;
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if(pg > etp->last)
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etp->last = pg;
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switch(type) {
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default:
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panic("fault");
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break;
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case SG_TEXT: /* Demand load */
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if(pagedout(*pg))
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pio(s, addr, soff, pg);
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mmuphys = PPN((*pg)->pa) | PTERONLY|PTEVALID;
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(*pg)->modref = PG_REF;
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break;
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case SG_BSS:
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case SG_SHARED: /* Zero fill on demand */
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case SG_STACK:
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if(*pg == 0) {
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new = newpage(1, &s, addr);
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if(s == 0)
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return -1;
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*pg = new;
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}
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goto common;
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case SG_DATA:
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common: /* Demand load/pagein/copy on write */
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if(pagedout(*pg))
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pio(s, addr, soff, pg);
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/*
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* It's only possible to copy on write if
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* we're the only user of the segment.
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*/
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if(read && conf.copymode == 0 && s->ref == 1) {
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mmuphys = PPN((*pg)->pa)|PTERONLY|PTEVALID;
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(*pg)->modref |= PG_REF;
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break;
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}
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lkp = *pg;
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lock(lkp);
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if(lkp->image == &swapimage)
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ref = lkp->ref + swapcount(lkp->daddr);
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else
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ref = lkp->ref;
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if(ref > 1) {
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unlock(lkp);
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new = newpage(0, &s, addr);
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if(s == 0)
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return -1;
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*pg = new;
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copypage(lkp, *pg);
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putpage(lkp);
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}
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else {
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/* save a copy of the original for the image cache */
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if(lkp->image)
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duppage(lkp);
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unlock(lkp);
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}
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mmuphys = PPN((*pg)->pa) | PTEWRITE | PTEVALID;
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(*pg)->modref = PG_MOD|PG_REF;
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break;
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case SG_PHYSICAL:
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if(*pg == 0) {
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fn = s->pseg->pgalloc;
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if(fn)
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*pg = (*fn)(s, addr);
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else {
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new = smalloc(sizeof(Page));
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new->va = addr;
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new->pa = s->pseg->pa+(addr-s->base);
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new->ref = 1;
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*pg = new;
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}
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}
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if (checkaddr && addr == addr2check)
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(*checkaddr)(addr, s, *pg);
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mmuphys = PPN((*pg)->pa) |PTEWRITE|PTEUNCACHED|PTEVALID;
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(*pg)->modref = PG_MOD|PG_REF;
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break;
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}
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qunlock(&s->lk);
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if(doputmmu)
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putmmu(addr, mmuphys, *pg);
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return 0;
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}
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void
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pio(Segment *s, ulong addr, ulong soff, Page **p)
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{
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Page *new;
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KMap *k;
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Chan *c;
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int n, ask;
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char *kaddr;
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ulong daddr;
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Page *loadrec;
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retry:
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loadrec = *p;
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if(loadrec == 0) { /* from a text/data image */
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daddr = s->fstart+soff;
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new = lookpage(s->image, daddr);
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if(new != nil) {
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*p = new;
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return;
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}
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c = s->image->c;
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ask = s->flen-soff;
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if(ask > BY2PG)
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ask = BY2PG;
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}
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else { /* from a swap image */
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daddr = swapaddr(loadrec);
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new = lookpage(&swapimage, daddr);
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if(new != nil) {
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putswap(loadrec);
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*p = new;
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return;
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}
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c = swapimage.c;
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ask = BY2PG;
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}
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qunlock(&s->lk);
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new = newpage(0, 0, addr);
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k = kmap(new);
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kaddr = (char*)VA(k);
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while(waserror()) {
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if(strcmp(up->errstr, Eintr) == 0)
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continue;
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kunmap(k);
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putpage(new);
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faulterror(Eioload, c, 0);
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}
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n = devtab[c->type]->read(c, kaddr, ask, daddr);
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if(n != ask)
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faulterror(Eioload, c, 0);
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if(ask < BY2PG)
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memset(kaddr+ask, 0, BY2PG-ask);
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poperror();
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kunmap(k);
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qlock(&s->lk);
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if(loadrec == 0) { /* This is demand load */
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/*
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* race, another proc may have gotten here first while
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* s->lk was unlocked
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*/
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if(*p == 0) {
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new->daddr = daddr;
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cachepage(new, s->image);
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*p = new;
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}
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else
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putpage(new);
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}
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else { /* This is paged out */
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/*
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* race, another proc may have gotten here first
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* (and the pager may have run on that page) while
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* s->lk was unlocked
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*/
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if(*p != loadrec){
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if(!pagedout(*p)){
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/* another process did it for me */
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putpage(new);
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goto done;
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} else {
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/* another process and the pager got in */
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putpage(new);
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goto retry;
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}
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}
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new->daddr = daddr;
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cachepage(new, &swapimage);
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*p = new;
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putswap(loadrec);
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}
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done:
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if(s->flushme)
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memset((*p)->cachectl, PG_TXTFLUSH, sizeof((*p)->cachectl));
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}
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/*
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* Called only in a system call
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*/
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int
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okaddr(ulong addr, ulong len, int write)
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{
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Segment *s;
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if((long)len >= 0) {
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for(;;) {
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s = seg(up, addr, 0);
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if(s == 0 || (write && (s->type&SG_RONLY)))
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break;
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if(addr+len > s->top) {
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len -= s->top - addr;
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addr = s->top;
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continue;
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}
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return 1;
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}
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}
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pprint("suicide: invalid address %#lux/%lud in sys call pc=%#lux\n", addr, len, userpc());
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return 0;
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}
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void
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validaddr(ulong addr, ulong len, int write)
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{
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if(!okaddr(addr, len, write)){
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postnote(up, 1, "sys: bad address in syscall", NDebug);
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error(Ebadarg);
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}
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}
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/*
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* &s[0] is known to be a valid address.
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*/
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void*
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vmemchr(void *s, int c, int n)
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{
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int m;
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ulong a;
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void *t;
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a = (ulong)s;
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while(PGROUND(a) != PGROUND(a+n-1)){
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/* spans pages; handle this page */
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m = BY2PG - (a & (BY2PG-1));
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t = memchr((void*)a, c, m);
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if(t)
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return t;
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a += m;
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n -= m;
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if(a < KZERO)
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validaddr(a, 1, 0);
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}
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/* fits in one page */
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return memchr((void*)a, c, n);
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}
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Segment*
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seg(Proc *p, ulong addr, int dolock)
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{
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Segment **s, **et, *n;
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et = &p->seg[NSEG];
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for(s = p->seg; s < et; s++) {
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n = *s;
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if(n == 0)
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continue;
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if(addr >= n->base && addr < n->top) {
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if(dolock == 0)
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return n;
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qlock(&n->lk);
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if(addr >= n->base && addr < n->top)
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return n;
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qunlock(&n->lk);
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}
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}
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return 0;
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}
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extern void checkmmu(ulong, ulong);
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void
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checkpages(void)
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{
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int checked;
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ulong addr, off;
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Pte *p;
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Page *pg;
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Segment **sp, **ep, *s;
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if(up == nil)
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return;
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checked = 0;
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for(sp=up->seg, ep=&up->seg[NSEG]; sp<ep; sp++){
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s = *sp;
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if(s == nil)
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continue;
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qlock(&s->lk);
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for(addr=s->base; addr<s->top; addr+=BY2PG){
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off = addr - s->base;
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p = s->map[off/PTEMAPMEM];
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if(p == 0)
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continue;
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pg = p->pages[(off&(PTEMAPMEM-1))/BY2PG];
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if(pg == 0 || pagedout(pg))
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continue;
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checkmmu(addr, pg->pa);
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checked++;
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}
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qunlock(&s->lk);
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}
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print("%ld %s: checked %d page table entries\n", up->pid, up->text, checked);
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}
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