void
segpage(Segment *s, Page *p)
{
Pte **pte;
ulong off;
Page **pg;
if(p->va < s->base || p->va >= s->top)
panic("segpage");
off = p->va - s->base;
pte = &s->map[off/PTEMAPMEM];
if(*pte == 0)
*pte = ptealloc();
pg = &(*pte)->pages[(off&(PTEMAPMEM-1))/BY2PG];
*pg = p;
if(pg < (*pte)->first)
(*pte)->first = pg;
if(pg > (*pte)->last)
(*pte)->last = pg;
}
int
fixfault(Segment *s, uintptr addr, int read, int doputmmu)
{
int type;
int ref;
Pte **p, *etp;
uintptr mmuphys=0, soff;
Page **pg, *lkp, *new;
Page *(*fn)(Segment*, uintptr);
addr &= ~(BY2PG-1);
soff = addr-s->base;
p = &s->map[soff/PTEMAPMEM];
if(*p == 0)
*p = ptealloc();
etp = *p;
pg = &etp->pages[(soff&(PTEMAPMEM-1))/BY2PG];
type = s->type&SG_TYPE;
if(pg < etp->first)
etp->first = pg;
if(pg > etp->last)
etp->last = pg;
switch(type) {
default:
panic("fault");
break;
case SG_TEXT: /* Demand load */
if(pagedout(*pg))
pio(s, addr, soff, pg);
mmuphys = PPN((*pg)->pa) | PTERONLY|PTEVALID;
(*pg)->modref = PG_REF;
break;
case SG_BSS:
case SG_SHARED: /* Zero fill on demand */
case SG_STACK:
if(*pg == 0) {
new = newpage(1, &s, addr);
if(s == 0)
return -1;
*pg = new;
}
goto common;
case SG_DATA:
common: /* Demand load/pagein/copy on write */
if(pagedout(*pg))
pio(s, addr, soff, pg);
/*
* It's only possible to copy on write if
* we're the only user of the segment.
*/
if(read && conf.copymode == 0 && s->ref == 1) {
mmuphys = PPN((*pg)->pa)|PTERONLY|PTEVALID;
(*pg)->modref |= PG_REF;
break;
}
lkp = *pg;
lock(lkp);
if(lkp->image == &swapimage)
ref = lkp->ref + swapcount(lkp->daddr);
else
ref = lkp->ref;
if(ref == 1 && lkp->image){
/* save a copy of the original for the image cache */
duppage(lkp);
ref = lkp->ref;
}
unlock(lkp);
if(ref > 1){
new = newpage(0, &s, addr);
if(s == 0)
return -1;
*pg = new;
copypage(lkp, *pg);
putpage(lkp);
}
