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kernel: simplify mmuput

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This commit is contained in:
Giacomo Tesio 2017-05-30 22:41:44 +02:00
parent 28c426055d
commit 7108477c32
1 changed files with 17 additions and 20 deletions
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37
sys/src/kern/amd64/mmu.c
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@ -36,6 +36,8 @@ static struct{
} ptpfreelist;
int ptpcount;
#define DO_mmuptpcheck
#ifdef DO_mmuptpcheck
static void mmuptpcheck(Proc*);
#endif
@ -232,39 +234,30 @@ void
mmuput(uintptr_t va, uintptr_t pa)
{
Mpl pl;
int l, x, tl;
PTE *pte, *ptp;
int l, x;
PTE *pte, *ptp, opte;
Ptpage *prev;
uint32_t attr;
tl = (PGSHFT-12)/9;
pl = splhi();
#ifdef DO_mmuptpcheck
mmuptpcheck(up);
#endif
for(l = 3; l != tl; l--){
for(l = 3; l > 0; l--){
ptp = mmuptpget(va, l);
pte = &ptp[PTLX(va,l)];
if(l == tl)
break;
if((*pte & PteP) == 0 || *pte & PtePS)
if(l == 0 || (*pte & PteP) == 0 || (*pte & PtePS))
break;
}
if(l != tl){
if(l != 0){
/* add missing intermediate level */
prev = m->pml4;
for(l = 3; l > tl; l--){
for(l = 3; l > 0; l--){
ptp = mmuptpget(va, l);
x = PTLX(va, l);
prev = makeptp(prev, l, ptp, x);
}
}
ptp = mmuptpget(va, tl);
pte = &ptp[PTLX(va, tl)];
attr = 0;
if(tl > 0)
attr |= PtePS;
*pte = pa | attr | PteU;
ptp = mmuptpget(va, 0);
pte = &ptp[PTLX(va, 0)];
opte = *pte;
*pte = pa | PteU;
DBG("%d mach%d: put pte %#p: %#p -> %#P\n", up->pid, m->machno, pte, va, *pte);
/* Simple and safe: programs can either write memory or execute it.
@ -273,8 +266,12 @@ mmuput(uintptr_t va, uintptr_t pa)
if(pa & PteRW)
*pte |= PteNX;
#ifdef DO_mmuptpcheck
mmuptpcheck(up);
#endif
splx(pl);
invlpg(va); /* only if old entry valid? */
if(opte & PTEVALID)
invlpg(va);
}
static PTE