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Change pmap_extract() and pmap_extract_and_hold() to use PG_FRAME rather

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than ~PDRMASK to extract the physical address of a superpage from a PDE.
The use of ~PDRMASK is problematic if the PDE has PG_NX set.  Specifically,
the PG_NX bit will be included in the physical address if ~PDRMASK is used.

Reviewed by:	peter
This commit is contained in:
Alan Cox 2005-08-22 07:23:51 +00:00
parent b1a6f1d8a2
commit 2c15852e1e
1 changed files with 6 additions and 2 deletions
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8
sys/amd64/amd64/pmap.c
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@ -802,7 +802,9 @@ pmap_extract(pmap_t pmap, vm_offset_t va)
pde = *pdep;
if (pde) {
if ((pde & PG_PS) != 0) {
rtval = (pde & ~PDRMASK) | (va & PDRMASK);
KASSERT((pde & PG_FRAME & PDRMASK) == 0,
("pmap_extract: bad pde"));
rtval = (pde & PG_FRAME) | (va & PDRMASK);
PMAP_UNLOCK(pmap);
return rtval;
}
@ -835,7 +837,9 @@ pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
if (pdep != NULL && (pde = *pdep)) {
if (pde & PG_PS) {
if ((pde & PG_RW) || (prot & VM_PROT_WRITE) == 0) {
m = PHYS_TO_VM_PAGE((pde & ~PDRMASK) |
KASSERT((pde & PG_FRAME & PDRMASK) == 0,
("pmap_extract_and_hold: bad pde"));
m = PHYS_TO_VM_PAGE((pde & PG_FRAME) |
(va & PDRMASK));
vm_page_hold(m);
}