diff options
| -rw-r--r-- | sys/amd64/amd64/pmap.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 81b26691bd79..4ab963062a2e 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -801,18 +801,34 @@ pmap_extract(pmap, va) vm_page_t pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot) { - vm_paddr_t pa; + pd_entry_t pde, *pdep; + pt_entry_t pte; vm_page_t m; m = NULL; - mtx_lock(&Giant); - if ((pa = pmap_extract(pmap, va)) != 0) { - m = PHYS_TO_VM_PAGE(pa); - vm_page_lock_queues(); - vm_page_hold(m); - vm_page_unlock_queues(); + if (pmap == NULL) + return (m); + vm_page_lock_queues(); + PMAP_LOCK(pmap); + pdep = pmap_pde(pmap, va); + 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) | + (va & PDRMASK)); + vm_page_hold(m); + } + } else { + pte = *pmap_pte(pmap, va); + if ((pte & PG_V) && + ((pte & PG_RW) || (prot & VM_PROT_WRITE) == 0)) { + m = PHYS_TO_VM_PAGE(pte & PG_FRAME); + vm_page_hold(m); + } + } } - mtx_unlock(&Giant); + vm_page_unlock_queues(); + PMAP_UNLOCK(pmap); return (m); } |