Author: alc
Date: Thu Jul 5 07:20:16 2012
New Revision: 238126
URL: http://svn.freebsd.org/changeset/base/238126
Log:
Calculate the new PTE value in pmap_enter() before acquiring any locks.
Move an assertion to the beginning of pmap_enter().
Modified:
head/sys/amd64/amd64/pmap.c
Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c Thu Jul 5 00:52:23 2012 (r238125)
+++ head/sys/amd64/amd64/pmap.c Thu Jul 5 07:20:16 2012 (r238126)
@@ -3446,11 +3446,28 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
KASSERT(va < UPT_MIN_ADDRESS || va >= UPT_MAX_ADDRESS,
("pmap_enter: invalid to pmap_enter page table pages (va: 0x%lx)",
va));
+ KASSERT((m->oflags & VPO_UNMANAGED) != 0 || va < kmi.clean_sva ||
+ va >= kmi.clean_eva,
+ ("pmap_enter: managed mapping within the clean submap"));
KASSERT((m->oflags & (VPO_UNMANAGED | VPO_BUSY)) != 0 ||
VM_OBJECT_LOCKED(m->object),
("pmap_enter: page %p is not busy", m));
+ pa = VM_PAGE_TO_PHYS(m);
+ newpte = (pt_entry_t)(pa | pmap_cache_bits(m->md.pat_mode, 0) | PG_V);
+ if ((m->oflags & VPO_UNMANAGED) == 0)
+ newpte |= PG_MANAGED;
+ if ((prot & VM_PROT_WRITE) != 0)
+ newpte |= PG_RW;
+ if ((prot & VM_PROT_EXECUTE) == 0)
+ newpte |= pg_nx;
+ if (wired)
+ newpte |= PG_W;
+ if (va < VM_MAXUSER_ADDRESS)
+ newpte |= PG_U;
+ if (pmap == kernel_pmap)
+ newpte |= PG_G;
- mpte = NULL;
+ mpte = om = NULL;
lock = NULL;
rw_rlock(&pvh_global_lock);
@@ -3471,8 +3488,6 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
} else
panic("pmap_enter: invalid page directory va=%#lx", va);
- pa = VM_PAGE_TO_PHYS(m);
- om = NULL;
origpte = *pte;
opa = origpte & PG_FRAME;
@@ -3497,10 +3512,8 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
if (mpte)
mpte->wire_count--;
- if (origpte & PG_MANAGED) {
+ if ((origpte & PG_MANAGED) != 0)
om = m;
- pa |= PG_MANAGED;
- }
goto validate;
}
@@ -3530,15 +3543,12 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
/*
* Enter on the PV list if part of our managed memory.
*/
- if ((m->oflags & VPO_UNMANAGED) == 0) {
- KASSERT(va < kmi.clean_sva || va >= kmi.clean_eva,
- ("pmap_enter: managed mapping within the clean submap"));
+ if ((newpte & PG_MANAGED) != 0) {
if (pv == NULL)
pv = get_pv_entry(pmap, &lock);
CHANGE_PV_LIST_LOCK_TO_VM_PAGE(&lock, m);
pv->pv_va = va;
TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
- pa |= PG_MANAGED;
} else if (pv != NULL)
free_pv_entry(pmap, pv);
@@ -3549,40 +3559,25 @@ pmap_enter(pmap_t pmap, vm_offset_t va,
pmap->pm_stats.wired_count++;
validate:
- /*
- * Now validate mapping with desired protection/wiring.
- */
- newpte = (pt_entry_t)(pa | pmap_cache_bits(m->md.pat_mode, 0) | PG_V);
- if ((prot & VM_PROT_WRITE) != 0) {
- newpte |= PG_RW;
- if ((newpte & PG_MANAGED) != 0)
- vm_page_aflag_set(m, PGA_WRITEABLE);
- }
- if ((prot & VM_PROT_EXECUTE) == 0)
- newpte |= pg_nx;
- if (wired)
- newpte |= PG_W;
- if (va < VM_MAXUSER_ADDRESS)
- newpte |= PG_U;
- if (pmap == kernel_pmap)
- newpte |= PG_G;
/*
- * if the mapping or permission bits are different, we need
- * to update the pte.
+ * Update the PTE only if the mapping or protection/wiring bits are
+ * different.
*/
- if ((origpte & ~(PG_M|PG_A)) != newpte) {
+ if ((origpte & ~(PG_M | PG_A)) != newpte) {
newpte |= PG_A;
if ((access & VM_PROT_WRITE) != 0)
newpte |= PG_M;
+ if ((newpte & (PG_MANAGED | PG_RW)) == (PG_MANAGED | PG_RW))
+ vm_page_aflag_set(m, PGA_WRITEABLE);
if (origpte & PG_V) {
invlva = FALSE;
origpte = pte_load_store(pte, newpte);
if (origpte & PG_A) {
if (origpte & PG_MANAGED)
vm_page_aflag_set(om, PGA_REFERENCED);
- if (opa != VM_PAGE_TO_PHYS(m) || ((origpte &
- PG_NX) == 0 && (newpte & PG_NX)))
+ if (opa != pa || ((origpte & PG_NX) == 0 &&
+ (newpte & PG_NX) != 0))
invlva = TRUE;
}
if ((origpte & (PG_M | PG_RW)) == (PG_M | PG_RW)) {
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