Author: imp
Date: Tue Dec 10 19:48:48 2013
New Revision: 259190
URL: http://svnweb.freebsd.org/changeset/base/259190
Log:
Hand merge from current r235717:
Implement pmap_mincore for arm. Now programs using it don't cause a
flood of console messages.
Reviewed by: alc@
Modified:
stable/9/sys/arm/arm/pmap.c
Modified: stable/9/sys/arm/arm/pmap.c
==============================================================================
--- stable/9/sys/arm/arm/pmap.c Tue Dec 10 19:42:35 2013 (r259189)
+++ stable/9/sys/arm/arm/pmap.c Tue Dec 10 19:48:48 2013 (r259190)
@@ -4675,9 +4675,59 @@ pmap_remove_write(vm_page_t m)
int
pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
{
- printf("pmap_mincore()\n");
-
- return (0);
+ struct l2_bucket *l2b;
+ pt_entry_t *ptep, pte;
+ vm_paddr_t pa;
+ vm_page_t m;
+ int val;
+ boolean_t managed;
+
+ PMAP_LOCK(pmap);
+retry:
+ l2b = pmap_get_l2_bucket(pmap, addr);
+ if (l2b == NULL) {
+ val = 0;
+ goto out;
+ }
+ ptep = &l2b->l2b_kva[l2pte_index(addr)];
+ pte = *ptep;
+ if (!l2pte_valid(pte)) {
+ val = 0;
+ goto out;
+ }
+ val = MINCORE_INCORE;
+ if (pte & L2_S_PROT_W)
+ val |= MINCORE_MODIFIED | MINCORE_MODIFIED_OTHER;
+ managed = false;
+ pa = l2pte_pa(pte);
+ m = PHYS_TO_VM_PAGE(pa);
+ if (m != NULL && !(m->oflags & VPO_UNMANAGED))
+ managed = true;
+ if (managed) {
+ /*
+ * The ARM pmap tries to maintain a per-mapping
+ * reference bit. The trouble is that it's kept in
+ * the PV entry, not the PTE, so it's costly to access
+ * here. You would need to acquire the pvh global
+ * lock, call pmap_find_pv(), and introduce a custom
+ * version of vm_page_pa_tryrelock() that releases and
+ * reacquires the pvh global lock. In the end, I
+ * doubt it's worthwhile. This may falsely report
+ * the given address as referenced.
+ */
+ if ((m->md.pvh_attrs & PVF_REF) != 0)
+ val |= MINCORE_REFERENCED | MINCORE_REFERENCED_OTHER;
+ }
+ if ((val & (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER)) !=
+ (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER) && managed) {
+ /* Ensure that "PHYS_TO_VM_PAGE(pa)->object" doesn't change. */
+ if (vm_page_pa_tryrelock(pmap, pa, locked_pa))
+ goto retry;
+ } else
+out:
+ PA_UNLOCK_COND(*locked_pa);
+ PMAP_UNLOCK(pmap);
+ return (val);
}
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