Fix a leak of the wired pages when unwiring of the PROT_NONE-mapped

wired region.  Rework the handling of unwire to do the it in batch,
both at pmap and object level.

All commits below are by alc.

MFC r268327:
Introduce pmap_unwire().

MFC r268591:
Implement pmap_unwire() for powerpc.

MFC r268776:
Implement pmap_unwire() for arm.

MFC r268806:
pmap_unwire(9) man page.

MFC r269134:
When unwiring a region of an address space, do not assume that the
underlying physical pages are mapped by the pmap.  This fixes a leak
of the wired pages on the unwiring of the region mapped with no access
allowed.

MFC r269339:
In the implementation of the new function pmap_unwire(), the call to
MOEA64_PVO_TO_PTE() must be performed before any changes are made to the
PVO. Otherwise, MOEA64_PVO_TO_PTE() will panic.

MFC r269365:
Correct a long-standing problem in moea{,64}_pvo_enter() that was revealed
by the combination of r268591 and r269134: When we attempt to add the
wired attribute to an existing mapping, moea{,64}_pvo_enter() do nothing.
(They only set the wired attribute on newly created mappings.)

MFC r269433:
Handle wiring failures in vm_map_wire() with the new functions
pmap_unwire() and vm_object_unwire().
Retire vm_fault_{un,}wire(), since they are no longer used.

MFC r269438:
Rewrite a loop in vm_map_wire() so that gcc doesn't think that the variable
"rv" is uninitialized.

MFC r269485:
Retire pmap_change_wiring().

Reviewed by:	alc

2 files changed, 94 insertions, 52 deletions

diff --git a/sys/arm/arm/pmap-v6.c b/sys/arm/arm/pmap-v6.c
index 197a2eb..b2be785 100644
--- a/sys/arm/arm/pmap-v6.c
+++ b/sys/arm/arm/pmap-v6.c
@@ -3264,53 +3264,76 @@ pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
 }
 
 /*
- *	Routine:	pmap_change_wiring
- *	Function:	Change the wiring attribute for a map/virtual-address
- *			pair.
- *	In/out conditions:
- *			The mapping must already exist in the pmap.
+ *	Clear the wired attribute from the mappings for the specified range of
+ *	addresses in the given pmap.  Every valid mapping within that range
+ *	must have the wired attribute set.  In contrast, invalid mappings
+ *	cannot have the wired attribute set, so they are ignored.
+ *
+ *	XXX Wired mappings of unmanaged pages cannot be counted by this pmap
+ *	implementation.
  */
 void
-pmap_change_wiring(pmap_t pmap, vm_offset_t va, boolean_t wired)
+pmap_unwire(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
 {
 	struct l2_bucket *l2b;
 	struct md_page *pvh;
-	struct pv_entry *pve;
-	pd_entry_t *pl1pd, l1pd;
+	pd_entry_t l1pd;
 	pt_entry_t *ptep, pte;
+	pv_entry_t pv;
+	vm_offset_t next_bucket;
+	vm_paddr_t pa;
 	vm_page_t m;
-
+ 
 	rw_wlock(&pvh_global_lock);
 	PMAP_LOCK(pmap);
-	pl1pd = &pmap->pm_l1->l1_kva[L1_IDX(va)];
-	l1pd = *pl1pd;
-	if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
-		m = PHYS_TO_VM_PAGE(l1pd & L1_S_FRAME);
-		KASSERT((m != NULL) && ((m->oflags & VPO_UNMANAGED) == 0),
-		    ("pmap_change_wiring: unmanaged superpage should not "
-		     "be changed"));
-		KASSERT(pmap != pmap_kernel(),
-		    ("pmap_change_wiring: managed kernel superpage "
-		     "should not exist"));
-		pvh = pa_to_pvh(l1pd & L1_S_FRAME);
-		pve = pmap_find_pv(pvh, pmap, trunc_1mpage(va));
-		if (!wired != ((pve->pv_flags & PVF_WIRED) == 0)) {
-			if (!pmap_demote_section(pmap, va))
-				panic("pmap_change_wiring: demotion failed");
-		} else
-			goto out;
+	while (sva < eva) {
+		next_bucket = L2_NEXT_BUCKET(sva);
+		l1pd = pmap->pm_l1->l1_kva[L1_IDX(sva)];
+		if ((l1pd & L1_TYPE_MASK) == L1_S_PROTO) {
+			pa = l1pd & L1_S_FRAME;
+			m = PHYS_TO_VM_PAGE(pa);
+			KASSERT(m != NULL && (m->oflags & VPO_UNMANAGED) == 0,
+			    ("pmap_unwire: unmanaged 1mpage %p", m));
+			pvh = pa_to_pvh(pa);
+			pv = pmap_find_pv(pvh, pmap, trunc_1mpage(sva));
+			if ((pv->pv_flags & PVF_WIRED) == 0)
+				panic("pmap_unwire: pv %p isn't wired", pv);
+
+			/*
+			 * Are we unwiring the entire large page? If not,
+			 * demote the mapping and fall through.
+			 */
+			if (sva + L1_S_SIZE == next_bucket &&
+			    eva >= next_bucket) {
+				pv->pv_flags &= ~PVF_WIRED;
+				pmap->pm_stats.wired_count -= L2_PTE_NUM_TOTAL;
+				sva = next_bucket;
+				continue;
+			} else if (!pmap_demote_section(pmap, sva))
+				panic("pmap_unwire: demotion failed");
+		}
+		if (next_bucket > eva)
+			next_bucket = eva;
+		l2b = pmap_get_l2_bucket(pmap, sva);
+		if (l2b == NULL) {
+			sva = next_bucket;
+			continue;
+		}
+		for (ptep = &l2b->l2b_kva[l2pte_index(sva)]; sva < next_bucket;
+		    sva += PAGE_SIZE, ptep++) {
+			if ((pte = *ptep) == 0 ||
+			    (m = PHYS_TO_VM_PAGE(l2pte_pa(pte))) == NULL ||
+			    (m->oflags & VPO_UNMANAGED) != 0)
+				continue;
+			pv = pmap_find_pv(&m->md, pmap, sva);
+			if ((pv->pv_flags & PVF_WIRED) == 0)
+				panic("pmap_unwire: pv %p isn't wired", pv);
+			pv->pv_flags &= ~PVF_WIRED;
+			pmap->pm_stats.wired_count--;
+		}
 	}
-	l2b = pmap_get_l2_bucket(pmap, va);
-	KASSERT(l2b, ("No l2b bucket in pmap_change_wiring"));
-	ptep = &l2b->l2b_kva[l2pte_index(va)];
-	pte = *ptep;
-	m = PHYS_TO_VM_PAGE(l2pte_pa(pte));
-	if (m != NULL)
-		pmap_modify_pv(m, pmap, va, PVF_WIRED,
-		    wired == TRUE ? PVF_WIRED : 0);
-out:
 	rw_wunlock(&pvh_global_lock);
-	PMAP_UNLOCK(pmap);
+ 	PMAP_UNLOCK(pmap);
 }
 
 
diff --git a/sys/arm/arm/pmap.c b/sys/arm/arm/pmap.c
index 802d5ee..f4e44d7 100644
--- a/sys/arm/arm/pmap.c
+++ b/sys/arm/arm/pmap.c
@@ -3542,28 +3542,47 @@ pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot)
 }
 
 /*
- *	Routine:	pmap_change_wiring
- *	Function:	Change the wiring attribute for a map/virtual-address
- *			pair.
- *	In/out conditions:
- *			The mapping must already exist in the pmap.
+ *	Clear the wired attribute from the mappings for the specified range of
+ *	addresses in the given pmap.  Every valid mapping within that range
+ *	must have the wired attribute set.  In contrast, invalid mappings
+ *	cannot have the wired attribute set, so they are ignored.
+ *
+ *	XXX Wired mappings of unmanaged pages cannot be counted by this pmap
+ *	implementation.
  */
 void
-pmap_change_wiring(pmap_t pmap, vm_offset_t va, boolean_t wired)
+pmap_unwire(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
 {
 	struct l2_bucket *l2b;
 	pt_entry_t *ptep, pte;
-	vm_page_t pg;
-
+	pv_entry_t pv;
+	vm_offset_t next_bucket;
+	vm_page_t m;
+ 
 	rw_wlock(&pvh_global_lock);
- 	PMAP_LOCK(pmap);
-	l2b = pmap_get_l2_bucket(pmap, va);
-	KASSERT(l2b, ("No l2b bucket in pmap_change_wiring"));
-	ptep = &l2b->l2b_kva[l2pte_index(va)];
-	pte = *ptep;
-	pg = PHYS_TO_VM_PAGE(l2pte_pa(pte));
-	if (pg)
-		pmap_modify_pv(pg, pmap, va, PVF_WIRED, wired ? PVF_WIRED : 0);
+	PMAP_LOCK(pmap);
+	while (sva < eva) {
+		next_bucket = L2_NEXT_BUCKET(sva);
+		if (next_bucket > eva)
+			next_bucket = eva;
+		l2b = pmap_get_l2_bucket(pmap, sva);
+		if (l2b == NULL) {
+			sva = next_bucket;
+			continue;
+		}
+		for (ptep = &l2b->l2b_kva[l2pte_index(sva)]; sva < next_bucket;
+		    sva += PAGE_SIZE, ptep++) {
+			if ((pte = *ptep) == 0 ||
+			    (m = PHYS_TO_VM_PAGE(l2pte_pa(pte))) == NULL ||
+			    (m->oflags & VPO_UNMANAGED) != 0)
+				continue;
+			pv = pmap_find_pv(m, pmap, sva);
+			if ((pv->pv_flags & PVF_WIRED) == 0)
+				panic("pmap_unwire: pv %p isn't wired", pv);
+			pv->pv_flags &= ~PVF_WIRED;
+			pmap->pm_stats.wired_count--;
+		}
+	}
 	rw_wunlock(&pvh_global_lock);
  	PMAP_UNLOCK(pmap);
 }