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

1 files changed, 29 insertions, 14 deletions

diff --git a/sys/sparc64/sparc64/pmap.c b/sys/sparc64/sparc64/pmap.c
index 54e0b22..9073760 100644
--- a/sys/sparc64/sparc64/pmap.c
+++ b/sys/sparc64/sparc64/pmap.c
@@ -141,6 +141,8 @@ static void pmap_bootstrap_set_tte(struct tte *tp, u_long vpn, u_long data);
 static void pmap_cache_remove(vm_page_t m, vm_offset_t va);
 static int pmap_protect_tte(struct pmap *pm1, struct pmap *pm2,
     struct tte *tp, vm_offset_t va);
+static int pmap_unwire_tte(pmap_t pm, pmap_t pm2, struct tte *tp,
+    vm_offset_t va);
 
 /*
  * Map the given physical page at the specified virtual address in the
@@ -1668,27 +1670,40 @@ pmap_object_init_pt(pmap_t pm, vm_offset_t addr, vm_object_t object,
 	    ("pmap_object_init_pt: non-device object"));
 }
 
+static int
+pmap_unwire_tte(pmap_t pm, pmap_t pm2, struct tte *tp, vm_offset_t va)
+{
+
+	PMAP_LOCK_ASSERT(pm, MA_OWNED);
+	if ((tp->tte_data & TD_WIRED) == 0)
+		panic("pmap_unwire_tte: tp %p is missing TD_WIRED", tp);
+	atomic_clear_long(&tp->tte_data, TD_WIRED);
+	pm->pm_stats.wired_count--;
+	return (1);
+}
+
 /*
- * Change the wiring attribute for a map/virtual-address pair.
- * 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.
+ *
+ * The wired attribute of the translation table entry is not a hardware
+ * feature, so there is no need to invalidate any TLB entries.
  */
 void
-pmap_change_wiring(pmap_t pm, vm_offset_t va, boolean_t wired)
+pmap_unwire(pmap_t pm, vm_offset_t sva, vm_offset_t eva)
 {
+	vm_offset_t va;
 	struct tte *tp;
-	u_long data;
 
 	PMAP_LOCK(pm);
-	if ((tp = tsb_tte_lookup(pm, va)) != NULL) {
-		if (wired) {
-			data = atomic_set_long(&tp->tte_data, TD_WIRED);
-			if ((data & TD_WIRED) == 0)
-				pm->pm_stats.wired_count++;
-		} else {
-			data = atomic_clear_long(&tp->tte_data, TD_WIRED);
-			if ((data & TD_WIRED) != 0)
-				pm->pm_stats.wired_count--;
-		}
+	if (eva - sva > PMAP_TSB_THRESH)
+		tsb_foreach(pm, NULL, sva, eva, pmap_unwire_tte);
+	else {
+		for (va = sva; va < eva; va += PAGE_SIZE)
+			if ((tp = tsb_tte_lookup(pm, va)) != NULL)
+				pmap_unwire_tte(pm, NULL, tp, va);
 	}
 	PMAP_UNLOCK(pm);
 }