Oops, bring back pmap_collect1() and the check for pmap_kernel() in

pmap_collect() as we do an explicit pmap_collect(pmap_kernel()) in dire
memory situations.

1 files changed, 135 insertions, 11 deletions

diff --git a/sys/arch/m68k/m68k/pmap_motorola.c b/sys/arch/m68k/m68k/pmap_motorola.c
index 292dfcb26f5..b4d2433cf01 100644
--- a/sys/arch/m68k/m68k/pmap_motorola.c
+++ b/sys/arch/m68k/m68k/pmap_motorola.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap_motorola.c,v 1.49 2007/02/17 19:08:58 miod Exp $ */
+/*	$OpenBSD: pmap_motorola.c,v 1.50 2007/03/04 16:59:03 miod Exp $ */
 
 /*
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -308,6 +308,7 @@ void		 pmap_changebit(struct vm_page *, int, int);
 int		 pmap_enter_ptpage(pmap_t, vaddr_t);
 void		 pmap_ptpage_addref(vaddr_t);
 int		 pmap_ptpage_delref(vaddr_t);
+void		 pmap_collect1(paddr_t, paddr_t);
 
 
 #ifdef PMAP_DEBUG
@@ -777,6 +778,7 @@ void
 pmap_remove_flags(pmap, sva, eva, flags)
 	pmap_t pmap;
 	vaddr_t sva, eva;
+	int flags;
 {
 	vaddr_t nssva;
 	pt_entry_t *pte;
@@ -1671,16 +1673,138 @@ pmap_collect(pmap)
 
 	PMAP_DPRINTF(PDB_FOLLOW, ("pmap_collect(%p)\n", pmap));
 
-	/*
-	 * This process is about to be swapped out; free all of
-	 * the PT pages by removing the physical mappings for its
-	 * entire address space.  Note: pmap_remove() performs
-	 * all necessary locking.
-	 */
-	flags = active_pmap(pmap) ? PRM_TFLUSH : 0;
-	pmap_remove_flags(pmap, VM_MIN_ADDRESS, VM_MAX_ADDRESS,
-	    flags | PRM_SKIPWIRED);
-	pmap_update(pmap);
+	if (pmap == pmap_kernel()) {
+		int bank, s;
+
+		/*
+		 * XXX This is very bogus.  We should handle kernel PT
+		 * XXX pages much differently.
+		 */
+
+		s = splvm();
+		for (bank = 0; bank < vm_nphysseg; bank++)
+			pmap_collect1(ptoa(vm_physmem[bank].start),
+			    ptoa(vm_physmem[bank].end));
+		splx(s);
+	} else {
+		/*
+		 * This process is about to be swapped out; free all of
+		 * the PT pages by removing the physical mappings for its
+		 * entire address space.  Note: pmap_remove() performs
+		 * all necessary locking.
+		 */
+		flags = active_pmap(pmap) ? PRM_TFLUSH : 0;
+		pmap_remove_flags(pmap, VM_MIN_ADDRESS, VM_MAX_ADDRESS,
+		    flags | PRM_SKIPWIRED);
+		pmap_update(pmap);
+	}
+}
+
+/*
+ * pmap_collect1:
+ *
+ *	Garbage-collect KPT pages.  Helper for the above (bogus)
+ *	pmap_collect().
+ *
+ *	Note: THIS SHOULD GO AWAY, AND BE REPLACED WITH A BETTER
+ *	WAY OF HANDLING PT PAGES!
+ */
+void
+pmap_collect1(startpa, endpa)
+	paddr_t		startpa, endpa;
+{
+	paddr_t pa;
+	struct pv_entry *pv;
+	pt_entry_t *pte;
+	paddr_t kpa;
+#ifdef PMAP_DEBUG
+	st_entry_t *ste;
+	int opmapdebug = 0 /* XXX initialize to quiet gcc -Wall */;
+#endif
+
+	for (pa = startpa; pa < endpa; pa += PAGE_SIZE) {
+		struct kpt_page *kpt, **pkpt;
+
+		/*
+		 * Locate physical pages which are being used as kernel
+		 * page table pages.
+		 */
+		pv = pa_to_pvh(pa);
+		if (pv->pv_pmap != pmap_kernel() || !(pv->pv_flags & PV_PTPAGE))
+			continue;
+		do {
+			if (pv->pv_ptste && pv->pv_ptpmap == pmap_kernel())
+				break;
+		} while ((pv = pv->pv_next));
+		if (pv == NULL)
+			continue;
+#ifdef PMAP_DEBUG
+		if (pv->pv_va < (vaddr_t)Sysmap ||
+		    pv->pv_va >= (vaddr_t)Sysmap + MACHINE_MAX_PTSIZE)
+			printf("collect: kernel PT VA out of range\n");
+		else
+			goto ok;
+		pmap_pvdump(pa);
+		continue;
+ok:
+#endif
+		pte = (pt_entry_t *)(pv->pv_va + PAGE_SIZE);
+		while (--pte >= (pt_entry_t *)pv->pv_va && *pte == PG_NV)
+			;
+		if (pte >= (pt_entry_t *)pv->pv_va)
+			continue;
+
+#ifdef PMAP_DEBUG
+		if (pmapdebug & (PDB_PTPAGE|PDB_COLLECT)) {
+			printf("collect: freeing KPT page at %lx (ste %x@%p)\n",
+			       pv->pv_va, *pv->pv_ptste, pv->pv_ptste);
+			opmapdebug = pmapdebug;
+			pmapdebug |= PDB_PTPAGE;
+		}
+
+		ste = pv->pv_ptste;
+#endif
+		/*
+		 * If all entries were invalid we can remove the page.
+		 * We call pmap_remove_entry to take care of invalidating
+		 * ST and Sysptmap entries.
+		 */
+		pmap_extract(pmap_kernel(), pv->pv_va, &kpa);
+		pmap_remove_mapping(pmap_kernel(), pv->pv_va, PT_ENTRY_NULL,
+				    PRM_TFLUSH|PRM_CFLUSH);
+		/*
+		 * Use the physical address to locate the original
+		 * (kmem_alloc assigned) address for the page and put
+		 * that page back on the free list.
+		 */
+		for (pkpt = &kpt_used_list, kpt = *pkpt;
+		     kpt != NULL;
+		     pkpt = &kpt->kpt_next, kpt = *pkpt)
+			if (kpt->kpt_pa == kpa)
+				break;
+#ifdef PMAP_DEBUG
+		if (kpt == NULL)
+			panic("pmap_collect: lost a KPT page");
+		if (pmapdebug & (PDB_PTPAGE|PDB_COLLECT))
+			printf("collect: %lx (%lx) to free list\n",
+			       kpt->kpt_va, kpa);
+#endif
+		*pkpt = kpt->kpt_next;
+		kpt->kpt_next = kpt_free_list;
+		kpt_free_list = kpt;
+#ifdef PMAP_DEBUG
+		if (pmapdebug & (PDB_PTPAGE|PDB_COLLECT))
+			pmapdebug = opmapdebug;
+
+		if (*ste & SG_V)
+			printf("collect: kernel STE at %p still valid (%x)\n",
+			       ste, *ste);
+		ste = &Sysptmap[ste - pmap_ste(pmap_kernel(), 0)];
+		if (*ste & SG_V)
+			printf("collect: kernel PTmap at %p still valid (%x)\n",
+			       ste, *ste);
+#endif
+	}
 }
 
 /*