Module Name: src
Committed By: skrll
Date: Mon Apr 27 08:19:59 UTC 2009
Modified Files:
src/sys/arch/hppa/hppa [nick-hppapmap]: pmap.c
Log Message:
Update some comments.
To generate a diff of this commit:
cvs rdiff -u -r1.43.8.51 -r1.43.8.52 src/sys/arch/hppa/hppa/pmap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/hppa/hppa/pmap.c
diff -u src/sys/arch/hppa/hppa/pmap.c:1.43.8.51 src/sys/arch/hppa/hppa/pmap.c:1.43.8.52
--- src/sys/arch/hppa/hppa/pmap.c:1.43.8.51 Mon Apr 27 08:11:19 2009
+++ src/sys/arch/hppa/hppa/pmap.c Mon Apr 27 08:19:59 2009
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.43.8.51 2009/04/27 08:11:19 skrll Exp $ */
+/* $NetBSD: pmap.c,v 1.43.8.52 2009/04/27 08:19:59 skrll Exp $ */
/*-
* Copyright (c) 2001, 2002 The NetBSD Foundation, Inc.
@@ -65,7 +65,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.43.8.51 2009/04/27 08:11:19 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.43.8.52 2009/04/27 08:19:59 skrll Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -499,9 +499,13 @@
#endif
/*
- * Check for non-equiv aliases for this PA. If we find any then mark
- * all PTEs as uncacheable including the one we're checking.
+ * Check for non-equiv aliases for this page and the mapping being added or
+ * removed. If, when adding, we find a new non-equiv alias then mark all PTEs
+ * as uncacheable including the one we're checking. If, when removing, there
+ * are no non-equiv aliases left then we mark PTEs as cacheable.
*
+ * - Shouldn't be called for pages that have been marked uncacheable by
+ * pmap_kenter_pa.
* - Must be called with pg->mdpage.pvh_lock held.
*/
void
@@ -569,8 +573,8 @@
if ((attrs & (PVF_WRITE|PVF_MOD)) != 0) {
/*
* We have non-equiv aliases and the new/some
- * mapping(s) is/are is writable (or modified). We must
- * mark the all mappings as uncacheable (if they're not
+ * mapping(s) is/are writable (or modified). We must
+ * mark all mappings as uncacheable (if they're not
* already marked as such).
*/
pg->mdpage.pvh_aliases++;
@@ -586,8 +590,8 @@
} else {
if ((attrs & PVF_UNCACHEABLE) != 0) {
/*
- * We've removed a non-equiv aliases. We can check
- * marked uncacheable. We can now mark it cacheable.
+ * We've removed a non-equiv aliases. We can now mark
+ * it cacheable if all non-equiv aliases are gone.
*/
pg->mdpage.pvh_aliases--;
@@ -737,7 +741,7 @@
/*
* cpuid() found out how big the HPT should be, so align addr to
* what will be its beginning. We don't waste the pages skipped
- * for the alignment; they become struct pv_entry pages.
+ * for the alignment.
*/
#ifdef USE_HPT
if (pmap_hptsize) {
@@ -1093,7 +1097,7 @@
* pmap_create()
*
* Create and return a physical map.
- * the map is an actual physical map, and may be referenced by the hardware.
+ * The map is an actual physical map, and may be referenced by the hardware.
*/
pmap_t
pmap_create(void)
@@ -1709,10 +1713,7 @@
/*
* pmap_copy_page(src, dst)
*
- * pmap_copy_page copies the src page to the destination page. If a mapping
- * can be found for the source, we use that virtual address. Otherwise, a
- * slower physical page copy must be done. The destination is always a
- * physical address since there is usually no mapping for it.
+ * pmap_copy_page copies the source page to the destination page.
*/
void
pmap_copy_page(paddr_t spa, paddr_t dpa)
@@ -1744,9 +1745,8 @@
int opmapdebug = pmapdebug;
/*
- * If we're being told to map page zero, we can't
- * call printf() at all, because doing so would
- * lead to an infinite recursion on this call.
+ * If we're being told to map page zero, we can't call printf() at all,
+ * because doing so would lead to an infinite recursion on this call.
* (printf requires page zero to be mapped).
*/
if (va == 0)
@@ -1810,10 +1810,8 @@
int opmapdebug = pmapdebug;
/*
- * If we're being told to unmap page zero, we can't
- * call printf() at all, because doing so would
- * lead to an infinite recursion on this call.
- * (printf requires page zero to be mapped).
+ * If we're being told to unmap page zero, we can't call printf() at
+ * all as printf required page zero to be mapped.
*/
if (va == 0)
pmapdebug = 0;
@@ -1824,10 +1822,10 @@
#ifdef PMAPDEBUG
/*
- * Don't allow the VA == PA mappings, apart from
- * page zero, to be removed. Page zero is special
- * so that we get TLB faults when the kernel tries
- * to de-reference NULL.
+ * Don't allow the VA == PA mappings, apart from page zero, to be
+ * removed. Page zero is given special treatment so that we get TLB
+ * faults when the kernel tries to de-reference NULL or anything else
+ * in the first page when it shouldn't.
*/
if (va != 0 && va < ptoa(physmem)) {
DPRINTF(PDB_FOLLOW|PDB_REMOVE,
