Module Name: src
Committed By: bouyer
Date: Thu Feb 23 18:59:22 UTC 2012
Modified Files:
src/sys/arch/x86/x86: pmap.c
src/sys/arch/xen/x86: x86_xpmap.c
Log Message:
On Xen, there is variable-sized Xen data after the kernel's text+data+bss
(this include the physical->machine table).
(vaddr_t)(KERNBASE + NKL2_KIMG_ENTRIES * NBPD_L2) is after text+data+bss but,
on a domU with lots of RAM (more than 4GB) (so large
xpmap_phys_to_machine_mapping table) this can point to some of Xen's data
setup at bootstrap (either the xpmap_phys_to_machine_mapping table,
some page shared with the hypervisor, or our kernel page table). Using it for
early_zerop will cause of these pages to be unmapped after bootstrap.
This will cause a kernel page fault for the domU, either immediatly or
eventually much later, depending on where early_zerop points to.
To fix this, account for early_zerop when building the bootstrap pages,
and its VA from here.
May fix PR port-xen/38699
To generate a diff of this commit:
cvs rdiff -u -r1.169 -r1.170 src/sys/arch/x86/x86/pmap.c
cvs rdiff -u -r1.39 -r1.40 src/sys/arch/xen/x86/x86_xpmap.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/x86/x86/pmap.c
diff -u src/sys/arch/x86/x86/pmap.c:1.169 src/sys/arch/x86/x86/pmap.c:1.170
--- src/sys/arch/x86/x86/pmap.c:1.169 Tue Feb 21 21:09:51 2012
+++ src/sys/arch/x86/x86/pmap.c Thu Feb 23 18:59:21 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.169 2012/02/21 21:09:51 rmind Exp $ */
+/* $NetBSD: pmap.c,v 1.170 2012/02/23 18:59:21 bouyer Exp $ */
/*-
* Copyright (c) 2008, 2010 The NetBSD Foundation, Inc.
@@ -171,7 +171,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.169 2012/02/21 21:09:51 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.170 2012/02/23 18:59:21 bouyer Exp $");
#include "opt_user_ldt.h"
#include "opt_lockdebug.h"
@@ -513,7 +513,12 @@ extern int mem_cluster_cnt;
* special VAs and the PTEs that map them
*/
static pt_entry_t *csrc_pte, *cdst_pte, *zero_pte, *ptp_pte, *early_zero_pte;
-static char *csrcp, *cdstp, *zerop, *ptpp, *early_zerop;
+static char *csrcp, *cdstp, *zerop, *ptpp;
+#ifdef XEN
+char *early_zerop; /* also referenced from xen_pmap_bootstrap() */
+#else
+static char *early_zerop;
+#endif
#endif
@@ -1384,8 +1389,11 @@ pmap_bootstrap(vaddr_t kva_start)
* when it's called for the first time.
* XXXfvdl fix this for MULTIPROCESSOR later.
*/
-
+#ifdef XEN
+ /* early_zerop initialized in xen_pmap_bootstrap() */
+#else
early_zerop = (void *)(KERNBASE + NKL2_KIMG_ENTRIES * NBPD_L2);
+#endif
early_zero_pte = PTE_BASE + pl1_i((vaddr_t)early_zerop);
}
Index: src/sys/arch/xen/x86/x86_xpmap.c
diff -u src/sys/arch/xen/x86/x86_xpmap.c:1.39 src/sys/arch/xen/x86/x86_xpmap.c:1.40
--- src/sys/arch/xen/x86/x86_xpmap.c:1.39 Fri Feb 17 18:40:20 2012
+++ src/sys/arch/xen/x86/x86_xpmap.c Thu Feb 23 18:59:21 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: x86_xpmap.c,v 1.39 2012/02/17 18:40:20 bouyer Exp $ */
+/* $NetBSD: x86_xpmap.c,v 1.40 2012/02/23 18:59:21 bouyer Exp $ */
/*
* Copyright (c) 2006 Mathieu Ropert <m...@adviseo.fr>
@@ -69,7 +69,7 @@
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: x86_xpmap.c,v 1.39 2012/02/17 18:40:20 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: x86_xpmap.c,v 1.40 2012/02/23 18:59:21 bouyer Exp $");
#include "opt_xen.h"
#include "opt_ddb.h"
@@ -595,6 +595,7 @@ xen_pmap_bootstrap(void)
* - UAREA
* - dummy user PGD (x86_64)
* - HYPERVISOR_shared_info
+ * - early_zerop
* - ISA I/O mem (if needed)
*/
mapsize += UPAGES * NBPG;
@@ -602,6 +603,7 @@ xen_pmap_bootstrap(void)
mapsize += NBPG;
#endif
mapsize += NBPG;
+ mapsize += NBPG;
#ifdef DOM0OPS
if (xendomain_is_dom0()) {
@@ -690,6 +692,7 @@ xen_bootstrap_tables (vaddr_t old_pgd, v
vaddr_t page, avail, text_end, map_end;
int i;
extern char __data_start;
+ extern char *early_zerop; /* from pmap.c */
__PRINTK(("xen_bootstrap_tables(%#" PRIxVADDR ", %#" PRIxVADDR ","
" %d, %d)\n",
@@ -704,6 +707,7 @@ xen_bootstrap_tables (vaddr_t old_pgd, v
* UAREA
* dummy user PGD (x86_64 only)/gdt page (i386 only)
* HYPERVISOR_shared_info
+ * early_zerop
* ISA I/O mem (if needed)
*/
map_end = new_pgd + ((new_count + l2_4_count) * NBPG);
@@ -711,6 +715,8 @@ xen_bootstrap_tables (vaddr_t old_pgd, v
map_end += (UPAGES + 1) * NBPG;
HYPERVISOR_shared_info = (shared_info_t *)map_end;
map_end += NBPG;
+ early_zerop = (char *)map_end;
+ map_end += NBPG;
}
/*
* we always set atdevbase, as it's used by init386 to find the first
