From: Andrei Vagin <avagin@xxxxxxxxxx>
Introduce offsets for time namespace. They will contain adjustment
needed to convert clocks to/from host's.
Allocate one page for each time namespace that will be premapped into
userspace with vvar pages.
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxxx>
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
---
include/linux/time_namespace.h | 2 ++
include/linux/timens_offsets.h | 8 ++++++++
kernel/time_namespace.c | 14 ++++++++++++--
3 files changed, 22 insertions(+), 2 deletions(-)
create mode 100644 include/linux/timens_offsets.h
diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index bf98f35efe07..4960c54f1b33 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -8,6 +8,7 @@
#include <linux/nsproxy.h>
#include <linux/ns_common.h>
#include <linux/err.h>
+#include <linux/timens_offsets.h>
struct user_namespace;
extern struct user_namespace init_user_ns;
@@ -17,6 +18,7 @@ struct time_namespace {
struct user_namespace *user_ns;
struct ucounts *ucounts;
struct ns_common ns;
+ struct timens_offsets *offsets;
} __randomize_layout;
extern struct time_namespace init_time_ns;
diff --git a/include/linux/timens_offsets.h b/include/linux/timens_offsets.h
new file mode 100644
index 000000000000..7d7cb68ea778
--- /dev/null
+++ b/include/linux/timens_offsets.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TIME_OFFSETS_H
+#define _LINUX_TIME_OFFSETS_H
+
+struct timens_offsets {
+};
+
+#endif
diff --git a/kernel/time_namespace.c b/kernel/time_namespace.c
index 902cd9c22159..a985529754b4 100644
--- a/kernel/time_namespace.c
+++ b/kernel/time_namespace.c
@@ -13,6 +13,7 @@
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
#include <linux/sched/task.h>
+#include <linux/mm.h>
static struct ucounts *inc_time_namespaces(struct user_namespace *ns)
{
@@ -44,6 +45,7 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns,
{
struct time_namespace *ns;
struct ucounts *ucounts;
+ struct page *page;
int err;
err = -ENOSPC;
@@ -56,15 +58,22 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns,
if (!ns)
goto fail_dec;
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page)
+ goto fail_free;
+ ns->offsets = page_address(page);
+ BUILD_BUG_ON(sizeof(*ns->offsets) > PAGE_SIZE);
+
err = ns_alloc_inum(&ns->ns);
if (err)
- goto fail_free;
+ goto fail_page;
ns->ucounts = ucounts;
ns->ns.ops = &timens_operations;
ns->user_ns = get_user_ns(user_ns);
return ns;
-
+fail_page:
+ free_page((unsigned long)ns->offsets);
fail_free:
kfree(ns);
fail_dec:
@@ -93,6 +102,7 @@ void free_time_ns(struct kref *kref)
struct time_namespace *ns;
ns = container_of(kref, struct time_namespace, kref);
+ free_page((unsigned long)ns->offsets);
dec_time_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
--
2.13.6
