From: Andrei Vagin <[email protected]> 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 <[email protected]> Signed-off-by: Dmitry Safonov <[email protected]> --- 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
