[PATCHv4 05/28] timens: Introduce CLOCK_BOOTTIME offset

[Dmitry Safonov]

From: Andrei Vagin <avagin@xxxxxxxxx>

Adds boottime virtualisation for time namespace.
Introduce timespec for boottime clock into timens offsets and wire
clock_gettime() syscall.

Signed-off-by: Andrei Vagin <avagin@xxxxxxxxx>
Co-developed-by: Dmitry Safonov <dima@xxxxxxxxxx>
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
---
 include/linux/time_namespace.h | 9 +++++++++
 include/linux/timens_offsets.h | 1 +
 kernel/time/alarmtimer.c       | 1 +
 kernel/time/posix-stubs.c      | 1 +
 kernel/time/posix-timers.c     | 1 +
 5 files changed, 13 insertions(+)

diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index 81d0c989df3c..1dda8af6b9fe 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -48,6 +48,14 @@ static inline void timens_add_monotonic(struct timespec64 *ts)
                 *ts = timespec64_add(*ts, ns_offsets->monotonic);
 }
 
+static inline void timens_add_boottime(struct timespec64 *ts)
+{
+        struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
+
+        if (ns_offsets)
+                *ts = timespec64_add(*ts, ns_offsets->boottime);
+}
+
 #else
 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
 {
@@ -73,6 +81,7 @@ static inline int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *ts
 }
 
 static inline void timens_add_monotonic(struct timespec64 *ts) {}
+static inline void timens_add_boottime(struct timespec64 *ts) {}
 #endif
 
 #endif /* _LINUX_TIMENS_H */
diff --git a/include/linux/timens_offsets.h b/include/linux/timens_offsets.h
index eaac2c82be5c..e93aabaa5e45 100644
--- a/include/linux/timens_offsets.h
+++ b/include/linux/timens_offsets.h
@@ -4,6 +4,7 @@
 
 struct timens_offsets {
 	struct timespec64 monotonic;
+	struct timespec64 boottime;
 };
 
 #endif
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 68a163c8b4f2..6346e6ee0d32 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -26,6 +26,7 @@
 #include <linux/freezer.h>
 #include <linux/compat.h>
 #include <linux/module.h>
+#include <linux/time_namespace.h>
 
 #include "posix-timers.h"
 
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 17c67e0aecd8..edaf075d1ee4 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -82,6 +82,7 @@ int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
 		break;
 	case CLOCK_BOOTTIME:
 		ktime_get_boottime_ts64(tp);
+		timens_add_boottime(tp);
 		break;
 	default:
 		return -EINVAL;
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 52098f6ad596..573942ae2629 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -240,6 +240,7 @@ static int posix_get_coarse_res(const clockid_t which_clock, struct timespec64 *
 int posix_get_boottime_timespec(const clockid_t which_clock, struct timespec64 *tp)
 {
 	ktime_get_boottime_ts64(tp);
+	timens_add_boottime(tp);
 	return 0;
 }
 
-- 
2.22.0