[PATCH 2/3] vdso/gettimeofday: Add support for CLOCK_BOOTTIME_ALARM

[Thomas Weißschuh]

CLOCK_BOOTTIME_ALARM behaves exactly as CLOCK_BOOTTIME as far as the
vDSO is concerned. The vDSO library can handle it automatically
correctly. Only the basetime needs to be maintained during the tick.

The namespace offset is already set correctly, although it was not
used before.

Reuse the CLOCK_BOOTTIME basetime for CLOCK_BOOTTIME_ALARM and update
the userspace hres clock mask to include CLOCK_BOOTTIME_ALARM.
---
 include/vdso/datapage.h | 1 +
 kernel/time/vsyscall.c  | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 09897f76ae07..33297b5e2521 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -35,6 +35,7 @@ struct vdso_arch_data {
 #define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
 			 BIT(CLOCK_MONOTONIC)		| \
 			 BIT(CLOCK_BOOTTIME)		| \
+			 BIT(CLOCK_BOOTTIME_ALARM)	| \
 			 BIT(CLOCK_TAI))
 #define VDSO_COARSE	(BIT(CLOCK_REALTIME_COARSE)	| \
 			 BIT(CLOCK_MONOTONIC_COARSE))
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
index aa59919b8f2c..24082b9d7869 100644
--- a/kernel/time/vsyscall.c
+++ b/kernel/time/vsyscall.c
@@ -63,6 +63,9 @@ static inline void update_vdso_time_data(struct vdso_time_data *vdata, struct ti
 	}
 	vdso_ts->nsec	= nsec;
 
+	/* CLOCK_BOOTTIME_ALARM, copy of CLOCK_BOOTIME */
+	vc[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME_ALARM] = *vdso_ts;
+
 	/* CLOCK_MONOTONIC_RAW */
 	vdso_ts		= &vc[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
 	vdso_ts->sec	= tk->raw_sec;

-- 
2.55.0