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authorJohannes Berg <johannes.berg@intel.com>2020-12-02 20:58:05 +0100
committerRichard Weinberger <richard@nod.at>2020-12-13 22:22:41 +0100
commit2701c1bd91dda815b8541aa8c23e1e548cdb6349 (patch)
tree95932e9779b22c189d7b2c60f32b37799f5ad920 /arch/um
parent49da38a3ef330b7a1643e12c51913d58158e5abe (diff)
downloadlinux-2701c1bd91dda815b8541aa8c23e1e548cdb6349.tar.gz
um: time: Fix read_persistent_clock64() in time-travel
In time-travel mode, we've relied on read_persistent_clock64()
being called only once at system startup, but this is both the
right thing to call from the pseudo-RTC, and also gets called
by the timekeeping core during suspend/resume.

Thus, fix this to always fall make use of the time_travel_time
in any time-travel mode, initializing time_travel_start at boot
to the right value depending on the time-travel mode.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/kernel/time.c23
1 files changed, 20 insertions, 3 deletions
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 8e8eb8ba04a4..80d33735cfd2 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -676,10 +676,8 @@ void read_persistent_clock64(struct timespec64 *ts)
 {
 	long long nsecs;
 
-	if (time_travel_start_set)
+	if (time_travel_mode != TT_MODE_OFF)
 		nsecs = time_travel_start + time_travel_time;
-	else if (time_travel_mode == TT_MODE_EXTERNAL)
-		nsecs = time_travel_ext_req(UM_TIMETRAVEL_GET_TOD, -1);
 	else
 		nsecs = os_persistent_clock_emulation();
 
@@ -689,6 +687,25 @@ void read_persistent_clock64(struct timespec64 *ts)
 
 void __init time_init(void)
 {
+#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
+	switch (time_travel_mode) {
+	case TT_MODE_EXTERNAL:
+		time_travel_start = time_travel_ext_req(UM_TIMETRAVEL_GET_TOD, -1);
+		/* controller gave us the *current* time, so adjust by that */
+		time_travel_ext_get_time();
+		time_travel_start -= time_travel_time;
+		break;
+	case TT_MODE_INFCPU:
+	case TT_MODE_BASIC:
+		if (!time_travel_start_set)
+			time_travel_start = os_persistent_clock_emulation();
+		break;
+	case TT_MODE_OFF:
+		/* we just read the host clock with os_persistent_clock_emulation() */
+		break;
+	}
+#endif
+
 	timer_set_signal_handler();
 	late_time_init = um_timer_setup;
 }