timekeeping: Prevent false warning when persistent clock is not available

Pavel Tatashin · KAGA-KOKO · commit 684ad537abff · 2018-07-30T19:32:29.000+02:00
On arches with no persistent clock a message like this is printed during boot: [ 0.000000] Persistent clock returned invalid value The value is not invalid: Zero means that no persistent clock is available and the absence of persistent clock should be quietly accepted. Fixes: 3eca993 ("timekeeping: Replace read_boot_clock64() with read_persistent_wall_and_boot_offset()") Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Cc: sboyd@kernel.org Cc: john.stultz@linaro.org Link: https://lkml.kernel.org/r/20180725200018.23722-1-pasha.tatashin@oracle.com
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
@@ -1536,7 +1536,7 @@ void __init timekeeping_init(void)
 	if (timespec64_valid_strict(&wall_time) &&
 	    timespec64_to_ns(&wall_time) > 0) {
 		persistent_clock_exists = true;
-	} else {
+	} else if (timespec64_to_ns(&wall_time) != 0) {
 		pr_warn("Persistent clock returned invalid value");
 		wall_time = (struct timespec64){0};
 	}

Original file line number	Diff line number	Diff line change
`@@ -1536,7 +1536,7 @@ void __init timekeeping_init(void)`
`1536`	`1536`	`if (timespec64_valid_strict(&wall_time) &&`
`1537`	`1537`	`timespec64_to_ns(&wall_time) > 0) {`
`1538`	`1538`	`persistent_clock_exists = true;`
`1539`		`- } else {`
	`1539`	`+ } else if (timespec64_to_ns(&wall_time) != 0) {`
`1540`	`1540`	`pr_warn("Persistent clock returned invalid value");`
`1541`	`1541`	`wall_time = (struct timespec64){0};`
`1542`	`1542`	`}`