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authorThomas Gleixner <tglx@linutronix.de>2020-12-09 09:09:27 +0300
committerMarc Zyngier <maz@kernel.org>2021-04-07 18:33:20 +0300
commitb2c67cbe9f447312f5cdd7c6641b463f2349aec0 (patch)
tree3df86da966a25b85da7c84cb893edb2705ccd720 /include/linux/clocksource.h
parenta8cf291bdac5d415eadb55e79df1fca8c3f0dfef (diff)
downloadlinux-b2c67cbe9f447312f5cdd7c6641b463f2349aec0.tar.xz
time: Add mechanism to recognize clocksource in time_get_snapshot
System time snapshots are not conveying information about the current clocksource which was used, but callers like the PTP KVM guest implementation have the requirement to evaluate the clocksource type to select the appropriate mechanism. Introduce a clocksource id field in struct clocksource which is by default set to CSID_GENERIC (0). Clocksource implementations can set that field to a value which allows to identify the clocksource. Store the clocksource id of the current clocksource in the system_time_snapshot so callers can evaluate which clocksource was used to take the snapshot and act accordingly. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-5-jianyong.wu@arm.com
Diffstat (limited to 'include/linux/clocksource.h')
-rw-r--r--include/linux/clocksource.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 86d143db6523..1290d0dce840 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -17,6 +17,7 @@
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/of.h>
+#include <linux/clocksource_ids.h>
#include <asm/div64.h>
#include <asm/io.h>
@@ -62,6 +63,10 @@ struct module;
* 400-499: Perfect
* The ideal clocksource. A must-use where
* available.
+ * @id: Defaults to CSID_GENERIC. The id value is captured
+ * in certain snapshot functions to allow callers to
+ * validate the clocksource from which the snapshot was
+ * taken.
* @flags: Flags describing special properties
* @enable: Optional function to enable the clocksource
* @disable: Optional function to disable the clocksource
@@ -100,6 +105,7 @@ struct clocksource {
const char *name;
struct list_head list;
int rating;
+ enum clocksource_ids id;
enum vdso_clock_mode vdso_clock_mode;
unsigned long flags;