x86/vdso: Move VDSO clocksource state tracking to callback

All architectures which use the generic VDSO code have their own storage
for the VDSO clock mode. That's pointless and just requires duplicate code.

X86 abuses the function which retrieves the architecture specific clock
mode storage to mark the clocksource as used in the VDSO. That's silly
because this is invoked on every tick when the VDSO data is updated.

Move this functionality to the clocksource::enable() callback so it gets
invoked once when the clocksource is installed. This allows to make the
clock mode storage generic.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>  (Hyper-V parts)
Reviewed-by: Vincenzo Frascino <[email protected]> (VDSO parts)
Acked-by: Juergen Gross <[email protected]> (Xen parts)
Link: https://lkml.kernel.org/r/[email protected]

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 9d808d595ca8..a86859ccc61b 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -369,6 +369,12 @@ static void resume_hv_clock_tsc(struct clocksource *arg)
 	hv_set_reference_tsc(tsc_msr);
 }
 
+static int hv_cs_enable(struct clocksource *cs)
+{
+	hv_enable_vdso_clocksource();
+	return 0;
+}
+
 static struct clocksource hyperv_cs_tsc = {
 	.name	= "hyperv_clocksource_tsc_page",
 	.rating	= 250,
@@ -377,6 +383,7 @@ static struct clocksource hyperv_cs_tsc = {
 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
 	.suspend= suspend_hv_clock_tsc,
 	.resume	= resume_hv_clock_tsc,
+	.enable = hv_cs_enable,
 };
 
 static u64 notrace read_hv_clock_msr(void)