From: Yubo Xie yuboxie@microsoft.com
[ Upstream commit 0af3e137c144377fbaf5025ba784ff5ba7ad40c9 ]
hyperv_timer.c exports hyperv_cs, which is used by stimers and the timesync mechanism. However, the clocksource dependency is not needed: these mechanisms only depend on the partition reference counter (which can be read via a MSR or via the TSC Reference Page).
Introduce the (function) pointer hv_read_reference_counter, as an embodiment of the partition reference counter read, and export it in place of the hyperv_cs pointer. The latter can be removed.
This should clarify that there's no relationship between Hyper-V stimers & timesync and the Linux clocksource abstractions. No functional or semantic change.
Suggested-by: Michael Kelley mikelley@microsoft.com Signed-off-by: Andrea Parri parri.andrea@gmail.com Reviewed-by: Michael Kelley mikelley@microsoft.com Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Link: https://lore.kernel.org/r/20200109160650.16150-2-parri.andrea@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clocksource/hyperv_timer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -233,7 +233,8 @@ static u64 notrace read_hv_clock_tsc(str
static u64 read_hv_sched_clock_tsc(void) { - return read_hv_clock_tsc(NULL) - hv_sched_clock_offset; + return (read_hv_clock_tsc(NULL) - hv_sched_clock_offset) * + (NSEC_PER_SEC / HV_CLOCK_HZ); }
static struct clocksource hyperv_cs_tsc = { @@ -258,7 +259,8 @@ static u64 notrace read_hv_clock_msr(str
static u64 read_hv_sched_clock_msr(void) { - return read_hv_clock_msr(NULL) - hv_sched_clock_offset; + return (read_hv_clock_msr(NULL) - hv_sched_clock_offset) * + (NSEC_PER_SEC / HV_CLOCK_HZ); }
static struct clocksource hyperv_cs_msr = {