On 08/03/2021 14:49, Michael Kelley wrote:
> From: Michael Kelley <mikelley@xxxxxxxxxxxxx> Sent: Tuesday, March 2, 2021 3:07 PM
>>
>> From: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> Sent: Tuesday, March 2, 2021 2:14 PM
>>>
>>> On 02/03/2021 22:38, Michael Kelley wrote:
>>>> While the driver for the Hyper-V Reference TSC and STIMERs is architecture
>>>> neutral, vDSO is implemented for x86/x64, but not for ARM64. Current code
>>>> calls into utility functions under arch/x86 (and coming, under arch/arm64)
>>>> to handle the difference.
>>>>
>>>> Change this approach to handle the difference inline based on whether
>>>> VDSO_CLOCK_MODE_HVCLOCK is present. The new approach removes code under
>>>> arch/* since the difference is tied more to the specifics of the Linux
>>>> implementation than to the architecture.
>>>>
>>>> No functional change.
>>>>
>>>> Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
>>>> Reviewed-by: Boqun Feng <boqun.feng@xxxxxxxxx>
>>>> ---
>>>> arch/x86/include/asm/mshyperv.h | 4 ----
>>>> drivers/clocksource/hyperv_timer.c | 10 ++++++++--
>>>> 2 files changed, 8 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
>>>> index c10dd1c..4f566db 100644
>>>> --- a/arch/x86/include/asm/mshyperv.h
>>>> +++ b/arch/x86/include/asm/mshyperv.h
>>>> @@ -27,10 +27,6 @@ static inline u64 hv_get_register(unsigned int reg)
>>>> return value;
>>>> }
>>>>
>>>> -#define hv_set_clocksource_vdso(val) \
>>>> - ((val).vdso_clock_mode = VDSO_CLOCKMODE_HVCLOCK)
>>>> -#define hv_enable_vdso_clocksource() \
>>>> - vclocks_set_used(VDSO_CLOCKMODE_HVCLOCK);
>>>> #define hv_get_raw_timer() rdtsc_ordered()
>>>>
>>>> /*
>>>> diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
>>>> index c73c127..06984fa 100644
>>>> --- a/drivers/clocksource/hyperv_timer.c
>>>> +++ b/drivers/clocksource/hyperv_timer.c
>>>> @@ -370,11 +370,13 @@ static void resume_hv_clock_tsc(struct clocksource *arg)
>>>> hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr);
>>>> }
>>>>
>>>> +#ifdef VDSO_CLOCKMODE_HVCLOCK
>>>> static int hv_cs_enable(struct clocksource *cs)
>>>> {
>>>> - hv_enable_vdso_clocksource();
>>>> + vclocks_set_used(VDSO_CLOCKMODE_HVCLOCK);
>>>> return 0;
>>>> }
>>>> +#endif
>>>
>>> We had a confusion here. The suggestion was to remove the #ifdef here
>>> and add the __maybe_unused annotation to the function.
>>
>> I wondered if maybe that's what you were getting at with your
>> most recent comments. But the code doesn't compile on ARM64
>> with __maybe_unused instead of the #ifdef because
>> VDSO_CLOCKMODE_HVCLOCK is undefined.
>>
>> Michael
>>
>
> Daniel -- any additional comments/feedback? Getting your Ack on
> this patch should be the last step to wrap up the patch series.
It would have been nice to simplify those #ifdef but I don't see a
straightforward change for that... :(
Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
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