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    Subject[PATCH 07/10] clocksource/drivers/hyper-v: Handle vDSO differences inline
    Date
    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@microsoft.com>
    ---
    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 4d3e0c5..ed9dc56 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 9425308..9cee6db 100644
    --- a/drivers/clocksource/hyperv_timer.c
    +++ b/drivers/clocksource/hyperv_timer.c
    @@ -372,7 +372,9 @@ static void resume_hv_clock_tsc(struct clocksource *arg)

    static int hv_cs_enable(struct clocksource *cs)
    {
    - hv_enable_vdso_clocksource();
    +#ifdef VDSO_CLOCKMODE_HVCLOCK
    + vclocks_set_used(VDSO_CLOCKMODE_HVCLOCK);
    +#endif
    return 0;
    }

    @@ -385,6 +387,11 @@ static int hv_cs_enable(struct clocksource *cs)
    .suspend= suspend_hv_clock_tsc,
    .resume = resume_hv_clock_tsc,
    .enable = hv_cs_enable,
    +#ifdef VDSO_CLOCKMODE_HVCLOCK
    + .vdso_clock_mode = VDSO_CLOCKMODE_HVCLOCK,
    +#else
    + .vdso_clock_mode = VDSO_CLOCKMODE_NONE,
    +#endif
    };

    static u64 notrace read_hv_clock_msr(void)
    @@ -439,7 +446,6 @@ static bool __init hv_init_tsc_clocksource(void)
    tsc_msr = tsc_msr | 0x1 | (u64)phys_addr;
    hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr);

    - hv_set_clocksource_vdso(hyperv_cs_tsc);
    clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);

    hv_sched_clock_offset = hv_read_reference_counter();
    --
    1.8.3.1
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