Re: [PATCH v2 07/10] clocksource/drivers/hyper-v: Handle vDSO differences inline
From: Daniel Lezcano <hidden>
Date: 2021-03-01 12:22:55
Also in:
linux-arch, linux-hyperv
On 01/03/2021 02:15, 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.
A suggestion below
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Signed-off-by: Michael Kelley <redacted> Reviewed-by: Boqun Feng <redacted> --- 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..5e5e08aa 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)
static __maybe_unused int hv_cs_enable(struct clocksource *cs)
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{ - 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
#ifdef VDSO_CLOCKMODE_HVCLOCK .enable = hv_cs_enable, .vdso_clock_mode = VDSO_CLOCKMODE_HVCLOCK, #else .vdso_clock_mode = VDSO_CLOCKMODE_NONE, #endif
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}; static u64 notrace read_hv_clock_msr(void)@@ -442,7 +449,6 @@ 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();
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