Commit e4ab4658 authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

clocksource/drivers/hyper-v: Handle vDSO differences inline 



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: default avatarMichael Kelley <mikelley@microsoft.com>
Reviewed-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Acked-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1614721102-2241-8-git-send-email-mikelley@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent d608715d

arch/x86/include/asm/mshyperv.h

+0 −4
Original line number Diff line number Diff line
@@ -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()



/*

drivers/clocksource/hyperv_timer.c

+8 −2
Original line number Diff line number Diff line
@@ -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



static struct clocksource hyperv_cs_tsc = {

	.name	= "hyperv_clocksource_tsc_page",
@@ -384,7 +386,12 @@ static struct clocksource hyperv_cs_tsc = { 
	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,

	.suspend= suspend_hv_clock_tsc,

	.resume	= resume_hv_clock_tsc,

#ifdef VDSO_CLOCKMODE_HVCLOCK

	.enable = hv_cs_enable,

	.vdso_clock_mode = VDSO_CLOCKMODE_HVCLOCK,

#else

	.vdso_clock_mode = VDSO_CLOCKMODE_NONE,

#endif

};



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();