Commit eb3e1d37 authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

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



While the Hyper-V Reference TSC code is architecture neutral, the
pv_ops.time.sched_clock() function is implemented for x86/x64, but not
for ARM64. Current code calls a utility function under arch/x86 (and
coming, under arch/arm64) to handle the difference.

Change this approach to handle the difference inline based on whether
GENERIC_SCHED_CLOCK 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/1614721102-2241-9-git-send-email-mikelley@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent e4ab4658

arch/x86/include/asm/mshyperv.h

+0 −11
Original line number Diff line number Diff line
@@ -29,17 +29,6 @@ static inline u64 hv_get_register(unsigned int reg) 


#define hv_get_raw_timer() rdtsc_ordered()



/*

 * Reference to pv_ops must be inline so objtool

 * detection of noinstr violations can work correctly.

 */

static __always_inline void hv_setup_sched_clock(void *sched_clock)

{

#ifdef CONFIG_PARAVIRT

	pv_ops.time.sched_clock = sched_clock;

#endif

}



void hyperv_vector_handler(struct pt_regs *regs);



static inline void hv_enable_stimer0_percpu_irq(int irq) {}

drivers/clocksource/hyperv_timer.c

+24 −0
Original line number Diff line number Diff line
@@ -423,6 +423,30 @@ static struct clocksource hyperv_cs_msr = { 
	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,

};



/*

 * Reference to pv_ops must be inline so objtool

 * detection of noinstr violations can work correctly.

 */

#ifdef CONFIG_GENERIC_SCHED_CLOCK

static __always_inline void hv_setup_sched_clock(void *sched_clock)

{

	/*

	 * We're on an architecture with generic sched clock (not x86/x64).

	 * The Hyper-V sched clock read function returns nanoseconds, not

	 * the normal 100ns units of the Hyper-V synthetic clock.

	 */

	sched_clock_register(sched_clock, 64, NSEC_PER_SEC);

}

#elif defined CONFIG_PARAVIRT

static __always_inline void hv_setup_sched_clock(void *sched_clock)

{

	/* We're on x86/x64 *and* using PV ops */

	pv_ops.time.sched_clock = sched_clock;

}

#else /* !CONFIG_GENERIC_SCHED_CLOCK && !CONFIG_PARAVIRT */

static __always_inline void hv_setup_sched_clock(void *sched_clock) {}

#endif /* CONFIG_GENERIC_SCHED_CLOCK */



static bool __init hv_init_tsc_clocksource(void)

{

	u64		tsc_msr;