[PATCH 08/10] clocksource/drivers/hyper-v: Handle sched_clock differences inline
From: Michael Kelley <hidden>
Date: 2021-01-27 20:29:39
Also in:
linux-arch, lkml
Subsystem:
clocksource, clockevent drivers, hyper-v/azure core and drivers, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Daniel Lezcano, Thomas Gleixner, "K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Linus Torvalds, Ingo Molnar, Borislav Petkov, Dave Hansen
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: Michael Kelley <redacted> --- arch/x86/include/asm/mshyperv.h | 11 ----------- drivers/clocksource/hyperv_timer.c | 21 +++++++++++++++++++++ 2 files changed, 21 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index ed9dc56..5ccbba8 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h@@ -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) {}
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 9cee6db..a2bee50 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c@@ -423,6 +423,27 @@ static u64 notrace read_hv_sched_clock_msr(void) .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; +/* + * 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_GENERIC_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); +#else +#ifdef CONFIG_PARAVIRT + /* We're on x86/x64 *and* using PV ops */ + pv_ops.time.sched_clock = sched_clock; +#endif +#endif +} + static bool __init hv_init_tsc_clocksource(void) { u64 tsc_msr;
--
1.8.3.1