clocksource/drivers: Make Hyper-V clocksource ISA agnostic (fd1fea68) · Commits · 戴 / test

MAINTAINERS

+2 −0

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		@@ -7313,6 +7313,7 @@ F: arch/x86/include/asm/trace/hyperv.h
		F: arch/x86/include/asm/hyperv-tlfs.h
		F: arch/x86/kernel/cpu/mshyperv.c
		F: arch/x86/hyperv
		F: drivers/clocksource/hyperv_timer.c
		F: drivers/hid/hid-hyperv.c
		F: drivers/hv/
		F: drivers/input/serio/hyperv-keyboard.c
		@@ -7323,6 +7324,7 @@ F: drivers/uio/uio_hv_generic.c
		F: drivers/video/fbdev/hyperv_fb.c
		F: drivers/iommu/hyperv_iommu.c
		F: net/vmw_vsock/hyperv_transport.c
		F: include/clocksource/hyperv_timer.h
		F: include/linux/hyperv.h
		F: include/uapi/linux/hyperv.h
		F: tools/hv/

arch/x86/include/asm/hyperv-tlfs.h

+6 −0

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		@@ -401,6 +401,12 @@ enum HV_GENERIC_SET_FORMAT {
		#define HV_STATUS_INVALID_CONNECTION_ID 18
		#define HV_STATUS_INSUFFICIENT_BUFFERS 19

		/*
		* The Hyper-V TimeRefCount register and the TSC
		* page provide a guest VM clock with 100ns tick rate
		*/
		#define HV_CLOCK_HZ (NSEC_PER_SEC/100)

		typedef struct _HV_REFERENCE_TSC_PAGE {
		__u32 tsc_sequence;
		__u32 res1;

arch/x86/kernel/cpu/mshyperv.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#include <linux/irq.h>
		#include <linux/kexec.h>
		#include <linux/i8253.h>
		#include <linux/random.h>
		#include <asm/processor.h>
		#include <asm/hypervisor.h>
		#include <asm/hyperv-tlfs.h>
		@@ -80,6 +81,7 @@ __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
		inc_irq_stat(hyperv_stimer0_count);
		if (hv_stimer0_handler)
		hv_stimer0_handler();
		add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
		ack_APIC_irq();

		exiting_irq();
		@@ -89,7 +91,7 @@ __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
		int hv_setup_stimer0_irq(int irq, int vector, void (*handler)(void))
		{
		*vector = HYPERV_STIMER0_VECTOR;
		irq = 0; / Unused on x86/x64 */
		irq = -1; / Unused on x86/x64 */
		hv_stimer0_handler = handler;
		return 0;
		}

drivers/clocksource/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -86,3 +86,4 @@ obj-$(CONFIG_ATCPIT100_TIMER) += timer-atcpit100.o
		obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o
		obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o
		obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
		obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o

drivers/clocksource/hyperv_timer.c

0 → 100644

+200 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0

		/*
		* Clocksource driver for the synthetic counter and timers
		* provided by the Hyper-V hypervisor to guest VMs, as described
		* in the Hyper-V Top Level Functional Spec (TLFS). This driver
		* is instruction set architecture independent.
		*
		* Copyright (C) 2019, Microsoft, Inc.
		*
		* Author: Michael Kelley <mikelley@microsoft.com>
		*/

		#include <linux/percpu.h>
		#include <linux/cpumask.h>
		#include <linux/clockchips.h>
		#include <linux/mm.h>
		#include <clocksource/hyperv_timer.h>
		#include <asm/hyperv-tlfs.h>
		#include <asm/mshyperv.h>

		static struct clock_event_device __percpu *hv_clock_event;

		/*
		* If false, we're using the old mechanism for stimer0 interrupts
		* where it sends a VMbus message when it expires. The old
		* mechanism is used when running on older versions of Hyper-V
		* that don't support Direct Mode. While Hyper-V provides
		* four stimer's per CPU, Linux uses only stimer0.
		*/
		static bool direct_mode_enabled;

		static int stimer0_irq;
		static int stimer0_vector;
		static int stimer0_message_sint;

		/*
		* ISR for when stimer0 is operating in Direct Mode. Direct Mode
		* does not use VMbus or any VMbus messages, so process here and not
		* in the VMbus driver code.
		*/
		void hv_stimer0_isr(void)
		{
		struct clock_event_device *ce;

		ce = this_cpu_ptr(hv_clock_event);
		ce->event_handler(ce);
		}
		EXPORT_SYMBOL_GPL(hv_stimer0_isr);

		static int hv_ce_set_next_event(unsigned long delta,
		struct clock_event_device *evt)
		{
		u64 current_tick;

		current_tick = hyperv_cs->read(NULL);
		current_tick += delta;
		hv_init_timer(0, current_tick);
		return 0;
		}

		static int hv_ce_shutdown(struct clock_event_device *evt)
		{
		hv_init_timer(0, 0);
		hv_init_timer_config(0, 0);
		if (direct_mode_enabled)
		hv_disable_stimer0_percpu_irq(stimer0_irq);

		return 0;
		}

		static int hv_ce_set_oneshot(struct clock_event_device *evt)
		{
		union hv_stimer_config timer_cfg;

		timer_cfg.as_uint64 = 0;
		timer_cfg.enable = 1;
		timer_cfg.auto_enable = 1;
		if (direct_mode_enabled) {
		/*
		* When it expires, the timer will directly interrupt
		* on the specified hardware vector/IRQ.
		*/
		timer_cfg.direct_mode = 1;
		timer_cfg.apic_vector = stimer0_vector;
		hv_enable_stimer0_percpu_irq(stimer0_irq);
		} else {
		/*
		* When it expires, the timer will generate a VMbus message,
		* to be handled by the normal VMbus interrupt handler.
		*/
		timer_cfg.direct_mode = 0;
		timer_cfg.sintx = stimer0_message_sint;
		}
		hv_init_timer_config(0, timer_cfg.as_uint64);
		return 0;
		}

		/*
		* hv_stimer_init - Per-cpu initialization of the clockevent
		*/
		void hv_stimer_init(unsigned int cpu)
		{
		struct clock_event_device *ce;

		/*
		* Synthetic timers are always available except on old versions of
		* Hyper-V on x86. In that case, just return as Linux will use a
		* clocksource based on emulated PIT or LAPIC timer hardware.
		*/
		if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
		return;

		ce = per_cpu_ptr(hv_clock_event, cpu);
		ce->name = "Hyper-V clockevent";
		ce->features = CLOCK_EVT_FEAT_ONESHOT;
		ce->cpumask = cpumask_of(cpu);
		ce->rating = 1000;
		ce->set_state_shutdown = hv_ce_shutdown;
		ce->set_state_oneshot = hv_ce_set_oneshot;
		ce->set_next_event = hv_ce_set_next_event;

		clockevents_config_and_register(ce,
		HV_CLOCK_HZ,
		HV_MIN_DELTA_TICKS,
		HV_MAX_MAX_DELTA_TICKS);
		}
		EXPORT_SYMBOL_GPL(hv_stimer_init);

		/*
		* hv_stimer_cleanup - Per-cpu cleanup of the clockevent
		*/
		void hv_stimer_cleanup(unsigned int cpu)
		{
		struct clock_event_device *ce;

		/* Turn off clockevent device */
		if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
		ce = per_cpu_ptr(hv_clock_event, cpu);
		hv_ce_shutdown(ce);
		}
		}
		EXPORT_SYMBOL_GPL(hv_stimer_cleanup);

		/* hv_stimer_alloc - Global initialization of the clockevent and stimer0 */
		int hv_stimer_alloc(int sint)
		{
		int ret;

		hv_clock_event = alloc_percpu(struct clock_event_device);
		if (!hv_clock_event)
		return -ENOMEM;

		direct_mode_enabled = ms_hyperv.misc_features &
		HV_STIMER_DIRECT_MODE_AVAILABLE;
		if (direct_mode_enabled) {
		ret = hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
		hv_stimer0_isr);
		if (ret) {
		free_percpu(hv_clock_event);
		hv_clock_event = NULL;
		return ret;
		}
		}

		stimer0_message_sint = sint;
		return 0;
		}
		EXPORT_SYMBOL_GPL(hv_stimer_alloc);

		/* hv_stimer_free - Free global resources allocated by hv_stimer_alloc() */
		void hv_stimer_free(void)
		{
		if (direct_mode_enabled && (stimer0_irq != 0)) {
		hv_remove_stimer0_irq(stimer0_irq);
		stimer0_irq = 0;
		}
		free_percpu(hv_clock_event);
		hv_clock_event = NULL;
		}
		EXPORT_SYMBOL_GPL(hv_stimer_free);

		/*
		* Do a global cleanup of clockevents for the cases of kexec and
		* vmbus exit
		*/
		void hv_stimer_global_cleanup(void)
		{
		int cpu;
		struct clock_event_device *ce;

		if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
		for_each_present_cpu(cpu) {
		ce = per_cpu_ptr(hv_clock_event, cpu);
		clockevents_unbind_device(ce, cpu);
		}
		}
		hv_stimer_free();
		}
		EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);

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