From fd1fea6834d0f9f93062ae6685862908a9baed39 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Mon, 1 Jul 2019 04:25:56 +0000 Subject: clocksource/drivers: Make Hyper-V clocksource ISA agnostic Hyper-V clock/timer code and data structures are currently mixed in with other code in the ISA independent drivers/hv directory as well as the ISA dependent Hyper-V code under arch/x86. Consolidate this code and data structures into a Hyper-V clocksource driver to better follow the Linux model. In doing so, separate out the ISA dependent portions so the new clocksource driver works for x86 and for the in-process Hyper-V on ARM64 code. To start, move the existing clockevents code to create the new clocksource driver. Update the VMbus driver to call initialization and cleanup routines since the Hyper-V synthetic timers are not independently enumerated in ACPI. No behavior is changed and no new functionality is added. Suggested-by: Marc Zyngier Signed-off-by: Michael Kelley Signed-off-by: Thomas Gleixner Reviewed-by: Vitaly Kuznetsov Cc: "bp@alien8.de" Cc: "will.deacon@arm.com" Cc: "catalin.marinas@arm.com" Cc: "mark.rutland@arm.com" Cc: "linux-arm-kernel@lists.infradead.org" Cc: "gregkh@linuxfoundation.org" Cc: "linux-hyperv@vger.kernel.org" Cc: "olaf@aepfle.de" Cc: "apw@canonical.com" Cc: "jasowang@redhat.com" Cc: "marcelo.cerri@canonical.com" Cc: Sunil Muthuswamy Cc: KY Srinivasan Cc: "sashal@kernel.org" Cc: "vincenzo.frascino@arm.com" Cc: "linux-arch@vger.kernel.org" Cc: "linux-mips@vger.kernel.org" Cc: "linux-kselftest@vger.kernel.org" Cc: "arnd@arndb.de" Cc: "linux@armlinux.org.uk" Cc: "ralf@linux-mips.org" Cc: "paul.burton@mips.com" Cc: "daniel.lezcano@linaro.org" Cc: "salyzyn@android.com" Cc: "pcc@google.com" Cc: "shuah@kernel.org" Cc: "0x7f454c46@gmail.com" <0x7f454c46@gmail.com> Cc: "linux@rasmusvillemoes.dk" Cc: "huw@codeweavers.com" Cc: "sfr@canb.auug.org.au" Cc: "pbonzini@redhat.com" Cc: "rkrcmar@redhat.com" Cc: "kvm@vger.kernel.org" Link: https://lkml.kernel.org/r/1561955054-1838-2-git-send-email-mikelley@microsoft.com --- drivers/clocksource/Makefile | 1 + drivers/clocksource/hyperv_timer.c | 200 +++++++++++++++++++++++++++++++++++++ 2 files changed, 201 insertions(+) create mode 100644 drivers/clocksource/hyperv_timer.c (limited to 'drivers/clocksource') diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 5582252efb31..2e7936e7833f 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -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 diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c new file mode 100644 index 000000000000..68a28af31561 --- /dev/null +++ b/drivers/clocksource/hyperv_timer.c @@ -0,0 +1,200 @@ +// 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 + */ + +#include +#include +#include +#include +#include +#include +#include + +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); -- cgit v1.2.3-55-g7522