diff options
Diffstat (limited to 'drivers/clocksource/hyperv_timer.c')
| -rw-r--r-- | drivers/clocksource/hyperv_timer.c | 150 |
1 files changed, 20 insertions, 130 deletions
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index df567795d175..dddfff458ebf 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -31,44 +31,20 @@ static struct clock_event_device __percpu *hv_clock_event; /* Note: offset can hold negative values after hibernation. */ static u64 hv_sched_clock_offset __read_mostly; -/* - * 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. - * - * Because Direct Mode does not require processing a VMbus - * message, stimer interrupts can be enabled earlier in the - * process of booting a CPU, and consistent with when timer - * interrupts are enabled for other clocksource drivers. - * However, for legacy versions of Hyper-V when Direct Mode - * is not enabled, setting up stimer interrupts must be - * delayed until VMbus is initialized and can process the - * interrupt message. - */ -static bool direct_mode_enabled; - static int stimer0_irq = -1; -static int stimer0_message_sint; static __maybe_unused DEFINE_PER_CPU(long, stimer0_evt); -/* - * Common code for stimer0 interrupts coming via Direct Mode or - * as a VMbus message. - */ -void hv_stimer0_isr(void) +static 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); /* * stimer0 interrupt handler for architectures that support - * per-cpu interrupts, which also implies Direct Mode. + * per-cpu interrupts */ static irqreturn_t __maybe_unused hv_stimer0_percpu_isr(int irq, void *dev_id) { @@ -91,7 +67,7 @@ static int hv_ce_shutdown(struct clock_event_device *evt) { hv_set_msr(HV_MSR_STIMER0_COUNT, 0); hv_set_msr(HV_MSR_STIMER0_CONFIG, 0); - if (direct_mode_enabled && stimer0_irq >= 0) + if (stimer0_irq >= 0) disable_percpu_irq(stimer0_irq); return 0; @@ -104,23 +80,16 @@ static int hv_ce_set_oneshot(struct clock_event_device *evt) 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 = HYPERV_STIMER0_VECTOR; - if (stimer0_irq >= 0) - enable_percpu_irq(stimer0_irq, IRQ_TYPE_NONE); - } 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; - } + + /* + * When it expires, the timer will directly interrupt + * on the specified hardware vector/IRQ. + */ + timer_cfg.direct_mode = 1; + timer_cfg.apic_vector = HYPERV_STIMER0_VECTOR; + if (stimer0_irq >= 0) + enable_percpu_irq(stimer0_irq, IRQ_TYPE_NONE); + hv_set_msr(HV_MSR_STIMER0_CONFIG, timer_cfg.as_uint64); return 0; } @@ -175,25 +144,8 @@ int hv_stimer_cleanup(unsigned int cpu) if (!hv_clock_event) return 0; - /* - * In the legacy case where Direct Mode is not enabled - * (which can only be on x86/64), stimer cleanup happens - * relatively early in the CPU offlining process. We - * must unbind the stimer-based clockevent device so - * that the LAPIC timer can take over until clockevents - * are no longer needed in the offlining process. Note - * that clockevents_unbind_device() eventually calls - * hv_ce_shutdown(). - * - * The unbind should not be done when Direct Mode is - * enabled because we may be on an architecture where - * there are no other clockevent devices to fallback to. - */ ce = per_cpu_ptr(hv_clock_event, cpu); - if (direct_mode_enabled) - hv_ce_shutdown(ce); - else - clockevents_unbind_device(ce, cpu); + hv_ce_shutdown(ce); return 0; } @@ -268,23 +220,14 @@ int hv_stimer_alloc(bool have_percpu_irqs) * Hyper-V on x86. In that case, return as error as Linux will use a * clockevent based on emulated LAPIC timer hardware. */ - if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)) + if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) || + !(ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)) return -EINVAL; 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 isn't enabled, the remainder of the initialization - * is done later by hv_stimer_legacy_init() - */ - if (!direct_mode_enabled) - return 0; - if (have_percpu_irqs) { ret = hv_setup_stimer0_irq(); if (ret) @@ -293,11 +236,6 @@ int hv_stimer_alloc(bool have_percpu_irqs) hv_setup_stimer0_handler(hv_stimer0_isr); } - /* - * Since we are in Direct Mode, stimer initialization - * can be done now with a CPUHP value in the same range - * as other clockevent devices. - */ ret = cpuhp_setup_state(CPUHP_AP_HYPERV_TIMER_STARTING, "clockevents/hyperv/stimer:starting", hv_stimer_init, hv_stimer_cleanup); @@ -315,66 +253,18 @@ free_clock_event: EXPORT_SYMBOL_GPL(hv_stimer_alloc); /* - * hv_stimer_legacy_init -- Called from the VMbus driver to handle - * the case when Direct Mode is not enabled, and the stimer - * must be initialized late in the CPU onlining process. - * - */ -void hv_stimer_legacy_init(unsigned int cpu, int sint) -{ - if (direct_mode_enabled) - return; - - /* - * This function gets called by each vCPU, so setting the - * global stimer_message_sint value each time is conceptually - * not ideal, but the value passed in is always the same and - * it avoids introducing yet another interface into this - * clocksource driver just to set the sint in the legacy case. - */ - stimer0_message_sint = sint; - (void)hv_stimer_init(cpu); -} -EXPORT_SYMBOL_GPL(hv_stimer_legacy_init); - -/* - * hv_stimer_legacy_cleanup -- Called from the VMbus driver to - * handle the case when Direct Mode is not enabled, and the - * stimer must be cleaned up early in the CPU offlining - * process. - */ -void hv_stimer_legacy_cleanup(unsigned int cpu) -{ - if (direct_mode_enabled) - return; - (void)hv_stimer_cleanup(cpu); -} -EXPORT_SYMBOL_GPL(hv_stimer_legacy_cleanup); - -/* * Do a global cleanup of clockevents for the cases of kexec and * vmbus exit */ void hv_stimer_global_cleanup(void) { - int cpu; - - /* - * hv_stime_legacy_cleanup() will stop the stimer if Direct - * Mode is not enabled, and fallback to the LAPIC timer. - */ - for_each_present_cpu(cpu) { - hv_stimer_legacy_cleanup(cpu); - } - if (!hv_clock_event) return; - if (direct_mode_enabled) { - cpuhp_remove_state(CPUHP_AP_HYPERV_TIMER_STARTING); - hv_remove_stimer0_irq(); - stimer0_irq = -1; - } + cpuhp_remove_state(CPUHP_AP_HYPERV_TIMER_STARTING); + hv_remove_stimer0_irq(); + stimer0_irq = -1; + free_percpu(hv_clock_event); hv_clock_event = NULL; |