From ec866be6ec547c9e1cc4451f04250e08b5fe67c7 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Tue, 2 Mar 2021 13:38:22 -0800 Subject: clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts STIMER0 interrupts are most naturally modeled as per-cpu IRQs. But because x86/x64 doesn't have per-cpu IRQs, the core STIMER0 interrupt handling machinery is done in code under arch/x86 and Linux IRQs are not used. Adding support for ARM64 means adding equivalent code using per-cpu IRQs under arch/arm64. A better model is to treat per-cpu IRQs as the normal path (which it is for modern architectures), and the x86/x64 path as the exception. Do this by incorporating standard Linux per-cpu IRQ allocation into the main SITMER0 driver code, and bypass it in the x86/x64 exception case. For x86/x64, special case code is retained under arch/x86, but no STIMER0 interrupt handling code is needed under arch/arm64. No functional change. Signed-off-by: Michael Kelley Acked-by: Daniel Lezcano Link: https://lore.kernel.org/r/1614721102-2241-11-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 2 +- arch/x86/include/asm/mshyperv.h | 4 - arch/x86/kernel/cpu/mshyperv.c | 10 +-- drivers/clocksource/hyperv_timer.c | 168 +++++++++++++++++++++++++------------ include/asm-generic/mshyperv.h | 5 -- include/clocksource/hyperv_timer.h | 3 +- 6 files changed, 120 insertions(+), 72 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 9af4f8a57f36..9d100257b3af 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -327,7 +327,7 @@ static void __init hv_stimer_setup_percpu_clockev(void) * Ignore any errors in setting up stimer clockevents * as we can run with the LAPIC timer as a fallback. */ - (void)hv_stimer_alloc(); + (void)hv_stimer_alloc(false); /* * Still register the LAPIC timer, because the direct-mode STIMER is diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 5433312c9041..6d4891bced80 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -31,10 +31,6 @@ static inline u64 hv_get_register(unsigned int reg) void hyperv_vector_handler(struct pt_regs *regs); -static inline void hv_enable_stimer0_percpu_irq(int irq) {} -static inline void hv_disable_stimer0_percpu_irq(int irq) {} - - #if IS_ENABLED(CONFIG_HYPERV) extern int hyperv_init_cpuhp; diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 41fd84a88783..cebed535ec56 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -90,21 +90,17 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0) set_irq_regs(old_regs); } -int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)) +/* For x86/x64, override weak placeholders in hyperv_timer.c */ +void hv_setup_stimer0_handler(void (*handler)(void)) { - *vector = HYPERV_STIMER0_VECTOR; - *irq = -1; /* Unused on x86/x64 */ hv_stimer0_handler = handler; - return 0; } -EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq); -void hv_remove_stimer0_irq(int irq) +void hv_remove_stimer0_handler(void) { /* We have no way to deallocate the interrupt gate */ hv_stimer0_handler = NULL; } -EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq); void hv_setup_kexec_handler(void (*handler)(void)) { diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 7a9030ca68c4..ce94f78eb851 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -18,6 +18,9 @@ #include #include #include +#include +#include +#include #include #include #include @@ -43,14 +46,13 @@ static u64 hv_sched_clock_offset __ro_after_init; */ static bool direct_mode_enabled; -static int stimer0_irq; -static int stimer0_vector; +static int stimer0_irq = -1; static int stimer0_message_sint; +static DEFINE_PER_CPU(long, stimer0_evt); /* - * 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. + * Common code for stimer0 interrupts coming via Direct Mode or + * as a VMbus message. */ void hv_stimer0_isr(void) { @@ -61,6 +63,16 @@ void hv_stimer0_isr(void) } EXPORT_SYMBOL_GPL(hv_stimer0_isr); +/* + * stimer0 interrupt handler for architectures that support + * per-cpu interrupts, which also implies Direct Mode. + */ +static irqreturn_t hv_stimer0_percpu_isr(int irq, void *dev_id) +{ + hv_stimer0_isr(); + return IRQ_HANDLED; +} + static int hv_ce_set_next_event(unsigned long delta, struct clock_event_device *evt) { @@ -76,8 +88,8 @@ static int hv_ce_shutdown(struct clock_event_device *evt) { hv_set_register(HV_REGISTER_STIMER0_COUNT, 0); hv_set_register(HV_REGISTER_STIMER0_CONFIG, 0); - if (direct_mode_enabled) - hv_disable_stimer0_percpu_irq(stimer0_irq); + if (direct_mode_enabled && stimer0_irq >= 0) + disable_percpu_irq(stimer0_irq); return 0; } @@ -95,8 +107,9 @@ static int hv_ce_set_oneshot(struct clock_event_device *evt) * on the specified hardware vector/IRQ. */ timer_cfg.direct_mode = 1; - timer_cfg.apic_vector = stimer0_vector; - hv_enable_stimer0_percpu_irq(stimer0_irq); + 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, @@ -169,10 +182,58 @@ int hv_stimer_cleanup(unsigned int cpu) } EXPORT_SYMBOL_GPL(hv_stimer_cleanup); +/* + * These placeholders are overridden by arch specific code on + * architectures that need special setup of the stimer0 IRQ because + * they don't support per-cpu IRQs (such as x86/x64). + */ +void __weak hv_setup_stimer0_handler(void (*handler)(void)) +{ +}; + +void __weak hv_remove_stimer0_handler(void) +{ +}; + +/* Called only on architectures with per-cpu IRQs (i.e., not x86/x64) */ +static int hv_setup_stimer0_irq(void) +{ + int ret; + + ret = acpi_register_gsi(NULL, HYPERV_STIMER0_VECTOR, + ACPI_EDGE_SENSITIVE, ACPI_ACTIVE_HIGH); + if (ret < 0) { + pr_err("Can't register Hyper-V stimer0 GSI. Error %d", ret); + return ret; + } + stimer0_irq = ret; + + ret = request_percpu_irq(stimer0_irq, hv_stimer0_percpu_isr, + "Hyper-V stimer0", &stimer0_evt); + if (ret) { + pr_err("Can't request Hyper-V stimer0 IRQ %d. Error %d", + stimer0_irq, ret); + acpi_unregister_gsi(stimer0_irq); + stimer0_irq = -1; + } + return ret; +} + +static void hv_remove_stimer0_irq(void) +{ + if (stimer0_irq == -1) { + hv_remove_stimer0_handler(); + } else { + free_percpu_irq(stimer0_irq, &stimer0_evt); + acpi_unregister_gsi(stimer0_irq); + stimer0_irq = -1; + } +} + /* hv_stimer_alloc - Global initialization of the clockevent and stimer0 */ -int hv_stimer_alloc(void) +int hv_stimer_alloc(bool have_percpu_irqs) { - int ret = 0; + int ret; /* * Synthetic timers are always available except on old versions of @@ -188,29 +249,37 @@ int hv_stimer_alloc(void) 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 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) - goto free_percpu; + goto free_clock_event; + } else { + 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); - if (ret < 0) - goto free_stimer0_irq; + /* + * 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); + if (ret < 0) { + hv_remove_stimer0_irq(); + goto free_clock_event; } return ret; -free_stimer0_irq: - hv_remove_stimer0_irq(stimer0_irq); - stimer0_irq = 0; -free_percpu: +free_clock_event: free_percpu(hv_clock_event); hv_clock_event = NULL; return ret; @@ -254,23 +323,6 @@ void hv_stimer_legacy_cleanup(unsigned int cpu) } EXPORT_SYMBOL_GPL(hv_stimer_legacy_cleanup); - -/* hv_stimer_free - Free global resources allocated by hv_stimer_alloc() */ -void hv_stimer_free(void) -{ - if (!hv_clock_event) - return; - - if (direct_mode_enabled) { - cpuhp_remove_state(CPUHP_AP_HYPERV_TIMER_STARTING); - 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 @@ -287,12 +339,17 @@ void hv_stimer_global_cleanup(void) hv_stimer_legacy_cleanup(cpu); } - /* - * If Direct Mode is enabled, the cpuhp teardown callback - * (hv_stimer_cleanup) will be run on all CPUs to stop the - * stimers. - */ - hv_stimer_free(); + if (!hv_clock_event) + return; + + if (direct_mode_enabled) { + cpuhp_remove_state(CPUHP_AP_HYPERV_TIMER_STARTING); + hv_remove_stimer0_irq(); + stimer0_irq = -1; + } + free_percpu(hv_clock_event); + hv_clock_event = NULL; + } EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup); @@ -457,9 +514,14 @@ static bool __init hv_init_tsc_clocksource(void) * Hyper-V Reference TSC rating, causing the generic TSC to be used. * TSC_INVARIANT is not offered on ARM64, so the Hyper-V Reference * TSC will be preferred over the virtualized ARM64 arch counter. + * While the Hyper-V MSR clocksource won't be used since the + * Reference TSC clocksource is present, change its rating as + * well for consistency. */ - if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) + if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) { hyperv_cs_tsc.rating = 250; + hyperv_cs_msr.rating = 250; + } hv_read_reference_counter = read_hv_clock_tsc; phys_addr = virt_to_phys(hv_get_tsc_page()); diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 43dc3715a98a..69e7fe0254cf 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -183,9 +183,4 @@ static inline bool hv_is_hibernation_supported(void) { return false; } static inline void hyperv_cleanup(void) {} #endif /* CONFIG_HYPERV */ -#if IS_ENABLED(CONFIG_HYPERV) -extern int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)); -extern void hv_remove_stimer0_irq(int irq); -#endif - #endif diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h index 34eef083c988..b6774aa5a4b8 100644 --- a/include/clocksource/hyperv_timer.h +++ b/include/clocksource/hyperv_timer.h @@ -21,8 +21,7 @@ #define HV_MIN_DELTA_TICKS 1 /* Routines called by the VMbus driver */ -extern int hv_stimer_alloc(void); -extern void hv_stimer_free(void); +extern int hv_stimer_alloc(bool have_percpu_irqs); extern int hv_stimer_cleanup(unsigned int cpu); extern void hv_stimer_legacy_init(unsigned int cpu, int sint); extern void hv_stimer_legacy_cleanup(unsigned int cpu); -- cgit v1.2.3