| Quellcodebibliothek Statistik Leitseite products/sources/formale Sprachen/C/Linux/include/clocksource/ (Open Source Betriebssystem Version 6.17.9©) Datei vom 24.10.2025 mit Größe 3 kB |
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Quelle hyperv_timer.h Sprache: C |
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/* SPDX-License-Identifier: GPL-2.0 */
/* * Definitions for the clocksource provided by the Hyper-V * hypervisor to guest VMs, as described in the Hyper-V Top * Level Functional Spec (TLFS). * * Copyright (C) 2019, Microsoft, Inc. * * Author: Michael Kelley <mikelley@microsoft.com> */ #ifndef __CLKSOURCE_HYPERV_TIMER_H #define __CLKSOURCE_HYPERV_TIMER_H #include <linux/clocksource.h> #include <linux/math64.h> #include <hyperv/hvhdk.h> #define HV_MAX_MAX_DELTA_TICKS 0xffffffff #define HV_MIN_DELTA_TICKS 1 #ifdef CONFIG_HYPERV_TIMER #include <asm/hyperv_timer.h> /* Routines called by the VMbus driver */ 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); extern void hv_stimer_global_cleanup(void); extern void hv_stimer0_isr(void); extern void hv_init_clocksource(void); extern void hv_remap_tsc_clocksource(void); extern unsigned long hv_get_tsc_pfn(void); extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void); extern void hv_adj_sched_clock_offset(u64 offset); static __always_inline bool hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc, u64 *time) { u64 scale, offset; u32 sequence; /* * The protocol for reading Hyper-V TSC page is specified in Hypervisor * Top-Level Functional Specification ver. 3.0 and above. To get the * reference time we must do the following: * - READ ReferenceTscSequence * A special '0' value indicates the time source is unreliable and we * need to use something else. The currently published specification * versions (up to 4.0b) contain a mistake and wrongly claim '-1' * instead of '0' as the special value, see commit c35b82ef0294. * - ReferenceTime = * ((RDTSC() * ReferenceTscScale) >> 64) + ReferenceTscOffset * - READ ReferenceTscSequence again. In case its value has changed * since our first reading we need to discard ReferenceTime and repeat * the whole sequence as the hypervisor was updating the page in * between. */ do { sequence = READ_ONCE(tsc_pg->tsc_sequence); if (!sequence) return false; /* * Make sure we read sequence before we read other values from * TSC page. */ smp_rmb(); scale = READ_ONCE(tsc_pg->tsc_scale); offset = READ_ONCE(tsc_pg->tsc_offset); *cur_tsc = hv_get_raw_timer(); /* * Make sure we read sequence after we read all other values * from TSC page. */ smp_rmb(); } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); *time = mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; return true; } #else /* CONFIG_HYPERV_TIMER */ static inline unsigned long hv_get_tsc_pfn(void) { return 0; } static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) { return NULL; } static __always_inline bool hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc, u64 *time) { return false; } static inline int hv_stimer_cleanup(unsigned int cpu) { return 0; } static inline void hv_stimer_legacy_init(unsigned int cpu, int sint) {} static inline void hv_stimer_legacy_cleanup(unsigned int cpu) {} static inline void hv_stimer_global_cleanup(void) {} static inline void hv_stimer0_isr(void) {} #endif /* CONFIG_HYPERV_TIMER */ #endif ¤ Dauer der Verarbeitung: 0.5 Sekunden ¤*© Formatika GbR, Deutschland |
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2026-03-28