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fdfc66db61
This patch adds a vDSO-like mechanism for exposing the current time as an array of per-clock-source timestamps. LibC's clock_gettime() calls sys$map_time_page() to map the kernel's "time page" into the process address space (at a random address, ofc.) This is only done on first call, and from then on the timestamps are fetched from the time page. This first patch only adds support for CLOCK_REALTIME, but eventually we should be able to support all clock sources this way and get rid of sys$clock_gettime() in the kernel entirely. :^) Accesses are synchronized using two atomic integers that are incremented at the start and finish of the kernel's time page update cycle.
115 lines
3.5 KiB
C++
115 lines
3.5 KiB
C++
/*
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* Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/NonnullRefPtrVector.h>
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#include <AK/OwnPtr.h>
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#include <AK/RefPtr.h>
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#include <AK/Time.h>
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#include <AK/Types.h>
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#include <Kernel/API/TimePage.h>
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#include <Kernel/Arch/x86/RegisterState.h>
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#include <Kernel/KResult.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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#define OPTIMAL_TICKS_PER_SECOND_RATE 250
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#define OPTIMAL_PROFILE_TICKS_PER_SECOND_RATE 1000
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class HardwareTimerBase;
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enum class TimePrecision {
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Coarse = 0,
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Precise
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};
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class TimeManagement {
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AK_MAKE_ETERNAL;
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public:
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TimeManagement();
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static void initialize(u32 cpu);
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static TimeManagement& the();
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static bool is_valid_clock_id(clockid_t);
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Time current_time(clockid_t) const;
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Time monotonic_time(TimePrecision = TimePrecision::Coarse) const;
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Time monotonic_time_raw() const
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{
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// TODO: implement
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return monotonic_time(TimePrecision::Precise);
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}
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Time epoch_time(TimePrecision = TimePrecision::Precise) const;
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void set_epoch_time(Time);
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time_t ticks_per_second() const;
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time_t boot_time() const;
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bool is_system_timer(const HardwareTimerBase&) const;
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static void update_time(const RegisterState&);
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static void update_time_hpet(const RegisterState&);
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void increment_time_since_boot_hpet();
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void increment_time_since_boot();
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static bool is_hpet_periodic_mode_allowed();
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bool enable_profile_timer();
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bool disable_profile_timer();
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u64 uptime_ms() const;
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static Time now();
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// FIXME: Should use AK::Time internally
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// FIXME: Also, most likely broken, because it does not check m_update[12] for in-progress updates.
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timespec remaining_epoch_time_adjustment() const { return m_remaining_epoch_time_adjustment; }
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// FIXME: Should use AK::Time internally
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// FIXME: Also, most likely broken, because it does not check m_update[12] for in-progress updates.
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void set_remaining_epoch_time_adjustment(const timespec& adjustment) { m_remaining_epoch_time_adjustment = adjustment; }
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bool can_query_precise_time() const { return m_can_query_precise_time; }
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Memory::VMObject& time_page_vmobject();
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private:
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TimePage* time_page();
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void update_time_page();
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bool probe_and_set_legacy_hardware_timers();
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bool probe_and_set_non_legacy_hardware_timers();
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Vector<HardwareTimerBase*> scan_and_initialize_periodic_timers();
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Vector<HardwareTimerBase*> scan_for_non_periodic_timers();
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NonnullRefPtrVector<HardwareTimerBase> m_hardware_timers;
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void set_system_timer(HardwareTimerBase&);
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static void system_timer_tick(const RegisterState&);
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static u64 scheduling_current_time(bool);
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// Variables between m_update1 and m_update2 are synchronized
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Atomic<u32> m_update1 { 0 };
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u32 m_ticks_this_second { 0 };
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u64 m_seconds_since_boot { 0 };
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// FIXME: Should use AK::Time internally
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timespec m_epoch_time { 0, 0 };
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timespec m_remaining_epoch_time_adjustment { 0, 0 };
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Atomic<u32> m_update2 { 0 };
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u32 m_time_ticks_per_second { 0 }; // may be different from interrupts/second (e.g. hpet)
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bool m_can_query_precise_time { false };
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bool m_updating_time { false }; // may only be accessed from the BSP!
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RefPtr<HardwareTimerBase> m_system_timer;
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RefPtr<HardwareTimerBase> m_time_keeper_timer;
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Atomic<u32> m_profile_enable_count { 0 };
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RefPtr<HardwareTimerBase> m_profile_timer;
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OwnPtr<Memory::Region> m_time_page_region;
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};
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}
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