Kernel: Set up and calibrate APIC timer, and enable timer on all CPUs

This enables the APIC timer on all CPUs, which means Scheduler::timer_tick
is now called on all CPUs independently. We still don't do anything on
the APs as it instantly crashes due to a number of other problems.

Kernel/CMakeLists.txt

@@ -169,9 +169,9 @@ set(KERNEL_SOURCES
     Tasks/SyncTask.cpp
     Thread.cpp
     ThreadTracer.cpp
+    Time/APICTimer.cpp
     Time/HPET.cpp
     Time/HPETComparator.cpp
-    Time/HardwareTimer.cpp
     Time/PIT.cpp
     Time/RTC.cpp
     Time/TimeManagement.cpp

Kernel/Interrupts/APIC.cpp

@@ -36,6 +36,7 @@
 #include <Kernel/Interrupts/APIC.h>
 #include <Kernel/Interrupts/SpuriousInterruptHandler.h>
 #include <Kernel/Thread.h>
+#include <Kernel/Time/APICTimer.h>
 #include <Kernel/VM/MemoryManager.h>
 #include <Kernel/VM/PageDirectory.h>
 #include <Kernel/VM/TypedMapping.h>
@@ -43,6 +44,7 @@
 //#define APIC_DEBUG
 //#define APIC_SMP_DEBUG
 
+#define IRQ_APIC_TIMER (0xfc - IRQ_VECTOR_BASE)
 #define IRQ_APIC_IPI (0xfd - IRQ_VECTOR_BASE)
 #define IRQ_APIC_ERR (0xfe - IRQ_VECTOR_BASE)
 #define IRQ_APIC_SPURIOUS (0xff - IRQ_VECTOR_BASE)
@@ -66,6 +68,9 @@
 #define APIC_REG_LVT_LINT0 0x350
 #define APIC_REG_LVT_LINT1 0x360
 #define APIC_REG_LVT_ERR 0x370
+#define APIC_REG_TIMER_INITIAL_COUNT 0x380
+#define APIC_REG_TIMER_CURRENT_COUNT 0x390
+#define APIC_REG_TIMER_CONFIGURATION 0x3e0
 
 namespace Kernel {
 
@@ -197,9 +202,13 @@ void APIC::write_icr(const ICRReg& icr)
     write_register(APIC_REG_ICR_LOW, icr.low());
 }
 
+#define APIC_LVT_TIMER_ONESHOT 0
+#define APIC_LVT_TIMER_PERIODIC (1 << 17)
+#define APIC_LVT_TIMER_TSCDEADLINE (1 << 18)
+
 #define APIC_LVT_MASKED (1 << 16)
 #define APIC_LVT_TRIGGER_LEVEL (1 << 14)
-#define APIC_LVT(iv, dm) ((iv & 0xff) | ((dm & 0x7) << 8))
+#define APIC_LVT(iv, dm) (((iv)&0xff) | (((dm)&0x7) << 8))
 
 extern "C" void apic_ap_start(void);
 extern "C" u16 apic_ap_start_size;
@@ -519,6 +528,83 @@ void APIC::send_ipi(u32 cpu)
     write_icr(ICRReg(IRQ_APIC_IPI + IRQ_VECTOR_BASE, ICRReg::Fixed, ICRReg::Logical, ICRReg::Assert, ICRReg::TriggerMode::Edge, ICRReg::NoShorthand, 1u << cpu));
 }
 
+APICTimer* APIC::initialize_timers(HardwareTimerBase& calibration_timer)
+{
+    if (!m_apic_base)
+        return nullptr;
+
+    // We should only initialize and calibrate the APIC timer once on the BSP!
+    ASSERT(Processor::current().id() == 0);
+    ASSERT(!m_apic_timer);
+
+    m_apic_timer = APICTimer::initialize(IRQ_APIC_TIMER, calibration_timer);
+    return m_apic_timer;
+}
+
+void APIC::setup_local_timer(u32 ticks, TimerMode timer_mode, bool enable)
+{
+    u32 flags = 0;
+    switch (timer_mode) {
+    case TimerMode::OneShot:
+        flags |= APIC_LVT_TIMER_ONESHOT;
+        break;
+    case TimerMode::Periodic:
+        flags |= APIC_LVT_TIMER_PERIODIC;
+        break;
+    case TimerMode::TSCDeadline:
+        flags |= APIC_LVT_TIMER_TSCDEADLINE;
+        break;
+    }
+    if (!enable)
+        flags |= APIC_LVT_MASKED;
+    write_register(APIC_REG_LVT_TIMER, APIC_LVT(IRQ_APIC_TIMER + IRQ_VECTOR_BASE, 0) | flags);
+
+    u32 config = read_register(APIC_REG_TIMER_CONFIGURATION);
+    config &= ~0xf; // clear divisor (bits 0-3)
+    switch (get_timer_divisor()) {
+    case 1:
+        config |= (1 << 3) | 3;
+        break;
+    case 2:
+        break;
+    case 4:
+        config |= 1;
+        break;
+    case 8:
+        config |= 2;
+        break;
+    case 16:
+        config |= 3;
+        break;
+    case 32:
+        config |= (1 << 3);
+        break;
+    case 64:
+        config |= (1 << 3) | 1;
+        break;
+    case 128:
+        config |= (1 << 3) | 2;
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+    }
+    config |= 3; // divide by 16
+    write_register(APIC_REG_TIMER_CONFIGURATION, config);
+
+    if (timer_mode == TimerMode::Periodic)
+        write_register(APIC_REG_TIMER_INITIAL_COUNT, ticks / get_timer_divisor());
+}
+
+u32 APIC::get_timer_current_count()
+{
+    return read_register(APIC_REG_TIMER_CURRENT_COUNT);
+}
+
+u32 APIC::get_timer_divisor()
+{
+    return 16;
+}
+
 void APICIPIInterruptHandler::handle_interrupt(const RegisterState&)
 {
 #ifdef APIC_SMP_DEBUG
@@ -546,4 +632,10 @@ bool APICErrInterruptHandler::eoi()
     return true;
 }
 
+bool HardwareTimer<GenericInterruptHandler>::eoi()
+{
+    APIC::the().eoi();
+    return true;
+}
+
 }

Kernel/Interrupts/APIC.h

@@ -27,10 +27,13 @@
 #pragma once
 
 #include <AK/Types.h>
+#include <Kernel/Time/HardwareTimer.h>
 #include <Kernel/VM/MemoryManager.h>
 
 namespace Kernel {
 
+class APICTimer;
+
 struct LocalAPIC {
     u32 apic_id;
 };
@@ -52,6 +55,17 @@ public:
     Thread* get_idle_thread(u32 cpu) const;
     u32 enabled_processor_count() const { return m_processor_enabled_cnt; }
 
+    APICTimer* initialize_timers(HardwareTimerBase&);
+    APICTimer* get_timer() const { return m_apic_timer; }
+    enum class TimerMode {
+        OneShot,
+        Periodic,
+        TSCDeadline
+    };
+    void setup_local_timer(u32, TimerMode, bool);
+    u32 get_timer_current_count();
+    u32 get_timer_divisor();
+
 private:
     class ICRReg {
         u32 m_low { 0 };
@@ -102,6 +116,7 @@ private:
     AK::Atomic<u8> m_apic_ap_continue { 0 };
     u32 m_processor_cnt { 0 };
     u32 m_processor_enabled_cnt { 0 };
+    APICTimer* m_apic_timer { nullptr };
 
     static PhysicalAddress get_base();
     static void set_base(const PhysicalAddress& base);

Kernel/Interrupts/GenericInterruptHandler.h

@@ -65,6 +65,8 @@ protected:
     void change_interrupt_number(u8 number);
     GenericInterruptHandler(u8 interrupt_number, bool disable_remap = false);
 
+    void disable_remap() { m_disable_remap = true; }
+
 private:
     size_t m_invoking_count { 0 };
     u8 m_interrupt_number { 0 };

Kernel/Scheduler.cpp

@@ -777,15 +777,19 @@ void Scheduler::timer_tick(const RegisterState& regs)
     ASSERT_INTERRUPTS_DISABLED();
     ASSERT(Processor::current().in_irq());
 
-    if (Processor::current().id() > 0)
-        return;
     auto current_thread = Processor::current().current_thread();
     if (!current_thread)
         return;
 
+    bool is_bsp = Processor::current().id() == 0;
+    if (!is_bsp)
+        return; // TODO: This prevents scheduling on other CPUs!
+    if (is_bsp) {
+        // TODO: We should probably move this out of the scheduler
         ++g_uptime;
 
         g_timeofday = TimeManagement::now_as_timeval();
+    }
 
     if (current_thread->process().is_profiling()) {
         SmapDisabler disabler;
@@ -799,6 +803,7 @@ void Scheduler::timer_tick(const RegisterState& regs)
         }
     }
 
+    if (is_bsp)
         TimerQueue::the().fire();
 
     if (current_thread->tick())

Kernel/Time/APICTimer.cpp

@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Kernel/Arch/i386/CPU.h>
+#include <Kernel/IO.h>
+#include <Kernel/Interrupts/APIC.h>
+#include <Kernel/Scheduler.h>
+#include <Kernel/Thread.h>
+#include <Kernel/Time/APICTimer.h>
+#include <Kernel/Time/TimeManagement.h>
+
+namespace Kernel {
+
+#define APIC_TIMER_MEASURE_CPU_CLOCK
+
+APICTimer* APICTimer::initialize(u8 interrupt_number, HardwareTimerBase& calibration_source)
+{
+    auto* timer = new APICTimer(interrupt_number, nullptr);
+    if (!timer->calibrate(calibration_source)) {
+        delete timer;
+        return nullptr;
+    }
+    return timer;
+}
+
+APICTimer::APICTimer(u8 interrupt_number, Function<void(const RegisterState&)> callback)
+    : HardwareTimer<GenericInterruptHandler>(interrupt_number, move(callback))
+{
+    disable_remap();
+}
+
+bool APICTimer::calibrate(HardwareTimerBase& calibration_source)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+
+    klog() << "APICTimer: Using " << calibration_source.model() << " as calibration source";
+
+    auto& apic = APIC::the();
+#ifdef APIC_TIMER_MEASURE_CPU_CLOCK
+    bool supports_tsc = Processor::current().has_feature(CPUFeature::TSC);
+#endif
+
+    // temporarily replace the timer callbacks
+    const size_t ticks_in_100ms = calibration_source.ticks_per_second() / 10;
+    Atomic<size_t> calibration_ticks = 0;
+#ifdef APIC_TIMER_MEASURE_CPU_CLOCK
+    volatile u64 start_tsc = 0, end_tsc = 0;
+#endif
+    volatile u32 start_apic_count = 0, end_apic_count = 0;
+    auto original_source_callback = calibration_source.set_callback([&](const RegisterState&) {
+        u32 current_timer_count = apic.get_timer_current_count();
+#ifdef APIC_TIMER_MEASURE_CPU_CLOCK
+        u64 current_tsc = supports_tsc ? read_tsc() : 0;
+#endif
+
+        auto prev_tick = calibration_ticks.fetch_add(1, AK::memory_order_acq_rel);
+        if (prev_tick == 0) {
+#ifdef APIC_TIMER_MEASURE_CPU_CLOCK
+            start_tsc = current_tsc;
+#endif
+            start_apic_count = current_timer_count;
+        } else if (prev_tick + 1 == ticks_in_100ms) {
+#ifdef APIC_TIMER_MEASURE_CPU_CLOCK
+            end_tsc = current_tsc;
+#endif
+            end_apic_count = current_timer_count;
+        }
+    });
+
+    // Setup a counter that should be much longer than our calibration time.
+    // We don't want the APIC timer to actually fire. We do however want the
+    // calbibration_source timer to fire so that we can read the current
+    // tick count from the APIC timer
+    auto original_callback = set_callback([&](const RegisterState&) {
+        klog() << "APICTimer: Timer fired during calibration!";
+        ASSERT_NOT_REACHED(); // TODO: How should we handle this?
+    });
+    apic.setup_local_timer(0xffffffff, APIC::TimerMode::Periodic, true);
+
+    sti();
+    // Loop for about 100 ms
+    while (calibration_ticks.load(AK::memory_order_relaxed) < ticks_in_100ms)
+        ;
+    cli();
+
+    // Restore timer callbacks
+    calibration_source.set_callback(move(original_source_callback));
+    set_callback(move(original_callback));
+
+    disable_local_timer();
+
+    auto delta_apic_count = end_apic_count - start_apic_count;
+    m_timer_period = (delta_apic_count * apic.get_timer_divisor()) / ticks_in_100ms;
+
+    auto apic_freq = (delta_apic_count * 16) / apic.get_timer_divisor();
+    if (apic_freq < 1000000) {
+        klog() << "APICTimer: Frequency too slow!";
+        return false;
+    }
+    klog() << "APICTimer: Bus clock speed: " << (apic_freq / 1000000) << "." << (apic_freq % 1000000) << " MHz";
+#ifdef APIC_TIMER_MEASURE_CPU_CLOCK
+    if (supports_tsc) {
+        auto delta_tsc = end_tsc - start_tsc;
+        klog() << "APICTimer: CPU clock speed: " << (delta_tsc / 1000000) << "." << (delta_tsc % 1000000) << " MHz";
+    }
+#endif
+
+    enable_local_timer();
+    return true;
+}
+
+void APICTimer::enable_local_timer()
+{
+    APIC::the().setup_local_timer(m_timer_period, m_timer_mode, true);
+}
+
+void APICTimer::disable_local_timer()
+{
+    APIC::the().setup_local_timer(0, APIC::TimerMode::OneShot, false);
+}
+
+size_t APICTimer::ticks_per_second() const
+{
+    return m_frequency;
+}
+
+void APICTimer::set_periodic()
+{
+    // FIXME: Implement it...
+    ASSERT_NOT_REACHED();
+}
+void APICTimer::set_non_periodic()
+{
+    // FIXME: Implement it...
+    ASSERT_NOT_REACHED();
+}
+
+void APICTimer::reset_to_default_ticks_per_second()
+{
+}
+
+bool APICTimer::try_to_set_frequency(size_t frequency)
+{
+    (void)frequency;
+    return true;
+}
+
+bool APICTimer::is_capable_of_frequency(size_t frequency) const
+{
+    (void)frequency;
+    return false;
+}
+
+size_t APICTimer::calculate_nearest_possible_frequency(size_t frequency) const
+{
+    (void)frequency;
+    return 0;
+}
+
+}

Kernel/Time/APICTimer.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
+ * Copyright (c) 2020, the SerenityOS developers
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -24,35 +24,42 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#pragma once
+
+#include <AK/NonnullRefPtr.h>
+#include <AK/Types.h>
+#include <Kernel/Interrupts/GenericInterruptHandler.h>
 #include <Kernel/Time/HardwareTimer.h>
-#include <Kernel/Time/TimeManagement.h>
 
 namespace Kernel {
 
-HardwareTimer::HardwareTimer(u8 irq_number, Function<void(const RegisterState&)> callback)
-    : IRQHandler(irq_number)
-    , m_callback(move(callback))
-{
-}
+class APICTimer final : public HardwareTimer<GenericInterruptHandler> {
+public:
+    static APICTimer* initialize(u8, HardwareTimerBase&);
+    virtual HardwareTimerType timer_type() const override { return HardwareTimerType::LocalAPICTimer; }
+    virtual const char* model() const override { return "LocalAPIC"; }
+    virtual size_t ticks_per_second() const override;
 
-void HardwareTimer::handle_irq(const RegisterState& regs)
-{
-    if (m_callback)
-        m_callback(regs);
-}
+    virtual bool is_periodic() const override { return m_timer_mode == APIC::TimerMode::Periodic; }
+    virtual bool is_periodic_capable() const override { return true; }
+    virtual void set_periodic() override;
+    virtual void set_non_periodic() override;
 
-const char* HardwareTimer::purpose() const
-{
-    if (TimeManagement::the().is_system_timer(*this))
-        return "System Timer";
-    return model();
-}
+    virtual void reset_to_default_ticks_per_second() override;
+    virtual bool try_to_set_frequency(size_t frequency) override;
+    virtual bool is_capable_of_frequency(size_t frequency) const override;
+    virtual size_t calculate_nearest_possible_frequency(size_t frequency) const override;
 
-void HardwareTimer::set_callback(Function<void(const RegisterState&)> callback)
-{
-    disable_irq();
-    m_callback = move(callback);
-    enable_irq();
-}
+    void enable_local_timer();
+    void disable_local_timer();
+
+private:
+    explicit APICTimer(u8, Function<void(const RegisterState&)>);
+
+    bool calibrate(HardwareTimerBase&);
+
+    u32 m_timer_period { 0 };
+    APIC::TimerMode m_timer_mode { APIC::TimerMode::Periodic };
+};
 
 }

Kernel/Time/HPETComparator.h

@@ -32,7 +32,7 @@
 #include <Kernel/Time/HardwareTimer.h>
 
 namespace Kernel {
-class HPETComparator final : public HardwareTimer {
+class HPETComparator final : public HardwareTimer<IRQHandler> {
     friend class HPET;
 
 public:

Kernel/Time/HardwareTimer.h

@@ -37,35 +37,112 @@ namespace Kernel {
 enum class HardwareTimerType {
     i8253 = 0x1,                   /* PIT */
     RTC = 0x2,                     /* Real Time Clock */
-    HighPrecisionEventTimer = 0x3 /* also known as IA-PC HPET */
+    HighPrecisionEventTimer = 0x3, /* also known as IA-PC HPET */
+    LocalAPICTimer = 0x4           /* Local APIC */
 };
 
-class HardwareTimer
-    : public RefCounted<HardwareTimer>
-    , public IRQHandler {
+template<typename InterruptHandlerType>
+class HardwareTimer;
+
+class HardwareTimerBase
+    : public RefCounted<HardwareTimerBase> {
 public:
-    virtual HardwareTimerType timer_type() const = 0;
+    virtual ~HardwareTimerBase() { }
+
     virtual const char* model() const = 0;
-    virtual const char* purpose() const override;
-
-    void set_callback(Function<void(const RegisterState&)>);
-
-    virtual size_t ticks_per_second() const = 0;
+    virtual HardwareTimerType timer_type() const = 0;
+    virtual Function<void(const RegisterState&)> set_callback(Function<void(const RegisterState&)>) = 0;
 
     virtual bool is_periodic() const = 0;
     virtual bool is_periodic_capable() const = 0;
     virtual void set_periodic() = 0;
     virtual void set_non_periodic() = 0;
 
+    virtual size_t ticks_per_second() const = 0;
+
     virtual void reset_to_default_ticks_per_second() = 0;
     virtual bool try_to_set_frequency(size_t frequency) = 0;
     virtual bool is_capable_of_frequency(size_t frequency) const = 0;
     virtual size_t calculate_nearest_possible_frequency(size_t frequency) const = 0;
+};
+
+template<>
+class HardwareTimer<IRQHandler>
+    : public HardwareTimerBase
+    , public IRQHandler {
+public:
+    virtual const char* purpose() const override
+    {
+        if (TimeManagement::the().is_system_timer(*this))
+            return "System Timer";
+        return model();
+    }
+
+    virtual Function<void(const RegisterState&)> set_callback(Function<void(const RegisterState&)> callback) override
+    {
+        disable_irq();
+        auto previous_callback = move(m_callback);
+        m_callback = move(callback);
+        enable_irq();
+        return previous_callback;
+    }
 
 protected:
-    HardwareTimer(u8 irq_number, Function<void(const RegisterState&)> = nullptr);
-    //^IRQHandler
-    virtual void handle_irq(const RegisterState&) override;
+    HardwareTimer(u8 irq_number, Function<void(const RegisterState&)> callback = nullptr)
+        : IRQHandler(irq_number)
+        , m_callback(move(callback))
+    {
+    }
+
+    virtual void handle_irq(const RegisterState& regs) override
+    {
+        if (m_callback)
+            m_callback(regs);
+    }
+
+    u64 m_frequency { OPTIMAL_TICKS_PER_SECOND_RATE };
+
+private:
+    Function<void(const RegisterState&)> m_callback;
+};
+
+template<>
+class HardwareTimer<GenericInterruptHandler>
+    : public HardwareTimerBase
+    , public GenericInterruptHandler {
+public:
+    virtual const char* purpose() const override
+    {
+        return model();
+    }
+
+    virtual Function<void(const RegisterState&)> set_callback(Function<void(const RegisterState&)> callback) override
+    {
+        auto previous_callback = move(m_callback);
+        m_callback = move(callback);
+        return previous_callback;
+    }
+
+    virtual size_t sharing_devices_count() const override { return 0; }
+    virtual bool is_shared_handler() const override { return false; }
+    virtual bool is_sharing_with_others() const { return false; }
+    virtual HandlerType type() const override { return HandlerType::IRQHandler; }
+    virtual const char* controller() const override { return nullptr; }
+    virtual bool eoi() override;
+
+protected:
+    HardwareTimer(u8 irq_number, Function<void(const RegisterState&)> callback = nullptr)
+        : GenericInterruptHandler(irq_number)
+        , m_callback(move(callback))
+    {
+    }
+
+    virtual void handle_interrupt(const RegisterState& regs) override
+    {
+        if (m_callback)
+            m_callback(regs);
+    }
+
     u64 m_frequency { OPTIMAL_TICKS_PER_SECOND_RATE };
 
 private:

Kernel/Time/PIT.h

@@ -52,7 +52,7 @@ namespace Kernel {
 
 #define BASE_FREQUENCY 1193182
 
-class PIT final : public HardwareTimer {
+class PIT final : public HardwareTimer<IRQHandler> {
 public:
     static NonnullRefPtr<PIT> initialize(Function<void(const RegisterState&)>);
     virtual HardwareTimerType timer_type() const override { return HardwareTimerType::i8253; }

Kernel/Time/RTC.h

@@ -31,7 +31,7 @@
 #include <Kernel/Time/HardwareTimer.h>
 
 namespace Kernel {
-class RealTimeClock final : public HardwareTimer {
+class RealTimeClock final : public HardwareTimer<IRQHandler> {
 public:
     static NonnullRefPtr<RealTimeClock> create(Function<void(const RegisterState&)> callback);
     virtual HardwareTimerType timer_type() const override { return HardwareTimerType::RTC; }

Kernel/Time/TimeManagement.cpp

@@ -28,7 +28,9 @@
 #include <AK/Time.h>
 #include <Kernel/ACPI/Parser.h>
 #include <Kernel/CommandLine.h>
+#include <Kernel/Interrupts/APIC.h>
 #include <Kernel/Scheduler.h>
+#include <Kernel/Time/APICTimer.h>
 #include <Kernel/Time/HPET.h>
 #include <Kernel/Time/HPETComparator.h>
 #include <Kernel/Time/HardwareTimer.h>
@@ -48,7 +50,7 @@ TimeManagement& TimeManagement::the()
     return *s_the;
 }
 
-bool TimeManagement::is_system_timer(const HardwareTimer& timer) const
+bool TimeManagement::is_system_timer(const HardwareTimerBase& timer) const
 {
     return &timer == m_system_timer.ptr();
 }
@@ -69,11 +71,36 @@ timespec TimeManagement::epoch_time() const
     return ts;
 }
 
-void TimeManagement::initialize()
+void TimeManagement::initialize(u32 cpu)
 {
+    if (cpu == 0) {
         ASSERT(!s_the.is_initialized());
         s_the.ensure_instance();
+
+        // Initialize the APIC timers after the other timers as the
+        // initialization needs to briefly enable interrupts, which then
+        // would trigger a deadlock trying to get the s_the instance while
+        // creating it.
+        if (auto* apic_timer = APIC::the().initialize_timers(*s_the->m_system_timer)) {
+            klog() << "Time: Using APIC timer as system timer";
+            s_the->set_system_timer(*apic_timer);
         }
+    } else {
+        ASSERT(s_the.is_initialized());
+        if (auto* apic_timer = APIC::the().get_timer()) {
+            klog() << "Time: Enable APIC timer on CPU #" << cpu;
+            apic_timer->enable_local_timer();
+        }
+    }
+}
+
+void TimeManagement::set_system_timer(HardwareTimerBase& timer)
+{
+    auto original_callback = m_system_timer->set_callback(nullptr);
+    timer.set_callback(move(original_callback));
+    m_system_timer = timer;
+}
+
 time_t TimeManagement::seconds_since_boot() const
 {
     return m_seconds_since_boot;
@@ -112,12 +139,10 @@ TimeManagement::TimeManagement()
         if (!probe_and_set_non_legacy_hardware_timers())
             if (!probe_and_set_legacy_hardware_timers())
                 ASSERT_NOT_REACHED();
-        return;
-    }
-    if (probe_and_set_legacy_hardware_timers())
-        return;
+    } else if (!probe_and_set_legacy_hardware_timers()) {
         ASSERT_NOT_REACHED();
     }
+}
 
 timeval TimeManagement::now_as_timeval()
 {
@@ -127,11 +152,11 @@ timeval TimeManagement::now_as_timeval()
     return tv;
 }
 
-Vector<HardwareTimer*> TimeManagement::scan_and_initialize_periodic_timers()
+Vector<HardwareTimerBase*> TimeManagement::scan_and_initialize_periodic_timers()
 {
     bool should_enable = is_hpet_periodic_mode_allowed();
     dbg() << "Time: Scanning for periodic timers";
-    Vector<HardwareTimer*> timers;
+    Vector<HardwareTimerBase*> timers;
     for (auto& hardware_timer : m_hardware_timers) {
         if (hardware_timer.is_periodic_capable()) {
             timers.append(&hardware_timer);
@@ -142,10 +167,10 @@ Vector<HardwareTimer*> TimeManagement::scan_and_initialize_periodic_timers()
     return timers;
 }
 
-Vector<HardwareTimer*> TimeManagement::scan_for_non_periodic_timers()
+Vector<HardwareTimerBase*> TimeManagement::scan_for_non_periodic_timers()
 {
     dbg() << "Time: Scanning for non-periodic timers";
-    Vector<HardwareTimer*> timers;
+    Vector<HardwareTimerBase*> timers;
     for (auto& hardware_timer : m_hardware_timers) {
         if (!hardware_timer.is_periodic_capable())
             timers.append(&hardware_timer);

Kernel/Time/TimeManagement.h

@@ -35,7 +35,7 @@ namespace Kernel {
 
 #define OPTIMAL_TICKS_PER_SECOND_RATE 1000
 
-class HardwareTimer;
+class HardwareTimerBase;
 
 class TimeManagement {
     AK_MAKE_ETERNAL;
@@ -43,7 +43,7 @@ class TimeManagement {
 public:
     TimeManagement();
     static bool initialized();
-    static void initialize();
+    static void initialize(u32 cpu);
     static TimeManagement& the();
 
     timespec epoch_time() const;
@@ -53,7 +53,7 @@ public:
     time_t ticks_this_second() const;
     time_t boot_time() const;
 
-    bool is_system_timer(const HardwareTimer&) const;
+    bool is_system_timer(const HardwareTimerBase&) const;
 
     static void update_time(const RegisterState&);
     void increment_time_since_boot(const RegisterState&);
@@ -65,15 +65,16 @@ public:
 private:
     bool probe_and_set_legacy_hardware_timers();
     bool probe_and_set_non_legacy_hardware_timers();
-    Vector<HardwareTimer*> scan_and_initialize_periodic_timers();
-    Vector<HardwareTimer*> scan_for_non_periodic_timers();
-    NonnullRefPtrVector<HardwareTimer> m_hardware_timers;
+    Vector<HardwareTimerBase*> scan_and_initialize_periodic_timers();
+    Vector<HardwareTimerBase*> scan_for_non_periodic_timers();
+    NonnullRefPtrVector<HardwareTimerBase> m_hardware_timers;
+    void set_system_timer(HardwareTimerBase&);
 
     u32 m_ticks_this_second { 0 };
     u32 m_seconds_since_boot { 0 };
     timespec m_epoch_time { 0, 0 };
-    RefPtr<HardwareTimer> m_system_timer;
-    RefPtr<HardwareTimer> m_time_keeper_timer;
+    RefPtr<HardwareTimerBase> m_system_timer;
+    RefPtr<HardwareTimerBase> m_time_keeper_timer;
 };
 
 }

Kernel/init.cpp

@@ -149,7 +149,7 @@ extern "C" [[noreturn]] void init()
 
     __stack_chk_guard = get_fast_random<u32>();
 
-    TimeManagement::initialize();
+    TimeManagement::initialize(0);
 
     NullDevice::initialize();
     if (!get_serial_debug())
@@ -208,6 +208,7 @@ extern "C" void init_finished(u32 cpu)
         // TODO: we can reuse the boot stack, maybe for kmalloc()?
     } else {
         APIC::the().init_finished(cpu);
+        TimeManagement::initialize(cpu);
     }
 }