Kernel: Introduce ProcessorSpecific<T> for per-CPU data structures

To add a new per-CPU data structure, add an ID for it to the
ProcessorSpecificDataID enum.

Then call ProcessorSpecific<T>::initialize() when you are ready to
construct the per-CPU data structure on the current CPU. It can then
be accessed via ProcessorSpecific<T>::get().

This patch replaces the existing hard-coded mechanisms for Scheduler
and MemoryManager per-CPU data structure.

Kernel/Arch/x86/Processor.h

@@ -21,10 +21,14 @@
 namespace Kernel {
 
 class ProcessorInfo;
-class SchedulerPerProcessorData;
-struct MemoryManagerData;
 struct ProcessorMessageEntry;
 
+enum class ProcessorSpecificDataID {
+    MemoryManager,
+    Scheduler,
+    __Count,
+};
+
 #if ARCH(X86_64)
 #    define MSR_FS_BASE 0xc0000100
 #    define MSR_GS_BASE 0xc0000101
@@ -127,8 +131,6 @@ class Processor {
     u8 m_physical_address_bit_width;
 
     ProcessorInfo* m_info;
-    MemoryManagerData* m_mm_data;
-    SchedulerPerProcessorData* m_scheduler_data;
     Thread* m_current_thread;
     Thread* m_idle_thread;
 
@@ -142,6 +144,8 @@ class Processor {
     DeferredCallEntry* m_free_deferred_call_pool_entry;
     DeferredCallEntry m_deferred_call_pool[5];
 
+    void* m_processor_specific_data[(size_t)ProcessorSpecificDataID::__Count];
+
     void gdt_init();
     void write_raw_gdt_entry(u16 selector, u32 low, u32 high);
     void write_gdt_entry(u16 selector, Descriptor& descriptor);
@@ -259,24 +263,15 @@ public:
             read_gs_ptr(__builtin_offsetof(Processor, m_self)) != 0;
     }
 
-    ALWAYS_INLINE void set_scheduler_data(SchedulerPerProcessorData& scheduler_data)
-    {
-        m_scheduler_data = &scheduler_data;
-    }
-
-    ALWAYS_INLINE SchedulerPerProcessorData& get_scheduler_data() const
-    {
-        return *m_scheduler_data;
-    }
-
-    ALWAYS_INLINE void set_mm_data(MemoryManagerData& mm_data)
+    template<typename T>
+    T* get_specific()
     {
-        m_mm_data = &mm_data;
+        return static_cast<T*>(m_processor_specific_data[static_cast<size_t>(T::processor_specific_data_id())]);
     }
 
-    ALWAYS_INLINE MemoryManagerData& get_mm_data() const
+    void set_specific(ProcessorSpecificDataID specific_id, void* ptr)
     {
-        return *m_mm_data;
+        m_processor_specific_data[static_cast<size_t>(specific_id)] = ptr;
     }
 
     ALWAYS_INLINE void set_idle_thread(Thread& idle_thread)
@@ -449,4 +444,17 @@ public:
     String platform_string() const;
 };
 
+template<typename T>
+class ProcessorSpecific {
+public:
+    static void initialize()
+    {
+        Processor::current().set_specific(T::processor_specific_data_id(), new T);
+    }
+    static T& get()
+    {
+        return *Processor::current().get_specific<T>();
+    }
+};
+
 }

Kernel/Arch/x86/common/Processor.cpp

@@ -304,8 +304,6 @@ UNMAP_AFTER_INIT void Processor::early_initialize(u32 cpu)
     m_message_queue = nullptr;
     m_idle_thread = nullptr;
     m_current_thread = nullptr;
-    m_scheduler_data = nullptr;
-    m_mm_data = nullptr;
     m_info = nullptr;
 
     m_halt_requested = false;

Kernel/Forward.h

@@ -55,7 +55,7 @@ class RangeAllocator;
 class RecursiveSpinLock;
 class Region;
 class Scheduler;
-class SchedulerPerProcessorData;
+class SchedulerData;
 class SharedInodeVMObject;
 class Socket;
 class Space;

Kernel/Scheduler.cpp

@@ -21,12 +21,14 @@
 
 namespace Kernel {
 
-class SchedulerPerProcessorData {
-    AK_MAKE_NONCOPYABLE(SchedulerPerProcessorData);
-    AK_MAKE_NONMOVABLE(SchedulerPerProcessorData);
+class SchedulerData {
+    AK_MAKE_NONCOPYABLE(SchedulerData);
+    AK_MAKE_NONMOVABLE(SchedulerData);
 
 public:
-    SchedulerPerProcessorData() = default;
+    static ProcessorSpecificDataID processor_specific_data_id() { return ProcessorSpecificDataID::Scheduler; }
+
+    SchedulerData() = default;
 
     bool m_in_scheduler { true };
 };
@@ -190,7 +192,7 @@ UNMAP_AFTER_INIT void Scheduler::start()
     g_scheduler_lock.lock();
 
     auto& processor = Processor::current();
-    processor.set_scheduler_data(*new SchedulerPerProcessorData());
+    ProcessorSpecific<SchedulerData>::initialize();
     VERIFY(processor.is_initialized());
     auto& idle_thread = *Processor::idle_thread();
     VERIFY(processor.current_thread() == &idle_thread);
@@ -212,13 +214,12 @@ bool Scheduler::pick_next()
     // prevents a recursive call into Scheduler::invoke_async upon
     // leaving the scheduler lock.
     ScopedCritical critical;
-    auto& scheduler_data = Processor::current().get_scheduler_data();
-    scheduler_data.m_in_scheduler = true;
+    ProcessorSpecific<SchedulerData>::get().m_in_scheduler = true;
     ScopeGuard guard(
         []() {
             // We may be on a different processor after we got switched
             // back to this thread!
-            auto& scheduler_data = Processor::current().get_scheduler_data();
+            auto& scheduler_data = ProcessorSpecific<SchedulerData>::get();
             VERIFY(scheduler_data.m_in_scheduler);
             scheduler_data.m_in_scheduler = false;
         });
@@ -358,7 +359,7 @@ void Scheduler::leave_on_first_switch(u32 flags)
     // Scheduler::context_switch is not in the call stack we need to
     // clean up and release locks manually here
     g_scheduler_lock.unlock(flags);
-    auto& scheduler_data = Processor::current().get_scheduler_data();
+    auto& scheduler_data = ProcessorSpecific<SchedulerData>::get();
     VERIFY(scheduler_data.m_in_scheduler);
     scheduler_data.m_in_scheduler = false;
 }
@@ -368,7 +369,7 @@ void Scheduler::prepare_after_exec()
     // This is called after exec() when doing a context "switch" into
     // the new process. This is called from Processor::assume_context
     VERIFY(g_scheduler_lock.own_lock());
-    auto& scheduler_data = Processor::current().get_scheduler_data();
+    auto& scheduler_data = ProcessorSpecific<SchedulerData>::get();
     VERIFY(!scheduler_data.m_in_scheduler);
     scheduler_data.m_in_scheduler = true;
 }
@@ -379,7 +380,7 @@ void Scheduler::prepare_for_idle_loop()
     // and is about to run it. We need to acquire he scheduler lock
     VERIFY(!g_scheduler_lock.own_lock());
     g_scheduler_lock.lock();
-    auto& scheduler_data = Processor::current().get_scheduler_data();
+    auto& scheduler_data = ProcessorSpecific<SchedulerData>::get();
     VERIFY(!scheduler_data.m_in_scheduler);
     scheduler_data.m_in_scheduler = true;
 }
@@ -509,13 +510,13 @@ void Scheduler::timer_tick(const RegisterState& regs)
 void Scheduler::invoke_async()
 {
     VERIFY_INTERRUPTS_DISABLED();
-    auto& proc = Processor::current();
-    VERIFY(!proc.in_irq());
+    auto& processor = Processor::current();
+    VERIFY(!processor.in_irq());
 
     // Since this function is called when leaving critical sections (such
     // as a SpinLock), we need to check if we're not already doing this
     // to prevent recursion
-    if (!proc.get_scheduler_data().m_in_scheduler)
+    if (!ProcessorSpecific<SchedulerData>::get().m_in_scheduler)
         pick_next();
 }
 

Kernel/VM/MemoryManager.cpp

@@ -598,8 +598,7 @@ void MemoryManager::release_pte(PageDirectory& page_directory, VirtualAddress va
 
 UNMAP_AFTER_INIT void MemoryManager::initialize(u32 cpu)
 {
-    auto mm_data = new MemoryManagerData;
-    Processor::current().set_mm_data(*mm_data);
+    ProcessorSpecific<MemoryManagerData>::initialize();
 
     if (cpu == 0) {
         new MemoryManager;

Kernel/VM/MemoryManager.h

@@ -91,6 +91,8 @@ struct PhysicalMemoryRange {
 #define MM Kernel::MemoryManager::the()
 
 struct MemoryManagerData {
+    static ProcessorSpecificDataID processor_specific_data_id() { return ProcessorSpecificDataID::MemoryManager; }
+
     SpinLock<u8> m_quickmap_in_use;
     u32 m_quickmap_prev_flags;
 
@@ -115,7 +117,7 @@ public:
 
     static inline MemoryManagerData& get_data()
     {
-        return Processor::current().get_mm_data();
+        return ProcessorSpecific<MemoryManagerData>::get();
     }
 
     PageFaultResponse handle_page_fault(PageFault const&);