Kernel: Add basic aarch64 support to MemoryManager

FIXME: There's still a lot to do like for example, port `quickmap_page`.
This does however get us further into the boot process than before.

Kernel/Arch/aarch64/PageDirectory.cpp

@@ -5,6 +5,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <Kernel/Arch/aarch64/ASM_wrapper.h>
 #include <Kernel/Memory/PageDirectory.h>
 
 namespace Kernel::Memory {
@@ -27,7 +28,7 @@ LockRefPtr<PageDirectory> PageDirectory::find_current()
 
 void activate_kernel_page_directory(PageDirectory const&)
 {
-    VERIFY_NOT_REACHED();
+    // FIXME: Implement this
 }
 
 void activate_page_directory(PageDirectory const&, Thread*)

Kernel/Arch/aarch64/Processor.cpp

@@ -39,4 +39,9 @@ void Processor::initialize(u32 cpu)
         asm volatile("wfi");
 }
 
+void Processor::flush_tlb_local(VirtualAddress, size_t)
+{
+    // FIXME: Implement this
+}
+
 }

Kernel/Arch/aarch64/Processor.h

@@ -13,8 +13,7 @@
 
 #include <Kernel/Arch/ProcessorSpecificDataID.h>
 #include <Kernel/Arch/aarch64/Registers.h>
-
-class VirtualAddress;
+#include <Kernel/VirtualAddress.h>
 
 namespace Kernel {
 
@@ -36,18 +35,19 @@ struct [[gnu::aligned(16)]] FPUState
 extern Processor* g_current_processor;
 
 class Processor {
+    void* m_processor_specific_data[static_cast<size_t>(ProcessorSpecificDataID::__Count)];
+
 public:
     void initialize(u32 cpu);
 
-    void set_specific(ProcessorSpecificDataID /*specific_id*/, void* /*ptr*/)
-    {
-        VERIFY_NOT_REACHED();
-    }
     template<typename T>
     T* get_specific()
     {
-        VERIFY_NOT_REACHED();
-        return 0;
+        return static_cast<T*>(m_processor_specific_data[static_cast<size_t>(T::processor_specific_data_id())]);
+    }
+    void set_specific(ProcessorSpecificDataID specific_id, void* ptr)
+    {
+        m_processor_specific_data[static_cast<size_t>(specific_id)] = ptr;
     }
 
     ALWAYS_INLINE static void pause()
@@ -76,11 +76,7 @@ public:
         return false;
     }
 
-    ALWAYS_INLINE static void flush_tlb_local(VirtualAddress&, size_t&)
-    {
-        VERIFY_NOT_REACHED();
-    }
-
+    static void flush_tlb_local(VirtualAddress vaddr, size_t page_count);
     ALWAYS_INLINE static void flush_tlb(Memory::PageDirectory const*, VirtualAddress const&, size_t)
     {
         VERIFY_NOT_REACHED();

Kernel/Arch/aarch64/init.cpp

@@ -26,6 +26,7 @@
 #include <Kernel/Devices/DeviceManagement.h>
 #include <Kernel/Graphics/Console/BootFramebufferConsole.h>
 #include <Kernel/KSyms.h>
+#include <Kernel/Memory/MemoryManager.h>
 #include <Kernel/Panic.h>
 
 extern "C" void exception_common(Kernel::TrapFrame const* const trap_frame);
@@ -91,6 +92,17 @@ extern "C" [[noreturn]] void init()
 {
     g_in_early_boot = true;
 
+    // FIXME: Don't hardcode this
+    multiboot_memory_map_t mmap[] = {
+        { sizeof(struct multiboot_mmap_entry) - sizeof(u32),
+            (u64)0x0,
+            (u64)0xA2F000,
+            MULTIBOOT_MEMORY_AVAILABLE }
+    };
+
+    multiboot_memory_map = mmap;
+    multiboot_memory_map_count = 1;
+
     dbgln("Welcome to Serenity OS!");
     dbgln("Imagine this being your ideal operating system.");
     dbgln("Observed deviations from that ideal are shortcomings of your imagination.");
@@ -119,6 +131,9 @@ extern "C" [[noreturn]] void init()
     }
     dmesgln("Starting SerenityOS...");
 
+    dmesgln("Initialize MMU");
+    init_page_tables();
+    Memory::MemoryManager::initialize(0);
     DeviceManagement::initialize();
 
     // Invoke all static global constructors in the kernel.
@@ -133,9 +148,6 @@ extern "C" [[noreturn]] void init()
     auto firmware_version = query_firmware_version();
     dmesgln("Firmware version: {}", firmware_version);
 
-    dmesgln("Initialize MMU");
-    init_page_tables();
-
     auto& timer = RPi::Timer::the();
     timer.set_interrupt_interval_usec(1'000'000);
     timer.enable_interrupt_mode();
@@ -146,6 +158,8 @@ extern "C" [[noreturn]] void init()
     // interrupts are working!
     for (;;)
         asm volatile("wfi");
+
+    VERIFY_NOT_REACHED();
 }
 
 class QueryFirmwareVersionMboxMessage : RPi::Mailbox::Message {

Kernel/Memory/MemoryManager.cpp

@@ -487,8 +487,10 @@ UNMAP_AFTER_INIT void MemoryManager::initialize_physical_pages()
             auto* pd = reinterpret_cast<PageDirectoryEntry*>(quickmap_page(boot_pd_kernel));
             PageDirectoryEntry& pde = pd[page_directory_index];
 
+            // FIXME: port quickmap_page to aarch64
+#if !ARCH(AARCH64)
             VERIFY(!pde.is_present()); // Nothing should be using this PD yet
-
+#endif
             // We can't use ensure_pte quite yet!
             pde.set_page_table_base(pt_paddr.get());
             pde.set_user_allowed(false);

Kernel/Multiboot.h

@@ -43,7 +43,12 @@ struct multiboot_mmap_entry {
     u64 addr;
     u64 len;
     u32 type;
+#if ARCH(AARCH64)
+    // __attribute__((packed)) causes alignment issues on aarch64
+};
+#else
 } __attribute__((packed));
+#endif
 typedef struct multiboot_mmap_entry multiboot_memory_map_t;
 
 #define MULTIBOOT_INFO_FRAMEBUFFER_INFO (1 << 12)