text: /*
   * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
   *
   * SPDX-License-Identifier: BSD-2-Clause
   */
  
  #include <AK/Types.h>
  #include <Kernel/ACPI/DynamicParser.h>
  #include <Kernel/ACPI/Initialize.h>
  #include <Kernel/ACPI/MultiProcessorParser.h>
  #include <Kernel/Arch/x86/CPU.h>
  #include <Kernel/CMOS.h>
  #include <Kernel/CommandLine.h>
  #include <Kernel/DMI.h>
  #include <Kernel/Devices/FullDevice.h>
  #include <Kernel/Devices/HID/HIDManagement.h>
  #include <Kernel/Devices/MemoryDevice.h>
  #include <Kernel/Devices/NullDevice.h>
  #include <Kernel/Devices/RandomDevice.h>
  #include <Kernel/Devices/SB16.h>
  #include <Kernel/Devices/SerialDevice.h>
  #include <Kernel/Devices/USB/UHCIController.h>
  #include <Kernel/Devices/VMWareBackdoor.h>
  #include <Kernel/Devices/ZeroDevice.h>
  #include <Kernel/FileSystem/Ext2FileSystem.h>
  #include <Kernel/FileSystem/VirtualFileSystem.h>
  #include <Kernel/Graphics/GraphicsManagement.h>
  #include <Kernel/Heap/SlabAllocator.h>
  #include <Kernel/Heap/kmalloc.h>
  #include <Kernel/Interrupts/APIC.h>
  #include <Kernel/Interrupts/InterruptManagement.h>
  #include <Kernel/Interrupts/PIC.h>
  #include <Kernel/KSyms.h>
  #include <Kernel/Multiboot.h>
  #include <Kernel/Net/E1000NetworkAdapter.h>
  #include <Kernel/Net/LoopbackAdapter.h>
  #include <Kernel/Net/NE2000NetworkAdapter.h>
  #include <Kernel/Net/NetworkTask.h>
  #include <Kernel/Net/RTL8139NetworkAdapter.h>
  #include <Kernel/PCI/Access.h>
  #include <Kernel/PCI/Initializer.h>
  #include <Kernel/Panic.h>
  #include <Kernel/Process.h>
  #include <Kernel/RTC.h>
  #include <Kernel/Random.h>
  #include <Kernel/Scheduler.h>
  #include <Kernel/Storage/StorageManagement.h>
  #include <Kernel/TTY/ConsoleManagement.h>
  #include <Kernel/TTY/PTYMultiplexer.h>
  #include <Kernel/TTY/VirtualConsole.h>
  #include <Kernel/Tasks/FinalizerTask.h>
  #include <Kernel/Tasks/SyncTask.h>
  #include <Kernel/Time/TimeManagement.h>
  #include <Kernel/VM/MemoryManager.h>
  #include <Kernel/VirtIO/VirtIO.h>
  #include <Kernel/WorkQueue.h>
  #include <Kernel/kstdio.h>
  
  // Defined in the linker script
  typedef void (*ctor_func_t)();
  extern ctor_func_t start_heap_ctors;
  extern ctor_func_t end_heap_ctors;
  extern ctor_func_t start_ctors;
  extern ctor_func_t end_ctors;
  
  extern u32 __stack_chk_guard;
  u32 __stack_chk_guard;
  
  extern "C" u8* start_of_safemem_text;
  extern "C" u8* end_of_safemem_text;
  extern "C" u8* start_of_safemem_atomic_text;
  extern "C" u8* end_of_safemem_atomic_text;
  
  extern "C" u8* end_of_kernel_image;
  
  multiboot_module_entry_t multiboot_copy_boot_modules_array[16];
  size_t multiboot_copy_boot_modules_count;
  
  extern "C" const char kernel_cmdline[4096];
  
  namespace Kernel {
  
  [[noreturn]] static void init_stage2(void*);
  static void setup_serial_debug();
  
  // boot.S expects these functions to exactly have the following signatures.
  // We declare them here to ensure their signatures don't accidentally change.
  extern "C" void init_finished(u32 cpu) __attribute__((used));
  extern "C" [[noreturn]] void init_ap(u32 cpu, Processor* processor_info);
  extern "C" [[noreturn]] void init();
  
  READONLY_AFTER_INIT VirtualConsole* tty0;
  
  static Processor s_bsp_processor; // global but let's keep it "private"
  
  // SerenityOS Kernel C++ entry point :^)
  //
  // This is where C++ execution begins, after boot.S transfers control here.
  //
  // The purpose of init() is to start multi-tasking. It does the bare minimum
  // amount of work needed to start the scheduler.
  //
  // Once multi-tasking is ready, we spawn a new thread that starts in the
  // init_stage2() function. Initialization continues there.
  
  extern "C" UNMAP_AFTER_INIT [[noreturn]] void init()
  {
      if ((FlatPtr)&end_of_kernel_image >= 0xc2000000u) {
          // The kernel has grown too large again!
          asm volatile("cli;hlt");
      }
  
      setup_serial_debug();
  
      // We need to copy the command line before kmalloc is initialized,
      // as it may overwrite parts of multiboot!
      CommandLine::early_initialize(kernel_cmdline);
      memcpy(multiboot_copy_boot_modules_array, (u8*)low_physical_to_virtual(multiboot_info_ptr->mods_addr), multiboot_info_ptr->mods_count * sizeof(multiboot_module_entry_t));
      multiboot_copy_boot_modules_count = multiboot_info_ptr->mods_count;
      s_bsp_processor.early_initialize(0);
  
      // Invoke the constructors needed for the kernel heap
      for (ctor_func_t* ctor = &start_heap_ctors; ctor < &end_heap_ctors; ctor++)
          (*ctor)();
      kmalloc_init();
      slab_alloc_init();
  
      ConsoleDevice::initialize();
      s_bsp_processor.initialize(0);
  
      CommandLine::initialize();
      MemoryManager::initialize(0);
  
      // Ensure that the safemem sections are not empty. This could happen if the linker accidentally discards the sections.
      VERIFY(&start_of_safemem_text != &end_of_safemem_text);
      VERIFY(&start_of_safemem_atomic_text != &end_of_safemem_atomic_text);
  
      // Invoke all static global constructors in the kernel.
      // Note that we want to do this as early as possible.
      for (ctor_func_t* ctor = &start_ctors; ctor < &end_ctors; ctor++)
          (*ctor)();
  
      APIC::initialize();
      InterruptManagement::initialize();
      ACPI::initialize();
  
      VFS::initialize();
  
      dmesgln("Starting SerenityOS...");
  
      TimeManagement::initialize(0);
  
      __stack_chk_guard = get_fast_random<u32>();
  
      NullDevice::initialize();
      if (!get_serial_debug())
          new SerialDevice(SERIAL_COM1_ADDR, 64);
      new SerialDevice(SERIAL_COM2_ADDR, 65);
      new SerialDevice(SERIAL_COM3_ADDR, 66);
      new SerialDevice(SERIAL_COM4_ADDR, 67);
  
      VMWareBackdoor::the(); // don't wait until first mouse packet
      HIDManagement::initialize();
  
      PCI::initialize();
      GraphicsManagement::the().initialize();
      ConsoleManagement::the().initialize();
  
      Thread::initialize();
      Process::initialize();
      Scheduler::initialize();
  
      WorkQueue::initialize();
  
      {
          RefPtr<Thread> init_stage2_thread;
          Process::create_kernel_process(init_stage2_thread, "init_stage2", init_stage2, nullptr);
          // We need to make sure we drop the reference for init_stage2_thread
          // before calling into Scheduler::start, otherwise we will have a
          // dangling Thread that never gets cleaned up
      }
  
      Scheduler::start();
      VERIFY_NOT_REACHED();
  }
  
  //
  // This is where C++ execution begins for APs, after boot.S transfers control here.
  //
  // The purpose of init_ap() is to initialize APs for multi-tasking.
  //
  extern "C" UNMAP_AFTER_INIT [[noreturn]] void init_ap(u32 cpu, Processor* processor_info)
  {
      processor_info->early_initialize(cpu);
  
      processor_info->initialize(cpu);
      MemoryManager::initialize(cpu);
  
      Scheduler::set_idle_thread(APIC::the().get_idle_thread(cpu));
  
      Scheduler::start();
      VERIFY_NOT_REACHED();
  }
  
  //
  // This method is called once a CPU enters the scheduler and its idle thread
  // At this point the initial boot stack can be freed
  //
  extern "C" UNMAP_AFTER_INIT void init_finished(u32 cpu)
  {
      if (cpu == 0) {
          // TODO: we can reuse the boot stack, maybe for kmalloc()?
      } else {
          APIC::the().init_finished(cpu);
          TimeManagement::initialize(cpu);
      }
  }
  
  void init_stage2(void*)
  {
      if (APIC::initialized() && APIC::the().enabled_processor_count() > 1) {
          // We can't start the APs until we have a scheduler up and running.
          // We need to be able to process ICI messages, otherwise another
          // core may send too many and end up deadlocking once the pool is
          // exhausted
          APIC::the().boot_aps();
      }
  
      SyncTask::spawn();
      FinalizerTask::spawn();
  
      auto boot_profiling = kernel_command_line().is_boot_profiling_enabled();
  
      USB::UHCIController::detect();
  
      DMIExpose::initialize();
  
      VirtIO::detect();
  
      E1000NetworkAdapter::detect();
      NE2000NetworkAdapter::detect();
      RTL8139NetworkAdapter::detect();
  
      LoopbackAdapter::the();
  
      Syscall::initialize();
  
      new MemoryDevice;
      new ZeroDevice;
      new FullDevice;
      new RandomDevice;
      PTYMultiplexer::initialize();
      SB16::detect();
  
      StorageManagement::initialize(kernel_command_line().root_device(), kernel_command_line().is_force_pio());
      if (!VFS::the().mount_root(StorageManagement::the().root_filesystem())) {
          PANIC("VFS::mount_root failed");
      }
  
      Process::current()->set_root_directory(VFS::the().root_custody());
  
      load_kernel_symbol_table();
  
      // NOTE: Everything marked READONLY_AFTER_INIT becomes non-writable after this point.
      MM.protect_readonly_after_init_memory();
  
      // NOTE: Everything marked UNMAP_AFTER_INIT becomes inaccessible after this point.
      MM.unmap_memory_after_init();
  
      int error;
  
      // FIXME: It would be nicer to set the mode from userspace.
      // FIXME: It would be smarter to not hardcode that the first tty is the only graphical one
      ConsoleManagement::the().first_tty()->set_graphical(GraphicsManagement::the().framebuffer_devices_exist());
      RefPtr<Thread> thread;
      auto userspace_init = kernel_command_line().userspace_init();
      auto init_args = kernel_command_line().userspace_init_args();
      Process::create_user_process(thread, userspace_init, (uid_t)0, (gid_t)0, ProcessID(0), error, move(init_args), {}, tty0);
      if (error != 0) {
          PANIC("init_stage2: Error spawning SystemServer: {}", error);
      }
      thread->set_priority(THREAD_PRIORITY_HIGH);
  
      if (boot_profiling) {
          dbgln("Starting full system boot profiling");
          auto result = Process::current()->sys$profiling_enable(-1);
          VERIFY(!result.is_error());
      }
  
      NetworkTask::spawn();
  
      Process::current()->sys$exit(0);
      VERIFY_NOT_REACHED();
  }
  
  UNMAP_AFTER_INIT void setup_serial_debug()
  {
      // serial_debug will output all the dbgln() data to COM1 at
      // 8-N-1 57600 baud. this is particularly useful for debugging the boot
      // process on live hardware.
      if (StringView(kernel_cmdline).contains("serial_debug")) {
          set_serial_debug(true);
      }
  }
  
  extern "C" {
  multiboot_info_t* multiboot_info_ptr;
  }
  
  // Define some Itanium C++ ABI methods to stop the linker from complaining.
  // If we actually call these something has gone horribly wrong
  void* __dso_handle __attribute__((visibility("hidden")));
  
  }
  