text: /*
   * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
   * 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.
   */
  
  #pragma once
  
  #include <AK/HashTable.h>
  #include <AK/NonnullRefPtrVector.h>
  #include <AK/String.h>
  #include <Kernel/Arch/i386/CPU.h>
  #include <Kernel/Forward.h>
  #include <Kernel/VM/PhysicalPage.h>
  #include <Kernel/VM/Region.h>
  #include <Kernel/VM/VMObject.h>
  
  namespace Kernel {
  
  #define PAGE_ROUND_UP(x) ((((u32)(x)) + PAGE_SIZE - 1) & (~(PAGE_SIZE - 1)))
  
  template<typename T>
  inline T* low_physical_to_virtual(T* physical)
  {
      return (T*)(((u8*)physical) + 0xc0000000);
  }
  
  inline u32 low_physical_to_virtual(u32 physical)
  {
      return physical + 0xc0000000;
  }
  
  template<typename T>
  inline T* virtual_to_low_physical(T* physical)
  {
      return (T*)(((u8*)physical) - 0xc0000000);
  }
  
  inline u32 virtual_to_low_physical(u32 physical)
  {
      return physical - 0xc0000000;
  }
  
  class KBuffer;
  class SynthFSInode;
  
  #define MM Kernel::MemoryManager::the()
  
  class MemoryManager {
      AK_MAKE_ETERNAL
      friend class PageDirectory;
      friend class PhysicalPage;
      friend class PhysicalRegion;
      friend class Region;
      friend class VMObject;
      friend Optional<KBuffer> procfs$mm(InodeIdentifier);
      friend Optional<KBuffer> procfs$memstat(InodeIdentifier);
  
  public:
      static MemoryManager& the();
  
      static void initialize();
  
      PageFaultResponse handle_page_fault(const PageFault&);
  
      void enter_process_paging_scope(Process&);
  
      bool validate_user_stack(const Process&, VirtualAddress) const;
      bool validate_user_read(const Process&, VirtualAddress, size_t) const;
      bool validate_user_write(const Process&, VirtualAddress, size_t) const;
  
      bool validate_kernel_read(const Process&, VirtualAddress, size_t) const;
  
      bool can_read_without_faulting(const Process&, VirtualAddress, size_t) const;
  
      enum class ShouldZeroFill {
          No,
          Yes
      };
  
      RefPtr<PhysicalPage> allocate_user_physical_page(ShouldZeroFill = ShouldZeroFill::Yes);
      RefPtr<PhysicalPage> allocate_supervisor_physical_page();
      NonnullRefPtrVector<PhysicalPage> allocate_contiguous_supervisor_physical_pages(size_t size);
      void deallocate_user_physical_page(PhysicalPage&&);
      void deallocate_supervisor_physical_page(PhysicalPage&&);
  
      OwnPtr<Region> allocate_contiguous_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);
      OwnPtr<Region> allocate_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool should_commit = true, bool cacheable = true);
      OwnPtr<Region> allocate_kernel_region(PhysicalAddress, size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);
      OwnPtr<Region> allocate_kernel_region_with_vmobject(VMObject&, size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);
      OwnPtr<Region> allocate_kernel_region_with_vmobject(const Range&, VMObject&, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);
      OwnPtr<Region> allocate_user_accessible_kernel_region(size_t, const StringView& name, u8 access, bool cacheable = true);
  
      unsigned user_physical_pages() const { return m_user_physical_pages; }
      unsigned user_physical_pages_used() const { return m_user_physical_pages_used; }
      unsigned super_physical_pages() const { return m_super_physical_pages; }
      unsigned super_physical_pages_used() const { return m_super_physical_pages_used; }
  
      template<typename Callback>
      static void for_each_vmobject(Callback callback)
      {
          for (auto& vmobject : MM.m_vmobjects) {
              if (callback(vmobject) == IterationDecision::Break)
                  break;
          }
      }
  
      template<typename T, typename Callback>
      static void for_each_vmobject_of_type(Callback callback)
      {
          for (auto& vmobject : MM.m_vmobjects) {
              if (!is<T>(vmobject))
                  continue;
              if (callback(static_cast<T&>(vmobject)) == IterationDecision::Break)
                  break;
          }
      }
  
      static Region* region_from_vaddr(Process&, VirtualAddress);
      static const Region* region_from_vaddr(const Process&, VirtualAddress);
  
      void dump_kernel_regions();
  
      PhysicalPage& shared_zero_page() { return *m_shared_zero_page; }
  
  private:
      MemoryManager();
      ~MemoryManager();
  
      enum class AccessSpace { Kernel,
          User };
      enum class AccessType { Read,
          Write };
      template<AccessSpace, AccessType>
      bool validate_range(const Process&, VirtualAddress, size_t) const;
  
      void register_vmobject(VMObject&);
      void unregister_vmobject(VMObject&);
      void register_region(Region&);
      void unregister_region(Region&);
  
      void detect_cpu_features();
      void protect_kernel_image();
      void parse_memory_map();
      void flush_entire_tlb();
      void flush_tlb(VirtualAddress);
  
      static Region* user_region_from_vaddr(Process&, VirtualAddress);
      static Region* kernel_region_from_vaddr(VirtualAddress);
  
      static Region* region_from_vaddr(VirtualAddress);
  
      RefPtr<PhysicalPage> find_free_user_physical_page();
      u8* quickmap_page(PhysicalPage&);
      void unquickmap_page();
  
      PageDirectoryEntry* quickmap_pd(PageDirectory&, size_t pdpt_index);
      PageTableEntry* quickmap_pt(PhysicalAddress);
  
      PageDirectory& kernel_page_directory() { return *m_kernel_page_directory; }
  
      const PageTableEntry* pte(const PageDirectory&, VirtualAddress);
      PageTableEntry& ensure_pte(PageDirectory&, VirtualAddress);
  
      RefPtr<PageDirectory> m_kernel_page_directory;
      RefPtr<PhysicalPage> m_low_page_table;
  
      RefPtr<PhysicalPage> m_shared_zero_page;
  
      unsigned m_user_physical_pages { 0 };
      unsigned m_user_physical_pages_used { 0 };
      unsigned m_super_physical_pages { 0 };
      unsigned m_super_physical_pages_used { 0 };
  
      NonnullRefPtrVector<PhysicalRegion> m_user_physical_regions;
      NonnullRefPtrVector<PhysicalRegion> m_super_physical_regions;
  
      InlineLinkedList<Region> m_user_regions;
      InlineLinkedList<Region> m_kernel_regions;
  
      InlineLinkedList<VMObject> m_vmobjects;
  
      bool m_quickmap_in_use { false };
  
      RefPtr<PhysicalPage> m_low_pseudo_identity_mapping_pages[4];
  };
  
  template<typename Callback>
  void VMObject::for_each_region(Callback callback)
  {
      // FIXME: Figure out a better data structure so we don't have to walk every single region every time an inode changes.
      //        Perhaps VMObject could have a Vector<Region*> with all of his mappers?
      for (auto& region : MM.m_user_regions) {
          if (&region.vmobject() == this)
              callback(region);
      }
      for (auto& region : MM.m_kernel_regions) {
          if (&region.vmobject() == this)
              callback(region);
      }
  }
  
  inline bool is_user_address(VirtualAddress vaddr)
  {
      return vaddr.get() < 0xc0000000;
  }
  
  inline bool is_user_range(VirtualAddress vaddr, size_t size)
  {
      if (vaddr.offset(size) < vaddr)
          return false;
      return is_user_address(vaddr) && is_user_address(vaddr.offset(size));
  }
  
  inline bool PhysicalPage::is_shared_zero_page() const
  {
      return this == &MM.shared_zero_page();
  }
  
  }
  