serenity/Kernel/MemoryManager.h
Andreas Kling 60d25f0f4a Kernel: Introduce threads, and refactor everything in support of it.
The scheduler now operates on threads, rather than on processes.
Each process has a main thread, and can have any number of additional
threads. The process exits when the main thread exits.

This patch doesn't actually spawn any additional threads, it merely
does all the plumbing needed to make it possible. :^)
2019-03-23 22:03:17 +01:00

420 lines
12 KiB
C++

#pragma once
#include "types.h"
#include "i386.h"
#include <AK/Bitmap.h>
#include <AK/ByteBuffer.h>
#include <AK/Retainable.h>
#include <AK/RetainPtr.h>
#include <AK/Vector.h>
#include <AK/HashTable.h>
#include <AK/AKString.h>
#include <AK/Badge.h>
#include <AK/Weakable.h>
#include <Kernel/VirtualFileSystem.h>
#define PAGE_ROUND_UP(x) ((((dword)(x)) + PAGE_SIZE-1) & (~(PAGE_SIZE-1)))
class SynthFSInode;
enum class PageFaultResponse {
ShouldCrash,
Continue,
};
class PhysicalPage {
friend class MemoryManager;
friend class PageDirectory;
friend class VMObject;
public:
PhysicalAddress paddr() const { return m_paddr; }
void retain()
{
ASSERT(m_retain_count);
++m_retain_count;
}
void release()
{
ASSERT(m_retain_count);
if (!--m_retain_count) {
if (m_may_return_to_freelist)
return_to_freelist();
else
delete this;
}
}
static Retained<PhysicalPage> create_eternal(PhysicalAddress, bool supervisor);
static Retained<PhysicalPage> create(PhysicalAddress, bool supervisor);
unsigned short retain_count() const { return m_retain_count; }
private:
PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true);
~PhysicalPage() { }
void return_to_freelist();
unsigned short m_retain_count { 1 };
bool m_may_return_to_freelist { true };
bool m_supervisor { false };
PhysicalAddress m_paddr;
};
class PageDirectory : public Retainable<PageDirectory> {
friend class MemoryManager;
public:
static Retained<PageDirectory> create() { return adopt(*new PageDirectory); }
static Retained<PageDirectory> create_at_fixed_address(PhysicalAddress paddr) { return adopt(*new PageDirectory(paddr)); }
~PageDirectory();
dword cr3() const { return m_directory_page->paddr().get(); }
dword* entries() { return reinterpret_cast<dword*>(cr3()); }
void flush(LinearAddress);
private:
PageDirectory();
explicit PageDirectory(PhysicalAddress);
RetainPtr<PhysicalPage> m_directory_page;
HashMap<unsigned, RetainPtr<PhysicalPage>> m_physical_pages;
};
class VMObject : public Retainable<VMObject>, public Weakable<VMObject> {
friend class MemoryManager;
public:
static Retained<VMObject> create_file_backed(RetainPtr<Inode>&&);
static Retained<VMObject> create_anonymous(size_t);
static Retained<VMObject> create_for_physical_range(PhysicalAddress, size_t);
Retained<VMObject> clone();
~VMObject();
bool is_anonymous() const { return m_anonymous; }
Inode* inode() { return m_inode.ptr(); }
const Inode* inode() const { return m_inode.ptr(); }
size_t inode_offset() const { return m_inode_offset; }
String name() const { return m_name; }
void set_name(const String& name) { m_name = name; }
size_t page_count() const { return m_size / PAGE_SIZE; }
const Vector<RetainPtr<PhysicalPage>>& physical_pages() const { return m_physical_pages; }
Vector<RetainPtr<PhysicalPage>>& physical_pages() { return m_physical_pages; }
void inode_contents_changed(Badge<Inode>, off_t, ssize_t, const byte*);
void inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size);
size_t size() const { return m_size; }
private:
VMObject(RetainPtr<Inode>&&);
explicit VMObject(VMObject&);
explicit VMObject(size_t);
VMObject(PhysicalAddress, size_t);
template<typename Callback> void for_each_region(Callback);
String m_name;
bool m_anonymous { false };
off_t m_inode_offset { 0 };
size_t m_size { 0 };
bool m_allow_cpu_caching { true };
RetainPtr<Inode> m_inode;
Vector<RetainPtr<PhysicalPage>> m_physical_pages;
Lock m_paging_lock;
};
class Region : public Retainable<Region> {
friend class MemoryManager;
public:
Region(LinearAddress, size_t, String&&, bool r, bool w, bool cow = false);
Region(LinearAddress, size_t, Retained<VMObject>&&, size_t offset_in_vmo, String&&, bool r, bool w, bool cow = false);
Region(LinearAddress, size_t, RetainPtr<Inode>&&, String&&, bool r, bool w);
~Region();
LinearAddress laddr() const { return m_laddr; }
size_t size() const { return m_size; }
bool is_readable() const { return m_readable; }
bool is_writable() const { return m_writable; }
String name() const { return m_name; }
void set_name(String&& name) { m_name = move(name); }
const VMObject& vmo() const { return *m_vmo; }
VMObject& vmo() { return *m_vmo; }
bool is_shared() const { return m_shared; }
void set_shared(bool shared) { m_shared = shared; }
bool is_bitmap() const { return m_is_bitmap; }
void set_is_bitmap(bool b) { m_is_bitmap = b; }
Retained<Region> clone();
bool contains(LinearAddress laddr) const
{
return laddr >= m_laddr && laddr < m_laddr.offset(size());
}
unsigned page_index_from_address(LinearAddress laddr) const
{
return (laddr - m_laddr).get() / PAGE_SIZE;
}
size_t first_page_index() const
{
return m_offset_in_vmo / PAGE_SIZE;
}
size_t last_page_index() const
{
return (first_page_index() + page_count()) - 1;
}
size_t page_count() const
{
return m_size / PAGE_SIZE;
}
bool page_in();
int commit();
size_t amount_resident() const;
size_t amount_shared() const;
PageDirectory* page_directory() { return m_page_directory.ptr(); }
void set_page_directory(PageDirectory& page_directory)
{
ASSERT(!m_page_directory || m_page_directory.ptr() == &page_directory);
m_page_directory = page_directory;
}
void release_page_directory()
{
ASSERT(m_page_directory);
m_page_directory.clear();
}
const Bitmap& cow_map() const { return m_cow_map; }
void set_writable(bool b) { m_writable = b; }
private:
RetainPtr<PageDirectory> m_page_directory;
LinearAddress m_laddr;
size_t m_size { 0 };
size_t m_offset_in_vmo { 0 };
Retained<VMObject> m_vmo;
String m_name;
bool m_readable { true };
bool m_writable { true };
bool m_shared { false };
bool m_is_bitmap { false };
Bitmap m_cow_map;
};
#define MM MemoryManager::the()
class MemoryManager {
AK_MAKE_ETERNAL
friend class PageDirectory;
friend class PhysicalPage;
friend class Region;
friend class VMObject;
friend ByteBuffer procfs$mm(InodeIdentifier);
friend ByteBuffer procfs$memstat(InodeIdentifier);
public:
[[gnu::pure]] static MemoryManager& the();
static void initialize();
PageFaultResponse handle_page_fault(const PageFault&);
bool map_region(Process&, Region&);
bool unmap_region(Region&);
void populate_page_directory(PageDirectory&);
void enter_process_paging_scope(Process&);
void enter_kernel_paging_scope();
bool validate_user_read(const Process&, LinearAddress) const;
bool validate_user_write(const Process&, LinearAddress) const;
enum class ShouldZeroFill { No, Yes };
RetainPtr<PhysicalPage> allocate_physical_page(ShouldZeroFill);
RetainPtr<PhysicalPage> allocate_supervisor_physical_page();
void remap_region(PageDirectory&, Region&);
size_t ram_size() const { return m_ram_size; }
int user_physical_pages_in_existence() const { return s_user_physical_pages_in_existence; }
int super_physical_pages_in_existence() const { return s_super_physical_pages_in_existence; }
void map_for_kernel(LinearAddress, PhysicalAddress);
private:
MemoryManager();
~MemoryManager();
void register_vmo(VMObject&);
void unregister_vmo(VMObject&);
void register_region(Region&);
void unregister_region(Region&);
void map_region_at_address(PageDirectory&, Region&, LinearAddress, bool user_accessible);
void remap_region_page(Region&, unsigned page_index_in_region, bool user_allowed);
void initialize_paging();
void flush_entire_tlb();
void flush_tlb(LinearAddress);
RetainPtr<PhysicalPage> allocate_page_table(PageDirectory&, unsigned index);
void map_protected(LinearAddress, size_t length);
void create_identity_mapping(PageDirectory&, LinearAddress, size_t length);
void remove_identity_mapping(PageDirectory&, LinearAddress, size_t);
static Region* region_from_laddr(Process&, LinearAddress);
static const Region* region_from_laddr(const Process&, LinearAddress);
bool copy_on_write(Region&, unsigned page_index_in_region);
bool page_in_from_inode(Region&, unsigned page_index_in_region);
bool zero_page(Region& region, unsigned page_index_in_region);
byte* quickmap_page(PhysicalPage&);
void unquickmap_page();
PageDirectory& kernel_page_directory() { return *m_kernel_page_directory; }
struct PageDirectoryEntry {
explicit PageDirectoryEntry(dword* pde) : m_pde(pde) { }
dword* page_table_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
void set_page_table_base(dword value)
{
*m_pde &= 0xfff;
*m_pde |= value & 0xfffff000;
}
dword raw() const { return *m_pde; }
dword* ptr() { return m_pde; }
enum Flags {
Present = 1 << 0,
ReadWrite = 1 << 1,
UserSupervisor = 1 << 2,
WriteThrough = 1 << 3,
CacheDisabled = 1 << 4,
};
bool is_present() const { return raw() & Present; }
void set_present(bool b) { set_bit(Present, b); }
bool is_user_allowed() const { return raw() & UserSupervisor; }
void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
bool is_writable() const { return raw() & ReadWrite; }
void set_writable(bool b) { set_bit(ReadWrite, b); }
bool is_write_through() const { return raw() & WriteThrough; }
void set_write_through(bool b) { set_bit(WriteThrough, b); }
bool is_cache_disabled() const { return raw() & CacheDisabled; }
void set_cache_disabled(bool b) { set_bit(CacheDisabled, b); }
void set_bit(byte bit, bool value)
{
if (value)
*m_pde |= bit;
else
*m_pde &= ~bit;
}
dword* m_pde;
};
struct PageTableEntry {
explicit PageTableEntry(dword* pte) : m_pte(pte) { }
dword* physical_page_base() { return reinterpret_cast<dword*>(raw() & 0xfffff000u); }
void set_physical_page_base(dword value)
{
*m_pte &= 0xfffu;
*m_pte |= value & 0xfffff000u;
}
dword raw() const { return *m_pte; }
dword* ptr() { return m_pte; }
enum Flags {
Present = 1 << 0,
ReadWrite = 1 << 1,
UserSupervisor = 1 << 2,
WriteThrough = 1 << 3,
CacheDisabled = 1 << 4,
};
bool is_present() const { return raw() & Present; }
void set_present(bool b) { set_bit(Present, b); }
bool is_user_allowed() const { return raw() & UserSupervisor; }
void set_user_allowed(bool b) { set_bit(UserSupervisor, b); }
bool is_writable() const { return raw() & ReadWrite; }
void set_writable(bool b) { set_bit(ReadWrite, b); }
bool is_write_through() const { return raw() & WriteThrough; }
void set_write_through(bool b) { set_bit(WriteThrough, b); }
bool is_cache_disabled() const { return raw() & CacheDisabled; }
void set_cache_disabled(bool b) { set_bit(CacheDisabled, b); }
void set_bit(byte bit, bool value)
{
if (value)
*m_pte |= bit;
else
*m_pte &= ~bit;
}
dword* m_pte;
};
static unsigned s_user_physical_pages_in_existence;
static unsigned s_super_physical_pages_in_existence;
PageTableEntry ensure_pte(PageDirectory&, LinearAddress);
RetainPtr<PageDirectory> m_kernel_page_directory;
dword* m_page_table_zero;
LinearAddress m_quickmap_addr;
Vector<Retained<PhysicalPage>> m_free_physical_pages;
Vector<Retained<PhysicalPage>> m_free_supervisor_physical_pages;
HashTable<VMObject*> m_vmos;
HashTable<Region*> m_regions;
size_t m_ram_size { 0 };
bool m_quickmap_in_use { false };
};
struct ProcessPagingScope {
ProcessPagingScope(Process&);
~ProcessPagingScope();
};
struct KernelPagingScope {
KernelPagingScope();
~KernelPagingScope();
};