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Kernel: Move VM-related files into Kernel/VM/.

Browse source 
Also break MemoryManager.{cpp,h} into one file per class.
This commit is contained in:
Andreas Kling 2019-04-03 15:13:07 +02:00
parent 39fd81174e
commit b9738fa8ac
21 changed files with 630 additions and 575 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Kernel/Devices/BXVGADevice.cpp
View file

@ -1,7 +1,7 @@
#include <Kernel/Devices/BXVGADevice.h>
#include <Kernel/IO.h>
#include <Kernel/PCI.h>
#include <Kernel/MemoryManager.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/Process.h>
#include <LibC/errno_numbers.h>

2
Kernel/FileDescriptor.cpp
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@ -10,7 +10,7 @@
#include <Kernel/Socket.h>
#include <Kernel/Process.h>
#include <Kernel/Devices/BlockDevice.h>
#include <Kernel/MemoryManager.h>
#include <Kernel/VM/MemoryManager.h>
Retained<FileDescriptor> FileDescriptor::create(RetainPtr<Inode>&& inode)
{

2
Kernel/FileSystem/FileSystem.cpp
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@ -3,7 +3,7 @@
#include <AK/StringBuilder.h>
#include <LibC/errno_numbers.h>
#include "FileSystem.h"
#include "MemoryManager.h"
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/LocalSocket.h>
static dword s_lastFileSystemID;

2
Kernel/FileSystem/ProcFS.cpp
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@ -2,7 +2,7 @@
#include "Process.h"
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include "system.h"
#include "MemoryManager.h"
#include <Kernel/VM/MemoryManager.h>
#include "StdLib.h"
#include "i386.h"
#include "KSyms.h"

6
Kernel/Makefile
View file

@ -11,7 +11,11 @@ KERNEL_OBJS = \
PIC.o \
Syscall.o \
Devices/IDEDiskDevice.o \
MemoryManager.o \
VM/MemoryManager.o \
VM/Region.o \
VM/VMObject.o \
VM/PageDirectory.o \
VM/PhysicalPage.o \
Console.o \
IRQHandler.o \
kprintf.o \

2
Kernel/Net/E1000NetworkAdapter.h
View file

@ -2,7 +2,7 @@
#include <Kernel/Net/NetworkAdapter.h>
#include <Kernel/PCI.h>
#include <Kernel/MemoryManager.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/IRQHandler.h>
#include <AK/OwnPtr.h>

2
Kernel/Process.cpp
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@ -8,7 +8,7 @@
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Devices/NullDevice.h>
#include <Kernel/ELF/ELFLoader.h>
#include "MemoryManager.h"
#include <Kernel/VM/MemoryManager.h>
#include "i8253.h"
#include "RTC.h"
#include <AK/StdLibExtras.h>

2
Kernel/Thread.cpp
View file

@ -2,7 +2,7 @@
#include <Kernel/Scheduler.h>
#include <Kernel/system.h>
#include <Kernel/Process.h>
#include <Kernel/MemoryManager.h>
#include <Kernel/VM/MemoryManager.h>
#include <LibC/signal_numbers.h>
InlineLinkedList<Thread>* g_threads;

2
Kernel/VM/.gitignore vendored Normal file
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@ -0,0 +1,2 @@
*.o
*.d

370
Kernel/MemoryManager.cpp → Kernel/VM/MemoryManager.cpp
View file

@ -1,10 +1,9 @@
#include "MemoryManager.h"
#include <Kernel/VM/MemoryManager.h>
#include <AK/Assertions.h>
#include <AK/kstdio.h>
#include "i386.h"
#include "StdLib.h"
#include "Process.h"
#include <LibC/errno_numbers.h>
#include "CMOS.h"
//#define MM_DEBUG
@ -43,16 +42,6 @@ MemoryManager::~MemoryManager()
{
}
PageDirectory::PageDirectory(PhysicalAddress paddr)
{
m_directory_page = PhysicalPage::create_eternal(paddr, true);
}
PageDirectory::PageDirectory()
{
MM.populate_page_directory(*this);
}
void MemoryManager::populate_page_directory(PageDirectory& page_directory)
{
page_directory.m_directory_page = allocate_supervisor_physical_page();
@ -296,25 +285,6 @@ bool MemoryManager::copy_on_write(Region& region, unsigned page_index_in_region)
return true;
}
bool Region::page_in()
{
ASSERT(m_page_directory);
ASSERT(!vmo().is_anonymous());
ASSERT(vmo().inode());
#ifdef MM_DEBUG
dbgprintf("MM: page_in %u pages\n", page_count());
#endif
for (size_t i = 0; i < page_count(); ++i) {
auto& vmo_page = vmo().physical_pages()[first_page_index() + i];
if (vmo_page.is_null()) {
bool success = MM.page_in_from_inode(*this, i);
if (!success)
return false;
}
MM.remap_region_page(*this, i, true);
}
return true;
}
bool MemoryManager::page_in_from_inode(Region& region, unsigned page_index_in_region)
{
@ -625,305 +595,6 @@ bool MemoryManager::validate_user_write(const Process& process, LinearAddress la
return region && region->is_writable();
}
Retained<Region> Region::clone()
{
ASSERT(current);
if (m_shared || (m_readable && !m_writable)) {
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): sharing %s (L%x)\n",
current->process().name().characters(),
current->pid(),
m_name.characters(),
laddr().get());
#endif
// Create a new region backed by the same VMObject.
return adopt(*new Region(laddr(), size(), m_vmo.copy_ref(), m_offset_in_vmo, String(m_name), m_readable, m_writable));
}
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): cowing %s (L%x)\n",
current->process().name().characters(),
current->pid(),
m_name.characters(),
laddr().get());
#endif
// Set up a COW region. The parent (this) region becomes COW as well!
for (size_t i = 0; i < page_count(); ++i)
m_cow_map.set(i, true);
MM.remap_region(current->process().page_directory(), *this);
return adopt(*new Region(laddr(), size(), m_vmo->clone(), m_offset_in_vmo, String(m_name), m_readable, m_writable, true));
}
Region::Region(LinearAddress a, size_t s, String&& n, bool r, bool w, bool cow)
: m_laddr(a)
, m_size(s)
, m_vmo(VMObject::create_anonymous(s))
, m_name(move(n))
, m_readable(r)
, m_writable(w)
, m_cow_map(Bitmap::create(m_vmo->page_count(), cow))
{
m_vmo->set_name(m_name);
MM.register_region(*this);
}
Region::Region(LinearAddress a, size_t s, RetainPtr<Inode>&& inode, String&& n, bool r, bool w)
: m_laddr(a)
, m_size(s)
, m_vmo(VMObject::create_file_backed(move(inode)))
, m_name(move(n))
, m_readable(r)
, m_writable(w)
, m_cow_map(Bitmap::create(m_vmo->page_count()))
{
MM.register_region(*this);
}
Region::Region(LinearAddress a, size_t s, Retained<VMObject>&& vmo, size_t offset_in_vmo, String&& n, bool r, bool w, bool cow)
: m_laddr(a)
, m_size(s)
, m_offset_in_vmo(offset_in_vmo)
, m_vmo(move(vmo))
, m_name(move(n))
, m_readable(r)
, m_writable(w)
, m_cow_map(Bitmap::create(m_vmo->page_count(), cow))
{
MM.register_region(*this);
}
Region::~Region()
{
if (m_page_directory) {
MM.unmap_region(*this);
ASSERT(!m_page_directory);
}
MM.unregister_region(*this);
}
Retained<PhysicalPage> PhysicalPage::create_eternal(PhysicalAddress paddr, bool supervisor)
{
void* slot = kmalloc_eternal(sizeof(PhysicalPage));
new (slot) PhysicalPage(paddr, supervisor);
return adopt(*(PhysicalPage*)slot);
}
Retained<PhysicalPage> PhysicalPage::create(PhysicalAddress paddr, bool supervisor)
{
void* slot = kmalloc(sizeof(PhysicalPage));
new (slot) PhysicalPage(paddr, supervisor, false);
return adopt(*(PhysicalPage*)slot);
}
PhysicalPage::PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist)
: m_may_return_to_freelist(may_return_to_freelist)
, m_supervisor(supervisor)
, m_paddr(paddr)
{
if (supervisor)
++MemoryManager::s_super_physical_pages_in_existence;
else
++MemoryManager::s_user_physical_pages_in_existence;
}
void PhysicalPage::return_to_freelist()
{
ASSERT((paddr().get() & ~PAGE_MASK) == 0);
InterruptDisabler disabler;
m_retain_count = 1;
if (m_supervisor)
MM.m_free_supervisor_physical_pages.append(adopt(*this));
else
MM.m_free_physical_pages.append(adopt(*this));
#ifdef MM_DEBUG
dbgprintf("MM: P%x released to freelist\n", m_paddr.get());
#endif
}
Retained<VMObject> VMObject::create_file_backed(RetainPtr<Inode>&& inode)
{
InterruptDisabler disabler;
if (inode->vmo())
return *inode->vmo();
auto vmo = adopt(*new VMObject(move(inode)));
vmo->inode()->set_vmo(*vmo);
return vmo;
}
Retained<VMObject> VMObject::create_anonymous(size_t size)
{
size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
return adopt(*new VMObject(size));
}
Retained<VMObject> VMObject::create_for_physical_range(PhysicalAddress paddr, size_t size)
{
size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
auto vmo = adopt(*new VMObject(paddr, size));
vmo->m_allow_cpu_caching = false;
return vmo;
}
Retained<VMObject> VMObject::clone()
{
return adopt(*new VMObject(*this));
}
VMObject::VMObject(VMObject& other)
: m_name(other.m_name)
, m_anonymous(other.m_anonymous)
, m_inode_offset(other.m_inode_offset)
, m_size(other.m_size)
, m_inode(other.m_inode)
, m_physical_pages(other.m_physical_pages)
{
MM.register_vmo(*this);
}
VMObject::VMObject(size_t size)
: m_anonymous(true)
, m_size(size)
{
MM.register_vmo(*this);
m_physical_pages.resize(page_count());
}
VMObject::VMObject(PhysicalAddress paddr, size_t size)
: m_anonymous(true)
, m_size(size)
{
MM.register_vmo(*this);
for (size_t i = 0; i < size; i += PAGE_SIZE) {
m_physical_pages.append(PhysicalPage::create(paddr.offset(i), false));
}
ASSERT(m_physical_pages.size() == page_count());
}
VMObject::VMObject(RetainPtr<Inode>&& inode)
: m_inode(move(inode))
{
ASSERT(m_inode);
m_size = ceil_div(m_inode->size(), PAGE_SIZE) * PAGE_SIZE;
m_physical_pages.resize(page_count());
MM.register_vmo(*this);
}
VMObject::~VMObject()
{
if (m_inode)
ASSERT(m_inode->vmo() == this);
MM.unregister_vmo(*this);
}
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_regions) {
if (&region->vmo() == this)
callback(*region);
}
}
void VMObject::inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size)
{
(void)old_size;
InterruptDisabler disabler;
size_t old_page_count = page_count();
m_size = new_size;
if (page_count() > old_page_count) {
// Add null pages and let the fault handler page these in when that day comes.
for (size_t i = old_page_count; i < page_count(); ++i)
m_physical_pages.append(nullptr);
} else {
// Prune the no-longer valid pages. I'm not sure this is actually correct behavior.
for (size_t i = page_count(); i < old_page_count; ++i)
m_physical_pages.take_last();
}
// FIXME: Consolidate with inode_contents_changed() so we only do a single walk.
for_each_region([] (Region& region) {
ASSERT(region.page_directory());
MM.remap_region(*region.page_directory(), region);
});
}
void VMObject::inode_contents_changed(Badge<Inode>, off_t offset, ssize_t size, const byte* data)
{
(void)size;
(void)data;
InterruptDisabler disabler;
ASSERT(offset >= 0);
// FIXME: Only invalidate the parts that actually changed.
for (auto& physical_page : m_physical_pages)
physical_page = nullptr;
#if 0
size_t current_offset = offset;
size_t remaining_bytes = size;
const byte* data_ptr = data;
auto to_page_index = [] (size_t offset) -> size_t {
return offset / PAGE_SIZE;
};
if (current_offset & PAGE_MASK) {
size_t page_index = to_page_index(current_offset);
size_t bytes_to_copy = min(size, PAGE_SIZE - (current_offset & PAGE_MASK));
if (m_physical_pages[page_index]) {
auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
memcpy(ptr, data_ptr, bytes_to_copy);
MM.unquickmap_page();
}
current_offset += bytes_to_copy;
data += bytes_to_copy;
remaining_bytes -= bytes_to_copy;
}
for (size_t page_index = to_page_index(current_offset); page_index < m_physical_pages.size(); ++page_index) {
size_t bytes_to_copy = PAGE_SIZE - (current_offset & PAGE_MASK);
if (m_physical_pages[page_index]) {
auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
memcpy(ptr, data_ptr, bytes_to_copy);
MM.unquickmap_page();
}
current_offset += bytes_to_copy;
data += bytes_to_copy;
}
#endif
// FIXME: Consolidate with inode_size_changed() so we only do a single walk.
for_each_region([] (Region& region) {
ASSERT(region.page_directory());
MM.remap_region(*region.page_directory(), region);
});
}
int Region::commit()
{
InterruptDisabler disabler;
#ifdef MM_DEBUG
dbgprintf("MM: commit %u pages in Region %p (VMO=%p) at L%x\n", vmo().page_count(), this, &vmo(), laddr().get());
#endif
for (size_t i = first_page_index(); i <= last_page_index(); ++i) {
if (!vmo().physical_pages()[i].is_null())
continue;
auto physical_page = MM.allocate_physical_page(MemoryManager::ShouldZeroFill::Yes);
if (!physical_page) {
kprintf("MM: commit was unable to allocate a physical page\n");
return -ENOMEM;
}
vmo().physical_pages()[i] = move(physical_page);
MM.remap_region_page(*this, i, true);
}
return 0;
}
void MemoryManager::register_vmo(VMObject& vmo)
{
InterruptDisabler disabler;
@ -948,45 +619,6 @@ void MemoryManager::unregister_region(Region& region)
m_regions.remove(&region);
}
size_t Region::amount_resident() const
{
size_t bytes = 0;
for (size_t i = 0; i < page_count(); ++i) {
if (m_vmo->physical_pages()[first_page_index() + i])
bytes += PAGE_SIZE;
}
return bytes;
}
size_t Region::amount_shared() const
{
size_t bytes = 0;
for (size_t i = 0; i < page_count(); ++i) {
auto& physical_page = m_vmo->physical_pages()[first_page_index() + i];
if (physical_page && physical_page->retain_count() > 1)
bytes += PAGE_SIZE;
}
return bytes;
}
PageDirectory::~PageDirectory()
{
#ifdef MM_DEBUG
dbgprintf("MM: ~PageDirectory K%x\n", this);
#endif
}
void PageDirectory::flush(LinearAddress laddr)
{
#ifdef MM_DEBUG
dbgprintf("MM: Flush page L%x\n", laddr.get());
#endif
if (!current)
return;
if (&current->process().page_directory() == this)
MM.flush_tlb(laddr);
}
ProcessPagingScope::ProcessPagingScope(Process& process)
{
ASSERT(current);

200
Kernel/MemoryManager.h → Kernel/VM/MemoryManager.h
View file

@ -11,7 +11,10 @@
#include <AK/AKString.h>
#include <AK/Badge.h>
#include <AK/Weakable.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/VM/PhysicalPage.h>
#include <Kernel/VM/Region.h>
#include <Kernel/VM/VMObject.h>
#include <Kernel/FileSystem/InodeIdentifier.h>
#define PAGE_ROUND_UP(x) ((((dword)(x)) + PAGE_SIZE-1) & (~(PAGE_SIZE-1)))
@ -22,201 +25,6 @@ enum class PageFaultResponse {
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 {

32
Kernel/VM/PageDirectory.cpp Normal file
View file

@ -0,0 +1,32 @@
#include <Kernel/VM/PageDirectory.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/Process.h>
#include <Kernel/Thread.h>
PageDirectory::PageDirectory(PhysicalAddress paddr)
{
m_directory_page = PhysicalPage::create_eternal(paddr, true);
}
PageDirectory::PageDirectory()
{
MM.populate_page_directory(*this);
}
PageDirectory::~PageDirectory()
{
#ifdef MM_DEBUG
dbgprintf("MM: ~PageDirectory K%x\n", this);
#endif
}
void PageDirectory::flush(LinearAddress laddr)
{
#ifdef MM_DEBUG
dbgprintf("MM: Flush page L%x\n", laddr.get());
#endif
if (!current)
return;
if (&current->process().page_directory() == this)
MM.flush_tlb(laddr);
}

26
Kernel/VM/PageDirectory.h Normal file
View file

@ -0,0 +1,26 @@
#pragma once
#include <Kernel/VM/PhysicalPage.h>
#include <AK/HashMap.h>
#include <AK/Retainable.h>
#include <AK/RetainPtr.h>
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;
};

42
Kernel/VM/PhysicalPage.cpp Normal file
View file

@ -0,0 +1,42 @@
#include <Kernel/VM/PhysicalPage.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/kmalloc.h>
Retained<PhysicalPage> PhysicalPage::create_eternal(PhysicalAddress paddr, bool supervisor)
{
void* slot = kmalloc_eternal(sizeof(PhysicalPage));
new (slot) PhysicalPage(paddr, supervisor);
return adopt(*(PhysicalPage*)slot);
}
Retained<PhysicalPage> PhysicalPage::create(PhysicalAddress paddr, bool supervisor)
{
void* slot = kmalloc(sizeof(PhysicalPage));
new (slot) PhysicalPage(paddr, supervisor, false);
return adopt(*(PhysicalPage*)slot);
}
PhysicalPage::PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist)
: m_may_return_to_freelist(may_return_to_freelist)
, m_supervisor(supervisor)
, m_paddr(paddr)
{
if (supervisor)
++MemoryManager::s_super_physical_pages_in_existence;
else
++MemoryManager::s_user_physical_pages_in_existence;
}
void PhysicalPage::return_to_freelist()
{
ASSERT((paddr().get() & ~PAGE_MASK) == 0);
InterruptDisabler disabler;
m_retain_count = 1;
if (m_supervisor)
MM.m_free_supervisor_physical_pages.append(adopt(*this));
else
MM.m_free_physical_pages.append(adopt(*this));
#ifdef MM_DEBUG
dbgprintf("MM: P%x released to freelist\n", m_paddr.get());
#endif
}

46
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#pragma once
#include <Kernel/Assertions.h>
#include <Kernel/types.h>
#include <AK/Retained.h>
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);
word retain_count() const { return m_retain_count; }
private:
PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true);
~PhysicalPage() { }
void return_to_freelist();
word m_retain_count { 1 };
bool m_may_return_to_freelist { true };
bool m_supervisor { false };
PhysicalAddress m_paddr;
};

142
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#include <Kernel/VM/Region.h>
#include <Kernel/VM/VMObject.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/Process.h>
#include <Kernel/Thread.h>
Region::Region(LinearAddress a, size_t s, String&& n, bool r, bool w, bool cow)
: m_laddr(a)
, m_size(s)
, m_vmo(VMObject::create_anonymous(s))
, m_name(move(n))
, m_readable(r)
, m_writable(w)
, m_cow_map(Bitmap::create(m_vmo->page_count(), cow))
{
m_vmo->set_name(m_name);
MM.register_region(*this);
}
Region::Region(LinearAddress a, size_t s, RetainPtr<Inode>&& inode, String&& n, bool r, bool w)
: m_laddr(a)
, m_size(s)
, m_vmo(VMObject::create_file_backed(move(inode)))
, m_name(move(n))
, m_readable(r)
, m_writable(w)
, m_cow_map(Bitmap::create(m_vmo->page_count()))
{
MM.register_region(*this);
}
Region::Region(LinearAddress a, size_t s, Retained<VMObject>&& vmo, size_t offset_in_vmo, String&& n, bool r, bool w, bool cow)
: m_laddr(a)
, m_size(s)
, m_offset_in_vmo(offset_in_vmo)
, m_vmo(move(vmo))
, m_name(move(n))
, m_readable(r)
, m_writable(w)
, m_cow_map(Bitmap::create(m_vmo->page_count(), cow))
{
MM.register_region(*this);
}
Region::~Region()
{
if (m_page_directory) {
MM.unmap_region(*this);
ASSERT(!m_page_directory);
}
MM.unregister_region(*this);
}
bool Region::page_in()
{
ASSERT(m_page_directory);
ASSERT(!vmo().is_anonymous());
ASSERT(vmo().inode());
#ifdef MM_DEBUG
dbgprintf("MM: page_in %u pages\n", page_count());
#endif
for (size_t i = 0; i < page_count(); ++i) {
auto& vmo_page = vmo().physical_pages()[first_page_index() + i];
if (vmo_page.is_null()) {
bool success = MM.page_in_from_inode(*this, i);
if (!success)
return false;
}
MM.remap_region_page(*this, i, true);
}
return true;
}
Retained<Region> Region::clone()
{
ASSERT(current);
if (m_shared || (m_readable && !m_writable)) {
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): sharing %s (L%x)\n",
current->process().name().characters(),
current->pid(),
m_name.characters(),
laddr().get());
#endif
// Create a new region backed by the same VMObject.
return adopt(*new Region(laddr(), size(), m_vmo.copy_ref(), m_offset_in_vmo, String(m_name), m_readable, m_writable));
}
#ifdef MM_DEBUG
dbgprintf("%s<%u> Region::clone(): cowing %s (L%x)\n",
current->process().name().characters(),
current->pid(),
m_name.characters(),
laddr().get());
#endif
// Set up a COW region. The parent (this) region becomes COW as well!
for (size_t i = 0; i < page_count(); ++i)
m_cow_map.set(i, true);
MM.remap_region(current->process().page_directory(), *this);
return adopt(*new Region(laddr(), size(), m_vmo->clone(), m_offset_in_vmo, String(m_name), m_readable, m_writable, true));
}
int Region::commit()
{
InterruptDisabler disabler;
#ifdef MM_DEBUG
dbgprintf("MM: commit %u pages in Region %p (VMO=%p) at L%x\n", vmo().page_count(), this, &vmo(), laddr().get());
#endif
for (size_t i = first_page_index(); i <= last_page_index(); ++i) {
if (!vmo().physical_pages()[i].is_null())
continue;
auto physical_page = MM.allocate_physical_page(MemoryManager::ShouldZeroFill::Yes);
if (!physical_page) {
kprintf("MM: commit was unable to allocate a physical page\n");
return -ENOMEM;
}
vmo().physical_pages()[i] = move(physical_page);
MM.remap_region_page(*this, i, true);
}
return 0;
}
size_t Region::amount_resident() const
{
size_t bytes = 0;
for (size_t i = 0; i < page_count(); ++i) {
if (m_vmo->physical_pages()[first_page_index() + i])
bytes += PAGE_SIZE;
}
return bytes;
}
size_t Region::amount_shared() const
{
size_t bytes = 0;
for (size_t i = 0; i < page_count(); ++i) {
auto& physical_page = m_vmo->physical_pages()[first_page_index() + i];
if (physical_page && physical_page->retain_count() > 1)
bytes += PAGE_SIZE;
}
return bytes;
}

97
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#pragma once
#include <AK/AKString.h>
#include <AK/Bitmap.h>
#include <Kernel/VM/PageDirectory.h>
class Inode;
class VMObject;
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;
};

167
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#include <Kernel/VM/VMObject.h>
#include <Kernel/VM/MemoryManager.h>
#include <FileSystem/FileSystem.h>
Retained<VMObject> VMObject::create_file_backed(RetainPtr<Inode>&& inode)
{
InterruptDisabler disabler;
if (inode->vmo())
return *inode->vmo();
auto vmo = adopt(*new VMObject(move(inode)));
vmo->inode()->set_vmo(*vmo);
return vmo;
}
Retained<VMObject> VMObject::create_anonymous(size_t size)
{
size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
return adopt(*new VMObject(size));
}
Retained<VMObject> VMObject::create_for_physical_range(PhysicalAddress paddr, size_t size)
{
size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
auto vmo = adopt(*new VMObject(paddr, size));
vmo->m_allow_cpu_caching = false;
return vmo;
}
Retained<VMObject> VMObject::clone()
{
return adopt(*new VMObject(*this));
}
VMObject::VMObject(VMObject& other)
: m_name(other.m_name)
, m_anonymous(other.m_anonymous)
, m_inode_offset(other.m_inode_offset)
, m_size(other.m_size)
, m_inode(other.m_inode)
, m_physical_pages(other.m_physical_pages)
{
MM.register_vmo(*this);
}
VMObject::VMObject(size_t size)
: m_anonymous(true)
, m_size(size)
{
MM.register_vmo(*this);
m_physical_pages.resize(page_count());
}
VMObject::VMObject(PhysicalAddress paddr, size_t size)
: m_anonymous(true)
, m_size(size)
{
MM.register_vmo(*this);
for (size_t i = 0; i < size; i += PAGE_SIZE) {
m_physical_pages.append(PhysicalPage::create(paddr.offset(i), false));
}
ASSERT(m_physical_pages.size() == page_count());
}
VMObject::VMObject(RetainPtr<Inode>&& inode)
: m_inode(move(inode))
{
ASSERT(m_inode);
m_size = ceil_div(m_inode->size(), PAGE_SIZE) * PAGE_SIZE;
m_physical_pages.resize(page_count());
MM.register_vmo(*this);
}
VMObject::~VMObject()
{
if (m_inode)
ASSERT(m_inode->vmo() == this);
MM.unregister_vmo(*this);
}
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_regions) {
if (&region->vmo() == this)
callback(*region);
}
}
void VMObject::inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size)
{
(void)old_size;
InterruptDisabler disabler;
size_t old_page_count = page_count();
m_size = new_size;
if (page_count() > old_page_count) {
// Add null pages and let the fault handler page these in when that day comes.
for (size_t i = old_page_count; i < page_count(); ++i)
m_physical_pages.append(nullptr);
} else {
// Prune the no-longer valid pages. I'm not sure this is actually correct behavior.
for (size_t i = page_count(); i < old_page_count; ++i)
m_physical_pages.take_last();
}
// FIXME: Consolidate with inode_contents_changed() so we only do a single walk.
for_each_region([] (Region& region) {
ASSERT(region.page_directory());
MM.remap_region(*region.page_directory(), region);
});
}
void VMObject::inode_contents_changed(Badge<Inode>, off_t offset, ssize_t size, const byte* data)
{
(void)size;
(void)data;
InterruptDisabler disabler;
ASSERT(offset >= 0);
// FIXME: Only invalidate the parts that actually changed.
for (auto& physical_page : m_physical_pages)
physical_page = nullptr;
#if 0
size_t current_offset = offset;
size_t remaining_bytes = size;
const byte* data_ptr = data;
auto to_page_index = [] (size_t offset) -> size_t {
return offset / PAGE_SIZE;
};
if (current_offset & PAGE_MASK) {
size_t page_index = to_page_index(current_offset);
size_t bytes_to_copy = min(size, PAGE_SIZE - (current_offset & PAGE_MASK));
if (m_physical_pages[page_index]) {
auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
memcpy(ptr, data_ptr, bytes_to_copy);
MM.unquickmap_page();
}
current_offset += bytes_to_copy;
data += bytes_to_copy;
remaining_bytes -= bytes_to_copy;
}
for (size_t page_index = to_page_index(current_offset); page_index < m_physical_pages.size(); ++page_index) {
size_t bytes_to_copy = PAGE_SIZE - (current_offset & PAGE_MASK);
if (m_physical_pages[page_index]) {
auto* ptr = MM.quickmap_page(*m_physical_pages[page_index]);
memcpy(ptr, data_ptr, bytes_to_copy);
MM.unquickmap_page();
}
current_offset += bytes_to_copy;
data += bytes_to_copy;
}
#endif
// FIXME: Consolidate with inode_size_changed() so we only do a single walk.
for_each_region([] (Region& region) {
ASSERT(region.page_directory());
MM.remap_region(*region.page_directory(), region);
});
}

57
Kernel/VM/VMObject.h Normal file
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#pragma once
#include <AK/Badge.h>
#include <AK/Retainable.h>
#include <AK/Weakable.h>
#include <AK/RetainPtr.h>
#include <AK/Vector.h>
#include <AK/AKString.h>
#include <Kernel/Lock.h>
class Inode;
class PhysicalPage;
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;
};

2
Kernel/i386.cpp
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@ -3,7 +3,7 @@
#include "i386.h"
#include "Assertions.h"
#include "Process.h"
#include "MemoryManager.h"
#include <Kernel/VM/MemoryManager.h>
#include "IRQHandler.h"
#include "PIC.h"
#include "Scheduler.h"

2
Kernel/init.cpp
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@ -14,7 +14,7 @@
#include <Kernel/Devices/RandomDevice.h>
#include <Kernel/FileSystem/Ext2FileSystem.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include "MemoryManager.h"
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/FileSystem/ProcFS.h>
#include "RTC.h"
#include <Kernel/TTY/VirtualConsole.h>