ladybird/Kernel/Memory/VMObject.h
Liav A 3d22917548 Kernel/Memory: Introduce the SharedFramebufferVMObject class
This new type of VMObject will be used to coordinate switching safely
from graphical mode to text mode and vice-versa, by supplying a way to
remap all Regions that were created with this object, so mappings can be
changed according to the given state of system mode. This makes it quite
easy to give applications like WindowServer the feeling of having full
access to the framebuffer device from a DisplayConnector, but still keep
the Kernel in control to be able to safely switch to text console.
2022-06-06 20:11:05 +01:00

104 lines
2.8 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FixedArray.h>
#include <AK/IntrusiveList.h>
#include <AK/RefPtr.h>
#include <AK/Weakable.h>
#include <Kernel/Forward.h>
#include <Kernel/Library/ListedRefCounted.h>
#include <Kernel/Locking/Mutex.h>
#include <Kernel/Memory/Region.h>
namespace Kernel::Memory {
class VMObject
: public ListedRefCounted<VMObject, LockType::Spinlock>
, public Weakable<VMObject> {
friend class MemoryManager;
friend class Region;
public:
virtual ~VMObject();
virtual ErrorOr<NonnullRefPtr<VMObject>> try_clone() = 0;
virtual bool is_anonymous() const { return false; }
virtual bool is_inode() const { return false; }
virtual bool is_shared_inode() const { return false; }
virtual bool is_private_inode() const { return false; }
size_t page_count() const { return m_physical_pages.size(); }
virtual Span<RefPtr<PhysicalPage> const> physical_pages() const { return m_physical_pages.span(); }
virtual Span<RefPtr<PhysicalPage>> physical_pages() { return m_physical_pages.span(); }
size_t size() const { return m_physical_pages.size() * PAGE_SIZE; }
virtual StringView class_name() const = 0;
ALWAYS_INLINE void add_region(Region& region)
{
SpinlockLocker locker(m_lock);
m_regions.append(region);
}
ALWAYS_INLINE void remove_region(Region& region)
{
SpinlockLocker locker(m_lock);
m_regions.remove(region);
}
protected:
static ErrorOr<FixedArray<RefPtr<PhysicalPage>>> try_create_physical_pages(size_t);
ErrorOr<FixedArray<RefPtr<PhysicalPage>>> try_clone_physical_pages() const;
explicit VMObject(FixedArray<RefPtr<PhysicalPage>>&&);
template<typename Callback>
void for_each_region(Callback);
IntrusiveListNode<VMObject> m_list_node;
FixedArray<RefPtr<PhysicalPage>> m_physical_pages;
mutable RecursiveSpinlock m_lock;
private:
VMObject& operator=(VMObject const&) = delete;
VMObject& operator=(VMObject&&) = delete;
VMObject(VMObject&&) = delete;
Region::ListInVMObject m_regions;
public:
using AllInstancesList = IntrusiveList<&VMObject::m_list_node>;
static SpinlockProtected<VMObject::AllInstancesList>& all_instances();
};
template<typename Callback>
inline void VMObject::for_each_region(Callback callback)
{
SpinlockLocker lock(m_lock);
for (auto& region : m_regions) {
callback(region);
}
}
inline PhysicalPage const* Region::physical_page(size_t index) const
{
VERIFY(index < page_count());
return vmobject().physical_pages()[first_page_index() + index];
}
inline RefPtr<PhysicalPage>& Region::physical_page_slot(size_t index)
{
VERIFY(index < page_count());
return vmobject().physical_pages()[first_page_index() + index];
}
}