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Kernel: Add mapping from page directory base (PDB) to PageDirectory

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This allows the page fault code to find the owning PageDirectory and
corresponding process for faulting regions.

The mapping is implemented as a global hash map right now, which is
definitely not optimal. We can come up with something better when it
becomes necessary.
This commit is contained in:
Andreas Kling 2019-08-06 11:19:16 +02:00
parent 8d07bce12a
commit 2ad963d261
5 changed files with 60 additions and 16 deletions
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17
Kernel/VM/PageDirectory.h
View file

@ -1,17 +1,24 @@
#pragma once
#include <AK/HashMap.h>
#include <AK/RefPtr.h>
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
#include <Kernel/VM/PhysicalPage.h>
#include <Kernel/VM/RangeAllocator.h>
class Process;
class PageDirectory : public RefCounted<PageDirectory> {
friend class MemoryManager;
public:
static NonnullRefPtr<PageDirectory> create_for_userspace(const RangeAllocator* parent_range_allocator = nullptr) { return adopt(*new PageDirectory(parent_range_allocator)); }
static NonnullRefPtr<PageDirectory> create_for_userspace(Process& process, const RangeAllocator* parent_range_allocator = nullptr)
{
return adopt(*new PageDirectory(process, parent_range_allocator));
}
static NonnullRefPtr<PageDirectory> create_at_fixed_address(PhysicalAddress paddr) { return adopt(*new PageDirectory(paddr)); }
static RefPtr<PageDirectory> find_by_pdb(u32);
~PageDirectory();
u32 cr3() const { return m_directory_page->paddr().get(); }
@ -21,10 +28,14 @@ public:
RangeAllocator& range_allocator() { return m_range_allocator; }
Process* process() { return m_process; }
const Process* process() const { return m_process; }
private:
explicit PageDirectory(const RangeAllocator* parent_range_allocator);
PageDirectory(Process&, const RangeAllocator* parent_range_allocator);
explicit PageDirectory(PhysicalAddress);
Process* m_process { nullptr };
RangeAllocator m_range_allocator;
RefPtr<PhysicalPage> m_directory_page;
HashMap<unsigned, RefPtr<PhysicalPage>> m_physical_pages;