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			80 lines
		
	
	
	
		
			2.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			80 lines
		
	
	
	
		
			2.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * All rights reserved.
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|  *
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|  * Redistribution and use in source and binary forms, with or without
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|  * modification, are permitted provided that the following conditions are met:
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|  *
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|  * 1. Redistributions of source code must retain the above copyright notice, this
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|  *    list of conditions and the following disclaimer.
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|  *
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|  * 2. Redistributions in binary form must reproduce the above copyright notice,
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|  *    this list of conditions and the following disclaimer in the documentation
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|  *    and/or other materials provided with the distribution.
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|  *
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|  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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|  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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|  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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|  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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|  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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|  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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|  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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|  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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|  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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|  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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|  */
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| 
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| #pragma once
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| 
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| #include <AK/NonnullRefPtr.h>
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| #include <Kernel/Arch/i386/CPU.h>
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| #include <Kernel/Assertions.h>
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| #include <Kernel/Heap/SlabAllocator.h>
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| #include <Kernel/PhysicalAddress.h>
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| 
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| namespace Kernel {
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| 
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| class PhysicalPage {
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|     friend class MemoryManager;
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|     friend class PageDirectory;
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|     friend class VMObject;
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| 
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|     MAKE_SLAB_ALLOCATED(PhysicalPage)
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| public:
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|     PhysicalAddress paddr() const { return m_paddr; }
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| 
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|     void ref()
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|     {
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|         ASSERT(m_ref_count);
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|         ++m_ref_count;
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|     }
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| 
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|     void unref()
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|     {
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|         ASSERT(m_ref_count);
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|         if (!--m_ref_count) {
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|             if (m_may_return_to_freelist)
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|                 move(*this).return_to_freelist();
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|             delete this;
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|         }
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|     }
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| 
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|     static NonnullRefPtr<PhysicalPage> create(PhysicalAddress, bool supervisor, bool may_return_to_freelist = true);
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| 
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|     u32 ref_count() const { return m_ref_count; }
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| 
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|     bool is_shared_zero_page() const;
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| 
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| private:
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|     PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true);
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|     ~PhysicalPage() {}
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| 
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|     void return_to_freelist() &&;
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| 
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|     u32 m_ref_count { 1 };
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|     bool m_may_return_to_freelist { true };
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|     bool m_supervisor { false };
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|     PhysicalAddress m_paddr;
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| };
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| 
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| }
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