--- /dev/null
+/*
+ * Paging (virtual memory) support
+ * Copyright (c) 2003, Jeffrey K. Hollingsworth <hollings@cs.umd.edu>
+ * Copyright (c) 2003,2004 David H. Hovemeyer <daveho@cs.umd.edu>
+ * $Revision: 1.2 $
+ *
+ * This is free software. You are permitted to use,
+ * redistribute, and modify it as specified in the file "COPYING".
+ */
+
+#ifndef GEEKOS_PAGING_H
+#define GEEKOS_PAGING_H
+
+#include <geekos/ktypes.h>
+#include <geekos/defs.h>
+#include <geekos/bootinfo.h>
+#include <geekos/list.h>
+
+struct Page;
+struct User_Context;
+
+#define NUM_PAGE_TABLE_ENTRIES 1024
+#define NUM_PAGE_DIR_ENTRIES 1024
+
+#define PAGE_DIRECTORY_INDEX(x) ((((uint_t)x) >> 22) & 0x3ff)
+#define PAGE_TABLE_INDEX(x) ((((uint_t)x) >> 12) & 0x3ff)
+#define PAGE_OFFSET(x) ((((uint_t)x) & 0xfff))
+
+#define PAGE_ALLIGNED_ADDR(x) (((uint_t) (x)) >> 12)
+#define PAGE_ADDR(x) (PAGE_ALLIGNED_ADDR(x) << 12)
+
+/*
+ * Bits for flags field of pde_t and pte_t.
+ */
+#define VM_WRITE 1 /* Memory is writable */
+#define VM_USER 2 /* Memory is accessible to user code */
+#define VM_NOCACHE 8 /* Memory should not be cached */
+#define VM_READ 0 /* Memory can be read (ignored for x86) */
+#define VM_EXEC 0 /* Memory can be executed (ignored for x86) */
+
+
+/*
+ * Page directory entry datatype.
+ * If marked as present, it specifies the physical address
+ * and permissions of a page table.
+ */
+typedef struct {
+ uint_t present:1;
+ uint_t flags:4;
+ uint_t accessed:1;
+ uint_t reserved:1;
+ uint_t largePages:1;
+ uint_t globalPage:1;
+ uint_t kernelInfo:3;
+ uint_t pageTableBaseAddr:20;
+} pde_t;
+
+/*
+ * Page table entry datatype.
+ * If marked as present, it specifies the physical address
+ * and permissions of a page of memory.
+ */
+typedef struct {
+ uint_t present:1;
+ uint_t flags:4;
+ uint_t accessed:1;
+ uint_t dirty:1;
+ uint_t pteAttribute:1;
+ uint_t globalPage:1;
+ uint_t kernelInfo:3;
+ uint_t pageBaseAddr:20;
+} pte_t;
+
+/*
+ * Datatype representing the hardware error code
+ * pushed onto the stack by the processor on a page fault.
+ * The error code is stored in the "errorCode" field
+ * of the Interrupt_State struct.
+ */
+typedef struct {
+ uint_t protectionViolation:1;
+ uint_t writeFault:1;
+ uint_t userModeFault:1;
+ uint_t reservedBitFault:1;
+ uint_t reserved:28;
+} faultcode_t;
+
+/*
+ * Bits used in the kernelInfo field of the PTE's:
+ */
+#define KINFO_PAGE_ON_DISK 0x4 /* Page not present; contents in paging file */
+
+void Init_VM(struct Boot_Info *bootInfo);
+void Init_Paging(void);
+
+extern void Flush_TLB(void);
+extern void Set_PDBR(pde_t *pageDir);
+extern pde_t *Get_PDBR(void);
+extern void Enable_Paging(pde_t *pageDir);
+extern void Invalidate_PG(void * addr);
+
+/*
+ * Return the address that caused a page fault.
+ */
+static __inline__ ulong_t Get_Page_Fault_Address(void)
+{
+ ulong_t faultAddress;
+ __asm__ __volatile__ (
+ "mov %%cr2, %0"
+ : "=r" (faultAddress)
+ );
+ return faultAddress;
+}
+
+void SerialPrintPD(pde_t *pde);
+void SerialPrintPT(void *starting_address, pte_t *pte);
+void SerialPrintPDE(void *virtual_address, pde_t *pde);
+void SerialPrintPTE(void *virtual_address,pte_t *pte);
+void SerialDumpPageTables(pde_t *pde);
+
+pte_t *LookupPage(void *vaddr);
+
+pte_t *MapPage(void *vaddr, pte_t *pte, int alloc_pde);
+pte_t *UnMapPage(void *vaddr);
+
+int Find_Space_On_Paging_File(void);
+void Free_Space_On_Paging_File(int pagefileIndex);
+void Write_To_Paging_File(void *paddr, ulong_t vaddr, int pagefileIndex);
+void Read_From_Paging_File(void *paddr, ulong_t vaddr, int pagefileIndex);
+
+
+void VM_Test(struct Boot_Info *bootInfo, uint_t num_test_pages);
+
+#endif
