+++ /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: 1.1 $
- *
- * This is free software. You are permitted to use,
- * redistribute, and modify it as specified in the file "COPYING".
- */
-
-#include <geekos/string.h>
-#include <geekos/int.h>
-#include <geekos/idt.h>
-#include <geekos/kthread.h>
-#include <geekos/kassert.h>
-#include <geekos/screen.h>
-#include <geekos/mem.h>
-#include <geekos/malloc.h>
-#include <geekos/gdt.h>
-#include <geekos/segment.h>
-//#include <geekos/user.h>
-//#include <geekos/vfs.h>
-#include <geekos/crc32.h>
-#include <geekos/paging.h>
-#include <geekos/serial.h>
-#include <geekos/vmcs.h>
-
-/* ----------------------------------------------------------------------
- * Public data
- * ---------------------------------------------------------------------- */
-
-/* ----------------------------------------------------------------------
- * Private functions/data
- * ---------------------------------------------------------------------- */
-
-#define SECTORS_PER_PAGE (PAGE_SIZE / SECTOR_SIZE)
-
-/*
- * flag to indicate if debugging paging code
- */
-int debugFaults = 0;
-#define Debug(args...) if (debugFaults) Print(args)
-
-
-
-void SerialPrintPD(pde_t *pde)
-{
- int i;
-
- SerialPrint("Page Directory at %p:\n",pde);
- for (i=0;i<NUM_PAGE_DIR_ENTRIES && pde[i].present;i++) {
- SerialPrintPDE((void*)(PAGE_SIZE*NUM_PAGE_TABLE_ENTRIES*i),&(pde[i]));
- }
-}
-
-void SerialPrintPT(void *starting_address, pte_t *pte)
-{
- int i;
-
- SerialPrint("Page Table at %p:\n",pte);
- for (i=0;i<NUM_PAGE_TABLE_ENTRIES && pte[i].present;i++) {
- SerialPrintPTE(starting_address + PAGE_SIZE*i,&(pte[i]));
- }
-}
-
-
-void SerialPrintPDE(void *virtual_address, pde_t *pde)
-{
- SerialPrint("PDE %p -> %p : present=%x, flags=%x, accessed=%x, reserved=%x, largePages=%x, globalPage=%x, kernelInfo=%x\n",
- virtual_address,
- (void*) (pde->pageTableBaseAddr << PAGE_POWER),
- pde->present,
- pde->flags,
- pde->accessed,
- pde->reserved,
- pde->largePages,
- pde->globalPage,
- pde->kernelInfo);
-}
-
-void SerialPrintPTE(void *virtual_address, pte_t *pte)
-{
- SerialPrint("PTE %p -> %p : present=%x, flags=%x, accessed=%x, dirty=%x, pteAttribute=%x, globalPage=%x, kernelInfo=%x\n",
- virtual_address,
- (void*)(pte->pageBaseAddr << PAGE_POWER),
- pte->present,
- pte->flags,
- pte->accessed,
- pte->dirty,
- pte->pteAttribute,
- pte->globalPage,
- pte->kernelInfo);
-}
-
-
-void SerialDumpPageTables(pde_t *pde)
-{
- int i;
-
- SerialPrint("Dumping the pages starting with the pde page at %p\n",pde);
-
- for (i=0;i<NUM_PAGE_DIR_ENTRIES && pde[i].present;i++) {
- SerialPrintPDE((void*)(PAGE_SIZE*NUM_PAGE_TABLE_ENTRIES*i),&(pde[i]));
- SerialPrintPT((void*)(PAGE_SIZE*NUM_PAGE_TABLE_ENTRIES*i),(void*)(pde[i].pageTableBaseAddr<<PAGE_POWER));
- }
-}
-
-
-
-
-
-int checkPaging()
-{
- unsigned long reg=0;
- __asm__ __volatile__( "movl %%cr0, %0" : "=a" (reg));
- Print("Paging on ? : %d\n", (reg & (1<<31)) != 0);
- return (reg & (1<<31)) != 0;
-}
-
-
-/*
- * Print diagnostic information for a page fault.
- */
-static void Print_Fault_Info(uint_t address, faultcode_t faultCode)
-{
- extern uint_t g_freePageCount;
-
- g_freePageCount+=0;
-
- SerialPrintLevel(100,"Pid %d, Page Fault received, at address %x (%d pages free)\n",
- g_currentThread->pid, address, g_freePageCount);
- if (faultCode.protectionViolation)
- SerialPrintLevel(100," Protection Violation, ");
- else
- SerialPrintLevel(100," Non-present page, ");
- if (faultCode.writeFault)
- SerialPrintLevel(100,"Write Fault, ");
- else
- SerialPrintLevel(100,"Read Fault, ");
- if (faultCode.userModeFault)
- SerialPrintLevel(100,"in User Mode\n");
- else
- SerialPrintLevel(100,"in Supervisor Mode\n");
-}
-
-/*
- * Handler for page faults.
- * You should call the Install_Interrupt_Handler() function to
- * register this function as the handler for interrupt 14.
- */
-/*static*/ void Page_Fault_Handler(struct Interrupt_State* state)
-{
- ulong_t address;
- faultcode_t faultCode;
-
- KASSERT(!Interrupts_Enabled());
-
- /* Get the address that caused the page fault */
- address = Get_Page_Fault_Address();
- Debug("Page fault @%lx\n", address);
-
- /* Get the fault code */
- faultCode = *((faultcode_t *) &(state->errorCode));
-
- /* rest of your handling code here */
- SerialPrintLevel(100,"Unexpected Page Fault received\n");
- Print_Fault_Info(address, faultCode);
- Dump_Interrupt_State(state);
- SerialPrint_VMCS_ALL();
- /* user faults just kill the process */
- if (!faultCode.userModeFault) KASSERT(0);
-
- /* For now, just kill the thread/process. */
- Exit(-1);
-}
-
-/* ----------------------------------------------------------------------
- * Public functions
- * ---------------------------------------------------------------------- */
-
-
-
-/*
- * Initialize virtual memory by building page tables
- * for the kernel and physical memory.
- */
-void Init_VM(struct Boot_Info *bootInfo)
-{
- int numpages;
- int numpagetables;
- int i,j;
-
- pde_t *pd;
- pte_t *pt;
-
- PrintBoth("Intitialing Virtual Memory\n");
-
- if (checkPaging()) {
- SerialPrintLevel(100,"Paging is currently ON\n");
- return ;
- }
-
- SerialPrintLevel(100,"Paging is currently OFF - initializing the pages for a 1-1 map\n");
-
- numpages=bootInfo->memSizeKB / (PAGE_SIZE/1024);
- numpagetables = numpages / NUM_PAGE_TABLE_ENTRIES + ((numpages % NUM_PAGE_TABLE_ENTRIES) != 0 );
-
- SerialPrintLevel(100,"We need %d pages, and thus %d page tables, and one page directory\n",numpages, numpagetables);
-
- pd = (pde_t*)Alloc_Page();
-
- if (!pd) {
- SerialPrintLevel(100,"We are giving up since we can't allocate a page directory!\n");
- return;
- } else {
- SerialPrintLevel(100,"Our PDE is at physical address %p\n",pd);
- }
-
- for (i=0;i<NUM_PAGE_DIR_ENTRIES;i++) {
- if (i>=numpagetables) {
- pd[i].present=0;
- pd[i].flags=0;
- pd[i].accessed=0;
- pd[i].reserved=0;
- pd[i].largePages=0;
- pd[i].globalPage=0;
- pd[i].kernelInfo=0;
- pd[i].pageTableBaseAddr=0;
- } else {
- pt = (pte_t*)Alloc_Page();
- if (!pt) {
- SerialPrintLevel(100,"We are giving up since we can't allocate page table %d\n",i);
- } else {
- //SerialPrintLevel(100,"Page Table %d is at physical address %p\n",i,pt);
- }
- pd[i].present=1;
- pd[i].flags= VM_READ | VM_WRITE | VM_EXEC | VM_USER;
- pd[i].accessed=0;
- pd[i].reserved=0;
- pd[i].largePages=0;
- pd[i].globalPage=0;
- pd[i].kernelInfo=0;
- pd[i].pageTableBaseAddr = PAGE_ALLIGNED_ADDR(pt);
-
- for (j=0;j<NUM_PAGE_TABLE_ENTRIES;j++) {
- if (i*NUM_PAGE_TABLE_ENTRIES + j >= numpages) {
- pt[j].present=0;
- pt[j].flags=0;
- pt[j].accessed=0;
- pt[j].dirty=0;
- pt[j].pteAttribute=0;
- pt[j].globalPage=0;
- pt[j].kernelInfo=0;
- pt[j].pageBaseAddr=0;
- } else {
- pt[j].present=1;
- pt[j].flags=VM_READ | VM_WRITE | VM_EXEC | VM_USER;
- pt[j].accessed=0;
- pt[j].dirty=0;
- pt[j].pteAttribute=0;
- pt[j].globalPage=0;
- pt[j].kernelInfo=0;
- pt[j].pageBaseAddr=(i*NUM_PAGE_TABLE_ENTRIES + j);
- }
- }
- }
- }
- SerialPrintLevel(100,"Done creating 1<->1 initial page tables\n");
- SerialPrintLevel(100,"Now installing page fault handler\n");
- // SerialDumpPageTables(pd);
- Install_Interrupt_Handler(14,Page_Fault_Handler);
- SerialPrintLevel(100,"Now turning on the paging bit!\n");
- Enable_Paging(pd);
- SerialPrintLevel(100,"We are still alive after paging turned on!\n");
- SerialPrintLevel(100,"checkPaging returns %d\n",checkPaging());
-}
-
-
-//
-pte_t *LookupPage(void *vaddr)
-{
- uint_t pde_offset = ((uint_t)vaddr) >> 22;
- uint_t pte_offset = (((uint_t)vaddr) >> 12) & 0x3ff;
- pte_t *pte;
- pde_t *pde = Get_PDBR();
-
- KASSERT(pde);
-
- pde+=pde_offset;
-
- if (!(pde->present)) {
- return 0;
- }
-
- pte = (pte_t *)((pde->pageTableBaseAddr)<<12);
-
- pte+=pte_offset;
-
- return pte;
-}
-
-
-pte_t *CreateAndAddPageTable(void *vaddr, uint_t flags)
-{
- int i;
-
- KASSERT(!(PAGE_OFFSET(vaddr)));
-
- pte_t *pt = Alloc_Page();
-
- KASSERT(pt);
-
- for (i=0;i<NUM_PAGE_TABLE_ENTRIES;i++) {
- pt[i].present=0;
- }
-
- pde_t *pde = Get_PDBR();
-
- pde=&(pde[PAGE_DIRECTORY_INDEX(vaddr)]);
-
- KASSERT(!(pde->present));
-
- pde->present=1;
- pde->flags=flags;
- pde->accessed=0;
- pde->reserved=0;
- pde->largePages=0;
- pde->globalPage=0;
- pde->kernelInfo=0;
- pde->pageTableBaseAddr = PAGE_ALLIGNED_ADDR(pt);
-
- return pt;
-}
-
-pte_t *MapPage(void *vaddr, pte_t *pte, int alloc_pde)
-{
- pte_t *oldpte = LookupPage(vaddr);
-
- if (!pte) {
- if (alloc_pde) {
- CreateAndAddPageTable(vaddr,pte->flags);
- oldpte = LookupPage(vaddr);
- KASSERT(pte);
- } else {
- return 0;
- }
- }
-
- *oldpte = *pte;
-
- return oldpte;
-}
-
-pte_t *UnMapPage(void *vaddr)
-{
- pte_t *oldpte = LookupPage(vaddr);
-
- if (!oldpte) {
- return 0;
- }
- oldpte->present=0;
-
- return oldpte;
-}
-
-
-
-/**
- * Initialize paging file data structures.
- * All filesystems should be mounted before this function
- * is called, to ensure that the paging file is available.
- */
-void Init_Paging(void)
-{
- PrintBoth("Initializing Paging\n");
-}
-
-/**
- * Find a free bit of disk on the paging file for this page.
- * Interrupts must be disabled.
- * @return index of free page sized chunk of disk space in
- * the paging file, or -1 if the paging file is full
- */
-int Find_Space_On_Paging_File(void)
-{
- KASSERT(!Interrupts_Enabled());
- TODO("Find free page in paging file");
-}
-
-/**
- * Free a page-sized chunk of disk space in the paging file.
- * Interrupts must be disabled.
- * @param pagefileIndex index of the chunk of disk space
- */
-void Free_Space_On_Paging_File(int pagefileIndex)
-{
- KASSERT(!Interrupts_Enabled());
- TODO("Free page in paging file");
-}
-
-/**
- * Write the contents of given page to the indicated block
- * of space in the paging file.
- * @param paddr a pointer to the physical memory of the page
- * @param vaddr virtual address where page is mapped in user memory
- * @param pagefileIndex the index of the page sized chunk of space
- * in the paging file
- */
-void Write_To_Paging_File(void *paddr, ulong_t vaddr, int pagefileIndex)
-{
- struct Page *page = Get_Page((ulong_t) paddr);
- KASSERT(!(page->flags & PAGE_PAGEABLE)); /* Page must be locked! */
- TODO("Write page data to paging file");
-}
-
-/**
- * Read the contents of the indicated block
- * of space in the paging file into the given page.
- * @param paddr a pointer to the physical memory of the page
- * @param vaddr virtual address where page will be re-mapped in
- * user memory
- * @param pagefileIndex the index of the page sized chunk of space
- * in the paging file
- */
-void Read_From_Paging_File(void *paddr, ulong_t vaddr, int pagefileIndex)
-{
- struct Page *page = Get_Page((ulong_t) paddr);
- KASSERT(!(page->flags & PAGE_PAGEABLE)); /* Page must be locked! */
- TODO("Read page data from paging file");
-}
-
