--- /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".
+ */
+
+#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>
+
+
+/* ----------------------------------------------------------------------
+ * 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)
+{
+ uint_t i;
+
+ SerialPrint("Page Directory at %p:\n",pde);
+ for (i = 0; i < NUM_PAGE_DIR_ENTRIES; i++) {
+ if (pde[i].present) {
+ if ((i * PAGE_SIZE * 1024) > 0x40000000) {
+ 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;i++) {
+ if (pte[i].present) {
+ 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)
+{
+ uint_t i;
+
+ SerialPrint("Dumping the pages starting with the pde page at %p\n",pde);
+
+ for (i = 0; i < NUM_PAGE_DIR_ENTRIES; i++) {
+ if (pde[i].present) {
+ if ((i * PAGE_SIZE * 1024) >= 0x40000000) {
+ 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);
+ /* 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());
+}
+
+
+
+/* How we test...
+ * 1 <-> 1 mapping of physical memory,
+ * We assume that physical memory << 1G
+ * we setup the test so that 1G+ is mapped in a testable order
+ * then go through and ensure that all the paging operations work...
+ * The static mapping sits at 1G
+ * The tests are run at 2G
+
+ */
+
+void VM_Test(struct Boot_Info *bootInfo, uint_t num_test_pages) {
+ int i,j;
+
+ pde_t * pd;
+ //pde_t *pde;
+ // pte_t *pte;
+
+ PrintBoth("Running Paging Test\n");
+
+ pd = Get_PDBR();
+
+
+ void * one_gig = (void *)0x40000000;
+ void * two_gig = (void *)0x80000000;
+
+ /* Set up the 1 GIG static map */
+ ulong_t pde_offset = (((ulong_t)one_gig / PAGE_SIZE) / 1024);
+ for (i = 0; i < num_test_pages; i += 1024) {
+ pde_t * pde = &(pd[pde_offset + (i / 1024)]);
+ pte_t * pte = (pte_t *)Alloc_Page();
+ memset(pte, 0, PAGE_SIZE);
+
+ pde->present = 1;
+ pde->flags= VM_READ | VM_WRITE | VM_EXEC | VM_USER;
+ pde->pageTableBaseAddr = PAGE_ALLIGNED_ADDR(pte);
+
+ for (j = 0; (j + i) < num_test_pages ; j++) {
+ pte[j].present = 1;
+ pte[j].flags = VM_READ | VM_WRITE | VM_EXEC | VM_USER;
+ pte[j].pageBaseAddr = PAGE_ALLIGNED_ADDR(Alloc_Page());
+ }
+ }
+
+ PrintBoth("Setup VM Test static map\n");
+
+
+ /* Setup the Two Gig test area */
+ /* First is just a incrmental mirroring of the 1G area */
+
+ pde_offset = (((ulong_t)two_gig / PAGE_SIZE) / 1024);
+
+ for (i = 0; i < num_test_pages; i += 1024) {
+ pde_t * pde = &(pd[pde_offset + (i / 1024)]);
+ pte_t * pte = (pte_t *)Alloc_Page();
+ memset(pte, 0, PAGE_SIZE);
+
+ pde->present = 1;
+ pde->flags= VM_READ | VM_WRITE | VM_EXEC | VM_USER;
+ pde->pageTableBaseAddr = PAGE_ALLIGNED_ADDR(pte);
+
+ for (j = 0; (j + i) < num_test_pages; j++) {
+ pte_t * static_pte = LookupPage(one_gig + (PAGE_SIZE * (j+i)));
+ pte[j].present = 1;
+ pte[j].flags = VM_READ | VM_WRITE | VM_EXEC | VM_USER;
+ pte[j].pageBaseAddr = static_pte->pageBaseAddr;
+ }
+ }
+
+ PrintBoth("Setup initial test area\n");
+
+ PrintBoth("Loading CR3\n");
+ Set_PDBR(pd);
+
+ SerialDumpPageTables(pd);
+
+ PrintBoth("Writing to Test Area\n");
+
+ /* Write data to each page in the 2G test area */
+ uint_t * test_ptr = (uint_t *)two_gig;
+ for (i = 0; i < num_test_pages; i++) {
+
+ SerialPrint("Writing %d to %p\n", i, test_ptr);
+ *test_ptr = (uint_t)i;
+ test_ptr += PAGE_SIZE / 4;
+ }
+
+
+ PrintBoth("Reversing Page Mapping\n");
+
+ /* Reverse 2G test area mapping */
+
+ pde_offset = (((ulong_t)two_gig / PAGE_SIZE) / 1024);
+
+ for (i = 0; i < num_test_pages; i += 1024) {
+ pde_t * pde = &(pd[pde_offset + (i / 1024)]);
+ pte_t * pte = (pte_t *)(pde->pageTableBaseAddr << 12);
+
+ for (j = 0; (j + i) < num_test_pages ; j++) {
+ pte_t * static_pte = LookupPage(one_gig + (PAGE_SIZE * (num_test_pages - (j+i) - 1)));
+ pte[j].pageBaseAddr = static_pte->pageBaseAddr;
+ }
+ }
+
+
+ Set_PDBR(pd);
+
+ PrintBoth("Page Mapping Reversed\n");
+ SerialDumpPageTables(pd);
+
+
+ PrintBoth("Page Consistency Check\n");
+
+ test_ptr = (uint_t *)two_gig;
+ for (i = 0; i < num_test_pages; i++) {
+ if ((*test_ptr) != num_test_pages - (i+1)) {
+ PrintBoth("Consistency Error: (Test Value=%d; Actual Value=%d)\n", (num_test_pages - i), (*test_ptr));
+ while(1);
+ }
+ test_ptr += PAGE_SIZE / 4;
+ }
+
+ PrintBoth("Test Sucessful\n");
+
+
+ PrintBoth("Invalidation Test\n");
+
+
+ Invalidate_PG(two_gig);
+
+ uint_t foo = 0;
+
+ foo = *(uint_t *)two_gig;
+ *(uint_t *)((char *)two_gig + 4) = foo;
+
+
+ PrintBoth("Invalidation Test Successful\n");
+}
+
+
+//
+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");
+}
+