X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=blobdiff_plain;f=geekos%2Fsrc%2Fgeekos%2Fpaging.c;fp=geekos%2Fsrc%2Fgeekos%2Fpaging.c;h=5aab5b1ba57d29e880f2fe4d425a63f0daa95e9e;hp=0000000000000000000000000000000000000000;hb=ddc16b0737cf58f7aa90a69c6652cdf4090aec51;hpb=626595465a2c6987606a6bc697df65130ad8c2d3

diff --git a/geekos/src/geekos/paging.c b/geekos/src/geekos/paging.c
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+/*
+ * 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>
+ * (c) 2008, Peter Dinda <pdinda@northwestern.edu> 
+ * (c) 2008, Jack Lange <jarusl@cs.northwestern.edu> 
+ * (c) 2008, The V3VEE Project <http://www.v3vee.org> 
+ * $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>
+#include <geekos/debug.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");
+}
+