reactos/subsys/csrss/video.c

   1 #include <ddk/ntddk.h>
   2
   3 ULONG
   4 InitializeVideoAddressSpace(VOID)
   5 {
   6    OBJECT_ATTRIBUTES ObjectAttributes;
   7    UNICODE_STRING PhysMemName;
   8    NTSTATUS Status;
   9    HANDLE PhysMemHandle;
  10    PVOID BaseAddress;
  11    LARGE_INTEGER Offset;
  12    ULONG ViewSize;
  13    PUCHAR TextMap;
  14    CHAR IVT[1024];
  15    CHAR BDA[256];
  16
  17    /*
  18     * Open the physical memory section
  19     */
  20    RtlInitUnicodeString(&PhysMemName, L"\\Device\\PhysicalMemory");
  21    InitializeObjectAttributes(&ObjectAttributes,
  22                               &PhysMemName,
  23                               0,
  24                               NULL,
  25                               NULL);
  26    Status = NtOpenSection(&PhysMemHandle, SECTION_ALL_ACCESS,
  27                           &ObjectAttributes);
  28    if (!NT_SUCCESS(Status))
  29      {
  30         DbgPrint("Couldn't open \\Device\\PhysicalMemory\n");
  31         return(0);
  32      }
  33
  34    /*
  35     * Map the BIOS and device registers into the address space
  36     */
  37    Offset.QuadPart = 0xa0000;
  38    ViewSize = 0x100000 - 0xa0000;
  39    BaseAddress = (PVOID)0xa0000;
  40    Status = NtMapViewOfSection(PhysMemHandle,
  41                                NtCurrentProcess(),
  42                                &BaseAddress,
  43                                0,
  44                                8192,
  45                                &Offset,
  46                                &ViewSize,
  47                                ViewUnmap,
  48                                0,
  49                                PAGE_EXECUTE_READWRITE);
  50    if (!NT_SUCCESS(Status))
  51      {
  52         DbgPrint("Couldn't map physical memory (%x)\n", Status);
  53         NtClose(PhysMemHandle);
  54         return(0);
  55      }
  56    NtClose(PhysMemHandle);
  57    if (BaseAddress != (PVOID)0xa0000)
  58      {
  59        DbgPrint("Couldn't map physical memory at the right address "
  60                 "(was %x)\n", BaseAddress);
  61        return(0);
  62      }
  63
  64    /*
  65     * Map some memory to use for the non-BIOS parts of the v86 mode address
  66     * space
  67     */
  68    BaseAddress = (PVOID)0x1;
  69    ViewSize = 0xa0000 - 0x1000;
  70    Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
  71                                     &BaseAddress,
  72                                     0,
  73                                     &ViewSize,
  74                                     MEM_COMMIT,
  75                                     PAGE_EXECUTE_READWRITE);
  76    if (!NT_SUCCESS(Status))
  77      {
  78        DbgPrint("Failed to allocate virtual memory (Status %x)\n", Status);
  79        return(0);
  80      }
  81    if (BaseAddress != (PVOID)0x0)
  82      {
  83        DbgPrint("Failed to allocate virtual memory at right address "
  84                 "(was %x)\n", BaseAddress);
  85        return(0);
  86      }
  87
  88    /*
  89     * Get the real mode IVT from the kernel
  90     */
  91    Status = NtVdmControl(0, IVT);
  92    if (!NT_SUCCESS(Status))
  93      {
  94        DbgPrint("NtVdmControl failed (status %x)\n", Status);
  95        return(0);
  96      }
  97
  98    /*
  99     * Copy the real mode IVT into the right place
 100     */
 101    memcpy((PVOID)0x0, IVT, 1024);
 102
 103    /*
 104     * Get the BDA from the kernel
 105     */
 106    Status = NtVdmControl(1, BDA);
 107    if (!NT_SUCCESS(Status))
 108      {
 109        DbgPrint("NtVdmControl failed (status %x)\n", Status);
 110        return(0);
 111      }
 112
 113    /*
 114     * Copy the BDA into the right place
 115     */
 116    memcpy((PVOID)0x400, BDA, 256);
 117
 118    return(1);
 119 }