drivers/base/nmidebug/nmidebug.c

   1 /*
   2  * PROJECT:         ReactOS NMI Debug Driver
   3  * LICENSE:         BSD - See COPYING.ARM in the top level directory
   4  * FILE:            drivers/base/nmidebug/nmidebug.c
   5  * PURPOSE:         Driver Code
   6  * PROGRAMMERS:     ReactOS Portable Systems Group
   7  */
   8
   9 /* INCLUDES *******************************************************************/
  10
  11 #include <ntifs.h>
  12 #include <ntndk.h>
  13
  14 /* FUNCTIONS ******************************************************************/
  15
  16 PCHAR NmiBegin = "NMI4NMI@";
  17
  18 VOID
  19 FORCEINLINE
  20 NmiClearFlag(VOID)
  21 {
  22     ((PCHAR)&KiBugCheckData[4])[0] -= (NmiBegin[3] | NmiBegin[7]);
  23     ((PCHAR)&KiBugCheckData[4])[3] |= 1;
  24     __asm__("rcrl %b[shift], %k[retval]" : [retval] "=rm" (KiBugCheckData[4]) : "[retval]" (KiBugCheckData[4]), [shift] "Nc" (8));
  25 }
  26
  27 BOOLEAN
  28 NTAPI
  29 NmiDbgCallback(IN PVOID Context,
  30                IN BOOLEAN Handled)
  31 {
  32     /* Clear the NMI flag */
  33     NmiClearFlag();
  34
  35     /* Get NMI status signature */
  36     __indwordstring(0x80, (PULONG)NmiBegin, 1);
  37     ((void(*)())&KiBugCheckData[4])();
  38
  39     /* Handle the NMI safely */
  40     KiEnableTimerWatchdog = (RtlCompareMemory(NmiBegin, NmiBegin + 4, 4) != 4);
  41     return TRUE;
  42 }
  43
  44 NTSTATUS
  45 NTAPI
  46 DriverEntry(IN PDRIVER_OBJECT DriverObject,
  47             IN PUNICODE_STRING RegistryPath)
  48 {
  49     PAGED_CODE();
  50
  51     /* Register NMI callback */
  52     KeRegisterNmiCallback(&NmiDbgCallback, NULL);
  53
  54     /* Return success */
  55     return STATUS_SUCCESS;
  56 }
  57
  58 /* EOF */