Can i use KeSetEvent in a DPC for an ISR...??

NTDEV
1

Hi,

The following code crashes and reboots the system with message
IRQL_NOT_LESS_OR_EQUAL in ntoskrnl.exe

I want to run a user mode function using Kernel mode event notification to
user mode…so I created an event and sent it down to driver and I am
setting the event in the kernel mode driver…

I want to set the event on occuring of an interrupt…for that, I use the
KeSetEvent in the DPC code…but if i use there I am getting a crash…

I know I am going wrong somewhere with the IRQL is concerned…I am
attaching the code also…pls advice what i could do to set the event on
occuring of the interrupt…

#pragma LOCKEDCODE

BOOLEAN OnInterrupt(PKINTERRUPT InterruptObject, PDEVICE_EXTENSION pdx)
{
// TODO Is our device requesting an interrupt?
// if (!interrupting)
// return FALSE;
KdPrint((“Entering On Interrupt Function”));
pdx->intscr = READ_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
0x4c));
ULONG intscr_bit2_int1=pdx->intscr & 0x04;
intscr_bit2_int1=intscr_bit2_int1>>2;

ULONG intscr_bit5_int2=pdx->intscr & 0x20;
intscr_bit5_int2=intscr_bit5_int2>>5;

ULONG Interrupt1_2=intscr_bit2_int1 | intscr_bit5_int2;

if(!Interrupt1_2)
return FALSE;

//Disable pci interrupt by writing 0 to bit 6 in INTSCR
ULONG DisablePolarity=pdx->intscr & 0xffffffed;
WRITE_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
0x4c),DisablePolarity);
ULONG DisablePciIntr=pdx->intscr & 0xffffffbf;
WRITE_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
0x4c),DisablePciIntr);

KdPrint((“Requesting for DPC for ISR”));
IoRequestDpc(pdx->DeviceObject,NULL,pdx);

KdPrint((“Quitting OnInterrupt Function”));
if (!pdx->busy)
return TRUE;
return TRUE;
}

#pragma LOCKEDCODE

VOID DpcForIsr(PKDPC Dpc, PDEVICE_OBJECT fdo, PIRP junk, PDEVICE_EXTENSION
pdx)
{ // DpcForIsr
KdPrint((“Entering DpcForISR Function”));
NTSTATUS status=STATUS_SUCCESS;

KeSetEvent((KEVENT*)pdx->gpEventObject,
0,
FALSE);
KdPrint((“KeSetEvent sussfully!\n”));

//Enable Pci interrupt
ULONG EnablePciIntr=pdx->intscr & 0x0000005b;
WRITE_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
0x4c),EnablePciIntr);
KdPrint((“Quitting DpcForISR Function”));
} // DpcForIsr

Thanx very much,

shiv

2

KeSetEvent can be called at DISPATCH as long as the wait parameter is false.
Your probelm is that the event object MUST be in locked memory, since you
reference it at
an IRQL where inpage operations are not allowed, therfore it crashes.

----- Original Message -----
From: “Shiva Prasad. T. S.”
To: “NT Developers Interest List”
Sent: Thursday, August 29, 2002 11:53 AM
Subject: [ntdev] Can i use KeSetEvent in a DPC for an ISR…??

> Hi,
>
> The following code crashes and reboots the system with message
> IRQL_NOT_LESS_OR_EQUAL in ntoskrnl.exe
>
> I want to run a user mode function using Kernel mode event notification to
> user mode…so I created an event and sent it down to driver and I am
> setting the event in the kernel mode driver…
>
> I want to set the event on occuring of an interrupt…for that, I use the
> KeSetEvent in the DPC code…but if i use there I am getting a crash…
>
> I know I am going wrong somewhere with the IRQL is concerned…I am
> attaching the code also…pls advice what i could do to set the event on
> occuring of the interrupt…
>
>
> #pragma LOCKEDCODE
>
> BOOLEAN OnInterrupt(PKINTERRUPT InterruptObject, PDEVICE_EXTENSION pdx)
> {
> // TODO Is our device requesting an interrupt?
> // if (!interrupting)
> // return FALSE;
> KdPrint((“Entering On Interrupt Function”));
> pdx->intscr = READ_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
> 0x4c));
> ULONG intscr_bit2_int1=pdx->intscr & 0x04;
> intscr_bit2_int1=intscr_bit2_int1>>2;
>
> ULONG intscr_bit5_int2=pdx->intscr & 0x20;
> intscr_bit5_int2=intscr_bit5_int2>>5;
>
> ULONG Interrupt1_2=intscr_bit2_int1 | intscr_bit5_int2;
>
> if(!Interrupt1_2)
> return FALSE;
>
>
> //Disable pci interrupt by writing 0 to bit 6 in INTSCR
> ULONG DisablePolarity=pdx->intscr & 0xffffffed;
> WRITE_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
> 0x4c),DisablePolarity);
> ULONG DisablePciIntr=pdx->intscr & 0xffffffbf;
> WRITE_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
> 0x4c),DisablePciIntr);
>
>
> KdPrint((“Requesting for DPC for ISR”));
> IoRequestDpc(pdx->DeviceObject,NULL,pdx);
>
> KdPrint((“Quitting OnInterrupt Function”));
> if (!pdx->busy)
> return TRUE;
> return TRUE;
> }
>
>
>
> #pragma LOCKEDCODE
>
> VOID DpcForIsr(PKDPC Dpc, PDEVICE_OBJECT fdo, PIRP junk, PDEVICE_EXTENSION
> pdx)
> { // DpcForIsr
> KdPrint((“Entering DpcForISR Function”));
> NTSTATUS status=STATUS_SUCCESS;
>
> KeSetEvent((KEVENT*)pdx->gpEventObject,
> 0,
> FALSE);
> KdPrint((“KeSetEvent sussfully!\n”));
>
> //Enable Pci interrupt
> ULONG EnablePciIntr=pdx->intscr & 0x0000005b;
> WRITE_REGISTER_ULONG((PULONG)((ULONG)pdx->membase[0] +
> 0x4c),EnablePciIntr);
> KdPrint((“Quitting DpcForISR Function”));
> } // DpcForIsr
>
>
> Thanx very much,
>
> shiv
>
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