nixCraft

Hi ,
I have a question on interrupts:

how to pass interrupts from kernel mode to user mode..
details:
i would like to run spesific appication at user level, after receiving hard ware interrupt,
i have a method i am not sure about it?if anybody know about this please ans.

my ans: after receiving interrrupt, i am calling a function user_mode_helper(), this run the specific applicaion in kernal mode,

how to use this function:call_usermodehelper(),
how to pass interrupt request to user space

Well I'm not C/C++ guru but you can use following google.com link to get http://www.google.com/search?hs=2Hb&...ce&btnG=Search

Also see free book (Linux Device Drivers, Third Edition) http://www.oreilly.com/catalog/linux...book/index.csp -- it has info on Interrupt Handling (chapter 10)

If you have any futher question reply back

Hi,
I want to mask some hardware interrupts (selectively).
I'm using below code to mask interrupt 10.

#include <stdio.h>
#include <stdlib.h>
#include <sys/io.h>
int main()
{
int slave;
//Change the IO privilege level of current process.
if (iopl(3) < 0)
{
perror("cannot get i/o privileges");
return 1;
}
slave = 0;
slave = inb_p(0xA1); //get the contents of Interrupt Mask Regester (IMR)
printf("Before changing...\n");
printf("IMR :: %x\n",slave);
slave |= 0x4; //Mask interrupt 10
outb_p(slave,0xA1); //write new flag to IMR
slave = 0;
slave = inb_p(0xA1); //get the contents of Interrupt Mask Regester (IMR)
printf("After changing...\n");
printf("IMR :: %x\n",slave);
sleep(5); //Sleep for 5 seconds
printf("After sleep...\n");
printf("IMR :: %x\n",slave);
return 0;
}

This is user level application. It first changes the privilege level from 0 to 3. Then reads the contents of Interrupt Mask Register (IMR), which contains the status of interrupts 8 to 15. It then sets bit 3 (interrupt 10) and rewrites the value back to IMR.
When I run the application, it change the mask in IMR. But the mask gets reset to old value immediately, before exiting from the application. I want to keep the new mask till the completion of application.
Can anybody help me, how to do this?