2. How do I apply a probe to Linux kernel mode interrupts?

The probe: do_irq.spc
---------------------------

int Num_Of_Interrupts = 0;

probe thread
{
   probe "__do_IRQ" in "vmlinux"
   {
      on_entry
      {
         Num_Of_Interrupts++;   /* just count */

         if ((Num_Of_Interrupts % 100) == 0)    /* every 100 times */
         {
            printk (KERN_DEBUG "__do_IRQ was called %d times\n", 
                    Num_Of_Interrupts);
         }
      }
   }
}


Compile the do_irq.spc probe to create do_irq.usm:
--------------------------------------------------------

spc -C -t linuxkm:x86 -K $KERNEL_BUILD_PATH/linux-2.6.14-cgl do_irq.spc


Install and Run the probe on target:
-----------------------------------------

Use spkmtool to load and run the do_irq.usm probe.  Here, our target
machine is named "alfie".

# First, install the probe library and probe services modules,
# and load the kernel symbols file that they need:
spkmtool -v -d alfie.syms

# This turns on immediate formatting:
spkmtool -s -if 1

# Initialize the probe library module:
spkmtool -s init

# Load the probe module, and give it a handy ID (eg, 44):
spkmtool -v -s load do_irq.usm 44

# Enable the probe module:
spkmtool -v -s enable 44

# Run your program and wait for interrupts to accumulate...

# Disable the probe module:
spkmtool -v -s disable 44

# Unload the probe module:
spkmtool -v -s unload do_irq.usm

# Finalize the probe library module:
spkmtool -s fini

# Remove the probe library and probe services modules:
spkmtool -v -c