Thanks for the replies. I have another question. Thanks in advance for clarifications.
I was wondering who calls the do_irq function. I mean when interrupts occurs processor should handle it by interrupting current task. So, when interrupts occurs in linux kernel, then, did processor jumps directly to do_irq or does it executes any other function before entering in to do_irq. If processor directly jumps to do_irq, then how does processor knows what to execute when interrupts happens. I mean, Is there anyway to set in linux kernel to tell processor to jump to this location when an interrupt or exception happens. I am not talking about interrupt subsystem, which is done in do_irq, checking what interrupt occurred by reading bus, and calling appropriate handler. Let me know whether my understanding is right. Thanks, Sri. On Sun, Sep 19, 2010 at 7:27 AM, arshad hussain <[email protected]>wrote: > On 9/19/2010 4:49 AM, Sri Ram Vemulpali wrote: > >> Hi all, >> >> This question is regarding Interrupt descriptor table. Why is the >> IDTR 48-bits wide and >> > > 16Bit Limit + 32 bit Address = 48bits of IDTR. > > > why do we need limit field in the IDTR. > > Because if we access beyond defined interrupt there will > be general protection fault. > > > Since we know there are 256 interrupts or exceptions possible, can't >> we know boundary by deriving it by length of IDT field. >> > > All interrupts are not always defined. There may be fewer > interrupts defined depending upon the requirements. Looking > up the 'limits' field is faster & less error prone than > find the length of the IDT, which i guess could only be > done via probing for all slots with has present flag set to 0. > > > Also, why is the IDT entry is 8 bytes long. >> > This 8 byte data structure is explained in intel's manual. > > And how is the interrupt > >> line sharing is provided. Is sharing provided at OS code level. >> > > I did not see any explanation of sharing at Intel manual (data sheet >> of x86 system programming guide). Any thoughts. >> >> Please clarify. Thanks. >> >> >> -- >> Regards, >> Sri. >> >> > Thanks. > > -- > To unsubscribe from this list: send an email with > "unsubscribe kernelnewbies" to [email protected] > Please read the FAQ at http://kernelnewbies.org/FAQ > > -- Regards, Sri.
