when interrupt came, the kernel save pt_regs->eip always the same?

when interrupt came, the kernel save pt_regs->eip always the same?

[pl ice]

HI,
    These day i wanted get cpu context ,when interrupt came.BUT i
found when interrupt came kernel saved cpu context in struct pt_regs
and delivered to do_IRQ ,and i print the pt_regs->eip,they alway same
on the same interrupt?
     The interrupt can come anytime,i think the eip will be very
different every time.BUT i debug kernel ,print eip in the function
do_IRQ,found it didn't run as i thought.Can anybody tell me why?


sincerely yours

Re: when interrupt came, the kernel save pt_regs->eip always the same?

[Zwane Mwaikambo]

On Sat, 13 Dec 2008, pl ice wrote:

> HI,
>     These day i wanted get cpu context ,when interrupt came.BUT i
> found when interrupt came kernel saved cpu context in struct pt_regs
> and delivered to do_IRQ ,and i print the pt_regs->eip,they alway same
> on the same interrupt?
>      The interrupt can come anytime,i think the eip will be very
> different every time.BUT i debug kernel ,print eip in the function
> do_IRQ,found it didn't run as i thought.Can anybody tell me why?

If the cpu is idle, you have a higher probability that the idle function 
is in regs->eip

	Zwane

Re: when interrupt came, the kernel save pt_regs->eip always the same?

[pl ice]

And the prototype about irq_handler changed, the 3th parameter "struct
pt_regs" removed,How do i get the struct pt_regs in my interrupt
handler because kernel doesn't deliver to me?

2008/12/14 Zwane Mwaikambo <zwane@infradead.org>:
> On Sat, 13 Dec 2008, pl ice wrote:
>
>> HI,
>>     These day i wanted get cpu context ,when interrupt came.BUT i
>> found when interrupt came kernel saved cpu context in struct pt_regs
>> and delivered to do_IRQ ,and i print the pt_regs->eip,they alway same
>> on the same interrupt?
>>      The interrupt can come anytime,i think the eip will be very
>> different every time.BUT i debug kernel ,print eip in the function
>> do_IRQ,found it didn't run as i thought.Can anybody tell me why?
>
> If the cpu is idle, you have a higher probability that the idle function
> is in regs->eip
>
>        Zwane
>

Re: when interrupt came, the kernel save pt_regs->eip always the same?

[Jiri Slaby]

Sorry for the repost, following the thread now.
BTW. do not top-post.

On 12/14/2008 03:59 AM, pl ice wrote:
> And the prototype about irq_handler changed, the 3th parameter "struct
> pt_regs" removed,How do i get the struct pt_regs in my interrupt
> handler because kernel doesn't deliver to me?

get_irq_regs() should do that.