lkml.org 
[lkml]   [1999]   [Sep]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: SA_INTERRUPT
On Tue, 28 Sep 1999, Bradley D. LaRonde wrote:

> What is the current wisdom on SA_INTERRUPT?
>
> A comment in signal.h about it says "dummy -- ignored". Elsewhere it says
> that "SA_INTERRUPT is a no-op left for historical reasons".
>
> That certainly doesn't seem to be the case in irq.c. It appears to be used
> like this: if SA_INTERRUPT isn't set, enable interrupts during interrupt
> handling.
>
> So what is this flag for? How, when, and why should it be used?
>
> Thanks.
>
> Regards,
> Brad

It is unfortunate that the same #define is used for signals and
for kernel interrupts. They are not related. As you noticed,i
SA_INTERRUPT with respect to signals is a no-op since it doesn't change
the nature of signals. However, with respect to IRQ handling within the
kernel, it does enable interrupts before your possible bottom-half ISR
is checked to see if it exists and executed.
See line 726 (about) in ../arch/i386/kernel/irq.c


Cheers,
Dick Johnson
**** FILE SYSTEM WAS MODIFIED ****
Penguin : Linux version 2.3.13 on an i686 machine (400.59 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:54    [W:0.511 / U:0.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site