Corey Minyard wrote:
>
> Marko Rauhamaa <[EMAIL PROTECTED]> writes:
>
> > > X is a user space process, thus cannot disable interrupts, and
> > > therefore cannot block the system.
>
> This is not true. X is a user space processes, but it is possible for
> user space processes to disable interrupts. I have personally done
> it. You have to modify your iopl and you have to be a supervisor
> process, but you can do it. And some X servers do this, I'm pretty
> sure. I know they go directly to the hardware.
>
> And since X directly calls the cli and sti instructions instead of
> calling the Linux functions in the kernel, even RTLinux cannot stop
> this.
Are you sure, the non-kernel-space process could use STI & CLI
instructions ??? I've always though this is privileged instruction
and there is no way, user-space program could use them.
(This would break whole multitasking, and we are not on Amiga)
--
Good programmers know what to write.
Great ones know what to rewrite (and reuse).
Zdenek Kabelac http://www.fi.muni.cz/~kabi/ [EMAIL PROTECTED]
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