Re: [9fans] stupid kernel question

[Francisco J Ballesteros <nemo@lsub.org>]

I'm kind of sleepy. But if I managed to read your mail correctly...

when the kernel wants to do something that can be done with a system
call (mostly read, write, open, ...), it uses the device tab directly, like in

devtab[c->type].write(chan, ....),

using Chan instead of fds in this case.

I mean, I think that almost always you use the internal interface wrapped
by the system call code.

On Fri, Oct 1, 2010 at 9:17 PM, Steve Simon <steve@quintile.net> wrote:
> how does kernel code call plan9 system calls, does it perform a
> trap from kernel back into kernel space and make the request just
> like a user process or is there a more direct, subtle route?
>
> thanks,
>
> -Steve
>
>