Re: Change mode to kernel?

H. Peter Anvin (hpa@transmeta.com)
19 May 1998 21:11:45 GMT

Followup to: <19980519111908.A20937@planetfall.com>
By author: Jeff Noxon <jeff@planetfall.com>
In newsgroup: linux.dev.kernel
>
> Is it possible for user code to change to kernel mode and back? Or is
> that something that only VMS can do? :)
>
> I want to write a simple device driver that doesn't require IRQs or DMAs,
> and I'd rather not do the dirty part as a kernel module. Certain I/O
> operations need to be atomic to avoid races with other code tweaking the
> same hardware. I understand (possibly incorrectly) that it isn't safe
> (or possible) to disable IRQs in userland...
>
> What's the best approach?
>

Doing the dirty part as a kernel module.

-hpa

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