2004-04-29 18:58:55

by Tim Bird

[permalink] [raw]
Subject: CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

I'm looking at some sources for kernel Execute-in-place (XIP).

I see references to CONFIG_XIP_ROM and CONFIG_XIP_KERNEL,
in different architecture branches of the same kernel
source tree.

Is this difference merely the result of inconsistent
usage, or is there a functional difference between
these two options?

I can imagine that CONFIG_XIP_ROM is intended only to
handle XIP in ROM, and that CONFIG_XIP_KERNEL possibly
handles additional cases like XIP in flash. However,
before jumping to that conclusion I thought I would
ask if there is some intention behind the different
config names.

Thanks,

=============================
Tim Bird
Architecture Group Co-Chair
CE Linux Forum
Senior Staff Engineer
Sony Electronics
E-mail: Tim.Bird (at) am.sony.com
=============================



2004-04-29 20:10:13

by Ralf Baechle

[permalink] [raw]
Subject: Re: CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

On Thu, Apr 29, 2004 at 12:07:17PM -0700, Tim Bird wrote:

> I'm looking at some sources for kernel Execute-in-place (XIP).
>
> I see references to CONFIG_XIP_ROM and CONFIG_XIP_KERNEL,
> in different architecture branches of the same kernel
> source tree.
>
> Is this difference merely the result of inconsistent
> usage, or is there a functional difference between
> these two options?
>
> I can imagine that CONFIG_XIP_ROM is intended only to
> handle XIP in ROM, and that CONFIG_XIP_KERNEL possibly
> handles additional cases like XIP in flash. However,
> before jumping to that conclusion I thought I would
> ask if there is some intention behind the different
> config names.

Since you copied linux-mips - neither option is implemented for MIPS ...

Ralf

2004-04-29 20:53:53

by Nicolas Pitre

[permalink] [raw]
Subject: Re: CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

On Thu, 29 Apr 2004, Tim Bird wrote:

> I'm looking at some sources for kernel Execute-in-place (XIP).
>
> I see references to CONFIG_XIP_ROM and CONFIG_XIP_KERNEL,
> in different architecture branches of the same kernel
> source tree.
>
> Is this difference merely the result of inconsistent
> usage, or is there a functional difference between
> these two options?

It's the result of me deciding CONFIG_XIP_ROM wasn't totally appropriate ...

> I can imagine that CONFIG_XIP_ROM is intended only to
> handle XIP in ROM, and that CONFIG_XIP_KERNEL possibly
> handles additional cases like XIP in flash. However,
> before jumping to that conclusion I thought I would
> ask if there is some intention behind the different
> config names.

... so I renamed it to CONFIG_XIP_KERNEL. Especially since there is also
XIPable user space which also can be stored in ROM (or flash). So please
disregard CONFIG_XIP_ROM and use CONFIG_XIP_KERNEL. Whether ROM or Flash is
used is rather irrelevant to the code this option is linked to.


Nicolas