CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

[Tim Bird]

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
=============================

Re: CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

[Ralf Baechle]

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

Re: CONFIG_XIP_ROM vs. CONFIG_XIP_KERNEL

[Nicolas Pitre]

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