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,
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Tim Bird
Architecture Group Co-Chair
CE Linux Forum
Senior Staff Engineer
Sony Electronics
E-mail: Tim.Bird (at) am.sony.com
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Quoted 10 lines · Tim Bird
I'm looking at some sources for kernel Execute-in-place (XIP).
I see references to
CONFIG_XIP_ROMandCONFIG_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?
Quoted 6 lines
I can imagine that
CONFIG_XIP_ROMis intended only to handle XIP in ROM, and thatCONFIG_XIP_KERNELpossibly 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
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Quoted 11 lines · Tim Bird
Well this is interesting. One the architectures where this is supported in my tree is MIPS. I'm looking at the CELF source tree. The patch for this was submitted to me by Toshiba. I had assumed (based on some other indications) that they were submitting stuff to me that they had already submitted to kernel.org or to the MIPS list. This appears not to be the case.
We should discuss this. I have some patches for MIPS stuff in the
CELF tree from MontaVista, Toshiba, and NEC. Unfortunately, the
CELF tree is based on Linux 2.4.20, so I don't know how much of it, if any, would be useful to you.
Depends. The linux-mips.org tree is at 2.4.26. Some areas have changed significantly since 2.4.20, some not at all. If you want to send patches please make sure they still apply to the latest kernel.
Quoted 4 lines
How do I proceed with finding out what's interesting, and how to get it to you? Just post some stuff (even if old) to the mips mailing list? Request the originator to do such a post? Do things need to be migrated to 2.6?
Preferably yes. I don't really care who sends the patch as long as the sender takes responsibility also after the initial submission.
Any new features preferably for 2.6.
Quoted 1 line
Could we bypass that for a casual "is this interesting" review? Etc.
If all you need is a comment, sure.
Quoted 6 lines
The questions are endless.
Let me know what you think.And, BTW, in my tree the variable used for MIPS is
CONFIG_XIP_ROM. For SH, it'sCONFIG_XIP_KERNEL, and for ARM, it has conditionals for both, but only definesCONFIG_XIP_ROMin the config.in!
In the kernel.org kernel the only references to these symbols are to CONFIG_XIP_KERNEL in a few files under arch/arm26.
Ralf
Quoted 9 lines · Tim Bird
I'm looking at some sources for kernel Execute-in-place (XIP).
I see references to
CONFIG_XIP_ROMandCONFIG_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 ...
Quoted 6 lines
I can imagine that
CONFIG_XIP_ROMis intended only to handle XIP in ROM, and thatCONFIG_XIP_KERNELpossibly 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