Re: [PATCH -mm 0/3] i386 boot: replace boot_ioremap with enhancedbt_ioremap

From: H. Peter Anvin
Date: Tue Jan 15 2008 - 08:44:41 EST


Ingo Molnar wrote:
* H. Peter Anvin <hpa@xxxxxxxxx> wrote:

I did a quick scan over the patchset (not quite awake yet, so I may very well have missed something), but it looks like EFI (again!) is the only user of ioremapping before paging_init(). This makes me wonder if that code can't be restructured so that isn't necessary.

i think that in general making access to unmapped memory a bit easier is generally a good robustness idea as ACPI could be impacted by it as well.

Fundamentally, paging_init() has obvious dependency on "figuring out the memory setup" of the box, and "figuring out the memory setup" means interpreting various data structures passed in by the BIOS - some of which might be in not yet mapped areas or iommu areas (if we have to do some early quirk). So having a robust implementation of ioremap_early() sounds like a definitive plus.


Fair enough. If it's generally useful, I certainly have no objections.

-hpa
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