[SeaBIOS] [PATCH] coreboot: Add support for FMAP and multiple CBFS

Kevin O'Connor kevin at koconnor.net
Fri Mar 11 16:44:33 CET 2016

On Thu, Mar 10, 2016 at 11:11:59AM -0600, Ben Gardner wrote:
> Hi Kevin,
> I plan to have the default CBFS contain only coreboot and SeabIOS and
> a few payloads (coreinfo, memtest86, PXE) that I don't intend to
> change often.
> That would be protected with a hash and would be kept small for
> performance reasons.
> ChromeOS appears to do something similar and take it a step further
> and write-protect that "read only" region of flash.
> The other CBFS would contain larger images that I'm likely to change,
> such as Linux.
> There is a chance of name conflicts and that may cause problems.
> In my use case, the answer is "don't do that".
> From a random sampling of FMD files in the coreboot tree
> (google/glados/chromeos.fmd), I see that ChromeOS uses three:
> FW_MAIN_A, FW_MAIN_B, and the default COREBOOT.
> Assuming FW_MAIN_A and FW_MAIN_B contain files with similar names,
> that would cause confusion if they use SeaBIOS.
> But I think that ChromeOS is switching to use the Depthcharge bootloader.
> So, maybe this wouldn't work well for everyone.

Thanks.  If this may not work for everyone, then I suggest adding a
build time (kconfig) or runtime (cbfs) setting to enable/disable it.
Normally runtime settings are preferred, but that may not work here.


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