Re: [PATCH] firmware: coreboot: Don't skip CBMEM entries outside of known memory
From: Tzung-Bi Shih
Date: Thu Oct 22 2026 - 04:39:03 EST
On Sat, Oct 17, 2026 at 11:03:51AM +0200, Michał Kopeć wrote:
> coreboot leaves CBMEM out of the /memory node of the device tree that it
> passes to FIT payloads, e.g. LinuxBoot on arm64 Chromebooks, and only
> lists it in the memory reservation block. The kernel has no resource for
> that memory, so region_intersects() reports it as neither System RAM nor
> Reserved memory, and since commit e31ecda9e3af ("firmware: coreboot:
> Skip no-map CBMEM entries") all CBMEM entries are skipped on such boards.
> That loses the coreboot log, the TPM event log and everything else that
> CBMEM devices expose.
>
> Also accept entries that don't intersect any memory resource. No-map
> regions are still skipped, as they are IORESOURCE_MEM resources, as are
> device regions.
>
> Fixes: e31ecda9e3af ("firmware: coreboot: Skip no-map CBMEM entries")
> Signed-off-by: Michał Kopeć <michal@nozomi.space>
Thank you for your patch. I'll queue this after -rc1 and send it as a
fix.