Kernel 5.5.9 threw the following link failure on one out of three machines:
ld: arch/x86/mm/ioremap.o: in function `__ioremap_caller':
ioremap.c:(.text+0x3a6): undefined reference to `efi_mem_type'
make: *** [Makefile:1078: vmlinux] Error 1
The other two machines, which have a different hardware architecture from this one, built perfectly.
I find the following possibly-relevant config settings:
# CONFIG_EFI is not set
Reported upstream at https://lkml.org/lkml/2020/3/16/776
Patch at https://lkml.org/lkml/diff/2020/3/18/809/1
(In reply to Brian Evans from comment #1)
> Reported upstream at https://lkml.org/lkml/2020/3/16/776
> Patch at https://lkml.org/lkml/diff/2020/3/18/809/1
I confirm upstream patch works for me.
Thanks for posting the link to the patch.
This will be in the next release of gentoo-sources. (5.5.11)
Author: Mike Pagano <firstname.lastname@example.org>
Date: Thu Mar 19 19:21:27 2020 -0400
x86/ioremap: Fix CONFIG_EFI=n build. See bug #713460.
Thanks to Phil Stracchino.
Signed-off-by: Mike Pagano <email@example.com>