Re: Kconfig olddefconfig nukes 32-bit

[Nicolas Schier <nsc@kernel.org>]

Cc: linux-kbuild

On Sat, Apr 11, 2026 at 10:55:15AM -0700, Andrew Valencia wrote:
> Hi,
> 
> I'm working over in the 6.19..12 world, and brought over a working
> .config which I updated with olddefconfig.  Long story short, the
> config was converted to a x86 64-bit config.
> 
> The issue is the new config entry 64BIT, which has a default value of
> ARCH != "i386".

yes, there is a 64BIT Kconfig symbol defined at arch/x86/Kconfig which
is true by default for non-i386 builds.  According to my git tree, the
corresponding lines did not change since v4.18 [1].

[1]: https://git.kernel.org/kbuild/c/104daea149c45

> On my 32-bit x86 build machine with its 32-bit .config, the default Y
> is being selected.  Is it possible i386 is not the correct name for
> ARCH on this target?

I guess, that you want to cross-build a 32bit-Linux on a 64bit-machine,
right?  How did you call olddefconfig (e.g. make ARCH=i386 olddefconfig)?

Kind regards

-- 
Nicolas