Re: [PATCH v3 12/13] arm64: Kbuild: Remove vestigial big-endian support

[Will Deacon <will@kernel.org>]

On Tue, Sep 22, 2026 at 04:17:35PM +0100, Catalin Marinas wrote:
> On Tue, Sep 22, 2026 at 04:10:17PM +0100, Will Deacon wrote:
> > On Mon, Sep 21, 2026 at 11:24:36AM +0100, Catalin Marinas wrote:
> > > On Fri, Sep 18, 2026 at 03:52:14PM +0100, Will Deacon wrote:
> > > > -choice
> > > > -	prompt "Endianness"
> > > > -	default CPU_LITTLE_ENDIAN
> > > > -	help
> > > > -	  Select the endianness of data accesses performed by the CPU. Userspace
> > > > -	  applications will need to be compiled and linked for the endianness
> > > > -	  that is selected here.
> > > > -
> > > > -config CPU_BIG_ENDIAN
> > > > -	bool "Build big-endian kernel"
> > > > -	depends on BROKEN
> > > > -	help
> > > > -	  Say Y if you plan on running a kernel with a big-endian userspace.
> > > > -
> > > > -config CPU_LITTLE_ENDIAN
> > > > -	bool "Build little-endian kernel"
> > > > -	help
> > > > -	  Say Y if you plan on running a kernel with a little-endian userspace.
> > > > -	  This is usually the case for distributions targeting arm64.
> > > 
> > > Running the checks through an LLM found that CONFIG_GVE depends on
> > > X86 || CPU_LITTLE_ENDIAN, so it won't be enabled anymore.
> > > 
> > > I think that's the only positive test of CPU_LITTLE_ENDIAN.
> > 
> > Would you like me to add a '|| arm64' in there? I was a bit wary of doing
> > so, given that I don't have a way to test it. Removing CPU_LITTLE_ENDIAN
> > forces the issue, somewhat.
> 
> Or turn the dependency into X86 || !CPU_BIG_ENDIAN.

At which point it might as well just be !CPU_BIG_ENDIAN.

> Was arm64 the only one to define CPU_LITTLE_ENDIAN before?

Looks like there are a few:

$ find . -name 'Kconfig*' | xargs grep 'config\s\+CPU_LITTLE_ENDIAN'
./arch/sh/Kconfig.cpu:config CPU_LITTLE_ENDIAN
./arch/mips/Kconfig:config CPU_LITTLE_ENDIAN
./arch/arm64/Kconfig:config CPU_LITTLE_ENDIAN
./arch/xtensa/Kconfig:config CPU_LITTLE_ENDIAN
./arch/arm/mm/Kconfig:config CPU_LITTLE_ENDIAN
./arch/microblaze/Kconfig:config CPU_LITTLE_ENDIAN
./arch/powerpc/platforms/Kconfig.cputype:config CPU_LITTLE_ENDIAN

I'll play it safe and add the || ARM64 as I don't particularly want to
deal with the fallout of the driver getting additional exposure on
architectures (e.g. sparc) that don't define either of the symbols.

Will