Re: [PATCH 1/5] ARC: uapi: Stop leaking CONFIG_ARC_HAS_SWAPE reference to userspace

On Tue, Dec 30, 2025 at 10:23:08PM +0100, Arnd Bergmann wrote:

On Tue, Dec 30, 2025, at 08:10, Thomas Weißschuh wrote:

quoted

UAPI headers are not supposed to leak references to kconfig symbols.
These won't be set when building userspace. Hide the kconfig reference
behind 'if defined(__KERNEL__)', so it will be stripped by
headers_install.sh. The result for userspace will be the same, but the
exception in headers_install.sh can also be removed.

Signed-off-by: Thomas Weißschuh <redacted>

Acked-by: Arnd Bergmann <arnd@arndb.de>

Same as for the nios2 version, I think the nicer solution would
be to use the asm-generic header for uapi and move this one
to arch/arc/include/asm/swab.h for kernel-internal use.

Ack. Also to your other feedback on the series.

In theory, using 'select ARCH_USE_BUILTIN_BSWAP' in Kconfig should
let the compiler pick the best swap instruction, which would
be even less code, but I'm not sure if there was a reason that
nios2 and arc don't already do this.

I'd like to keep the current logic to avoid potential issues.
But maybe the arch maintainers will chime in.


Thomas