Re: [PATCH v8 16/29] arm64: Share arm64 headers with s390

[Andreas Grapentin]

On Sep 28 26, Steffen Eiden wrote:
> On Mon, Sep 28, 2026 at 05:07:52PM +0100, Catalin Marinas wrote:
> > On Fri, Sep 18, 2026 at 03:30:53PM +0200, Steffen Eiden wrote:
> > > +# Enable all code shared to s390
> > > +KBUILD_CFLAGS	+= -DARM64_S390_COMMON
> > > +KBUILD_AFLAGS	+= -DARM64_S390_COMMON
> > > +KBUILD_CPPFLAGS	+= -DARM64_S390_COMMON
> > 
> > Do we actually need these defines? They seem only to be used as markers
> > for the awk scripts to extract the definitions. Why do we need the C
> > preprocessor involved at all? Could we not just have comment markers:
> > 
> > /* ARM64_S390_COMMON_BEGIN */
> > ...
> > /* ARM64_S390_COMMON_END */
> >
> No technically we do not need those. They could be useful if we find out
> that AWK is the wrong tool and move to a C Preprocessor + diff based
> approach. 
> 
> if the ifdev is not closed the compiler will complain, but an 'arm did
> not destroy us' verifiaction tool ( I will send one soonish) could do
> the same.

iirc the last time we discussed this we didn't think that load-bearing
comments were the right tool here. We also briefly floated the idea of
using a #pragma region based approach, but in the end we went with the
#ifdef preprocessor directives instead, as the least invasive
non-comment marker that was available.

Best,
Andreas