Re: [PATCH 2/3] kbuild: generate asm-generic wrappers if mandatory headers are missing

From: Masahiro Yamada
Date: Tue Dec 11 2018 - 08:00:20 EST

Hi Christoph,

On Fri, Dec 7, 2018 at 12:04 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Wed, Dec 05, 2018 at 08:28:05PM +0900, Masahiro Yamada wrote:
> > Some time ago, Sam pointed out a certain degree of overwrap between
> > generic-y and mandatory-y. (
> >
> > I a bit tweaked the meaning of mandatory-y; now it defines the minimum
> > set of ASM headers that all architectures must have.
> >
> > If arch does not have specific implementation of a mandatory header,
> > Kbuild will let it fallback to the asm-generic one by automatically
> > generating a wrapper. This will allow to drop lots of redundant
> > generic-y defines.
> >
> > Previously, "mandatory" was used in the context of UAPI, but I guess
> > this can be extended to kernel space ASM headers.
> How useful is it to keep the generic-y behavior around at all vs making
> everything useful mandatory?

What I can tell is not all architectures
support kvm_para.h, ucontext.h

I guess they will stay as arch-specific generic-y,
but I am not an expert in this area.

kvm_para.h is missing csky, nds32, riscv.

ucontext.h is missing in alpha, arm, m68k, parisc, sparc, xtensa

bpf_perf_event.h could be promoted to mandatory-y ?
All architectures have it.

Best Regards
Masahiro Yamada