Re: [PATCHES] gnu: linux-libre: Update to 4.16

[Mark H Weaver <mhw@netris.org>]

Hi Vincent,

Vincent Legoll <vincent.legoll@gmail.com> writes:

> On Sun, Apr 8, 2018 at 3:10 AM, Mark H Weaver <mhw@netris.org> wrote:
>> Leo Famulari <leo@famulari.name> writes:
>>
>>> On Sat, Apr 07, 2018 at 02:36:04PM -0400, Mark H Weaver wrote:
>>>> One more thing: I had to add 'flex' and 'bison' as native-inputs because
>>>> the build system in 4.16 now concludes that they need to be re-run for
>>>> some reason.  This could perhaps be avoided by adding a phase to touch
>>>> the generated files, but I didn't try it.
>>>
>>> I noticed this too while building 4.16 with Debian's tooling (`make
>>> bindeb-pkg`).
>>
>> That's interesting.  I guess the timestamps in your unpacked source
>> directory were probably not zeroed, so I guess that timestamps are not
>> the issue here.
>
> This is not specific to guix / guixsd building the kernel.
>
> I think that's intentional, the kbuild system has been modified to always
> regenerate the files from their sources.
>
> See lkml discussion:
> https://lkml.org/lkml/2017/8/19/49
>
> See commit:
> 29c833061c1d8c2d1d23a62e7061561eadd76cdb
>
> Merged in :
> 562f36ed28e6faa4245ea2ca1392d90ab98ebbe8

Thank you for getting to the bottom of this, Vincent!

Note that although the original proposed patch would have removed _all_
*.c_shipped files in the tree, the merged patch removed only the ones
for scripts/kconfig/zconf.{l,y}.  The following generated files still
remain in the upstream 4.16 tarball:

  mhw@jojen ~$ find linux-4.16 | egrep '\.tab\.'
  linux-4.16/scripts/dtc/dtc-parser.tab.c_shipped
  linux-4.16/scripts/dtc/dtc-parser.tab.h_shipped
  linux-4.16/scripts/genksyms/parse.tab.c_shipped
  linux-4.16/scripts/genksyms/parse.tab.h_shipped

So, we still have a decision to make: whether to delete these generated
files (possibly in a snippet) to avoid using pre-generated non-source
files in our build.  I would be in favor of it.

I'd like to hear opinions on this.

       Mark