On Wed, 2019-09-11 at 21:17 +0900, Masahiro Yamada wrote: > Hi Ben, > > > Thanks for this. > Please let me add some comments. > > > On Wed, Sep 11, 2019 at 8:54 PM Ben Hutchings <[email protected]> wrote: [...] > > +Absolute filenames > > +------------------ > > + > > +When the kernel is built out-of-tree, debug information may include > > +absolute filenames for the source files. The ``__FILE__`` macro may > > +also expand to an absolute filename. This must be overridden by > > +including `prefix-map options`_ in the `KCFLAGS`_ variable. > > Do you mean -fmacro-prefix-map ?
No, I mean -ffile-prefix-map or the older -fdebug-prefix-map.
> If so, it is already taken care of by the top Makefile.
> If you use GCC 8 or newer, it is automatically added to
> KBUILD_CFLAGS.
Ah, that's helpful. So, I suppose I should just mention
-fdebug-prefix-map here and warn that __FILE__ will still be a proble
if using older compiler versions.
> > +Generated files in source packages
> > +----------------------------------
> > +
> > +The build processes for some programs under the ``tools/``
> > +subdirectory do not completely support out-of-tree builds. This may
> > +cause source packages built using e.g. ``make rpm-pkg`` to include
> > +generated files and so be unreproducible. It may be necessary to
> > +clean the source tree completely (``make mrproper`` or
> > +``git clean -d -f -x``) before building a source package.
>
> Currently, the source package building does not support
> out-of-tree build anyway.
Yes, I realise that.
> 'make O=foo rpm-pkg' fails with an error message.
>
> Building in a pristine source will solve the issue.
[...]
The issue I'm thinking about is that an out-of-tree build, prior to the
package build, *should* leave the source pristine and sometimes does
not.
For Debian's official kernel packages, we build a binary package of the
upstream source, and at some times this has unexpectedly included some
generated files. I believe a similar issue would affect the upstream
package scripts.
Ben.
--
Ben Hutchings
The obvious mathematical breakthrough [to break modern encryption]
would be development of an easy way to factor large prime numbers.
- Bill Gates
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