Re: [PATCH v2] codafs: Fix build using bare-metal toolchain

From: Sam Protsenko <semen.protsenko@linaro.org>
To: Jan Harkes <jaharkes@cs.cmu.edu>
Cc: hch@lst.de, Andrew Morton <akpm@linux-foundation.org>,
	kernel-janitors@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-scsi@vger.kernel.org, Praneeth Bajjuri <praneeth@ti.com>,
	Ruslan Bilovol <ruslan.bilovol@gmail.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>
Subject: Re: [PATCH v2] codafs: Fix build using bare-metal toolchain
Date: Wed, 21 Nov 2018 21:39:03 +0200	[thread overview]
Message-ID: <CAKaJLVvHZwJHu_uZuUDtCZrD7EKY-5xpGhNZN7cQ2M4Bz9osDA@mail.gmail.com> (raw)
In-Reply-To: <CAKaJLVs4MUws7sPPdDk7hnjZ+Z1V0V6bGt=eWn=gsF_B+yULeg@mail.gmail.com>

+ Jan Harkes back to "To:" list, slipped away somehow...

On Wed, Nov 21, 2018 at 9:36 PM Sam Protsenko
<semen.protsenko@linaro.org> wrote:
>
> On Wed, Nov 21, 2018 at 8:10 PM Jan Harkes <jaharkes@cs.cmu.edu> wrote:
> >
> > On Wed, Nov 21, 2018 at 06:41:13PM +0200, Andy Shevchenko wrote:
> > > I'm not sure how you managed to miss people in this list (perhaps by
> > > default you have suppress all Cc in your Git configuration), but I
> > > guess we may gently ask Christoph to apply this in case Jan will not
> > > appear.
> >
> > You have got to give me a little more than 10 minutes to respond before
> > assuming that I would not appear... I don't think I've ignored any
> > previous emails on this subject and the only issues has been some people
> > not receiving my responses for unknown reasons (agressive spam filter?).
> >
> > I have no problem with this patch, have it sitting with some other
> > non-urgent patches and in case it doesn't appear upstream it should
> > piggyback with whatever I have to send.
> >
>
> Thanks, Jan, really appreciate it. We need this patch to fix our tests
> with allmodconfig configuration (in Linaro CI loops).
>
> > I still don't know why the bare-metal toolchain couldn't just add a
> > -D__linux__.  I understand that this define is expected to be always
> > present while compiling kernel headers so that there is no good reason
> > to even bother testing for it, which is why I have no issue with the
> > patch. But it seems it would make your life a lot easier if you had it
> > defined.
> >
>
> As I understand it, from toolchain's point of view, if __linux__ is
> defined then it means that the program is being built *for* Linux
> (i.e. we can use Linux specific features, ABI, like syscalls).
> Checking this definition can make sense in uapi headers, but in kernel
> code we shouldn't use it (as kernel is baremetal program and not
> compiled for some OS). I presume that's why __linux__ is not defined
> in bare-metal toolchains (as those don't provide Linux specific
> features, libc, etc).
>
> > Jan
> >