From: "Michal Suchánek" <msuchanek@suse.de>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
"Nicolas Schier" <nicolas@fjasle.eu>,
linux-modules@vger.kernel.org, "Takashi Iwai" <tiwai@suse.com>,
"Lucas De Marchi" <lucas.de.marchi@gmail.com>,
"Michal Koutný" <mkoutny@suse.com>,
"Jiri Slaby" <jslaby@suse.com>,
"Jan Engelhardt" <jengelh@inai.de>,
"Nathan Chancellor" <nathan@kernel.org>,
"Nick Desaulniers" <ndesaulniers@google.com>
Subject: Re: [PATCH rebased] kbuild: rpm-pkg: Fix build with non-default MODLIB
Date: Tue, 10 Oct 2023 12:15:52 +0200 [thread overview]
Message-ID: <20231010101552.GW6241@kitsune.suse.cz> (raw)
In-Reply-To: <CAK7LNAQQMFUt4R1m_U8kBY5=BvxD_dMuE4MD4kpd48WK1E+AGA@mail.gmail.com>
On Tue, Oct 10, 2023 at 12:14:01AM +0900, Masahiro Yamada wrote:
> On Mon, Oct 9, 2023 at 11:07 PM Michal Suchánek <msuchanek@suse.de> wrote:
> >
> > On Mon, Oct 09, 2023 at 09:34:10PM +0900, Masahiro Yamada wrote:
> > > On Mon, Oct 9, 2023 at 5:52 PM Michal Suchánek <msuchanek@suse.de> wrote:
> > > >
> > > > Hello,
> > > >
> > > > On Mon, Oct 09, 2023 at 05:31:02PM +0900, Masahiro Yamada wrote:
> > > > > On Fri, Oct 6, 2023 at 12:49 AM Michal Suchanek <msuchanek@suse.de> wrote:
> > > > > >
> > > > > > The default MODLIB value is composed of two variables and the hardcoded
> > > > > > string '/lib/modules/'.
> > > > > >
> > > > > > MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
> > > > > >
> > > > > > Defining this middle part as a variable was rejected on the basis that
> > > > > > users can pass the whole MODLIB to make, such as
> > > > >
> > > > >
> > > > > In other words, do you want to say
> > > > >
> > > > > "If defining this middle part as a variable had been accepted,
> > > > > this patch would have been unneeded." ?
> > > >
> > > > If it were accepted I would not have to guess what the middle part is,
> > > > and could use the variable that unambiguosly defines it instead.
> > >
> > >
> > > How?
> > >
> > > scripts/package/kernel.spec hardcodes 'lib/modules'
> > > in a couple of places.
> > >
> > > I am asking how to derive the module path.
> >
> > Not sure what you are asking here. The path is hardcoded, everywhere.
> >
> > The current Makefile has
> >
> > MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
> >
> > and there is no reliable way to learn what the middle part was after the
> > fact - $(INSTALL_MOD_PATH) can be non-empty.
> >
> > The rejected patch was changing this to a variable, and also default to
> > adjusting the content to what kmod exports in pkgconfig after applying a
> > proposed patch to make this hardcoded part configurable:
> >
> > export KERNEL_MODULE_DIRECTORY := $(shell pkg-config --print-variables kmod 2>/dev/null | grep '^module_directory$$' >/dev/null && pkg-config --variable=module_directory kmod || echo /lib/modules)
> >
> > MODLIB = $(INSTALL_MOD_PATH)$(KERNEL_MODULE_DIRECTORY)/$(KERNELRELEASE)
> >
> > It would be completely posible to only define the middle part as a
> > variable that could then be used in rpm-pkg:
> >
> > export KERNEL_MODULE_DIRECTORY := /lib/modules
> >
> > MODLIB = $(INSTALL_MOD_PATH)$(KERNEL_MODULE_DIRECTORY)/$(KERNELRELEASE)
> >
> > Thanks
> >
> > Michal
> >
> >
>
>
> Let me add more context to my question.
>
>
> I am interested in the timing when
> 'pkg-config --print-variables kmod | grep module_directory'
> is executed.
>
>
>
> 1. Build a SRPM on machine A
>
> 2. Copy the SRPM from machine A to machine B
>
> 3. Run rpmbuild on machine B to build the SRPM into a RPM
>
> 4. Copy the RPM from machine B to machine C
>
> 5. Install the RPM to machine C
As far as I am aware the typical use case is two step:
1. run make rpm-pkg on machine A
2. install the binary rpm on machine C that might not have build tools
or powerful enough CPU
While it's theoretically possible to use the srpm to rebuild the binary
rpm independently of the kernel git tree I am not aware of people
commonly doing this.
If rebuilding the source rpm on a different machine from where the git
tree is located, and possibly on a different distribution is desirable
then the detection of the KERNEL_MODULE_DIRECTORY should be added in the
rpm spec file as well.
> Of course, we are most interested in the module path
> of machine C, but it is difficult/impossible to
> guess it at the time of building.
>
> We can assume machine B == machine C.
>
> We are the second most interested in the module
> path on machine B.
>
> The module path of machine A is not important.
>
> So, I am asking where you would inject
> 'pkg-config --print-variables kmod | grep module_directory'.
I don't. I don't think there will be a separate machine B.
And I can't really either - so far any attempt at adding support for
this has been rejected.
Technically the KERNEL_MODULE_DIRECTORY could be set in two steps - one
giving the script to run, and one running it, and then it could be run
independently in the SRPM as well.
Thanks
Michal
next prev parent reply other threads:[~2023-10-10 10:16 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 15:07 [PATCH rebased] kbuild: rpm-pkg: Fix build with non-default MODLIB Michal Suchanek
2023-10-06 16:58 ` Nathan Chancellor
2023-10-09 8:31 ` Masahiro Yamada
2023-10-09 8:52 ` Michal Suchánek
2023-10-09 12:34 ` Masahiro Yamada
2023-10-09 14:07 ` Michal Suchánek
2023-10-09 15:14 ` Masahiro Yamada
2023-10-09 16:01 ` Jan Engelhardt
2023-10-10 10:15 ` Michal Suchánek [this message]
2023-10-17 10:15 ` Masahiro Yamada
2023-10-17 10:44 ` Michal Suchánek
2023-10-17 12:05 ` Masahiro Yamada
2023-10-17 12:27 ` Michal Suchánek
2023-10-17 14:46 ` Masahiro Yamada
2023-10-17 15:10 ` Michal Suchánek
2023-10-18 1:12 ` Jan Engelhardt
2023-11-10 17:44 ` Michal Suchánek
2023-11-10 17:57 ` Jan Engelhardt
2023-12-06 19:47 ` [PATCH v6 1/2] depmod: Handle installing modules under a different directory Michal Suchanek
2023-12-10 18:43 ` Masahiro Yamada
2023-12-10 18:51 ` Woody Suwalski
2023-12-10 21:07 ` Michal Suchánek
2023-12-11 4:29 ` Masahiro Yamada
2023-12-12 13:03 ` Michal Suchánek
2023-12-18 14:05 ` Masahiro Yamada
2023-12-06 19:47 ` [PATCH v6 2/2] kbuild: rpm-pkg: Fix build with non-default MODLIB Michal Suchanek
2023-12-10 18:44 ` Masahiro Yamada
2023-12-10 21:08 ` Michal Suchánek
2023-12-11 4:33 ` Masahiro Yamada
2023-12-12 13:12 ` Michal Suchánek
2023-12-18 14:16 ` Masahiro Yamada
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