[RFC PATCH 0/8] Module and ARM Module updates and fixes

Masahiro Yamada masahiroy at kernel.org
Mon Jun 22 13:52:29 EDT 2020


On Thu, Jun 18, 2020 at 10:10 PM Sascha Hauer <s.hauer at pengutronix.de> wrote:
>
> On Wed, Jun 17, 2020 at 09:54:55PM -0400, David Dgien wrote:
> > Hi Sascha,
> >
> > On Wed, Jun 17, 2020 at 03:45:38PM +0200, Sascha Hauer wrote:
> > > Hi David,
> > >
> > > On Tue, Jun 16, 2020 at 11:43:56PM -0400, David Dgien wrote:
> > > > This series fixes various bugs and bit-rot issues with the module
> > > > loading code. It also ports a couple of modules features from the Linux
> > > > kernel: arch specific section fixups, and module PLTs for ARM modules,
> > > > to contain veneers for 'bl' instructions.
> > > >
> > > > There are two things in this series I'm looking for feedback on:
> > > > Linux implements module_frob_arch_sections as a weak symbol for the
> > > > default case. I didn't see any other "weak" functions in barebox, so I
> > > > wasn't sure if using that was acceptable.
> > >
> > > For things that are really mutually exclusive like different
> > > implementations on different architectures I think weak functions are
> > > ok. They are not ok as a quick hack for hooking something into something
> > > though.
> > >
> >
> > I'll make the change to a weak function here in a v2, since it will be a
> > bit cleaner.
> >
> > > > Since the Kconfig
> > > > HAVE_MOD_ARCH_SPECIFIC already exists as part of the change, I just used
> > > > that to define a static inline default implementation, but using a weak
> > > > function would make that slightly cleaner.
> > > >
> > > > And in the patch that added the init macros to module.h, I wasn't sure
> > > > if it would be okay to pollute init.h with the #ifndef MODULE
> > > > directives, so instead I just #undef'd all of the initcalls before
> > > > redefining them in module.h.  If it's okay to add the #ifndef MODULE to
> > > > init.h, that would be significantly cleaner than the current
> > > > implementation.
> > >
> > > I think it's ok to add #ifndef MODULE to init.h
> >
> > Same as above.
> >
> > >
> > > Anyway, what do you need modules for? Do you have a good reason or is it
> > > just for the fun of it?
> >
> > I'm working on a project that wants to use barebox as a very lightweight
> > OS replacement.
> > We're using modules to allow loading user code with
> > controlled access to hw interfaces via exported driver symbols.
>
> So barebOS again, we had that as an April fools joke once :)
>
> You'll probably miss things like interrupts, paging and multitasking
> very soon.
>
> Sascha


Does it make sense to choose y/m
depending on how often they are used?

- commands and drivers that are used quite often   ->  built-in
- commands and drivers that are sometimes used     ->  modules



-- 
Best Regards
Masahiro Yamada



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