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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 26 Jul 2022 08:13:37 +0200
Message-ID: <CAHp75VdJ=FVy6TXTEOci0b2kMrG3z8scDwWTjx8M6+8Y35iSXA@mail.gmail.com>
Subject: Re: [PATCH 1/2] powerpc: drop dependency on <asm/machdep.h> in archrandom.h
To:     Yury Norov <yury.norov@gmail.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        "open list:LINUX FOR POWERPC PA SEMI PWRFICIENT" 
        <linuxppc-dev@lists.ozlabs.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>
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On Tue, Jul 26, 2022 at 1:35 AM Yury Norov <yury.norov@gmail.com> wrote:
> On Mon, Jul 25, 2022 at 11:39:39PM +0200, Andy Shevchenko wrote:
> > On Mon, Jul 25, 2022 at 6:19 PM Yury Norov <yury.norov@gmail.com> wrote:
> > > On Mon, Jul 25, 2022 at 09:28:12AM +0200, Andy Shevchenko wrote:
> > > > On Sun, Jul 24, 2022 at 12:19 AM Yury Norov <yury.norov@gmail.com> wrote:

...

> > > > >  EXPORT_SYMBOL_GPL(pm_power_off);
> > > >
> > > > ^^^ (Note this and read below)
> > > >
> > > > ...
> > > >
> > > > > +EXPORT_SYMBOL(arch_get_random_seed_long);
> > > >
> > > > It can't be like this. Brief browsing of the callees shows that.
> > >
> > > Is my understanding correct that you're suggesting to make it GPL?
> > >
> > > ppc_md is exported with EXPORT_SYMBOL(), and the function is in header,
> > > so it's available for non-GPL code now. I don't want to change it.
> >
> > The symbols your function calls are GPL. As far as I understand (not a
> > lawyer!) it logically one may not call GPL and pretend to be non-GPL.
>
> Can you explain what you mean in details?
>
> The function is:
>         static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
>         {
>                if (ppc_md.get_random_seed)
>                        return ppc_md.get_random_seed(v);
>
>                return false;
>         }
>
> ppc_md is non-GPL:
>  77 /* The main machine-dep calls structure
>  78  */
>  79 struct machdep_calls ppc_md;
>  80 EXPORT_SYMBOL(ppc_md);

What a mess...

> And get_random_seed is initialized in in arch/powerpc/platforms/powernv/rng.c
> with different functions that are static and not exported at all.
>
> I don't understand where arch_get_random_seed_long calls GPL...

The ->get_random_seed() (aka "callees" in my previous mail) are all
GPL (maybe I missed one out of five which is non-GPL, but then it's
even more of a mess).

-- 
With Best Regards,
Andy Shevchenko