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From:   "Oliver O'Halloran" <oohall@gmail.com>
Date:   Mon, 15 Jul 2019 17:02:36 +1000
Message-ID: <CAOSf1CGB0k6qTN_uFtSoNBTs5Vt89n0_vLoRFLytq8OSfy7w6A@mail.gmail.com>
Subject: Re: [PATCH 2/4] powerpc/32: activate ARCH_HAS_PMEM_API and ARCH_HAS_UACCESS_FLUSHCACHE
To:     Michael Ellerman <mpe@ellerman.id.au>
Cc:     Christophe Leroy <christophe.leroy@c-s.fr>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Segher Boessenkool <segher@kernel.crashing.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
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On Mon, Jul 15, 2019 at 4:49 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
>
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
> > PPC32 also have flush_dcache_range() so it can also support
> > ARCH_HAS_PMEM_API and ARCH_HAS_UACCESS_FLUSHCACHE without changes.
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> > ---
> >  arch/powerpc/Kconfig | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index d7996cfaceca..cf6e30f637be 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -127,13 +127,13 @@ config PPC
> >       select ARCH_HAS_KCOV
> >       select ARCH_HAS_MMIOWB                  if PPC64
> >       select ARCH_HAS_PHYS_TO_DMA
> > -     select ARCH_HAS_PMEM_API                if PPC64
> > +     select ARCH_HAS_PMEM_API
> >       select ARCH_HAS_PTE_SPECIAL
> >       select ARCH_HAS_MEMBARRIER_CALLBACKS
> >       select ARCH_HAS_SCALED_CPUTIME          if VIRT_CPU_ACCOUNTING_NATIVE && PPC64
> >       select ARCH_HAS_STRICT_KERNEL_RWX       if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION)
> >       select ARCH_HAS_TICK_BROADCAST          if GENERIC_CLOCKEVENTS_BROADCAST
> > -     select ARCH_HAS_UACCESS_FLUSHCACHE      if PPC64
> > +     select ARCH_HAS_UACCESS_FLUSHCACHE
> >       select ARCH_HAS_UBSAN_SANITIZE_ALL
> >       select ARCH_HAS_ZONE_DEVICE             if PPC_BOOK3S_64
> >       select ARCH_HAVE_NMI_SAFE_CMPXCHG
>
> This didn't build for me, probably due to something that's changed in
> the long period between you posting it and me applying it?
>
> corenet32_smp_defconfig:
>
>   powerpc64-unknown-linux-gnu-ld: lib/iov_iter.o: in function `_copy_from_iter_flushcache':
>   powerpc64-unknown-linux-gnu-ld: /scratch/michael/build/maint/build~/../lib/iov_iter.c:825: undefined reference to `memcpy_page_flushcache'
>   powerpc64-unknown-linux-gnu-ld: /scratch/michael/build/maint/build~/../lib/iov_iter.c:825: undefined reference to `memcpy_flushcache'
>   powerpc64-unknown-linux-gnu-ld: /scratch/michael/build/maint/build~/../lib/iov_iter.c:825: undefined reference to `__copy_from_user_flushcache'
>   powerpc64-unknown-linux-gnu-ld: /scratch/michael/build/maint/build~/../lib/iov_iter.c:825: undefined reference to `memcpy_flushcache'

I think lib/pmem.c just needs to be moved out of obj64-y.

>
> cheers