PPC_FPU, ALTIVEC: enable_kernel_fp, put_vr, get_vr

From: Randy Dunlap <rdunlap@infradead.org>
To: PowerPC <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: PPC_FPU, ALTIVEC: enable_kernel_fp, put_vr, get_vr
Date: Sat, 17 Apr 2021 13:17:59 -0700	[thread overview]
Message-ID: <7107fcae-5c7a-ac94-8d89-326f2cd4cd33@infradead.org> (raw)

Hi,

kernel test robot reports:

>> drivers/cpufreq/pmac32-cpufreq.c:262:2: error: implicit declaration of function 'enable_kernel_fp' [-Werror,-Wimplicit-function-declaration]
           enable_kernel_fp();
           ^

when
# CONFIG_PPC_FPU is not set
CONFIG_ALTIVEC=y

I see at least one other place that does not handle that
combination well, here:

../arch/powerpc/lib/sstep.c: In function 'do_vec_load':
../arch/powerpc/lib/sstep.c:637:3: error: implicit declaration of function 'put_vr' [-Werror=implicit-function-declaration]
  637 |   put_vr(rn, &u.v);
      |   ^~~~~~
../arch/powerpc/lib/sstep.c: In function 'do_vec_store':
../arch/powerpc/lib/sstep.c:660:3: error: implicit declaration of function 'get_vr'; did you mean 'get_oc'? [-Werror=implicit-function-declaration]
  660 |   get_vr(rn, &u.v);
      |   ^~~~~~

Should the code + Kconfigs/Makefiles handle that kind of
kernel config or should ALTIVEC always mean PPC_FPU as well?

I have patches to fix the build errors with the config as
reported but I don't know if that's the right thing to do...

thanks.
-- 
~Randy