Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 21 Sep 2022 08:20:06 +1000
From:   Stephen Rothwell <sfr@canb.auug.org.au>
To:     Yury Norov <yury.norov@gmail.com>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Alan Modra <amodra@au1.ibm.com>, Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH] powerpc/64: don't refer nr_cpu_ids in asm code when
 it's undefined
Message-ID: <20220921082006.2235b7d2@canb.auug.org.au>
In-Reply-To: <20220920152935.1569605-1-yury.norov@gmail.com>
References: <20220920152935.1569605-1-yury.norov@gmail.com>
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="Sig_/1cQ.H=BGhInvidNYFoNGEGJ";
 protocol="application/pgp-signature"; micalg=pgp-sha256
Precedence: bulk

--Sig_/1cQ.H=BGhInvidNYFoNGEGJ
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable

Hi Yury,

On Tue, 20 Sep 2022 08:29:35 -0700 Yury Norov <yury.norov@gmail.com> wrote:
>

> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index cf2c08902c05..7cb97881635e 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -400,7 +400,11 @@ generic_secondary_common_init:
>  #else
>  	LOAD_REG_ADDR(r8, paca_ptrs)	/* Load paca_ptrs pointe	 */
>  	ld	r8,0(r8)		/* Get base vaddr of array	 */
> +#if (NR_CPUS =3D=3D 1) || defined(CONFIG_FORCE_NR_CPUS)
> +	LOAD_REG_IMMEDIATE(r7, NR_CPUS)
> +#else
>  	LOAD_REG_ADDR(r7, nr_cpu_ids)	/* Load nr_cpu_ids address       */
> +#endif
>  	lwz	r7,0(r7)		/* also the max paca allocated 	 */
>  	li	r5,0			/* logical cpu id                */
>  1:
> --=20
> 2.34.1
>=20

I don't know PPC assembly very well, but should the #endif be one line
lower so that the constant is not dereferenced in the non-#else case?=20

--=20
Cheers,
Stephen Rothwell

--Sig_/1cQ.H=BGhInvidNYFoNGEGJ
Content-Type: application/pgp-signature
Content-Description: OpenPGP digital signature

-----BEGIN PGP SIGNATURE-----

iQEzBAEBCAAdFiEENIC96giZ81tWdLgKAVBC80lX0GwFAmMqPJYACgkQAVBC80lX
0Gwr3Af/UChWHeWYob9IqQw/8bJH2CgzIK17TDOUa16U/RWb1MPcCNItY3652WX6
0XQA4oqVJkODYSwsU25iTYv81MXo3HxjMsXattrhnUM0mfwe/UeM00OK9Nao7jIt
FhGAtWldTdBt7Gju45zxNtCsJkK+pYidhFgXF/5w2VZGie8oU3N5J1Pd53gOtNW4
Cyp/YVNaCKYmk6A4P4nx6lqieFMn+3KSqzcYy3U6foEpzsa6rmyDQQG3Ex251Ct0
WW6BOzh3aKM/eZLoClSCQcrfKw+Q28loIBrQReL9krg3btZTrAyWb++bVOFeTXxA
HwBhQceRlM/gkVoHBrFEoQzuN8eraA==
=MWuQ
-----END PGP SIGNATURE-----

--Sig_/1cQ.H=BGhInvidNYFoNGEGJ--