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:   Mon, 27 Mar 2023 15:04:15 +0100
From:   Conor Dooley <conor.dooley@microchip.com>
To:     Pierre Gondois <pierre.gondois@arm.com>
CC:     <linux-kernel@vger.kernel.org>, Radu Rendec <rrendec@redhat.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Akihiko Odaki <akihiko.odaki@daynix.com>,
        Palmer Dabbelt <palmer@rivosinc.com>,
        Gavin Shan <gshan@redhat.com>,
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/3] cacheinfo: Check sib_leaf in
 cache_leaves_are_shared()
Message-ID: <267f5e37-2cfd-4833-a74c-bfc56fe3671c@spud>
References: <20230327115953.788244-1-pierre.gondois@arm.com>
 <20230327115953.788244-2-pierre.gondois@arm.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="b0IIy94NXv1sQNWD"
Content-Disposition: inline
In-Reply-To: <20230327115953.788244-2-pierre.gondois@arm.com>
Precedence: bulk

--b0IIy94NXv1sQNWD
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Mon, Mar 27, 2023 at 01:59:49PM +0200, Pierre Gondois wrote:
> If 'this_leaf' is a L2 cache (or higher) and 'sib_leaf' is a L1 cache,
> the caches are detected as shared.
> Indeed, cache_leaves_are_shared() only checks the cache level of
> 'this_leaf' when 'sib_leaf''s cache level should also be checked.

nit: this commit message reads quite weirdly as there's a missing "do
foo" statement, followed by "also do bar".

>=20
> Also update the comment: the function is called when populating
> 'shared_cpu_map'.
>=20
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> ---
>  drivers/base/cacheinfo.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>=20
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index f6573c335f4c..4ca117574af1 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -38,11 +38,10 @@ static inline bool cache_leaves_are_shared(struct cac=
heinfo *this_leaf,
>  {
>  	/*
>  	 * For non DT/ACPI systems, assume unique level 1 caches,
> -	 * system-wide shared caches for all other levels. This will be used
> -	 * only if arch specific code has not populated shared_cpu_map
> +	 * system-wide shared caches for all other levels.
>  	 */
>  	if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))
> -		return !(this_leaf->level =3D=3D 1);
> +		return (this_leaf->level !=3D 1) || (sib_leaf->level !=3D 1);

So this is
Fixes: f16d1becf96f ("cacheinfo: Use cache identifiers to check if the cach=
es are shared if available")
then?

Cheers,
Conor.

> =20
>  	if ((sib_leaf->attributes & CACHE_ID) &&
>  	    (this_leaf->attributes & CACHE_ID))
> --=20
> 2.25.1
>=20
>=20

--b0IIy94NXv1sQNWD
Content-Type: application/pgp-signature; name="signature.asc"

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

iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZCGiXwAKCRB4tDGHoIJi
0t/EAQDXe23dRWv4M0HrXDodpHLa9o3/okRxwNua4LZCvcOoRQD9EcPHWFt02qKp
clMayBcdu3gCTiSmliJnj8sLQ9YpLgI=
=G6Qk
-----END PGP SIGNATURE-----

--b0IIy94NXv1sQNWD--