From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B1397171AC for ; Tue, 8 Aug 2023 19:06:24 +0000 (UTC) Received: from pandora.armlinux.org.uk (unknown [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4A4D80BC for ; Tue, 8 Aug 2023 11:50:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=UqnbK5m2JzNJDclIbM5JoHiwPy/F8PxSzOtvdAUb6F8=; b=ZnUnSBjcF1FA7YbBtgxCKWSTJv VixK5jutjD0b+EpUUotx1OKkMLIUzbWaROJDOeHNQMaYJvqJa8L3yMI0lZ6/iU0XEUkWZmoZWDitR Hrh5Ztp6m1yWU+io4wCIn3tvM+ZPsJrNu6JuONby7s49f20+SSRoQ+TUNAosVK1hJldQDIOekcp3X w7d7fxgHRp3VBsFyrS16Oct1zHvn9eFV1npBdKVHGAXtsvBu1GVA2gBSDjookVGTHXCiYBXZ/0a42 x6LJo6dNwSvvBTPkXiXmdWEtij7f3k2UrkPUyICu7dvkvifQxaqRzpzQ2RkBkUNFGnUUiDBDCDIcD 4zu3UT+A==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:54020) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qTMHP-0007qC-2v; Tue, 08 Aug 2023 13:57:43 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qTMHP-000879-Fz; Tue, 08 Aug 2023 13:57:43 +0100 Date: Tue, 8 Aug 2023 13:57:43 +0100 From: "Russell King (Oracle)" To: Vladimir Oltean Cc: Andrew Lunn , Heiner Kallweit , Florian Fainelli , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org Subject: Re: [PATCH net-next] net: dsa: mark parsed interface mode for legacy switch drivers Message-ID: References: <20230808120652.fehnyzporzychfct@skbuf> <20230808120652.fehnyzporzychfct@skbuf> <20230808123901.3jrqsx7pe357hwkh@skbuf> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230808123901.3jrqsx7pe357hwkh@skbuf> Sender: Russell King (Oracle) X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED,RDNS_NONE, SPF_HELO_NONE,SPF_NONE,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Tue, Aug 08, 2023 at 03:39:01PM +0300, Vladimir Oltean wrote: > On Tue, Aug 08, 2023 at 01:30:16PM +0100, Russell King (Oracle) wrote: > > On Tue, Aug 08, 2023 at 03:06:52PM +0300, Vladimir Oltean wrote: > > > Hi Russell, > > > > > > On Tue, Aug 08, 2023 at 12:12:16PM +0100, Russell King (Oracle) wrote: > > > > If we successfully parsed an interface mode with a legacy switch > > > > driver, populate that mode into phylink's supported interfaces rather > > > > than defaulting to the internal and gmii interfaces. > > > > > > > > This hasn't caused an issue so far, because when the interface doesn't > > > > match a supported one, phylink_validate() doesn't clear the supported > > > > mask, but instead returns -EINVAL. phylink_parse_fixedlink() doesn't > > > > check this return value, and merely relies on the supported ethtool > > > > link modes mask being cleared. Therefore, the fixed link settings end > > > > up being allowed despite validation failing. > > > > > > > > Before this causes a problem, arrange for DSA to more accurately > > > > populate phylink's supported interfaces mask so validation can > > > > correctly succeed. > > > > > > > > Signed-off-by: Russell King (Oracle) > > > > --- > > > > > > How did you notice this? Is there any unconverted DSA switch which has a > > > phy-mode which isn't PHY_INTERFACE_MODE_INTERNAL or PHY_INTERFACE_MODE_NA? > > > > By looking at some of the legacy drivers, finding their DT compatibles > > and then grepping the dts files. > > > > For example, vitesse,vsc73* compatibles show up here: > > > > arch/arm/boot/dts/gemini/gemini-sq201.dts > > > > and generally, the ports are listed as: > > > > port@0 { > > reg = <0>; > > label = "lan1"; > > }; > > > > except for the CPU port which has: > > > > vsc: port@6 { > > reg = <6>; > > label = "cpu"; > > ethernet = <&gmac1>; > > phy-mode = "rgmii"; > > fixed-link { > > speed = <1000>; > > full-duplex; > > pause; > > }; > > }; > > > > Since the vitesse DSA driver doesn't populate .phylink_get_caps, it > > would have been failing as you discovered with dsa_loop before the > > previous patch. > > > > Fixing this by setting GMII and INTERNAL worked around the additional > > check that was using that failure and will work fine for the LAN > > ports as listed above. > > > > However, that CPU port uses "rgmii" which doesn't match the GMII and > > INTERNAL bits in the supported mask. > > > > Since phylink_validate() does this: > > > > const unsigned long *interfaces = pl->config->supported_interfaces; > > > > if (state->interface == PHY_INTERFACE_MODE_NA) > > > > ... it isn't, so we move on... > > > > if (!test_bit(state->interface, interfaces)) > > return -EINVAL; > > > > This will trigger and phylink_validate() in phylink_parse_fixedlink() > > will return -EINVAL without touching the passed supported mask. > > > > phylink_parse_fixedlink() does: > > > > bitmap_fill(pl->supported, __ETHTOOL_LINK_MODE_MASK_NBITS); > > linkmode_copy(pl->link_config.advertising, pl->supported); > > phylink_validate(pl, MLO_AN_FIXED, pl->supported, &pl->link_config); > > > > and then we have: > > > > s = phy_lookup_setting(pl->link_config.speed, pl->link_config.duplex, > > pl->supported, true); > > > > ... > > if (s) { > > ... success ... > > } else { > > phylink_warn(pl, "fixed link %s duplex %dMbps not recognised\n", > > pl->link_config.duplex == DUPLEX_FULL ? "full" : "half", > > pl->link_config.speed); > > } > > > > So, since phylink_validate() with an apparently unsupported interface > > exits early with -EINVAL, pl->supported ends up with all bits set, > > and phy_lookup_setting() allows any speed. > > > > If someone decides to fix that phylink_validate() error checking, then > > this will then lead to a warning/failure. > > > > I want to avoid that happening - fixing that latent bug before it > > becomes a problem. > > Aha, ok, thanks for explaining. Thanks for the r-b. At risk of delaying this patch through further discussion... so I'll say now that we're going off into discussions about future changes. I believe all DSA drivers that provide .phylink_get_caps fill in the .mac_capabilities member, which leaves just a few drivers that do not, which are: $ git grep -l dsa_switch_ops.*= drivers/net/dsa/ | xargs grep -L '\.phylink_get_caps' drivers/net/dsa/dsa_loop.c drivers/net/dsa/mv88e6060.c drivers/net/dsa/realtek/rtl8366rb.c drivers/net/dsa/vitesse-vsc73xx-core.c I've floated the idea to Linus W and Arinc about setting .mac_capabilities in the non-phylink_get_caps path as well, suggesting: MAC_1000 | MAC_100 | MAC_10 | MAC_SYM_PAUSE | MAC_ASYM_PAUSE support more than 1G speeds. I think the only exception to that may be dsa_loop, but as I think that makes use of the old fixed-link software emulated PHYs, I believe that would be limited to max. 1G as well. If we did set .mac_capabilities, then dsa_port_phylink_validate() would always call phylink_generic_validate() for all DSA drivers, and at that point, we don't need dsa_port_phylink_validate() anymore as it provides nothing that isn't already done inside phylink. Once dsa_port_phylink_validate() is gone, then I believe there are no drivers populating the .validate method in phylink_mac_ops, which then means there is the possibility to remove that method. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!