From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B5B9C433EF for ; Tue, 24 May 2022 17:03:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239688AbiEXRDX (ORCPT ); Tue, 24 May 2022 13:03:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236052AbiEXRDW (ORCPT ); Tue, 24 May 2022 13:03:22 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C7EE77F12 for ; Tue, 24 May 2022 10:03:20 -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=Lz0otVyUtFXeohL1/7oRGSZAWt7yYFABxglmdvZ5jn4=; b=r5wTJ1eLnvr5r4Aw8+N5/aiNA9 NyFwjqE4/VqIgtknbWV2et8W4ov0aoy7oC0ateRWbaJpbDSLuD451tZ+sl/x1alvcpniqdHZr/0/j hCvgpo0yvJNVnVJGowr94WDRqpOWj/1TFpCIgNhA6F7EZkVf6Cq5zzLCUUYV5OrBtV3Hc4ysvVXw+ wgUw04ucuCysx92N9fUj8Rf4OSuwGMspjsGHxB5OmMMMDs+3bQHkxUclUFFFgVSz2bBc6g5KleXwx wLo3ywMoF0A127DYjWiI9DVrBAy1P6UJrTApVOXZVInhjj7k5g1zUMwMGsscRU0duSJ8miyEz8ybi kBT4zW1w==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:60824) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ntXw6-0003kD-5w; Tue, 24 May 2022 18:03:10 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1ntXw4-00038J-Fu; Tue, 24 May 2022 18:03:08 +0100 Date: Tue, 24 May 2022 18:03:08 +0100 From: "Russell King (Oracle)" To: Jon Hunter Cc: Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, arnd@arndb.de, linus.walleij@linaro.org, "linux-tegra@vger.kernel.org" Subject: Re: [PATCH 1/6] ARM: spectre-bhb: enable for Cortex-A15 Message-ID: References: <20220328134714.205342-1-ardb@kernel.org> <20220328134714.205342-2-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On Tue, May 24, 2022 at 03:50:17PM +0100, Jon Hunter wrote: > Hi Ard, > > On 28/03/2022 14:47, Ard Biesheuvel wrote: > > The Spectre-BHB mitigations were inadvertently left disabled for > > Cortex-A15, due to the fact that cpu_v7_bugs_init() is not called in > > that case. So fix that. > > > > Signed-off-by: Ard Biesheuvel > > --- > > arch/arm/mm/proc-v7-bugs.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c > > index 06dbfb968182..fb9f3eb6bf48 100644 > > --- a/arch/arm/mm/proc-v7-bugs.c > > +++ b/arch/arm/mm/proc-v7-bugs.c > > @@ -288,6 +288,7 @@ void cpu_v7_ca15_ibe(void) > > { > > if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0))) > > cpu_v7_spectre_v2_init(); > > + cpu_v7_spectre_bhb_init(); > > } > > void cpu_v7_bugs_init(void) > > > Since this patch has been merged, I am seeing a ton of messages when booting > Linux on tegra124-jetson-tk1 ... > > [ 1233.327547] CPU0: Spectre BHB: using loop workaround > [ 1233.327795] CPU1: Spectre BHB: using loop workaround > [ 1233.328270] CPU1: Spectre BHB: using loop workaround Now that you mention this, I vaguely remember some email on the list a while ago about this being caused by something like cpuidle - but I'm unable to find it now. > [0] https://lore.kernel.org/linux-arm-kernel/20220519161310.1489625-1-dmitry.osipenko@collabora.com/T/ That was probably it. We can't really do this for the other print, because the system status can change as a result of CPUs being brought online. :( -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!