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 X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D76F9C47254 for ; Tue, 5 May 2020 15:09:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F5D6207DD for ; Tue, 5 May 2020 15:09:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588691363; bh=wehOs7TzzSRDwsIiBrb11QEbyguhnDAUrPFjehEcsWw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=r5z5PdzUxIlSY9/pVwqEx4KJX33onmraFmVSFE18nJDcX6TnQoh7OHKGMyOPu7CF2 Z2BXmmILcpW96gOe7N1eGV7zFaBUSRp8lYwRwzup5QYDB2OCAulYBFN3ub438kT5zj eXxhGAgmMKGIjvs6riYl141z682+3/WKMQNR1VJ0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729801AbgEEPJW (ORCPT ); Tue, 5 May 2020 11:09:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:37492 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729320AbgEEPJW (ORCPT ); Tue, 5 May 2020 11:09:22 -0400 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3E4DF2078D; Tue, 5 May 2020 15:09:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588691361; bh=wehOs7TzzSRDwsIiBrb11QEbyguhnDAUrPFjehEcsWw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EyaqCaFCUiFGU75ZiQ7lP/igTsu2wIlIHWUSD6+l2UJXUc/h+OJW+8gTjIs0ZICMo Py1MVzr2BsXo41HNEwcnLiGZG8HI3+eUekL+yTwId7gnF4Oz26D6m9Q74+aSJFNItE BmSem2l5jrxSksyLXkKfBJgNDYKiYzBrc4IxcT7Q= Date: Tue, 5 May 2020 16:09:16 +0100 From: Will Deacon To: Daniel Thompson Cc: Catalin Marinas , Douglas Anderson , Jason Wessel , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, patches@linaro.org Subject: Re: [PATCH v2] arm64: cacheflush: Fix KGDB trap detection Message-ID: <20200505150916.GC24239@willie-the-truck> References: <20200504170518.2959478-1-daniel.thompson@linaro.org> <20200504204803.GA5657@willie-the-truck> <20200505141529.2qb35fbqudtac3ys@holly.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200505141529.2qb35fbqudtac3ys@holly.lan> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 05, 2020 at 03:15:29PM +0100, Daniel Thompson wrote: > On Mon, May 04, 2020 at 09:48:04PM +0100, Will Deacon wrote: > > On Mon, May 04, 2020 at 06:05:18PM +0100, Daniel Thompson wrote: > > > diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h > > > index e6cca3d4acf7..ce50c1f1f1ea 100644 > > > --- a/arch/arm64/include/asm/cacheflush.h > > > +++ b/arch/arm64/include/asm/cacheflush.h > > > @@ -79,7 +79,7 @@ static inline void flush_icache_range(unsigned long start, unsigned long end) > > > * IPI all online CPUs so that they undergo a context synchronization > > > * event and are forced to refetch the new instructions. > > > */ > > > -#ifdef CONFIG_KGDB > > > + > > > /* > > > * KGDB performs cache maintenance with interrupts disabled, so we > > > * will deadlock trying to IPI the secondary CPUs. In theory, we can > > > @@ -89,9 +89,9 @@ static inline void flush_icache_range(unsigned long start, unsigned long end) > > > * the patching operation, so we don't need extra IPIs here anyway. > > > * In which case, add a KGDB-specific bodge and return early. > > > */ > > > - if (kgdb_connected && irqs_disabled()) > > > + if (in_dbg_master()) > > > > Does this imply that irqs are disabled? > > Yes. > > Assuming CONFIG_KGDB is enabled then in_dbg_master() expands to: > > (raw_smp_processor_id() == atomic_read(&kgdb_active)) Aha, so this can drop the raw_ prefix and call smp_processor_id() instead? I can queue the arm64 patch regardless. Cheers, Will