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 smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 680B6C433EF for ; Fri, 8 Apr 2022 14:59:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) id 3A1E4C385A6; Fri, 8 Apr 2022 14:59:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98262C385A3; Fri, 8 Apr 2022 14:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649429999; bh=71U0oqS5DrYUjZ1LnIjF+pi27wgwlYEGUni79PoPFtA=; h=Date:From:To:List-Id:Cc:Subject:References:In-Reply-To:From; b=w705BcmmICRkgt8T9jA8+rkSN4j69SMumLIkDqMVo7qcGR+S3Zasw9j+sjzr8bPDL sWWEfQZYxQPpb93JQpb177dWRLjDH19LdJd0CLdOpagjasvF+VCX+9ewGyL1SOihhy zqI/wad3JndwG8QpzUsZOdv5pnRpc1uSACZsfRiM= Date: Fri, 8 Apr 2022 16:59:56 +0200 From: Greg KH To: Arnd Bergmann List-Id: Cc: Daniel Thompson , Hitomi Hasegawa , Linux ARM , SoC Team , "open list:SERIAL DRIVERS" , Sumit Garg , Olof Johansson , Catalin Marinas , Will Deacon , Jiri Slaby , Jason Wessel , Doug Anderson , Linux Kernel Mailing List , kgdb-bugreport@lists.sourceforge.net, Peter Zijlstra , Mike Travis Subject: Re: [PATCH v3 1/1] soc: fujitsu: Add A64FX diagnostic interrupt driver Message-ID: References: <20220331092235.3000787-1-hasegawa-hitomi@fujitsu.com> <20220331092235.3000787-2-hasegawa-hitomi@fujitsu.com> <20220408133246.fyw5554lgli4olvg@maple.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Apr 08, 2022 at 04:49:31PM +0200, Arnd Bergmann wrote: > On Fri, Apr 8, 2022 at 4:21 PM Greg KH wrote: > > > > On Fri, Apr 08, 2022 at 04:17:16PM +0200, Arnd Bergmann wrote: > > > On Fri, Apr 8, 2022 at 3:32 PM Daniel Thompson > > > wrote: > > > > On Thu, Mar 31, 2022 at 05:44:55PM +0200, Arnd Bergmann wrote: > > > > > > > > There is some prior art for this sort of feature. AFAICT SGI UV has a > > > > similar mechanism that can send an NMI-with-no-side-channel to the > > > > kernel. The corresponding driver offers a range of actions using a > > > > module parameter: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/platform/uv/uv_nmi.c#n180 > > > > > > > > I don't think a hardcoded 'c' makes any sense. With a hardcoded argument > > > > it is just obfuscation. However it is certainly seems attractive to be > > > > able to reuse handle_sysrq() to provide a more powerful set of actions. > > > > > > How about a module parameter that allows picking a sysrq character then? > > > > Module parameters are so 1990, as this is a platform device, why not get > > it from DT? > > This machine doesn't use DT. I suppose the same could be done with an EFI > variable, but with a module parameter you get the added benefit of having both > a boot time kernel command line argument, and the option to override it at > run time. I thought it was a platform device? Worst case, make it a sysfs file :) 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 37FFBC433EF for ; Fri, 8 Apr 2022 15:01:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Iu9nwL+IZ8zSPVEAA+m1hODdB+WMMEf7sl892GkpdUI=; b=gFUuzvCFDk1DKk /GlWXMpwFNwjCAr0XdBtW5oSLub45w0G+swVTDjwjiueJWSWKBjSSuQ5YyYuOSeSmG0FVxs0wCqo9 sSYmjZfcKovo1Poy/dKyRZo4L+XhROWXwRzSLvvf6WFGXMC/t6BRH9yCv4ZqvL/nyBERWCv4sgFyE YHw30TIzGquVrebPUHfK1mbQytkNH1wSkaULWgGC3PFxTDrCXUKuMzDTb0vvDobBemi+i/pRYvLCU 3WyjEju/iYeNJ5SQRWddMjOb1jVlhj6yI7TJ3uQwySo9G4GIlxJ9qPVWqBlqM8P9wET8ymUMJRyhY OyV5RPAtCnVdMSIECZow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ncq5q-00080g-KX; Fri, 08 Apr 2022 15:00:10 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ncq5k-0007uK-A9 for linux-arm-kernel@lists.infradead.org; Fri, 08 Apr 2022 15:00:06 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 823DDB82BB0; Fri, 8 Apr 2022 15:00:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98262C385A3; Fri, 8 Apr 2022 14:59:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649429999; bh=71U0oqS5DrYUjZ1LnIjF+pi27wgwlYEGUni79PoPFtA=; h=Date:From:To:List-Id:Cc:Subject:References:In-Reply-To:From; b=w705BcmmICRkgt8T9jA8+rkSN4j69SMumLIkDqMVo7qcGR+S3Zasw9j+sjzr8bPDL sWWEfQZYxQPpb93JQpb177dWRLjDH19LdJd0CLdOpagjasvF+VCX+9ewGyL1SOihhy zqI/wad3JndwG8QpzUsZOdv5pnRpc1uSACZsfRiM= Date: Fri, 8 Apr 2022 16:59:56 +0200 From: Greg KH To: Arnd Bergmann Cc: Daniel Thompson , Hitomi Hasegawa , Linux ARM , SoC Team , "open list:SERIAL DRIVERS" , Sumit Garg , Olof Johansson , Catalin Marinas , Will Deacon , Jiri Slaby , Jason Wessel , Doug Anderson , Linux Kernel Mailing List , kgdb-bugreport@lists.sourceforge.net, Peter Zijlstra , Mike Travis Subject: Re: [PATCH v3 1/1] soc: fujitsu: Add A64FX diagnostic interrupt driver Message-ID: References: <20220331092235.3000787-1-hasegawa-hitomi@fujitsu.com> <20220331092235.3000787-2-hasegawa-hitomi@fujitsu.com> <20220408133246.fyw5554lgli4olvg@maple.lan> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220408_080004_561914_11FCF176 X-CRM114-Status: GOOD ( 26.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Apr 08, 2022 at 04:49:31PM +0200, Arnd Bergmann wrote: > On Fri, Apr 8, 2022 at 4:21 PM Greg KH wrote: > > > > On Fri, Apr 08, 2022 at 04:17:16PM +0200, Arnd Bergmann wrote: > > > On Fri, Apr 8, 2022 at 3:32 PM Daniel Thompson > > > wrote: > > > > On Thu, Mar 31, 2022 at 05:44:55PM +0200, Arnd Bergmann wrote: > > > > > > > > There is some prior art for this sort of feature. AFAICT SGI UV has a > > > > similar mechanism that can send an NMI-with-no-side-channel to the > > > > kernel. The corresponding driver offers a range of actions using a > > > > module parameter: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/platform/uv/uv_nmi.c#n180 > > > > > > > > I don't think a hardcoded 'c' makes any sense. With a hardcoded argument > > > > it is just obfuscation. However it is certainly seems attractive to be > > > > able to reuse handle_sysrq() to provide a more powerful set of actions. > > > > > > How about a module parameter that allows picking a sysrq character then? > > > > Module parameters are so 1990, as this is a platform device, why not get > > it from DT? > > This machine doesn't use DT. I suppose the same could be done with an EFI > variable, but with a module parameter you get the added benefit of having both > a boot time kernel command line argument, and the option to override it at > run time. I thought it was a platform device? Worst case, make it a sysfs file :) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel