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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 C544FC433DF for ; Mon, 19 Oct 2020 11:56:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A17222283 for ; Mon, 19 Oct 2020 11:56:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603108589; bh=QuduAn6k0rUFR+XlPjYg/pmTJf/ta7vn5SfuOao/njQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=2vYEvgjH01dqGcOKe1wiZFG5MOYP8PPyn42xxDmZFRnFuNcd0cg1KpMIXdFxqxpuF OIaM5KIS1/b/fzuANuvqdUd6wCTJh49CDuEzYzWa1AcOzovPS9I+OmrYv+cBVnpWdk WaVCR7yq2Af42lylEymxuR2yjRs6RR3nTMt0Tkog= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727629AbgJSL42 (ORCPT ); Mon, 19 Oct 2020 07:56:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:48436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726249AbgJSL42 (ORCPT ); Mon, 19 Oct 2020 07:56:28 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 3FD49221FC; Mon, 19 Oct 2020 11:56:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603108587; bh=QuduAn6k0rUFR+XlPjYg/pmTJf/ta7vn5SfuOao/njQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=t3odKDxneKRZ/sEMPTz0TQL5M6chluNLskMhfyBO0ZuIYQ3YaEVqxox/KSXnBDm+e WJk11sjxsyrC2c1tXBgd4cpAtFX7sCdeRQD9nM2pCFNE82rXDqbOp8HBCfG2pbU6pd HS8X22ByDu8S+h4Q/EAEjXcDihwG5oaoUvKfcfyI= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1kUTm5-002POa-8O; Mon, 19 Oct 2020 12:56:25 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 19 Oct 2020 12:56:25 +0100 From: Marc Zyngier To: Sumit Garg Cc: catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, tglx@linutronix.de, jason@lakedaemon.net, mark.rutland@arm.com, julien.thierry.kdev@gmail.com, dianders@chromium.org, daniel.thompson@linaro.org, jason.wessel@windriver.com, msys.mizuma@gmail.com, ito-yuichi@fujitsu.com, kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 1/5] arm64: Add framework to turn IPI as NMI In-Reply-To: <1602673931-28782-2-git-send-email-sumit.garg@linaro.org> References: <1602673931-28782-1-git-send-email-sumit.garg@linaro.org> <1602673931-28782-2-git-send-email-sumit.garg@linaro.org> User-Agent: Roundcube Webmail/1.4.9 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: sumit.garg@linaro.org, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, tglx@linutronix.de, jason@lakedaemon.net, mark.rutland@arm.com, julien.thierry.kdev@gmail.com, dianders@chromium.org, daniel.thompson@linaro.org, jason.wessel@windriver.com, msys.mizuma@gmail.com, ito-yuichi@fujitsu.com, kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-10-14 12:12, Sumit Garg wrote: > Introduce framework to turn an IPI as NMI using pseudo NMIs. In case a > particular platform doesn't support pseudo NMIs, then request IPI as a > regular IRQ. > > The main motivation for this feature is to have an IPI that can be > leveraged to invoke NMI functions on other CPUs. And current > prospective > users are NMI backtrace and KGDB CPUs round-up whose support is added > via future patches. > > Signed-off-by: Sumit Garg > --- > arch/arm64/include/asm/nmi.h | 16 +++++++++ > arch/arm64/kernel/Makefile | 2 +- > arch/arm64/kernel/ipi_nmi.c | 77 > ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 94 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/include/asm/nmi.h > create mode 100644 arch/arm64/kernel/ipi_nmi.c [...] > + irq_set_status_flags(ipi, IRQ_HIDDEN); Another thing is this. Why are you hiding this from /proc/interrupts? The only reason the other IPIs are hidden is that displaying them as "normal" interrupts would be a change in userspace ABI. In your case, this is something new that can perfectly appear as a standard interrupt (and I don't see how you'd display the statistics otherwise). M. -- Jazz is not dead. It just smells funny...