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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 2ADB5C54E4A for ; Tue, 12 May 2020 10:42:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDF28206DD for ; Tue, 12 May 2020 10:42:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="jVaQIBsA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729425AbgELKmI (ORCPT ); Tue, 12 May 2020 06:42:08 -0400 Received: from ozlabs.org ([203.11.71.1]:49809 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726187AbgELKmH (ORCPT ); Tue, 12 May 2020 06:42:07 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 49LvWJ4rq4z9sRf; Tue, 12 May 2020 20:42:04 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1589280125; bh=irXY0vtb9zPvMX2q8c25NXhSXgzVaOoD927epiNXh70=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=jVaQIBsA9/RvJnWQmp6Engcr92niJPir1oeJaEEd7rimbfWX8KTC7gMirQsjqBUab dtmzfksFEKiKvtXOI47pWgU/CjF6XP9nuiLgAuI+fwywpzGuqmQkHIwqpirlIeiwF+ d/iFl6RbsFFh3d+OBNoEVMUtaQxSOzYfG59/OZVCtVdQQkzuQ4SRq9XpN3ly97V7Sl szVGU3QoI8Ge4GZnZepSuK19bE2UI0UTc966yfM/9VhdHhDtycOUKrRLvqR1WtOFqx G0miMHvi9gdP4EZalGKz1uQoXKo5ulZ8ue6cUpjCLBHCiYDm8WbZi8sKl+kw9zA/2w cy8aYJSKkZtkQ== From: Michael Ellerman To: Paul Mackerras Cc: Leonardo Bras , Nicholas Piggin , Alexios Zavras , Benjamin Herrenschmidt , Christophe Leroy , Greg Kroah-Hartman , Enrico Weigelt , peterz@infradead.org, Thomas Gleixner , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v3 1/1] ppc/crash: Reset spinlocks during crash In-Reply-To: <20200409002726.GA5135@blackberry> References: <20200401000020.590447-1-leonardo@linux.ibm.com> <871rp6t9di.fsf@mpe.ellerman.id.au> <02e74be19534ab1db2f16a0c89ecb164e380c12a.camel@linux.ibm.com> <1585895551.7o9oa0ey62.astroid@bobo.none> <87v9majhh2.fsf@mpe.ellerman.id.au> <20200409002726.GA5135@blackberry> Date: Tue, 12 May 2020 20:42:21 +1000 Message-ID: <87mu6dbfjm.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paul Mackerras writes: > On Wed, Apr 08, 2020 at 10:21:29PM +1000, Michael Ellerman wrote: >> >> We should be able to just allocate the rtas_args on the stack, it's only >> ~80 odd bytes. And then we can use rtas_call_unlocked() which doesn't >> take the global lock. > > Do we instantiate a 64-bit RTAS these days, or is it still 32-bit? No, yes. > In the old days we had to make sure the RTAS argument buffer was > below the 4GB point. Yes you're right, that's still true. I was thinking we were on the emergency stack, but we may not be. > If that's still necessary then perhaps putting rtas_args inside the > PACA would be the way to go. Yeah I guess. Allocating a struct within the RMO for each CPU is not that simple vs just putting it in the paca. cheers