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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 CD461CA101F for ; Fri, 12 Sep 2025 13:24:56 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4cNZsg3rQNz3dDk; Fri, 12 Sep 2025 23:24:55 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=63.228.1.57 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1757683495; cv=none; b=me1uOt8aLxvSI5E9YgAupCxRPmP1j9UiVVurM1HVXQWbeZGUQfzno74ac8m5FR5oIiy8MTagk2AsYb/n9GO+M0htY9Mpx+BqmIAcUA+C3Zln3HG2sKbZ8LQEe6sPrbU/bPhNR3YPuMKJgNKBGt1+e5DNRSFetn9mk63/Wf4fKsDRUeA1Kp33UKi54NeQbCPQmB0OmZV8/iv95KECxcjSbB/iskErfmXphzEAjgfszfNZp/Pvjo/r3pOwfgU0IKSgwbe7cc/k3fOM3Ov+JYPEVgd+loB94j2rWEaNo1iMYmGv9fVgnFvfTd+axq7vfig75Obo5v3kBdnc+K13ThXM9g== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1757683495; c=relaxed/relaxed; bh=zog0kqBlhpuNaxjvu/lo373GkjPToe400+RXOsdRbH4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GfmGHfEvMMU+/ZCsLCCa2fS7VvD5AHxkanSbw7D1+6MeCiRY6BU+UBEZdl5/iu1XXJQLyj8ptlce+dN2ilu8k9Mh3weJ1Hx1l9lGCJrW0kI+z82H0mBQLpK/c4up9et8Qb1f2EOTXLVdFUg+IFfLHJjZNJoccXl3G203xKkfSfbmiBp6GoSwERoVwotzuOGU8HKWr3nBJ37ltrzs+mch1NyBkkqx2fYAbqU7sIg768ewnvZCfUrhIMYK/ES6VVYbo7T2zW4CUND26m22e6TR1qXsVsDfLu5bqC8Ke7hj2bB32w/0XOEkmkoHgqaccI840kGUkQJnrNh+gdOUMXQudA== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org; spf=pass (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.crashing.org Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=lists.ozlabs.org) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 4cNZsd71qjz3dDJ for ; Fri, 12 Sep 2025 23:24:53 +1000 (AEST) Received: from gate.crashing.org (localhost [127.0.0.1]) by gate.crashing.org (8.18.1/8.18.1/Debian-2) with ESMTP id 58CDOWIi048951; Fri, 12 Sep 2025 08:24:32 -0500 Received: (from segher@localhost) by gate.crashing.org (8.18.1/8.18.1/Submit) id 58CDOVJU048950; Fri, 12 Sep 2025 08:24:31 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 12 Sep 2025 08:24:31 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Michael Ellerman , Nicholas Piggin , Madhavan Srinivasan , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2] powerpc/32: Fix unpaired stwcx. on interrupt exit Message-ID: References: <6040b5dbcf5cdaa1cd919fcf0790f12974ea6e5a.1757666244.git.christophe.leroy@csgroup.eu> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6040b5dbcf5cdaa1cd919fcf0790f12974ea6e5a.1757666244.git.christophe.leroy@csgroup.eu> Hi! On Fri, Sep 12, 2025 at 10:37:34AM +0200, Christophe Leroy wrote: > BEGIN_FTR_SECTION > + lwarx r0,0,r1 > +END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) > stwcx. r0,0,r1 /* to clear the reservation */ > -FTR_SECTION_ELSE > - lwarx r0,0,r1 > -ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) Hrm. So this is for V'ger (mpc7450)? What kind of issues does that old thing have with unpaired larx/stcx., some performance impact? The extra "dummy" larx has serious performance impact itself, on most implementations (also on all newer stuff). Segher