From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6A64A13635C for ; Fri, 12 Sep 2025 13:30:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=63.228.1.57 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757683826; cv=none; b=q2y2qQUG/NURR/OzybzXs8180Pa3LbtIwGqGURRsb71vQlfzC5cOWA78dYb71FZINWAtDpSo66lsK90WQKYmmXXOvp+2Ws7sY/kUshaMjk8WI7K3IDkOYmUbXPZH7h+oKtiqKnZXjB+AxIRxlLosFtQWkKBVrb4UbO9xKAzVRNI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757683826; c=relaxed/simple; bh=Phvf/+4TTzo2+XZPAndnu+kUC9CkpgD9w0ZXtkj7VI4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fing5mrYg5JPBhZkBq60hReqV++B/ZeR3Qw8+V8/nZpGbrTVK+wJZQ7W+mVntebh0/+jImT2R3An//4Q8bTWphx9N/aMx6FQW9B+gwCwh9xGS8QW+NB3ePD6Sg1UDbqY+BUn/yBJoZjbJP3gGUxKm95ZPhRZTTqjtlSZ898AVqk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org; spf=pass smtp.mailfrom=kernel.crashing.org; arc=none smtp.client-ip=63.228.1.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.crashing.org 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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