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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45FD0C433F5 for ; Wed, 12 Jan 2022 15:38:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245128AbiALPim (ORCPT ); Wed, 12 Jan 2022 10:38:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234800AbiALPik (ORCPT ); Wed, 12 Jan 2022 10:38:40 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AEE5C06173F; Wed, 12 Jan 2022 07:38:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ZJZXi7uKPajL3QMTUFGMnMN7b0ltmbxkEaYGU+MZrck=; b=rX9qbDMnl+iED6l5LqCDVa2ucV fFaMZmyFgrCpzD4oj9qI3RuAMiWkHLHBMu1TGESCzPR+Wy9NuXnFNcDlIh3RtR9859H4LgdwBaOku qgTSBLvygkdBmF3Xc8vdG6zH/E3Su4fXMUyE0nXPvCEEoHZW+UwVHOk6FJE6EHa9RIan4vCsEtbuT BDqsEBAI7CkKS4hwjWATxq4LBuX/pkkSRBriyf0bcGY4Wuj82iMqeibIiMHWT0Pjwu3d6hVpYo2kt 52Haa59lBTKiDbcXUfYt2c9YKRGmhgxxQ8M9imc8OiLGPGKuldM55IbJgpCCgRCK2FGTZ8wP+vMtE durYpLuA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1n7fho-004Cwg-GE; Wed, 12 Jan 2022 15:38:32 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 79D9D300222; Wed, 12 Jan 2022 16:38:32 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5CAFA2B33E98B; Wed, 12 Jan 2022 16:38:32 +0100 (CET) Date: Wed, 12 Jan 2022 16:38:32 +0100 From: Peter Zijlstra To: Florian Weimer Cc: Mathieu Desnoyers , linux-kernel , Thomas Gleixner , paulmck , Boqun Feng , "H. Peter Anvin" , Paul Turner , linux-api , Christian Brauner , carlos Subject: Re: [RFC PATCH] rseq: x86: implement abort-at-ip extension Message-ID: References: <20220107170302.8325-1-mathieu.desnoyers@efficios.com> <87a6g7ny0j.fsf@mid.deneb.enyo.de> <1968088162.13310.1641584935813.JavaMail.zimbra@efficios.com> <87y23l6l2j.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87y23l6l2j.fsf@mid.deneb.enyo.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 12, 2022 at 04:16:36PM +0100, Florian Weimer wrote: > You could perhaps push a signal frame onto the stack. It's going to > be expensive, but it's already in the context switch path, so maybe it > does not matter. Please no! Signals are a trainwreck that need change (see the whole AVX-512 / AMX saga), we shouldn't use more of that just cause.