From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 227C1374EA; Sun, 21 Jan 2024 23:22:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705879344; cv=none; b=dR3goUmPWs1gLOgzUBOFyDlDprbtFj0WDLRjC/i+YwbmUuUGdTrUkSsWLHImBFe2bURdtvmMwlRjqd7sPLEoSeKmeFzobpurSiVYF7rANT0OTAPGWVd5VY8Hki9aZ+qvM3fSIh/WkrEaMA/cQDX8RpB3fPIlLZc349GO1mNX4Iw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705879344; c=relaxed/simple; bh=ehzyAReg4rP5zjQpD9surDz/ySyHRo1OYyKiUS1UE9E=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=BLwkAq4FepRujxPuETrryKYAg+pFWcp9a21WXPE+PL3SKzaUCsQpazHs4mNW1q8Wz29Ciys1JWgoAu4eC5fFLngB4ecPHxgHqCsnEEd7H934jnXw/H71JF825tBfIt0/G9oV3Snc/2nEPnxSGLL8bOD0HGRsxxR5xQkoON0UIPI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=aSu/M7sg; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="aSu/M7sg" Received: from [IPV6:2601:646:8002:4641:eb14:ad94:2806:1c1a] ([IPv6:2601:646:8002:4641:eb14:ad94:2806:1c1a]) (authenticated bits=0) by mail.zytor.com (8.17.2/8.17.1) with ESMTPSA id 40LNLxok2231331 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Sun, 21 Jan 2024 15:21:59 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 40LNLxok2231331 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2024011201; t=1705879320; bh=7jya2C1Xke7uzPYQqHJezOQiLdM+ZpoPy0MqrYayi18=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=aSu/M7sgXqZkeJg8FkOBDCNK+chhfVXZv+vz7jdiy/CtoYCC4GSdLu1wn70BSw3qr nnK9+hu1pw2e/gfFT6EkC3GfMzCRpo/63GdcIkAFe3wdbc/2LLByPBl3wCKhbPyzXI HgGoa8ABZjALAIXZiPqGQduF+MhkzGf8I2wQiYE8CnWLDhPR8IZ8GVsCopKHbAveAH oHX/t6noy00ScnBQuKPbNnI41aOHlKolCfkzxAl4gK2PJApx2GS5naCb7MCyEmohSm QblLRLK4Sv0Lb1VWj2KIbe2lF98JnQwgKk6xKpnGtRmek2kk/9MFiw24yHGtku+B7D fws/LV8NKECtQ== Message-ID: Date: Sun, 21 Jan 2024 15:21:54 -0800 Precedence: bulk X-Mailing-List: linux-toolchains@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] x86: Remove dynamic NOP selection To: Thorsten Glaser Cc: Peter Zijlstra , x86@kernel.org, rostedt@goodmis.org, torvalds@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org, jpoimboe@redhat.com, alexei.starovoitov@gmail.com, mhiramat@kernel.org References: <20210312113253.305040674@infradead.org> <20210312115749.065275711@infradead.org> Content-Language: en-US From: "H. Peter Anvin" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/20/24 08:53, Thorsten Glaser wrote: > H. Peter Anvin dixit: > >> %eiz was something that binutils used to put in when disassembling >> certain redundant encodings with SIB at some point. > > Ah, fair enough. Maybe this could be added as one more line in > the comment or something. > I think "proper" gas syntax would be 0(%esi,,1), although that doesn't assemble either (I don't believe there is a way to get gas to actually generate this sequence.) But yes, with all even remotely recent CPUs all actually handling nopl properly, this isn't relevant anymore. -hpa