From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (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 0AB7811713 for ; Fri, 5 Sep 2025 13:19:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757078373; cv=none; b=E8U8g16FD0+O1sn5lSNCBvSQYuAax3UAUSmvaZWb4LgUxF2aDSJTGNHp3u0Bmid9PPE+2yLjEAattXbkCrsO8hiJvUM2euHuMDeCBj0WPZUE5ZqWQsnwPxMkTR30gYokqwORPqVBshjA5EiCT9G6xNRW9i3Ji/wLuP6oW4B3y+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757078373; c=relaxed/simple; bh=4+aBu1QYPkiVf6s77hX2MEWDjitw9I++XXnLuguNv6s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=l3BPVI+Yk7noveQ1PPhsVSywZ15MQFWocW1Vo57xs64o1NRCSdyGpePnor/M7qnyJbS4SXwy/FzV4MFvn3Z2Kr+gKRL+ptlpyKgTdi+kDFDGZjlUzeX47uRVQjvenE3MMCiG69R4/0xR/hf7A1a5pL2ItCFnhf1D2FmBpJuZhfM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=fail (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=McPcmgFW reason="signature verification failed"; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="signature verification failed" (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="McPcmgFW" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id E95E140E01A5; Fri, 5 Sep 2025 13:19:26 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=fail (4096-bit key) reason="fail (body has been altered)" header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 8G6JW74q3WKi; Fri, 5 Sep 2025 13:19:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1757078362; bh=+75vthP3JRfPmr4G0ovrKndN5n6E7CyQChLfsO/D918=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=McPcmgFWWndOeR1OONO4boLM2w7NrPV2ABZuYAwmrobY4JXQwB2ff0/PfZZl5LAqh dhpiyXXZ8t3IcRXr+y3n/Hi1DsM1baU9tIJ9zKMjBoAsC7Dc0JxHUm6oE/AH2gbeM6 JBiRcvICSd1xriF97NKxM4QSGm+vKl/MtoNm8GUB7Yoe92G5QZwrhdZNdxkKJbGA/S +RC0ZoGf+X9nHTfzIbUv0Btxbl17GUn7JBpPz+mSqNOuA9nmKDwhhdpDmOLcAmX2ST 1q0hdcYZMj1Bn1ZWjys/+E7AEU47iruAl3a9mUwSklNz62XGAQISn5ByuPbqnYViLI s2VljS32Y0u99SnYm4HKIoBxGqnLscpF39FvZikpOG0j+/xW17zw9Q7rye0D7xB3+s ZBUXfQZ142QDhkUnQ6/nM8SuD3UWb88tIjTP3T8Tf/ckpdRvNs45ueeqlMQsnTsf/Q R6JVJy0Vr2/fM5JSimvJvLZBr4MA0LqT3HivJYxhfXdtOKtvabZFpzMMB9pGjt64wB 6rL8OUgTCd0TNxNEaClRhL9wGZTptXvyUHg8YF+NGLOhUiiC6RAJ8w1G7StaEmWTgm HiSu2v2QdOrowVUh4Rin+UNLaCumA6J6Dn7v8RAu7p81ET1KcLWQG820OASzx1czLJ aC8jRWGgoD4m6mWHatUT4Cms= Received: from zn.tnic (p5de8ed27.dip0.t-ipconnect.de [93.232.237.39]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with UTF8SMTPSA id 27C3B40E016D; Fri, 5 Sep 2025 13:19:15 +0000 (UTC) Date: Fri, 5 Sep 2025 15:19:09 +0200 From: Borislav Petkov To: Uros Bizjak Cc: X86 ML , LKML , Thomas Gleixner , Ingo Molnar , Dave Hansen , "H. Peter Anvin" Subject: Re: [PATCH -tip] x86: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ Message-ID: <20250905131909.GDaLrjTTw0PyFHeCHp@fat_crate.local> References: <20250828072958.3922703-1-ubizjak@gmail.com> <20250905121723.GCaLrU04lP2A50PT-B@fat_crate.local> 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=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable On Fri, Sep 05, 2025 at 02:36:24PM +0200, Uros Bizjak wrote: > There we are testing the value of a single flag bit, set by the CMPXCHG= =C2=A0 > instruction. =3D@ccz is used here to distinguish the CC user from compa= rison > instructions, where ZERO flag indeed means that values are equal. No, this is not what I mean. I mean SETE and SETZ are the same insn: 0F 9= 4 /0 What you mean is that CMPXCHG8B modifies the zero flag, thus you want to = use ccz which denotes the flag while "set equal" doesn't correspond to a flag= in rFLAGS. But then you need to say that in the commit message instead of me asking = about it. > The same situation is with carry bit setting BT instructions, where we = use > =3D@ccc instead of =3D@ccb. Ditto. Thx. --=20 Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette