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 9176E38F226 for ; Tue, 26 May 2026 15:55:27 +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=1779810929; cv=none; b=ss0LmWT3SitaSpK98OOvQ7RSPKbVl1TFOxcuh9O+BdD6ZcTa/CdlDHekwDimOYAXMelGaxAAY3dhKoLGyzzbXRNKxU8W1+Fkh2twdTaWyUIZfujZsRnEFr/Q5ZJZP3CQgAu9QQSgIlq2qz99WQADQKxBl8p289q8jV5+ZqaAmeQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779810929; c=relaxed/simple; bh=wMSOY6y2T/0kBKn8QK1rjJG7QZT0CZ7EkFlZKGMeg8s=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=JFrxSfDNwapPLRYsOa1yJaqk9dXuL7csnh+l7GEqikJPLNGo+WSKVvNMHdhAv52R7X7POCosWiHUAbzCc8fAf9hanYwytKpptEe/9EcBr8j1jq5p/E74Et6Qx4VLPgrK9zxILoyAIs+M/5RknA2oByvbBfr1uE+btQZDsz2BNi0= 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=HXhGCy35; 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="HXhGCy35" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 64QFt1Tk3579923 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 26 May 2026 08:55:02 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 64QFt1Tk3579923 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026042601; t=1779810902; bh=bM2JmbTAP2JFL1G7bVdULM4pUe3+lJgcjh2c+tNVRHo=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=HXhGCy35gfHhkkdlTKXkVSa+9W5TxWRrOcrGYtKA/Ko2PTV9FZ/S9wE6YAfDj6WJ+ uakjS0zG8a4ickprGBSGFtpTquk2hpluLbEpDP7MFlzYIt+OOkvoJ2cVfOPGCzbJ+N Kw1Gol1Pb6Iqpo5IcO/obPGjp6xrTOimFfhOk+2Un0eVukAGTLZsByknmFs6MeIR04 MLBMCVucxZ4rqMI0ZZsQXEJRByitvxm/581ji7M4eP22PSTpBcMe4VqyNhMRLed8hw QN3pYRzf1R2q3hqe1M3KaJ2bqJk2d0BFhLoZlPL5z5LiRViOVap6wXY3iFviLwYBKd LsqqnzHecgOeg== Date: Tue, 26 May 2026 08:54:56 -0700 From: "H. Peter Anvin" To: Sebastian Andrzej Siewior CC: linux-kernel@vger.kernel.org, x86@kernel.org, Borislav Petkov , Dave Hansen , Ingo Molnar , Jonathan Corbet , Thomas Gleixner Subject: Re: [PATCH] x86: Start removing X86_X32_ABI User-Agent: K-9 Mail for Android In-Reply-To: <20260526104051.MmQQ03a8@linutronix.de> References: <20260523093734.A3AR7reJ@linutronix.de> <10BF3F18-4709-43D6-979C-49067707F1C1@zytor.com> <20260526104051.MmQQ03a8@linutronix.de> Message-ID: <5FC3AA08-47C8-46CE-9758-20ECDE6CE018@zytor.com> 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-Transfer-Encoding: quoted-printable On May 26, 2026 3:40:51 AM PDT, Sebastian Andrzej Siewior wrote: >On 2026-05-23 14:43:52 [-0700], H=2E Peter Anvin wrote: >> However, we can not recycle the syscall numbers=2E The x32 flag in the >> syscall number was advisory originally; it was introduced late in the >> game to work around a design bug in the input subsystem (*)=2E > >If x32 is removed/ not supported why can't the 32/64 bit ABI use syscall >numbers 512+? It is an ELF32 with EM_X86_64 which should be rejected=2E >Shouldn't this free the space because there are no users anymore? > >> -hpa > >Sebastian System call numbers or even mechanisms are in no wise tied to the ELF type= =2E An x86-64 binary can issue x86-64, x32 or i386 system calls, even from = 64-bit mode!