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 CA8252192FA for ; Fri, 19 Dec 2025 23:24:53 +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=1766186695; cv=none; b=eo1Njb6an7AoqGzIf9YS41+0UNfWGkuposQ1xaPu7PNkK6awv/TnO2HqQ2kSNGwnVQLzkyVp00fqM6eNIYCSJjK4gUT+ppgteGZ9SmUBUhCljY56c61LYWgTb5AUMTpTxuUryfHLyhEhp0POud80QKbUXl65c88xjJDsNVyoxx4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766186695; c=relaxed/simple; bh=YHV4sZccw4XEKV/RitswkfmJgNzeSnzKJA4AxXEnuTM=; h=Message-ID:Date:MIME-Version:To:Cc:From:Subject:Content-Type; b=GqCTrxwZKKEO+nuuY3cfLln1u7+wdF2CdWQlpAFxeN6fqtLnlOMMGiWkXLZeDLSAcyXmhi0PpyrUEKCdFByQ0CFZ5ac/ml+/AhSLGNH3tvFqiE/YPY2/xsji5BhuibudN5mKwYt8CdkslewlPHiVyM+j8C3erUJDP6+mYPpZ7Xg= 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=kFrn/Xvw; 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="kFrn/Xvw" Received: from [IPV6:2601:646:8081:9483:a140:2beb:fe7:432d] ([IPv6:2601:646:8081:9483:a140:2beb:fe7:432d]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 5BJNORfD857605 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Fri, 19 Dec 2025 15:24:34 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 5BJNORfD857605 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025112201; t=1766186675; bh=GGlfb2GGWGfjCEMUkrhuOl6sk4YNPGEPAApQWkGJxR0=; h=Date:To:Cc:From:Subject:From; b=kFrn/XvwPTLz4uhF12f4phHvkJf4KfpIHdEfh5P+waHJgouBKaNA9uEHHfU+vnmhk RyNdb7nrkJQRLoeqLsJAn9072f8/vUKKwLKv8NKuzFWZvgQ8ON9B1PqswkfYHVsv7w uGupFlK0UMQTrHi9G+alRFIYzpszIwuw8WhPXuzHgtN0MMbhbi01y2csTPod/ukgiW 5iuEjhTzLenOpRyk2xH4wEt20QzmaJM07L0KuVSdqpBIGt49SkrmTxN/2WICs1JqGb 8fM+re+LTyyGjJT/5nwYcXlaGar8eBnHK7kI1C3kejKNcBF3CtzhuW9DiriOb1RB0i dufpb7hSGPe7w== Message-ID: Date: Fri, 19 Dec 2025 15:24:21 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US, sv-SE To: Uros Bizjak , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt Cc: "x86@kernel.org" , LKML , Andrew Morton From: "H. Peter Anvin" Subject: Do we still care about compilers without __seg_fs and __seg_gs support?? Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit As of Linux 6.16, we require: gcc 8.1 or higher clang 15.0.0 or higher If my reading of the release notes is correct, then both versions *should* supported __seg_fs and __seg_gs, but we have: config CC_HAS_NAMED_AS def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null) depends on CC_IS_GCC We don't even try on clang. Being able to actually rely on the compiler for this would make a lot of things cleaner. For one thing, I'm trying to untangle a bunch of ugliness in the code sharing between realmode and proper flat mode code... Uros, you seem to have touched this code as recently as earlier this year; any thoughts? What about the LLVM people, any insights? -hpa