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 2B60E211A3D; Tue, 25 Feb 2025 20:31:19 +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=1740515481; cv=none; b=UXUYgBR9PmLuAEJbTRXRJgr9UmWNwb4RgdjSoPK8MsioJ6NSF9Q6TJY6K9+GOwqdVxacx9y7qByxI/ecFKj5LGHEM7Dsr9CrzFgS6AbDwbeqZG2gOxVzY5zq6d0uu8gScpPY4XBT3UvcpbkBOVPGveBzAHw/btgYdYOTwghSeQg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740515481; c=relaxed/simple; bh=Q3MY/GdxKQqMGIPyfRPgojKwDuIC8+anQD9m52JAilg=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=cWTT3/JlbRZjYnfKfo96bGzDTGRRoLJ9DUzbeWWipO5VDQoweJ/mvW9klC09HUL5FK+RfyhqkYuVALPvXCarFPAucS/9B8kbzdZm4Er5CmpIvYyRhbsXjJuSecacNn11DcdP3zz9ognprAEdzC/cN+NVztkHhPOZJtiarpDRYnc= 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=OwOqSvQS; 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="OwOqSvQS" Received: from [127.0.0.1] ([76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 51PKUlSt1422052 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 25 Feb 2025 12:30:48 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 51PKUlSt1422052 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025021701; t=1740515449; bh=Q3MY/GdxKQqMGIPyfRPgojKwDuIC8+anQD9m52JAilg=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=OwOqSvQSipLIU+p0TxT+2SjwwKvhADNhj93srBgQ4E64s38xGb09x2XBPNV+2rVYc fZxUmjSHZGG2IXC7AUgzreXFcjXK+wDaOWZxXeNfSJfKVYStBQF7k7AdGBYnGlBZ7+ 4RES2rlfJhTOfePpphsx6FsPw+Iq1w2FofpiBlZAo+wOEayVBFn4OLG1MCsOFkkAFS bVEzz5HL+/gaNq8uqbUy87nX0HNA1gvK5cQZOwY55ELN0Nlg+02xMtwGowRfM5N466 E5/5p2vUt4842AaTO6UkikDkYcOtRkPvCrkQBAhVLutvrTMHXGLHjD3bpzUrjxkNbl HerTwdNoTNRsA== Date: Tue, 25 Feb 2025 12:30:46 -0800 From: "H. Peter Anvin" To: Borislav Petkov CC: Nikolay Borisov , Xin Li , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org, will@kernel.org, peterz@infradead.org, yury.norov@gmail.com, akpm@linux-foundation.org, acme@kernel.org, namhyung@kernel.org, brgerst@gmail.com, andrew.cooper3@citrix.com Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v5_0/5=5D_x86/cpufeatures=3A_Automatical?= =?US-ASCII?Q?ly_generate_required_and_disabled_feature_masks?= User-Agent: K-9 Mail for Android In-Reply-To: <20250225181551.GDZ74I1we9xqM_oj-b@fat_crate.local> References: <20250106070727.3211006-1-xin@zytor.com> <20250223102723.GAZ7r4C7C6sTUnbe4I@fat_crate.local> <1a444a2e-75b6-46f9-8f38-0458655873ac@zytor.com> <20250225174915.GBZ74Cm2Xpc_WwS3oe@fat_crate.local> <8973bfd4-d8b2-4dd7-ae1a-3f685dff769f@suse.com> <20250225180051.GCZ74FU-PrcosEHZb1@fat_crate.local> <20250225181551.GDZ74I1we9xqM_oj-b@fat_crate.local> Message-ID: <1BD9B089-9500-4956-9FE3-DAE75B2127B9@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 February 25, 2025 10:15:51 AM PST, Borislav Petkov wrot= e: >On Tue, Feb 25, 2025 at 10:10:03AM -0800, H=2E Peter Anvin wrote: >> Yeah we had that debate back and forth=2E Although I personally feel th= at any >> sensible build host would have or be able to have Perl, the consensus >> opinion seems to be that if it can be done with POSIX standard tools or >> host-side C it should be unless there is a very strong justification to= the >> contrary=2E=20 > >Right, Xin, please make sure you put this rationale in the commit message= so >that people can read it=2E > >> I guess at some point that will add host-side Rust, which will be fun s= ince >> that adds the whole Rust user space runtime=2E > >There's that too=2E And that'll be even more fun=2E I can't wait for the >compiler-specific workarounds=2E We're having a lot of fun with two C com= pilers >already but who says we can't have more?! > >/facepalm=2E > Yeah=2E See the thread on this topic, where it seems that the Rust languag= e people haven't even figured out basic things like their aliasing model ye= t=2E=2E=2E