From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17C78C04AAC for ; Sun, 5 May 2019 16:05:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA08D20578 for ; Sun, 5 May 2019 16:05:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727771AbfEEQFk (ORCPT ); Sun, 5 May 2019 12:05:40 -0400 Received: from shelob.surriel.com ([96.67.55.147]:55122 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726524AbfEEQFj (ORCPT ); Sun, 5 May 2019 12:05:39 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91) (envelope-from ) id 1hNJds-0005zM-Jx; Sun, 05 May 2019 12:05:32 -0400 Message-ID: <86b8d81d760ac1f6e622f1c873a5f9aad7862734.camel@surriel.com> Subject: Re: [PATCH] x86/fpu: Remove the _GPL from the kernel_fpu_begin/end() export From: Rik van Riel To: Sebastian Gottschall , Ingo Molnar , Jiri Kosina Cc: Sebastian Andrzej Siewior , Andy Lutomirski , Greg KH , LKML , "H. Peter Anvin" , "Jason A. Donenfeld" , Ard Biesheuvel , Dave Hansen , Ingo Molnar , Nicolai Stange , Paolo Bonzini , Radim =?UTF-8?Q?Kr=C4=8Dm=C3=A1=C5=99?= , Thomas Gleixner , x86@kernel.org, stable@vger.kernel.org, Jiri Kosina Date: Sun, 05 May 2019 12:05:32 -0400 In-Reply-To: <2238f6ed-9338-903c-760c-6200e73b1599@newmedia-net.de> References: <761345df6285930339aced868ebf8ec459091383.1556807897.git.luto@kernel.org> <20190502154043.gfv4iplcvzjz3mc6@linutronix.de> <20190504004747.GA107909@gmail.com> <2238f6ed-9338-903c-760c-6200e73b1599@newmedia-net.de> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-KJqJKfJKG1KaNhswI+ku" User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-KJqJKfJKG1KaNhswI+ku Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, 2019-05-04 at 04:28 +0200, Sebastian Gottschall wrote: > Using fpu code in kernel space in a kernel module is a derived work > of=20 > the kernel itself? > dont get me wrong, but this is absurd. i mean you limit the use of > cpu=20 > instructions. the use > of cpu instructions should be free of any licensing issue. i would > even=20 > argument you are violating > the license of the cpu ower given to the kernel by executing it, by=20 > restricting its use for no reason Using FPU code in kernel space in a kernel module does not require the use of kernel_fpu_begin/end(). The kernel module could simply disable preemption, save the FPU registers, use the FPU, restore the FPU registers, and reenable preemption. However, using kernel_fpu_begin/end() does get that module some nice optimizations that are specific to Linux. --=20 All Rights Reversed. --=-KJqJKfJKG1KaNhswI+ku Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAlzPCcwACgkQznnekoTE 3oP29Qf/T3Zcj5UuvogQBiLgNdSwVJSbdEDgvgAV797ZxOqO8Mst/2REoc0boFwo ChiG+LqAspHxwlocktLxjiS0DjW4mw6qKua0+5zEfB1ZeCXt0OJJ/ecnypzE2CV7 OgWfrCHyPW8sfxtbFQx1yZKoqmWd6RwgqdP0xGly39TXG3yP4NLbGRhEL4MSEQTW JKEfKX2d72NRpuGvoaHXHMfMEGWS9t0es8FczpCs2jS05MEnl6GiuqklE0XOPtL+ 4X+aiMMBzd6DTuhVPKLoK+F9r12T1OZlgUpT3TXoZ0FOYnv2pAuscLTRgbi5t9XE wyOjiF7ZF0vgpQfiihgNFFWthiWMvQ== =/At1 -----END PGP SIGNATURE----- --=-KJqJKfJKG1KaNhswI+ku--