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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63646C4332F for ; Mon, 28 Nov 2022 00:19:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229558AbiK1ATv (ORCPT ); Sun, 27 Nov 2022 19:19:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229504AbiK1ATr (ORCPT ); Sun, 27 Nov 2022 19:19:47 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 391DC6141; Sun, 27 Nov 2022 16:19:47 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D20A9B80B1A; Mon, 28 Nov 2022 00:19:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17F08C43470; Mon, 28 Nov 2022 00:19:43 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="GjPO03ju" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1669594781; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CGDNWDlrjoKkV18bX013f+9WmWZM0g+YAx70BBOO/2Q=; b=GjPO03juWqjidb6zzZMkl2qkH2uWs0O0x5Pxs3nWv0KJ+2r8iTUvJVFIBhmnACPzUtSIp/ 6/TTNYlJ0z7LKrrL7Jmhy1qQRy6fbyZPCOqySSAcAOn7g+G4XSRK689oPPz3kP++anYvyq 37HBzL4b4azCFC4Tdx9+TyNM4pjx6MM= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id d135daf3 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Mon, 28 Nov 2022 00:19:40 +0000 (UTC) Date: Mon, 28 Nov 2022 01:19:36 +0100 From: "Jason A. Donenfeld" To: Samuel Neves Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, patches@lists.linux.dev, linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell , Florian Weimer , Arnd Bergmann , Christian Brauner Subject: Re: [PATCH v7 3/3] x86: vdso: Wire up getrandom() vDSO implementation Message-ID: References: <20221124165536.1631325-1-Jason@zx2c4.com> <20221124165536.1631325-4-Jason@zx2c4.com> <874jumy6me.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 27, 2022 at 10:39:27PM +0000, Samuel Neves wrote: > On Sun, Nov 27, 2022 at 10:13 PM Jason A. Donenfeld wrote: > > > > Hi Thomas, > > > > On Sat, Nov 26, 2022 at 12:08:41AM +0100, Thomas Gleixner wrote: > > > Jason! > > > > > > On Thu, Nov 24 2022 at 17:55, Jason A. Donenfeld wrote: > > > > +++ b/arch/x86/entry/vdso/vgetrandom-chacha.S > > > > +/* > > > > + * Very basic SSE2 implementation of ChaCha20. Produces a given positive number > > > > + * of blocks of output with a nonce of 0, taking an input key and 8-byte > > > > + * counter. Importantly does not spill to the stack. Its arguments are: > > > > > > Basic or not. > > > > Heh, FYI I didn't mean "basic" here as in "doesn't need a review", but > > just that it's a straightforward technique and doesn't do any > > complicated multiblock pyrotechnics (which frankly aren't really > > needed). > > > > > This needs a Reviewed-by from someone who understands SSE2 > > > and ChaCha20 before this can go anywhere near the x86 tree. > > > > No problem. I'll see to it that somebody qualified gives this a review. > > > > I did look at this earlier. It looks fine. I would recommend changing > > + /* copy1,copy2 = key */ > + movdqu 0x00(key),copy1 > + movdqu 0x10(key),copy2 > > to > > + /* copy1,copy2 = key */ > + movups 0x00(key),copy1 > + movups 0x10(key),copy2 > > which has the same semantics, but saves a couple of code bytes. Likewise for > > + movdqu state0,0x00(output) > + movdqu state1,0x10(output) > + movdqu state2,0x20(output) > + movdqu state3,0x30(output) > > Otherwise, > > Reviewed-by: Samuel Neves # for vgetrandom-chacha.S Thanks for the review and for the suggestion. Will do. Jason