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=-6.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 3C32FC4727D for ; Mon, 5 Oct 2020 20:29:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2CF521481 for ; Mon, 5 Oct 2020 20:29:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601929786; bh=d4XpU2Q/J1qRRrp5vOFYEOBeWqWUmEYKvsPjMR46CUE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pkCgC5t9dbvEQwy1MPkP2qkA85pRSYtPZYV1mc4NF5XUjQe0zRgx/OC5JDzNgDu34 pd4AZGKe3+OhSOcuNe9v6BDMfKsQJbSDvOn1THZtt6uJOa+zeqXnbe85VO3MmxDm95 2OTkbHOrh7kFu/onWgVWCmNM1Wp+4GhT0UV761Po= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729715AbgJEU3o (ORCPT ); Mon, 5 Oct 2020 16:29:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:51976 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729575AbgJEU3o (ORCPT ); Mon, 5 Oct 2020 16:29:44 -0400 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 843522100A; Mon, 5 Oct 2020 20:29:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601929784; bh=d4XpU2Q/J1qRRrp5vOFYEOBeWqWUmEYKvsPjMR46CUE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=X0BNoMmbzt073ozAL6GqbsFEYoMwLBAX7Xy28FG81kawUIRlC72ZnxnHecrQ2JrxG C5Q+loCy83it5Fc9IxswLnN/w/hrpIWGtp0DefGZrkMLEBs8NEIh2I8JcY61VvQ0YT yv3KRp0BMnVcBd2xpxb/MNc9FdUPKjj0pxqnPbIA= Date: Mon, 5 Oct 2020 21:28:40 +0100 From: Mark Brown To: Jeremy Linton Cc: linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, ardb@kernel.org, will@kernel.org, catalin.marinas@arm.com, davem@davemloft.net, herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org Subject: Re: [BUG][PATCH] arm64: bti: fix BTI to handle local indirect branches Message-ID: <20201005202840.GJ5139@sirena.org.uk> References: <20201005181804.1331237-1-jeremy.linton@arm.com> <20201005195957.GF5139@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="LG0Ll82vYr46+VA1" Content-Disposition: inline In-Reply-To: X-Cookie: Most of your faults are not your fault. User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --LG0Ll82vYr46+VA1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Oct 05, 2020 at 03:10:42PM -0500, Jeremy Linton wrote: > On 10/5/20 2:59 PM, Mark Brown wrote: > > ...this is going to cause problems, SYM_CODE means that we should > > assemble *exactly* what was written since it's some non-standard thing - > > we use it for the vectors table for example. Looking at the code it's > > not 100% clear that the best approach here isn't just to change the call > > to a regular function call, this isn't a fast path or anything as far as > > I can see so it's unclear to me why we need to tail call. > Well for some workloads its could be AFAIK. OTOH, Ard mentioned dumping the > tail call too, and I think that is pretty reasonable. So it looks like that > is a better plan since it also avoids all this SYM_ flailing. Yeah, I think that's the easiest thing all round. --LG0Ll82vYr46+VA1 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl97gfcACgkQJNaLcl1U h9AGKgf/TpwsU5LActmSW1rJZkGgZPIPBP+iIcOuBL8Y5mjrzR3NagJHB5Du4BwG hgBKU5KYqasnZMpmoWOnjPY9j+N1KJmK3ew4VCHARKX4PSQN8KukRTCXWDmRe0UK F6drKioPyA1gnLOAjfEkKiLIGwFPbU7/KFeOY9Oe8bUELZyBgz7Jta8ipXR7sX5F sHcy3PXcPTqx3HUPYFtQHDZkECWL2/ckpdCsYfCj/iqald9xGo2PQiulZSWUfRxK //tCe0g/kVn2aGqHMhjs02VP98n0tiO0Z6SnlJahmTtjvDluONtGIAKhYsPjOAs6 1Fc2NVJRnkghtsY6HaoX1WMS91ghkQ== =SIFO -----END PGP SIGNATURE----- --LG0Ll82vYr46+VA1--