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[209.132.180.67]) by mx.google.com with ESMTP id l204si137904oig.31.2020.02.12.12.49.02; Wed, 12 Feb 2020 12:49:14 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@pobox.com header.s=sasl header.b=mex+J8Ow; dkim=temperror (no key for signature) header.i=@fluxnic.net header.s=2016-12.pbsmtp header.b="1l0/s3VC"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728767AbgBLUsy (ORCPT + 99 others); Wed, 12 Feb 2020 15:48:54 -0500 Received: from pb-smtp1.pobox.com ([64.147.108.70]:55868 "EHLO pb-smtp1.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727111AbgBLUsy (ORCPT ); Wed, 12 Feb 2020 15:48:54 -0500 Received: from pb-smtp1.pobox.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 12BBF55B30; Wed, 12 Feb 2020 15:48:52 -0500 (EST) (envelope-from nico@fluxnic.net) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=date:from:to :cc:subject:in-reply-to:message-id:references:mime-version :content-type; s=sasl; bh=5GPDyBY1KAAr0S2ZkUo91m7Bf6s=; b=mex+J8 Owd5Ze1R2YaA5KwoVnoQIT02jzOqHZRvUoNEYOMXCTzuChpEIczaNqEitgKMHR8P /9hHl9ln77mntYIFfuAtbTa80NexUB8ZQD/NUtF4cw9EjeTFPzlYlVWz+Oe2mTPz PHdWNwAPUJTN1/r8iiZ/aIV3aScnDpNI1+IjA= Received: from pb-smtp1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 096B755B2F; Wed, 12 Feb 2020 15:48:52 -0500 (EST) (envelope-from nico@fluxnic.net) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=fluxnic.net; h=date:from:to:cc:subject:in-reply-to:message-id:references:mime-version:content-type; s=2016-12.pbsmtp; bh=Bp0EdcbKaDs3gCEwDZM9KmJwa83NKzzAz84oizMrUV8=; b=1l0/s3VCLjBqIkeBerOUcSUT+1wyu73kWBGNLxUtuXlcNEymGHsLC7zDJF1xu8xvzlnbyCaPjb+UoFAduLa9DlqE9n8cjTMtOW8mwVVWKPi2LP1OcYZiOAL9n/2xkK1F4iGZ5SrOhKPSQMJuPAljIWTejVJOfdfU8fpqM3JQuMc= Received: from yoda.home (unknown [24.203.50.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp1.pobox.com (Postfix) with ESMTPSA id 7FB1655B2E; Wed, 12 Feb 2020 15:48:51 -0500 (EST) (envelope-from nico@fluxnic.net) Received: from xanadu.home (xanadu.home [192.168.2.2]) by yoda.home (Postfix) with ESMTPSA id 9CB7C2DA09EC; Wed, 12 Feb 2020 15:48:50 -0500 (EST) Date: Wed, 12 Feb 2020 15:48:50 -0500 (EST) From: Nicolas Pitre To: Quentin Perret cc: masahiroy@kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, maennich@google.com, kernel-team@android.com, jeyu@kernel.org, hch@infradead.org Subject: Re: [PATCH v4 0/3] kbuild: allow symbol whitelisting with TRIM_UNUSED_KSYM In-Reply-To: <20200212202140.138092-1-qperret@google.com> Message-ID: References: <20200212202140.138092-1-qperret@google.com> User-Agent: Alpine 2.21 (LFD 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Pobox-Relay-ID: 134EB9B8-4DD9-11EA-A8FA-C28CBED8090B-78420484!pb-smtp1.pobox.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 12 Feb 2020, Quentin Perret wrote: > The current norm on Android and many other systems is for vendors to > introduce significant changes to their downstream kernels, and to > contribute very little (if any) code back upstream. The Generic Kernel > Image (GKI) project in Android attempts to improve the status-quo by > having a unique kernel for all android devices of the same architecture, > regardless of the SoC vendor. The key idea is to make all interested > parties agree on a common solution, and contribute their code upstream > to make it available to use by the wider community. > > The kernel-to-drivers ABI on Android devices varies significantly from > one vendor kernel to another today because of changes to exported > symbols, dependencies on vendor symbols, and surely other things. The > first step for GKI is to try and put some order into this by agreeing on > one version of the ABI that works for everybody. > > For practical reasons, we need to reduce the ABI surface to a subset of > the exported symbols, simply to make the problem realistically solvable, > but there is currently no upstream support for this use-case. > > As such, this series attempts to improve the situation by enabling users > to specify a symbol 'whitelist' at compile time. Any symbol specified in > this whitelist will be kept exported when CONFIG_TRIM_UNUSED_KSYMS is > set, even if it has no in-tree user. The whitelist is defined as a > simple text file, listing symbols, one per line. For the whole series: Acked-by: Nicolas Pitre Nicolas