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=-11.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 1BA64C2BA83 for ; Fri, 7 Feb 2020 18:08:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E814B20726 for ; Fri, 7 Feb 2020 18:08:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Y91L1uXT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727347AbgBGSIB (ORCPT ); Fri, 7 Feb 2020 13:08:01 -0500 Received: from mail-vs1-f73.google.com ([209.85.217.73]:46763 "EHLO mail-vs1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726900AbgBGSIA (ORCPT ); Fri, 7 Feb 2020 13:08:00 -0500 Received: by mail-vs1-f73.google.com with SMTP id x71so17650vsx.13 for ; Fri, 07 Feb 2020 10:07:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=mSGi1BVNlmditJM4fRm+rDENjQW+HhkSF8B3glFVnpg=; b=Y91L1uXTf2awXQO+uBVdXHZU8HCUNdIQsjzQiuvYNcqr/Qg08ny8VJf+mhsL5QlXQO 8try15JSIXJiOSsR7EFMxnWN9X+orC1q09te8w78JzpzdLmfu53irZiF03QwEcfSvvBb UObLSjrTYF1feRZ89t4RTW2Vqfdgfw91TsWlrZglEmUrYDL+dAUz5TZCypq84K+WbjaL enMmP8OUSN3JKM96OObunWgzoESB1J6/x5MlBOR1NPZnsLA9NHrGhkg/34+0C14mGslt H6NQdWosuVmvxS35YeCmHk3dg+ezw7h52YNHk4nrHimsUKABwI4o1gR4H/m7NiyvsCvV qRlg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=mSGi1BVNlmditJM4fRm+rDENjQW+HhkSF8B3glFVnpg=; b=XcQbvzwITuo0iQezE0RE4hAxgSg9dU4oyfIrXMSROmNmi/ZTJr2W//655i64PkX3GJ D56CCTIYxicMOMUqi95oDOifWYBwKrQLww0rKQX1G29PoNPPPIRXWQ5ROzP1EukMqPtd XNQktRJuyOwkrzGkJmbjAxv6CYOup0RnYPrdSCNkxwAn8NERmh4OcoBEK/JQRm7oaB4m 4ub23NjFSvlZppQHnROO2EZDbBbcYCMUTt9dbDqrp0Ng2dufV5/hfd+iRskwoafmg5N9 azk84RPns9gdCUE+9OwQdMewyL5RFEfuiphZe4nv/IS3PYVZIoi5vmOIDr5ylrDiCPYv KfUQ== X-Gm-Message-State: APjAAAW9/7/+IbIP0cBaQVMdlFe4bdLXoSqR8rYGwOUODfOluVqkJKPx iUedAG22wSHBYVO97pQoyRr8fP1nK3ba X-Google-Smtp-Source: APXvYqziKEBW3W5mmaFfdbidi6/kSXkrtep5KXxVSIyrpuAILMZF8PBOLP6pqbApOFLsps39N7pkfSEcWx4a X-Received: by 2002:a1f:2753:: with SMTP id n80mr265425vkn.24.1581098878430; Fri, 07 Feb 2020 10:07:58 -0800 (PST) Date: Fri, 7 Feb 2020 18:07:52 +0000 Message-Id: <20200207180755.100561-1-qperret@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.25.0.341.g760bfbb309-goog Subject: [PATCH v3 0/3] kbuild: allow symbol whitelisting with TRIM_UNUSED_KSYM From: Quentin Perret To: masahiroy@kernel.org, nico@fluxnic.net Cc: linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, maennich@google.com, kernel-team@android.com, jeyu@kernel.org, hch@infradead.org, qperret@google.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. v2 -> v3: - added a cover letter to explain why this is in fact an attempt to help usptream in the long term (Christoph) - made path relative to the kernel source tree (Matthias) - made the Kconfig help text less confusing (Jessica) - added patch 02 and 03 to optimize build time when a whitelist is provided v2: - make sure to quote the whitelist path properly (Nicolas) Quentin Perret (3): kbuild: allow symbol whitelisting with TRIM_UNUSED_KSYMS kbuild: split adjust_autoksyms.sh in two parts kbuild: generate autoksyms.h early Makefile | 2 +- init/Kconfig | 13 +++++++++++ scripts/adjust_autoksyms.sh | 27 ++++------------------ scripts/gen_autoksyms.sh | 45 +++++++++++++++++++++++++++++++++++++ 4 files changed, 63 insertions(+), 24 deletions(-) create mode 100755 scripts/gen_autoksyms.sh -- 2.25.0.341.g760bfbb309-goog