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=-7.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 F3ED1C10F13 for ; Tue, 16 Apr 2019 05:24:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6E8A20645 for ; Tue, 16 Apr 2019 05:24:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="uQNKKAf7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726841AbfDPFY2 (ORCPT ); Tue, 16 Apr 2019 01:24:28 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:40634 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725802AbfDPFY2 (ORCPT ); Tue, 16 Apr 2019 01:24:28 -0400 Received: by mail-pl1-f193.google.com with SMTP id b3so9719969plr.7; Mon, 15 Apr 2019 22:24:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Y4PaT/tb5pp0x50T4tMHrD0XyibPpmE1/SdcsyibnZU=; b=uQNKKAf7Yxxo+eXANaF4NVXpRhWLICM+QALVEbTblPBbeNBGu31L6AGy1xkw3xasmC HC1AAaLqCCFpbUjMDy53loHMapVxb4ifFHs7GM2HzanyjX1QzgC8EM8FEN83ZgOc8lZd IL6XpX1cMC6sk24r5zpMw/CPBsu+W14w9WsKishttADTQB0YAPjynsa2X0neg1eCokIe rSnPVN6cAPe5rVGHU63b6Oxme6cv6B39humdeaGi1hCokIR3PQYegVoPdna/LfojnYBx xX16Y5rXSXCqv22FxxTn0rO0aA0vY9j38nNmtYAvbkxdtNb6ylUnygfAX0h0+M4KOxUF ENxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Y4PaT/tb5pp0x50T4tMHrD0XyibPpmE1/SdcsyibnZU=; b=BNPlP/FiBdsqy/BOUue7UwHvErXq+4lwb50L0Oua5602H9JTbQYa/o3eS/FjbkGpW3 ebMfC363CNjJIECbrTSkoELX3xdY2fsig8Zr5QXgVGs1w23ARZQNkv1NNaCgROWjvlwD QRRXYNLIL1cshMN/ovZZmpJVHyhYb3aquM7t89ageedAuwEIx86tNnQHQ/iYA2+y7oo5 PI5GGYoDIZZTH2ObZB47ubcF2pU/HTdPGT0s/8MJcNeKXpVG3+XboJnSLuA/ThX4Bfdn ZL4AsFxcGcqydp6IUph5OD7Og2ALaQLhnT9+VptrRu42qn9JiKyWstuathLBkvfxSl7z gj5w== X-Gm-Message-State: APjAAAXBYAqR3sLTvZk84dNFrH3UWk6iOfB2yFjAf/aaLrEf/s6MDgkj bh6tNC+ogq3ic+jayBmVbJ2BiPHx X-Google-Smtp-Source: APXvYqyGfJS7LSKysIgD5/yxP7AQIR3De2H00tgPevkIJ0J5YzBJHxzrfJqcXkJWXLvqQV7Qp1gRIg== X-Received: by 2002:a17:902:4381:: with SMTP id j1mr15773379pld.173.1555392266785; Mon, 15 Apr 2019 22:24:26 -0700 (PDT) Received: from localhost ([203.220.205.62]) by smtp.gmail.com with ESMTPSA id i129sm92762160pfc.163.2019.04.15.22.24.25 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 15 Apr 2019 22:24:25 -0700 (PDT) Date: Tue, 16 Apr 2019 15:24:22 +1000 From: Balbir Singh To: Joe Lawrence Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, linux-kbuild@vger.kernel.org, Jessica Yu , Jiri Kosina , Joao Moreira , Josh Poimboeuf , Konstantin Khlebnikov , Masahiro Yamada , Michael Matz , Miroslav Benes , Nicolai Stange , Petr Mladek Subject: Re: [PATCH v3 0/9] klp-convert livepatch build tooling Message-ID: <20190416052422.GA7482@350D> References: <20190410155058.9437-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190410155058.9437-1-joe.lawrence@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 10, 2019 at 11:50:49AM -0400, Joe Lawrence wrote: > Hi folks, > > This is the third installment of the klp-convert tool for generating and > processing livepatch symbols for livepatch module builds. For those > following along at home, archive links to previous versions: > > RFC: > https://lore.kernel.org/lkml/cover.1477578530.git.jpoimboe@redhat.com/ > v2: > https://lore.kernel.org/lkml/f52d29f7-7d1b-ad3d-050b-a9fa8878faf2@redhat.com/ > > (Note that I don't see v2 archived at lore, but that is a link to the > most recent subthread that lore did catch.) > > > Livepatches may use symbols which are not contained in its own scope, > and, because of that, may end up compiled with relocations that will > only be resolved during module load. Yet, when the referenced symbols are > not exported, solving this relocation requires information on the object > that holds the symbol (either vmlinux or modules) and its position inside > the object, as an object may contain multiple symbols with the same name. > Providing such information must be done accordingly to what is specified > in Documentation/livepatch/module-elf-format.txt. > Could we get some details with examples or a sample, sorry I might be dense and missing simple information. The problem being solved is not clear to me from the changelog. > Currently, there is no trivial way to embed the required information as > requested in the final livepatch elf object. klp-convert solves this > problem in two different forms: (i) by relying on a symbol map, which is > built during kernel compilation, to automatically infer the relocation > targeted symbol, and, when such inference is not possible (ii) by using > annotations in the elf object to convert the relocation accordingly to > the specification, enabling it to be handled by the livepatch loader. > > Given the above, add support for symbol mapping in the form of > Symbols.list file; add klp-convert tool; integrate klp-convert tool into > kbuild; make livepatch modules discernible during kernel compilation > pipeline; add data-structure and macros to enable users to annotate > livepatch source code; make modpost stage compatible with livepatches; > update livepatch-sample and update documentation. > > The patch was tested under three use-cases: > > use-case 1: There is a relocation in the lp that can be automatically > resolved by klp-convert. For example. see the saved_command_line > variable in lib/livepatch/test_klp_convert2.c. > > use-case 2: There is a relocation in the lp that cannot be automatically > resolved, as the name of the respective symbol appears in multiple > objects. The livepatch contains an annotation to enable a correct > relocation. See the KLP_MODULE_RELOC / KLP_SYMPOS annotation sections > in lib/livepatch/test_klp_convert{1,2}.c. > > use-case 3: There is a relocation in the lp that cannot be automatically > resolved similarly as 2, but no annotation was provided in the > livepatch, triggering an error during compilation. Reproducible by > removing the KLP_MODULE_RELOC / KLP_SYMPOS annotation sections in > lib/livepatch/test_klp_convert{1,2}.c. > Are these a part of the series? Balbir Singh > > Branches > -------- > > Since I spent some time tinkering with v2 and accumulated a bunch of > fixes, I collected them up and am posting this new version. For review > purposes, I posted two branches up to github: > > 1 - an expanded branch that with changes separate from the original > https://github.com/joe-lawrence/linux/commits/klp-convert-v3-expanded > > 2 - a squashed branch of (1) that comprises v3: > https://github.com/joe-lawrence/linux/commits/klp-convert-v3 > > Non-trivial commits in the expanded branch have some extra commentary > and details for debugging in the commit message that were dropped when > squashing into their respective parent commits. > > > TODO > ---- > > There are a few outstanding items that I came across while reviewing v2, > but as changes started accumulating, it made sense to defer those to a > later version. I'll reply to this thread individual topics to start > discussion sub-threads for those. > > > Changelogs > ---------- > > The commit changelogs were getting long, so I've moved them here for > posterity and review purposes: > > livepatch: Create and include UAPI headers > v2: > - jmoreira: split up and changelog > v3: > - joe: convert to SPDX license tags > > kbuild: Support for Symbols.list creation > v3: > - jmoreira: adjust for multiobject livepatch > - joe: add klpclean to PHONY > - joe: align KLP prefix > > livepatch: Add klp-convert tool > v2: > - khlebnikov: use HOSTLOADLIBES_ instead of HOSTLDFLAGS: -lelf must be > at the end > - jmoreira: add support to automatic relocation conversion in > klp-convert.c, changelog > v3: > - joe: convert to SPDX license tags > - jmoreira: add rela symbol name to WARNs > - jmoreira: ignore relocations to .TOC and symbols with index 0 > - joe: separate and fix valid_sympos() sympos=0 and sympos=1..n checks > - joe: fix symbol use-after-frees > - joe: fix remaining valgrind leak complaints (non-error paths only) > - joe: checkpatch nits > > livepatch: Add klp-convert annotation helpers > v2: > - jmoreira: split up: move KLP_MODULE_RELOC from previous patch to > here, add KLP_SYMPOS, move macros from include/uapi/livepatch.h to > include/linux/livepatch.h > v3: > - joe: suggested by jpoimboe, KLP_MODULE_RELOC macro should 4-byte > align klp_module_reloc structures > > modpost: Integrate klp-convert > v2: > - khlebnikov: save cmd_ld_ko_o into .module.cmd, if_changed_rule > doesn't do that.f > - khlebnikov: fix bashisms for debian where /bin/sh is a symlink to > /bin/dash > - khlebnikov: rename rule_link_module to rule_ld_ko_o, otherwise > arg-check inside if_changed_rule compares cmd_link_module and > cmd_ld_ko_o. > - khlebnikov: check modinfo -F livepatch only if CONFIG_LIVEPATCH is > true. > - mbenes: remove modinfo call. LIVEPATCH_ in Makefile > - jmoreira: split up: move the .livepatch file-based scheme for > identifying livepatches to a previous patch, as it was required for > correctly building Symbols.list there. > v3: > - joe: adjust rule_ld_ko_o to call echo-cmd > - joe: rebase for v5.1 > - joe: align KLP prefix > > modpost: Add modinfo flag to livepatch modules > v2: > - jmoreira: fix modpost.c (add_livepatch_flag) to update module > structure with livepatch flag and prevent modpost from breaking due to > unresolved symbols > v3: > - joe: adjust modpost.c::get_modinfo() call for v5.0 version > > livepatch: Add sample livepatch module > v3: > - joe: update all in-tree livepatches with LIVEPATCH_* modinfo flag > > documentation: Update on livepatch elf format > v2: > - jmoreira: update module to use KLP_SYMPOS > - jmoreira: Comments on symbol resolution scheme > - jmoreira: Update Makefile > - jmoreira: Remove MODULE_INFO statement > - jmoreira: Changelog > v3: > - joe: rebase for v5.1 > - joe: code shuffle to better match original source file > > livepatch/selftests: add klp-convert > v3: > - joe: clarify sympos=0 and sympos=1..n > > > And now the usual git cover-letter boilerplate... > > Joao Moreira (2): > kbuild: Support for Symbols.list creation > documentation: Update on livepatch elf format > > Joe Lawrence (1): > livepatch/selftests: add klp-convert > > Josh Poimboeuf (5): > livepatch: Create and include UAPI headers > livepatch: Add klp-convert tool > livepatch: Add klp-convert annotation helpers > modpost: Integrate klp-convert > livepatch: Add sample livepatch module > > Miroslav Benes (1): > modpost: Add modinfo flag to livepatch modules > > .gitignore | 1 + > Documentation/livepatch/livepatch.txt | 3 + > Documentation/livepatch/module-elf-format.txt | 50 +- > MAINTAINERS | 2 + > Makefile | 30 +- > include/linux/livepatch.h | 13 + > include/uapi/linux/livepatch.h | 22 + > kernel/livepatch/core.c | 4 +- > lib/livepatch/Makefile | 15 + > lib/livepatch/test_klp_atomic_replace.c | 1 - > lib/livepatch/test_klp_callbacks_demo.c | 1 - > lib/livepatch/test_klp_callbacks_demo2.c | 1 - > lib/livepatch/test_klp_convert1.c | 106 +++ > lib/livepatch/test_klp_convert2.c | 103 +++ > lib/livepatch/test_klp_convert_mod_a.c | 25 + > lib/livepatch/test_klp_convert_mod_b.c | 13 + > lib/livepatch/test_klp_livepatch.c | 1 - > samples/livepatch/Makefile | 7 + > .../livepatch/livepatch-annotated-sample.c | 102 +++ > samples/livepatch/livepatch-sample.c | 1 - > scripts/Kbuild.include | 4 +- > scripts/Makefile | 1 + > scripts/Makefile.build | 7 + > scripts/Makefile.modpost | 24 +- > scripts/livepatch/.gitignore | 1 + > scripts/livepatch/Makefile | 7 + > scripts/livepatch/elf.c | 753 ++++++++++++++++++ > scripts/livepatch/elf.h | 72 ++ > scripts/livepatch/klp-convert.c | 692 ++++++++++++++++ > scripts/livepatch/klp-convert.h | 39 + > scripts/livepatch/list.h | 391 +++++++++ > scripts/mod/modpost.c | 82 +- > scripts/mod/modpost.h | 1 + > .../selftests/livepatch/test-livepatch.sh | 64 ++ > 34 files changed, 2616 insertions(+), 23 deletions(-) > create mode 100644 include/uapi/linux/livepatch.h > create mode 100644 lib/livepatch/test_klp_convert1.c > create mode 100644 lib/livepatch/test_klp_convert2.c > create mode 100644 lib/livepatch/test_klp_convert_mod_a.c > create mode 100644 lib/livepatch/test_klp_convert_mod_b.c > create mode 100644 samples/livepatch/livepatch-annotated-sample.c > create mode 100644 scripts/livepatch/.gitignore > create mode 100644 scripts/livepatch/Makefile > create mode 100644 scripts/livepatch/elf.c > create mode 100644 scripts/livepatch/elf.h > create mode 100644 scripts/livepatch/klp-convert.c > create mode 100644 scripts/livepatch/klp-convert.h > create mode 100644 scripts/livepatch/list.h > > -- > 2.20.1