From patchwork Wed Sep 16 22:35:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Luo X-Patchwork-Id: 1365715 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20161025 header.b=N7Pvblze; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4BsJJl5VfvzB45t for ; Thu, 17 Sep 2020 10:49:43 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726494AbgIPWh5 (ORCPT ); Wed, 16 Sep 2020 18:37:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726311AbgIPWhy (ORCPT ); Wed, 16 Sep 2020 18:37:54 -0400 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D313C061788 for ; Wed, 16 Sep 2020 15:37:54 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id a2so7483244qkg.19 for ; Wed, 16 Sep 2020 15:37:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=P0/XHNACdLCUTE2NkPXDYLWlznqm7B496+cU0eLiRvs=; b=N7PvblzepT8TRkUNWA/I98PPBW+aNIvvd+M0mTCRrCSukeeCnVR01+tnMGSI0jzUAN QcGrx8lOIdgc2PYarRTJ9G8hQSBgRpM+lc/UDfCx40FDKUb7h7/+Y/fZiBWoTKQlN0gO hiqpFb8Y7eufHgYUv0pWv8y41/L8MmZ+ulRgGCUi2WELX8u0d4A54fGM0ylBghn09AQD mo9NYz/23bh4T5A+R/SpbQxCKBXsBUYD4efIJz5BqbhUYFIX9rKqZPbHDlZntc6BqbhZ S7c3wKgErQTmuYN3ltJEe32XcLFNKJa76iIUuzxvwR/EVPiZAOc4OiQ4/STFeiGnF1up LeTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=P0/XHNACdLCUTE2NkPXDYLWlznqm7B496+cU0eLiRvs=; b=TX5yMe8ROZp1UBNjCm6haynKDJFv0MaLW+GWQCW6I2ghxWeytwDLE4/WWiPrC3pDk0 4QVfyN09yXCEP7OBnB6J0udNO3URPmjC7tiXa8bEfXeBZFzDtZ7rb8dUArIEmDXnNVHg 1MLQ7+eitZVNaT6bIOZJsH5RXh+m8CzA0OcVJ38pOGWP05MJvoVZHqdiT8IHowfDpD/v diNSo0DQZqo2WI3c2R2CH8wTqrp5lQdPfHABwCHTzpUdcVTodgAeA6cKyMosueFZKCbl pTaf+0v+gx3Qm0ugjsPJVDW0tFoxKRGoxRUhf9vHg2EwEosoFspYV8Cn8znBu1C9oRIJ E4wQ== X-Gm-Message-State: AOAM5337hU/X7QCT2mfkCrh/98+F7Xui7b4Bkw/RGVua9vFaaxvypQsA FEMWMkINcoLjplSkAUlukf6XSJPT9W+euxNnsWAHw0CjbtCAMMDHmcQV05jZlESwSYu+vd/qF8k 1ztkxBxScbnGdw5O9iRSWMitsEDH8LbZIoSCWZOxNvme3THvoqiuxQWFkQU9WHA== X-Google-Smtp-Source: ABdhPJwjusGHTRhrPsKDw/1tJ1ThXkW8Ff0AXVS+0XHDja3t+9w1eo4pdYJtV3cCf7Fvj63YepgqZqOVn6c= X-Received: from haoluo.svl.corp.google.com ([2620:15c:2cd:202:f693:9fff:fef4:e444]) (user=haoluo job=sendgmr) by 2002:a0c:f0d1:: with SMTP id d17mr9473565qvl.34.1600295873277; Wed, 16 Sep 2020 15:37:53 -0700 (PDT) Date: Wed, 16 Sep 2020 15:35:06 -0700 Message-Id: <20200916223512.2885524-1-haoluo@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.618.gf4bc123cb7-goog Subject: [PATCH bpf-next v3 0/6] bpf: BTF support for ksyms From: Hao Luo To: netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Shuah Khan , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Quentin Monnet , Hao Luo , Steven Rostedt , Ingo Molnar Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org v2 -> v3: - Rename functions and variables in verifier for better readability. - Stick to logging message convention in libbpf. - Move bpf_per_cpu_ptr and bpf_this_cpu_ptr from trace-specific helper set to base helper set. - More specific test in ksyms_btf. - Fix return type cast in bpf_*_cpu_ptr. - Fix btf leak in ksyms_btf selftest. - Fix return error code for kallsyms_find(). v1 -> v2: - Move check_pseudo_btf_id from check_ld_imm() to replace_map_fd_with_map_ptr() and rename the latter. - Add bpf_this_cpu_ptr(). - Use bpf_core_types_are_compat() in libbpf.c for checking type compatibility. - Rewrite typed ksym extern type in BTF with int to save space. - Minor revision of bpf_per_cpu_ptr()'s comments. - Avoid using long in tests that use skeleton. - Refactored test_ksyms.c by moving kallsyms_find() to trace_helpers.c - Fold the patches that sync include/linux/uapi and tools/include/linux/uapi. rfc -> v1: - Encode VAR's btf_id for PSEUDO_BTF_ID. - More checks in verifier. Checking the btf_id passed as PSEUDO_BTF_ID is valid VAR, its name and type. - Checks in libbpf on type compatibility of ksyms. - Add bpf_per_cpu_ptr() to access kernel percpu vars. Introduced new ARG and RET types for this helper. This patch series extends the previously added __ksym externs with btf support. Right now the __ksym externs are treated as pure 64-bit scalar value. Libbpf replaces ld_imm64 insn of __ksym by its kernel address at load time. This patch series extend those externs with their btf info. Note that btf support for __ksym must come with the kernel btf that has VARs encoded to work properly. The corresponding chagnes in pahole is available at [1] (with a fix at [2] for gcc 4.9+). The first 3 patches in this series add support for general kernel global variables, which include verifier checking (01/06), libpf support (02/06) and selftests for getting typed ksym extern's kernel address (03/06). The next 3 patches extends that capability further by introducing helpers bpf_per_cpu_ptr() and bpf_this_cpu_ptr(), which allows accessing kernel percpu variables correctly (04/06 and 05/06). The tests of this feature were performed against pahole that is extended with [1] and [2]. For kernel BTF that does not have VARs encoded, the selftests will be skipped. [1] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=f3d9054ba8ff1df0fc44e507e3a01c0964cabd42 [2] https://www.spinics.net/lists/dwarves/msg00451.html Hao Luo (6): bpf: Introduce pseudo_btf_id bpf/libbpf: BTF support for typed ksyms selftests/bpf: ksyms_btf to test typed ksyms bpf: Introduce bpf_per_cpu_ptr() bpf: Introduce bpf_this_cpu_ptr() bpf/selftests: Test for bpf_per_cpu_ptr() and bpf_this_cpu_ptr() include/linux/bpf.h | 6 + include/linux/bpf_verifier.h | 7 + include/linux/btf.h | 26 +++ include/uapi/linux/bpf.h | 67 +++++- kernel/bpf/btf.c | 25 --- kernel/bpf/helpers.c | 32 +++ kernel/bpf/verifier.c | 190 ++++++++++++++++-- kernel/trace/bpf_trace.c | 4 + tools/include/uapi/linux/bpf.h | 67 +++++- tools/lib/bpf/libbpf.c | 112 +++++++++-- .../testing/selftests/bpf/prog_tests/ksyms.c | 38 ++-- .../selftests/bpf/prog_tests/ksyms_btf.c | 88 ++++++++ .../selftests/bpf/progs/test_ksyms_btf.c | 55 +++++ tools/testing/selftests/bpf/trace_helpers.c | 27 +++ tools/testing/selftests/bpf/trace_helpers.h | 4 + 15 files changed, 653 insertions(+), 95 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_btf.c create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf.c