From patchwork Tue Sep 29 23:50:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Luo X-Patchwork-Id: 255147 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=-19.9 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 DC6FDC4727C for ; Tue, 29 Sep 2020 23:50:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 705F521531 for ; Tue, 29 Sep 2020 23:50:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cRyJUap6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728684AbgI2Xu4 (ORCPT ); Tue, 29 Sep 2020 19:50:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728291AbgI2Xu4 (ORCPT ); Tue, 29 Sep 2020 19:50:56 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8E28C0613D0 for ; Tue, 29 Sep 2020 16:50:55 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id w32so39708qvw.8 for ; Tue, 29 Sep 2020 16:50:55 -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=y64gCzYCkai7AxMDOAccdFDI8O3APYfmcQlop7QJQJ8=; b=cRyJUap6ryOrDfaRkftF8F2PiQN5Kqv/zRq2pzb1QXs73YmyPESuX1xwfQs5AzZeSE k8JUbluHoDC4hEtO0ichR5bf31yvFzmZdMh49rWKQKqv0j1h9stJDj3+bxPwt/m97wtk v/Vwj0XRvfFRlC0NAQJuFGgNi8EtCs/ozaRlwFt6YBiWcco+iIQ6f3J9aC3vg4f1XqK1 gPZI3AuDkMMrM36qviYeXLRViBs1sejywtfvbEoFYvunNV0AlrylhbTiX6vy/9R7GkvH 5MbDiRuJ3438olcvxDEFNaba/9kcyrSoWnMYQEThNJzTjMelHXewl9J38ewLf4EUA3Qr 8Fpw== 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=y64gCzYCkai7AxMDOAccdFDI8O3APYfmcQlop7QJQJ8=; b=culxZq011do/L8NePn6tS204l70Fajj0W6ybMr0jWWy1KTS8UqizD7q+K6LwK5/Xrl 6yL2CXsteADIrqnxbK4DfvXCFsnjuxeJwdRTDFtqaSEbKWH2x84QxpA8PpT80MpYDg+5 4Dpv1FdZ1KosootV+NB81ghTDfG8rYH5xDGa3YQyYfAS8I30hoMP6AC/I3DdH4QxKvwD LP1u3q6sZZrukS9Em0Baim65il7LYLMbYP8PNR9cmgLhU0LydGo3fPg0Yj0Aw4zsriGB eoTKk2OKiNrps56dZt0ZA9dJL6LVMKCy4ee20ktK6u5gqS71mVNjb+ICVkUsL9I/mBjT LMfQ== X-Gm-Message-State: AOAM532YtQ5uPLeQtz09SGoTK7NDney3NWDMMdSCWDgr+PUgleNa/yWe 5rSdV00tNUbujqmS/ASklxeyXtbbtuY= X-Google-Smtp-Source: ABdhPJxxcDSvZKQ8KiekE+T4rYPWqxkFy0WW0Gn6rtGDsoJp0Wyi8mau2Z14k9GeUGSXm93hrJJTEq8MB8k= Sender: "haoluo via sendgmr" X-Received: from haoluo.svl.corp.google.com ([2620:15c:2cd:202:f693:9fff:fef4:e444]) (user=haoluo job=sendgmr) by 2002:ad4:5387:: with SMTP id i7mr6722288qvv.43.1601423454885; Tue, 29 Sep 2020 16:50:54 -0700 (PDT) Date: Tue, 29 Sep 2020 16:50:43 -0700 Message-Id: <20200929235049.2533242-1-haoluo@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.709.gb0816b6eb0-goog Subject: [PATCH bpf-next v4 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: linux-kselftest@vger.kernel.org v3 -> v4: - Rebasing - Cast bpf_[per|this]_cpu_ptr's parameter to void __percpu * before passing into per_cpu_ptr. 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: Introducte 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