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: 255204 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=-11.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 39080C43461 for ; Wed, 16 Sep 2020 22:37:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D50C020732 for ; Wed, 16 Sep 2020 22:37:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="N7Pvblze" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726336AbgIPWhz (ORCPT ); Wed, 16 Sep 2020 18:37:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726187AbgIPWhy (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 6815AC06174A for ; Wed, 16 Sep 2020 15:37:54 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id x191so7529431qkb.3 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=DFwu8P1+Zljl6eDpNJhhwK9TsQ+b4ur+N2oJIbJWaZDcON5i+6ABpQ+tjIJftr8XiI g4om6BgAeCax/CxwHv0+4mVptfk6HTLDNt9MybTSl9rlhOu/gwUirYOvYR8eECeNg8vX TMeOV4kI8iKaOyNLFj+ubOnp6f+Ot6M+5F1QQ+O61ayOcN7WrK+vyzKmjeBf/k09Ui6O EDm2poUbZdz4pCMhfH/WmExKgwPDLzj9VJDP1OzE99Rmo0AbvVXFOiea1eo39Z5vhVYg xDAG181pwUbVXimRHvMR8dZKmIXZ+SqmdfkIFZBG92tYTKrtWZC5K8BeITPAHu253+Gs Ycnw== X-Gm-Message-State: AOAM5304uOaXjUuIvKC+9wCv9vYvaGFvcjLsBYHBi1qaegeF9BNI+p3U YVfQul/4eGk5Ga0r4D2zmkhTt0qbi+0= 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: linux-kselftest@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 Acked-by: Andrii Nakryiko Acked-by: Andrii Nakryiko