From patchwork Wed Jul 12 08:47:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 13309812 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 079AD20E4 for ; Wed, 12 Jul 2023 08:50:30 +0000 (UTC) Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AB0CA9; Wed, 12 Jul 2023 01:50:29 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id d2e1a72fcca58-6686a05bc66so3963078b3a.1; Wed, 12 Jul 2023 01:50:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1689151829; x=1691743829; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=iRO0VgQOKWIhyr12EjEvkzc4obUWhSgU/tP39Q4+6M8=; b=sLD6dBsFzbwHQu73JiQ5cWZfI7lpzpaK7S6gmSbXndbWIcK7SqlTsfJ4LEi497owC7 GJ1v602MxZgovBtLFlDQPp+RBWaCcufF7ardUBT1dgf3B5Pb545KexnOKBnXDzV43S7I 3nz4CexqLzJID288uCjaVOagN2l6s3zZdIfHvlqZNFyukTcPKdCfuc7WHpeUCjDzJba4 KGxixA7v43/6pLmHc0TFJ8YxvTgZMz8YzNnnKez6rgDPTBYjd4yiCaDahiqDvZgpREvk kMiXBp306D95fTDGFAGubeJMAQhMbbOvcSHKkKQO7fYhGuQMJXkN2VKfTiLGKQu2NegI Y/8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689151829; x=1691743829; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=iRO0VgQOKWIhyr12EjEvkzc4obUWhSgU/tP39Q4+6M8=; b=NGuLqvWvYdo2++8tvQh2RKEF4jAVKaW5AI3eN/e0+YjPm8u7oXLeZeq040FaMalM7V P5b6+Ez7CxQ38PBA2UkxZcBPmJFwj1Gcki6pfbgytgoMHL+0OjEHG97bgTuNqpbHLral BoXXZEFoToxoL8i3l6KzbXhLeBL93Xbf5DaWKxFtGM/boh7RFDaMWl/bFRJANWZVLV9K L9bX9xQmCkN7XZO6AZuitaH5R5iiQjrJFkE3FPjVwE7x5doq/k5Stl7UCcRDoVbL7arV b4PbUExe4HHqHavN8NwFNoJqOlu5Prr8+48vPxki/ThUBj6zPZXsoSsHE2ANhYO+m4R2 8eKw== X-Gm-Message-State: ABy/qLZwaEeFuJO7E3G75XUjrDs32SbKhhVGllzCBL3FHUknn8yMg/OQ SuCpkj3nviLZlicAGt1N2bI= X-Google-Smtp-Source: APBJJlHCWYQv/x7sE+wUc45XH1ysEpDi6GYGaj7tVfAE+HAS1MTs9PfdEVJU7q4sXyaRC/y1p/5yDA== X-Received: by 2002:a05:6a00:198f:b0:67e:18c6:d2db with SMTP id d15-20020a056a00198f00b0067e18c6d2dbmr15716475pfl.28.1689151828855; Wed, 12 Jul 2023 01:50:28 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.11]) by smtp.gmail.com with ESMTPSA id e26-20020a62aa1a000000b006749c22d079sm3037066pff.167.2023.07.12.01.50.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 01:50:28 -0700 (PDT) From: menglong8.dong@gmail.com X-Google-Original-From: imagedong@tencent.com To: yhs@meta.com, daniel@iogearbox.net, alexei.starovoitov@gmail.com Cc: ast@kernel.org, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, dsahern@kernel.org, jolsa@kernel.org, x86@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Menglong Dong Subject: [PATCH bpf-next v9 0/3] bpf, x86: allow function arguments up to 12 for TRACING Date: Wed, 12 Jul 2023 16:47:43 +0800 Message-Id: <20230712084746.833965-1-imagedong@tencent.com> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net From: Menglong Dong For now, the BPF program of type BPF_PROG_TYPE_TRACING can only be used on the kernel functions whose arguments count less than or equal to 6, if not considering '> 8 bytes' struct argument. This is not friendly at all, as too many functions have arguments count more than 6. According to the current kernel version, below is a statistics of the function arguments count: argument count | function count 7 | 704 8 | 270 9 | 84 10 | 47 11 | 47 12 | 27 13 | 22 14 | 5 15 | 0 16 | 1 Therefore, let's enhance it by increasing the function arguments count allowed in arch_prepare_bpf_trampoline(), for now, only x86_64. In the 1st patch, we save/restore regs with BPF_DW size to make the code in save_regs()/restore_regs() simpler. In the 2nd patch, we make arch_prepare_bpf_trampoline() support to copy function arguments in stack for x86 arch. Therefore, the maximum arguments can be up to MAX_BPF_FUNC_ARGS for FENTRY, FEXIT and MODIFY_RETURN. Meanwhile, we clean the potential garbage value when we copy the arguments on-stack. And the 3rd patch is for the testcases of the this series. Changes since v8: - change the way to test fmod_ret in the 3rd patch Changes since v7: - split the testcases, and add fentry_many_args/fexit_many_args to DENYLIST.aarch64 in 3rd patch Changes since v6: - somit nits from commit message and comment in the 1st patch - remove the inline in get_nr_regs() in the 1st patch - rename some function and various in the 1st patch Changes since v5: - adjust the commit log of the 1st patch, avoiding confusing people that bugs exist in current code - introduce get_nr_regs() to get the space that used to pass args on stack correct in the 2nd patch - add testcases to tracing_struct.c instead of fentry_test.c and fexit_test.c Changes since v4: - consider the case of the struct in arguments can't be hold by regs - add comment for some code - add testcases for MODIFY_RETURN - rebase to the latest Changes since v3: - try make the stack pointer 16-byte aligned. Not sure if I'm right :) - introduce clean_garbage() to clean the grabage when argument count is 7 - use different data type in bpf_testmod_fentry_test{7,12} - add testcase for grabage values in ctx Changes since v2: - keep MAX_BPF_FUNC_ARGS still - clean garbage value in upper bytes in the 2nd patch - move bpf_fentry_test{7,12} to bpf_testmod.c and rename them to bpf_testmod_fentry_test{7,12} meanwhile in the 3rd patch Changes since v1: - change the maximun function arguments to 14 from 12 - add testcases (Jiri Olsa) - instead EMIT4 with EMIT3_off32 for "lea" to prevent overflow Menglong Dong (3): bpf, x86: save/restore regs with BPF_DW size bpf, x86: allow function arguments up to 12 for TRACING selftests/bpf: add testcase for TRACING with 6+ arguments arch/x86/net/bpf_jit_comp.c | 246 +++++++++++++++--- net/bpf/test_run.c | 14 +- tools/testing/selftests/bpf/DENYLIST.aarch64 | 2 + .../selftests/bpf/bpf_testmod/bpf_testmod.c | 49 +++- .../selftests/bpf/prog_tests/fentry_test.c | 43 ++- .../selftests/bpf/prog_tests/fexit_test.c | 43 ++- .../selftests/bpf/prog_tests/modify_return.c | 13 +- .../selftests/bpf/prog_tests/tracing_struct.c | 19 ++ .../selftests/bpf/progs/fentry_many_args.c | 39 +++ .../selftests/bpf/progs/fexit_many_args.c | 40 +++ .../selftests/bpf/progs/modify_return.c | 40 +++ .../selftests/bpf/progs/tracing_struct.c | 54 ++++ 12 files changed, 545 insertions(+), 57 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/fentry_many_args.c create mode 100644 tools/testing/selftests/bpf/progs/fexit_many_args.c