From patchwork Thu Jul 13 04:07:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 13311256 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 4CD3A468C for ; Thu, 13 Jul 2023 04:08:46 +0000 (UTC) Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 166241FFD; Wed, 12 Jul 2023 21:08:45 -0700 (PDT) Received: by mail-pf1-x443.google.com with SMTP id d2e1a72fcca58-666e3b15370so192113b3a.0; Wed, 12 Jul 2023 21:08:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1689221324; x=1691813324; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=TEwq2+q6JfV3n+3skv2W0fszZRn1aic7BmEleaUX5Kc=; b=nNdyIXRuVkdtNEzIvkMJtTHSa6vpvQ/sTY/wCj2NMRWBwH2Fgp/OuUYYWCH684LDPb ySrMpM4gk6l6YTrkm+caTpOniU+xQLqgkguxAW50cNJjITRg9VE+yuijAoT3Yu9pA79N WU107GHPlyZ/DatTrght5v1IQ+jnhMUAGR4TJjZ12nkPYYALBinp41CtJjdL9iPjdapg qBA4kXnnW/hsH+4b4yUgcw1n/yQmOFDX/3HntIQ+1OlcXBgeueNG8aiEzSXCcuVTTYXw EGk8GFG9twio4lO2xYMFg1j80O0fXgd6C6fe84OyNwJppPunRoASzReGFCmYZginXJ5y qRyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689221324; x=1691813324; 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=TEwq2+q6JfV3n+3skv2W0fszZRn1aic7BmEleaUX5Kc=; b=dhOWm2l2RWMuJUSWJi8Wj+AnGfbyy5LMdfGeUdsyHOgsaOzOmUkIiZLn0N4xQBDquT T+ZYAj4duCeP2Ept3sfwTi/BvMhloYtmt9ogEgw1GO7kRrG7zfMlQzrNC6c+sDTqWQAc XjU8DKUfv0z836MbO1+dVj7oTHYlFFQ3PW8k3MkMRPE2ZWNXaTfezeFRlXFvmN+gv9ho nqrPhRxIdM4OyKhAXLh0Sgf+TP3v4WVfjLTooQxWjkdrsX0UDr0yuzYhzoi32SRwLFXL FSqUD4s0CF/MijF5RH3sTee1Y8/pOV33yK04mfMZD7i7lIvummOrlV0zqbmRtQQ1yQN+ ajxw== X-Gm-Message-State: ABy/qLZ3G/+9OzLBOnoF/k+V4PaKSoGObug11ySNyxWd3uFULBwMmlk8 0w80X1hnY9gMlmEmb6i3R1iTZDq6iFuMFFWP X-Google-Smtp-Source: APBJJlEY120b734X5cPoDPB8G/pM26FDSWMSFId7fSoN6Yds/YcWb238LnW8kFYGhoM1BpAkdhHdpQ== X-Received: by 2002:a05:6a20:144d:b0:125:f3d8:e65b with SMTP id a13-20020a056a20144d00b00125f3d8e65bmr145540pzi.18.1689221324400; Wed, 12 Jul 2023 21:08:44 -0700 (PDT) Received: from localhost.localdomain ([43.132.98.100]) by smtp.gmail.com with ESMTPSA id c7-20020a170902d48700b001bb04755212sm483217plg.228.2023.07.12.21.08.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 21:08:43 -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 v10 0/3] bpf, x86: allow function arguments up to 12 for TRACING Date: Thu, 13 Jul 2023 12:07:35 +0800 Message-Id: <20230713040738.1789742-1-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 v9: - fix the failed test cases of trampoline_count and get_func_args_test in the 3rd patch 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 ++- .../bpf/prog_tests/get_func_args_test.c | 4 +- .../selftests/bpf/prog_tests/modify_return.c | 10 +- .../selftests/bpf/prog_tests/tracing_struct.c | 19 ++ .../bpf/prog_tests/trampoline_count.c | 4 +- .../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 ++++ 14 files changed, 548 insertions(+), 59 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