From nobody Sat Feb 7 20:58:02 2026 Received: from out-186.mta0.migadu.com (out-186.mta0.migadu.com [91.218.175.186]) (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 2E5BE34DB5B for ; Tue, 6 Jan 2026 17:21:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.186 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767720069; cv=none; b=g7fK9I/nUuLm7f+a0a7gijlWaJM8vt1R+0fGJlMtgIZC/s2wDnm4VtRMKthixJBGbI4vyLa8lnwCIOwNiN60ZyfEHTYIG+90ZKJynejE8DTVVh4DrBCIZ8KhoYx0rq+sXC5QEXLAwEuUCLAzdkqM6V10e0Iy9f+K7ZO07wZ14mA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767720069; c=relaxed/simple; bh=qdZdan8Bg/3zMmLeA4fE/+22k8U9TKV55zGuSzKMjWA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QhrOQCFwUe/txgiqPbE8gz4ObHjD6AW04KAy09WYXEHJeadIN52EXuEfikjrqyJViXduaBEPXpiJB4zJmZnaM9LVsFs17NrA8i7AVNi3tavAzLLc7tgjpnuS38n8Gf/qRl2tdaBgzb7Yzl2Pkh0qYZp6DELwbfVGsWv0/yuFFpI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=t9Ap5Gi9; arc=none smtp.client-ip=91.218.175.186 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="t9Ap5Gi9" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1767720065; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=el+zFEiv5MlCth3d6SGPMrwMvtewF+0XV0F7CsdC9cM=; b=t9Ap5Gi9xp+auW0Bk3FclI8wYWxDTul6sjO24BmGqXJzJVxJuhAIddY9hDLV6YoNVJWu1Q i1Ee+p2HseJFBRIA5e0LT2JLW4uuGPTyIgYxs4/w7aieStTDrnsyRj6/5k/BNinD1tpM5R PvTvU9SZ+kYBOiPddh9bLE5Ap7IHoMI= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Christian Brauner , Oleg Nesterov , Leon Hwang , Seth Forshee , Yuichiro Tsuji , Andrey Albershteyn , Willem de Bruijn , Jason Xing , Paul Chaignon , Mykyta Yatsenko , Kumar Kartikeya Dwivedi , Anton Protopopov , Amery Hung , Rong Tao , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-patches-bot@fb.com Subject: [RESEND PATCH bpf-next v4 2/9] libbpf: Add support for extended bpf syscall Date: Wed, 7 Jan 2026 01:20:11 +0800 Message-ID: <20260106172018.57757-3-leon.hwang@linux.dev> In-Reply-To: <20260106172018.57757-1-leon.hwang@linux.dev> References: <20260106172018.57757-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" To support the extended BPF syscall introduced in the previous commit, introduce the following internal APIs: * 'sys_bpf_ext()' * 'sys_bpf_ext_fd()' They wrap the raw 'syscall()' interface to support passing extended attributes. * 'probe_sys_bpf_ext()' Check whether current kernel supports the extended attributes. Signed-off-by: Leon Hwang --- tools/lib/bpf/bpf.c | 34 +++++++++++++++++++++++++++++++++ tools/lib/bpf/features.c | 8 ++++++++ tools/lib/bpf/libbpf_internal.h | 3 +++ 3 files changed, 45 insertions(+) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 21b57a629916..689ade4a822b 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -69,6 +69,40 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } =20 +static inline int sys_bpf_ext(enum bpf_cmd cmd, union bpf_attr *attr, + unsigned int size, + struct bpf_common_attr *common_attrs, + unsigned int size_common) +{ + cmd =3D common_attrs ? (cmd | BPF_COMMON_ATTRS) : (cmd & ~BPF_COMMON_ATTR= S); + return syscall(__NR_bpf, cmd, attr, size, common_attrs, size_common); +} + +static inline int sys_bpf_ext_fd(enum bpf_cmd cmd, union bpf_attr *attr, + unsigned int size, + struct bpf_common_attr *common_attrs, + unsigned int size_common) +{ + int fd; + + fd =3D sys_bpf_ext(cmd, attr, size, common_attrs, size_common); + return ensure_good_fd(fd); +} + +int probe_sys_bpf_ext(void) +{ + const size_t attr_sz =3D offsetofend(union bpf_attr, prog_token_fd); + union bpf_attr attr; + int fd; + + memset(&attr, 0, attr_sz); + fd =3D syscall(__NR_bpf, BPF_PROG_LOAD | BPF_COMMON_ATTRS, &attr, attr_sz= , NULL, + sizeof(struct bpf_common_attr)); + if (fd >=3D 0) + close(fd); + return errno =3D=3D EFAULT; +} + static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr, unsigned int size) { diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c index b842b83e2480..d786a815f1ae 100644 --- a/tools/lib/bpf/features.c +++ b/tools/lib/bpf/features.c @@ -506,6 +506,11 @@ static int probe_kern_arg_ctx_tag(int token_fd) return probe_fd(prog_fd); } =20 +static int probe_kern_extended_syscall(int token_fd) +{ + return probe_sys_bpf_ext(); +} + typedef int (*feature_probe_fn)(int /* token_fd */); =20 static struct kern_feature_cache feature_cache; @@ -581,6 +586,9 @@ static struct kern_feature_desc { [FEAT_BTF_QMARK_DATASEC] =3D { "BTF DATASEC names starting from '?'", probe_kern_btf_qmark_datasec, }, + [FEAT_EXTENDED_SYSCALL] =3D { + "Kernel supports extended syscall", probe_kern_extended_syscall, + }, }; =20 bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id= feat_id) diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_interna= l.h index fc59b21b51b5..e2a6ef4b45ae 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -392,6 +392,8 @@ enum kern_feature_id { FEAT_ARG_CTX_TAG, /* Kernel supports '?' at the front of datasec names */ FEAT_BTF_QMARK_DATASEC, + /* Kernel supports extended syscall */ + FEAT_EXTENDED_SYSCALL, __FEAT_CNT, }; =20 @@ -757,4 +759,5 @@ int probe_fd(int fd); #define SHA256_DWORD_SIZE SHA256_DIGEST_LENGTH / sizeof(__u64) =20 void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LE= NGTH]); +int probe_sys_bpf_ext(void); #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ --=20 2.52.0