From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) (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 22C8178F54 for ; Thu, 2 Oct 2025 15:49:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759420162; cv=none; b=mFGikBigE99m2sOIULMrPkiNOIU6mWQtynsJHkRyoZoH0YpNWzdNs7sW6s+qLhMHZL1SNsH7f5or7/KAGciY6wsVwzICreFnt1NzOVguOY0qpTZI1r1+uPgxDuqLh7ZFVo5gaVBTy4gYIsiZSJJTCzcsJkm3ITKIFr12zzHiiSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759420162; c=relaxed/simple; bh=VBCqnJU+hrpTf4EEol0smvmUCw+GPCuYkT2Nzo/AC2Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X9izUEqrObM64m6fVsiz+cu4+8KOMA6kiRJzodppEzQ6J3PQgexw9+ccrqOmJah3OKEbUv1JzrxvE64Q/ssPKZe9LKNKwjyUX+yQuiAVaAoF9szuXvBxYGDJHl+8kYjo++jNhTcLWFmYTEp2Fxo+Sg/xZxP5qO5WQeJRkOeBxbg= 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=SDPAFybr; arc=none smtp.client-ip=95.215.58.172 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="SDPAFybr" 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=1759420159; 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=/Vlu/hQHthmPhF+EZzWb/8uJq/AE+u4XS+KH/E1Bn5A=; b=SDPAFybrZ+ptPh2WQ5eYX1JL+qpIFRVEbub2LZg44UoDaspmt5Wdd5a8L9aVJZgwcVILeE FvqYtIjSCSRmZSflkJGUspVFg0kLXT8ppTyIaMzfdRn7NURpQI9KHTU6PRGdsM436Da+NL lzgLio4SPTC1LaBT9Vqu49KPXJPlOzw= From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, Leon Hwang Subject: [RFC PATCH bpf-next v3 02/10] libbpf: Add support for extended bpf syscall Date: Thu, 2 Oct 2025 23:48:33 +0800 Message-ID: <20251002154841.99348-3-leon.hwang@linux.dev> In-Reply-To: <20251002154841.99348-1-leon.hwang@linux.dev> References: <20251002154841.99348-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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 | 33 +++++++++++++++++++++++++++++++++ tools/lib/bpf/features.c | 8 ++++++++ tools/lib/bpf/libbpf_internal.h | 3 +++ 3 files changed, 44 insertions(+) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 339b197972374..9cd79beb13a2d 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -69,6 +69,39 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } +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 = common_attrs ? cmd | BPF_COMMON_ATTRS : cmd & ~BPF_COMMON_ATTRS; + 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 = 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 = offsetofend(union bpf_attr, prog_token_fd); + union bpf_attr attr; + int fd; + + memset(&attr, 0, attr_sz); + fd = syscall(__NR_bpf, BPF_PROG_LOAD | BPF_COMMON_ATTRS, &attr, attr_sz, NULL, + sizeof(struct bpf_common_attr)); + fd = errno == EFAULT ? syscall(__NR_memfd_create, "fd", 0) : fd; + return ensure_good_fd(fd); +} + 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 760657f5224c2..d01df62394f89 100644 --- a/tools/lib/bpf/features.c +++ b/tools/lib/bpf/features.c @@ -507,6 +507,11 @@ static int probe_kern_arg_ctx_tag(int token_fd) return probe_fd(prog_fd); } +static int probe_kern_extended_syscall(int token_fd) +{ + return probe_fd(probe_sys_bpf_ext()); +} + typedef int (*feature_probe_fn)(int /* token_fd */); static struct kern_feature_cache feature_cache; @@ -582,6 +587,9 @@ static struct kern_feature_desc { [FEAT_BTF_QMARK_DATASEC] = { "BTF DATASEC names starting from '?'", probe_kern_btf_qmark_datasec, }, + [FEAT_EXTENDED_SYSCALL] = { + "Kernel supports extended syscall", probe_kern_extended_syscall, + }, }; 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_internal.h index c93797dcaf5bc..af05df8d040ce 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -380,6 +380,8 @@ 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, }; @@ -740,4 +742,5 @@ int probe_fd(int fd); #define SHA256_DWORD_SIZE SHA256_DIGEST_LENGTH / sizeof(__u64) void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]); +int probe_sys_bpf_ext(void); #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ -- 2.51.0