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 262A613C914 for ; Fri, 16 May 2025 14:48:02 +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=1747406889; cv=none; b=YcOLhOkxMXieixgRzUsVDs54Tkfxrwdd5uy69rHRFF9lSYjurDrce4Wb0NXFfDnoNkstSioSX4yLWhn+T6XwewJ2WBMW7Doq5v5jF/g+hX377h/tcpDzUXxxp+xWvijjxzctU2sLNiNvseQRj6xm0Yw/V1JADIvd/bZZdIpcabI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747406889; c=relaxed/simple; bh=21gawLCo3zIyc5D8SEqgPmGnZlkNfnfz8XtmPkFv7SM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=PwkZHsqoJ1VgizY7QQXD60n4DSZWE3xDpJ54eg0XPr489BXjK/oRjb+utqg0kUlQy19SIUByfIuweH7E7wmI+iU9ZnonuqoOfK6mllOEkLa8cOAcIiXJ/qZiEwlueWjKr4UiOqlWkscwHPZn+2V/POTFLXF6JoV3FajlzCsN/fo= 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=RRbFF/2X; 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="RRbFF/2X" 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=1747406880; 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; bh=FyEVCctXmby7k7iloVDBeY4I+UGbC6F6wxFOef79nHU=; b=RRbFF/2XgrVewPDOh5ZMFplmM5NHskrLMRpjk7DylTXOjZGb9oC8AjhGwvrKlefGs7U8iJ TOJ6JyTvuFXabgoi5sQHDrJtOiehJv2Rm7W4WT0Iw/ygrffRI7K+P37jfwWUnLvQHet1Uo OeQv+EhM9b4P5IX+WoQao6V0maid3Fo= From: Jiayuan Chen To: bpf@vger.kernel.org Cc: Jiayuan Chen , Quentin Monnet , 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 , Daniel Xu , Tao Chen , Mykyta Yatsenko , linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v4] bpftool: Add support for custom BTF path in prog load/loadall Date: Fri, 16 May 2025 22:47:02 +0800 Message-ID: <20250516144708.298652-1-jiayuan.chen@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 This patch exposes the btf_custom_path feature to bpftool, allowing users to specify a custom BTF file when loading BPF programs using prog load or prog loadall commands. The argument 'btf_custom_path' in libbpf is used for those kernels that don't have CONFIG_DEBUG_INFO_BTF enabled but still want to perform CO-RE relocations. Suggested-by: Quentin Monnet Reviewed-by: Quentin Monnet Signed-off-by: Jiayuan Chen --- V3 -> V4: Improved documentation and added the Reviewed-by tag. V2 -> V3: Optimized document grammar and some prompts https://lore.kernel.org/bpf/20250515065018.240188-1-jiayuan.chen@linux.dev/ V1 -> V2: Added bash completion and documentation https://lore.kernel.org/bpf/20250513035853.75820-1-jiayuan.chen@linux.dev/ --- tools/bpf/bpftool/Documentation/bpftool-prog.rst | 10 ++++++++-- tools/bpf/bpftool/bash-completion/bpftool | 4 ++-- tools/bpf/bpftool/prog.c | 12 +++++++++++- 3 files changed, 21 insertions(+), 5 deletions(-) diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst index d6304e01afe0..da3152c16228 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst @@ -31,7 +31,7 @@ PROG COMMANDS | **bpftool** **prog dump xlated** *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] [**visual**] }] | **bpftool** **prog dump jited** *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] }] | **bpftool** **prog pin** *PROG* *FILE* -| **bpftool** **prog** { **load** | **loadall** } *OBJ* *PATH* [**type** *TYPE*] [**map** { **idx** *IDX* | **name** *NAME* } *MAP*] [{ **offload_dev** | **xdpmeta_dev** } *NAME*] [**pinmaps** *MAP_DIR*] [**autoattach**] +| **bpftool** **prog** { **load** | **loadall** } *OBJ* *PATH* [**type** *TYPE*] [**map** { **idx** *IDX* | **name** *NAME* } *MAP*] [{ **offload_dev** | **xdpmeta_dev** } *NAME*] [**pinmaps** *MAP_DIR*] [**autoattach**] [**kernel_btf** *BTF_FILE*] | **bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*] | **bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*] | **bpftool** **prog tracelog** @@ -127,7 +127,7 @@ bpftool prog pin *PROG* *FILE* Note: *FILE* must be located in *bpffs* mount. It must not contain a dot character ('.'), which is reserved for future extensions of *bpffs*. -bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach] +bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach] [kernel_btf *BTF_FILE*] Load bpf program(s) from binary *OBJ* and pin as *PATH*. **bpftool prog load** pins only the first program from the *OBJ* as *PATH*. **bpftool prog loadall** pins all programs from the *OBJ* under *PATH* directory. **type** @@ -153,6 +153,12 @@ bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | na program does not support autoattach, bpftool falls back to regular pinning for that program instead. + The **kernel_btf** option allows specifying an external BTF file to replace + the system's own vmlinux BTF file for CO-RE relocations. Note that any + other feature relying on BTF (such as fentry/fexit programs, struct_ops) + requires the BTF file for the actual kernel running on the host, often + exposed at /sys/kernel/btf/vmlinux. + Note: *PATH* must be located in *bpffs* mount. It must not contain a dot character ('.'), which is reserved for future extensions of *bpffs*. diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index 1ce409a6cbd9..27512feb5c70 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -505,13 +505,13 @@ _bpftool() _bpftool_get_map_names return 0 ;; - pinned|pinmaps) + pinned|pinmaps|kernel_btf) _filedir return 0 ;; *) COMPREPLY=( $( compgen -W "map" -- "$cur" ) ) - _bpftool_once_attr 'type pinmaps autoattach' + _bpftool_once_attr 'type pinmaps autoattach kernel_btf' _bpftool_one_of_list 'offload_dev xdpmeta_dev' return 0 ;; diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index f010295350be..96eea8a67225 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -1681,8 +1681,17 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) } else if (is_prefix(*argv, "autoattach")) { auto_attach = true; NEXT_ARG(); + } else if (is_prefix(*argv, "kernel_btf")) { + NEXT_ARG(); + + if (!REQ_ARGS(1)) + goto err_free_reuse_maps; + + open_opts.btf_custom_path = GET_ARG(); } else { - p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?", + p_err("expected no more arguments, " + "'type', 'map', 'offload_dev', 'xdpmeta_dev', 'pinmaps', " + "'autoattach', or 'kernel_btf', got: '%s'?", *argv); goto err_free_reuse_maps; } @@ -2474,6 +2483,7 @@ static int do_help(int argc, char **argv) " [map { idx IDX | name NAME } MAP]\\\n" " [pinmaps MAP_DIR]\n" " [autoattach]\n" + " [kernel_btf BTF_FILE]\n" " %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n" " %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n" " %1$s %2$s run PROG \\\n" -- 2.47.1