[v2,bpf-next,10/16] bpf: Add bpf_btf_find_by_name_kind() helper.

Message ID	20210423002646.35043-11-alexei.starovoitov@gmail.com (mailing list archive)
State	Superseded
Delegated to:	BPF
Headers	show Return-Path: <bpf-owner@kernel.org> From: Alexei Starovoitov <alexei.starovoitov@gmail.com> To: davem@davemloft.net Cc: daniel@iogearbox.net, andrii@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v2 bpf-next 10/16] bpf: Add bpf_btf_find_by_name_kind() helper. Date: Thu, 22 Apr 2021 17:26:40 -0700 Message-Id: <20210423002646.35043-11-alexei.starovoitov@gmail.com> In-Reply-To: <20210423002646.35043-1-alexei.starovoitov@gmail.com> References: <20210423002646.35043-1-alexei.starovoitov@gmail.com> Precedence: bulk
Series	bpf: syscall program, FD array, loader program, light skeleton. \| expand [v2,bpf-next,00/16] bpf: syscall program, FD array, loader program, light skeleton. [v2,bpf-next,01/16] bpf: Introduce bpf_sys_bpf() helper and program type. [v2,bpf-next,02/16] bpf: Introduce bpfptr_t user/kernel pointer. [v2,bpf-next,03/16] bpf: Prepare bpf syscall to be used from kernel and user space. [v2,bpf-next,04/16] libbpf: Support for syscall program type [v2,bpf-next,05/16] selftests/bpf: Test for syscall program type [v2,bpf-next,06/16] bpf: Make btf_load command to be bpfptr_t compatible. [v2,bpf-next,07/16] selftests/bpf: Test for btf_load command. [v2,bpf-next,08/16] bpf: Introduce fd_idx [v2,bpf-next,09/16] libbpf: Support for fd_idx [v2,bpf-next,10/16] bpf: Add bpf_btf_find_by_name_kind() helper. [v2,bpf-next,11/16] bpf: Add bpf_sys_close() helper. [v2,bpf-next,12/16] libbpf: Change the order of data and text relocations. [v2,bpf-next,13/16] libbpf: Add bpf_object pointer to kernel_supports(). [v2,bpf-next,14/16] libbpf: Generate loader program out of BPF ELF file. [v2,bpf-next,15/16] bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command. [v2,bpf-next,16/16] selftests/bpf: Convert few tests to light skeleton.

Context	Check	Description
netdev/cover_letter	success	Link
netdev/fixes_present	success	Link
netdev/patch_count	fail	Series longer than 15 patches
netdev/tree_selection	success	Clearly marked for bpf-next
netdev/subject_prefix	success	Link
netdev/cc_maintainers	warning	8 maintainers not CCed: joe@cilium.io yhs@fb.com kpsingh@kernel.org kafai@fb.com ast@kernel.org john.fastabend@gmail.com songliubraving@fb.com quentin@isovalent.com
netdev/source_inline	success	Was 0 now: 0
netdev/verify_signedoff	success	Link
netdev/module_param	success	Was 0 now: 0
netdev/build_32bit	success	Errors and warnings before: 11979 this patch: 11979
netdev/kdoc	success	Errors and warnings before: 0 this patch: 0
netdev/verify_fixes	success	Link
netdev/checkpatch	warning	CHECK: braces {} should be used on all arms of this statement WARNING: line length of 87 exceeds 80 columns WARNING: line length of 88 exceeds 80 columns WARNING: please, no space before tabs
netdev/build_allmodconfig_warn	success	Errors and warnings before: 12466 this patch: 12466
netdev/header_inline	success	Link

diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 0f841bd0cb85..4cf361eb6a80 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1972,6 +1972,7 @@ extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto; extern const struct bpf_func_proto bpf_task_storage_get_proto; extern const struct bpf_func_proto bpf_task_storage_delete_proto; extern const struct bpf_func_proto bpf_for_each_map_elem_proto; +extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto; const struct bpf_func_proto *bpf_tracing_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index de58a714ed36..253f5f031f08 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4748,6 +4748,13 @@ union bpf_attr { * Execute bpf syscall with given arguments. * Return * A syscall result. + * + * long bpf_btf_find_by_name_kind(u32 btf_fd, char *name, u32 kind, int flags) + * Description + * Find given name with given type in BTF pointed to by btf_fd. + * If btf_fd is zero look for the name in vmlinux BTF and in module's BTFs. + * Return + * Returns btf_id and btf_obj_fd in lower and upper 32 bits. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -4917,6 +4924,7 @@ union bpf_attr { FN(for_each_map_elem), \ FN(snprintf), \ FN(sys_bpf), \ + FN(btf_find_by_name_kind), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index fbf6c06a9d62..446c64171464 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6085,3 +6085,71 @@ struct module *btf_try_get_module(const struct btf *btf) return res; } + +BPF_CALL_4(bpf_btf_find_by_name_kind, int, btf_fd, char *, name, u32, kind, int, flags) +{ + char kname[KSYM_NAME_LEN]; + struct btf *btf; + long ret; + + if (flags) + return -EINVAL; + + ret = strncpy_from_kernel_nofault(kname, name, sizeof(kname)); + if (ret < 0) + return ret; + if (btf_fd) + btf = btf_get_by_fd(btf_fd); + else + btf = bpf_get_btf_vmlinux(); + if (IS_ERR(btf)) + return PTR_ERR(btf); + + ret = btf_find_by_name_kind(btf, kname, kind); + /* ret is never zero, since btf_find_by_name_kind returns + * positive btf_id or negative error. + */ + if (btf_fd) + btf_put(btf); + else if (ret < 0) { + struct btf *mod_btf; + int id; + + /* If name is not found in vmlinux's BTF then search in module's BTFs */ + spin_lock_bh(&btf_idr_lock); + idr_for_each_entry(&btf_idr, mod_btf, id) { + if (!btf_is_module(mod_btf)) + continue; + /* linear search could be slow hence unlock/lock + * the IDR to avoiding holding it for too long + */ + btf_get(mod_btf); + spin_unlock_bh(&btf_idr_lock); + ret = btf_find_by_name_kind(mod_btf, kname, kind); + if (ret > 0) { + int btf_obj_fd; + + btf_obj_fd = __btf_new_fd(mod_btf); + if (btf_obj_fd < 0) { + btf_put(mod_btf); + return btf_obj_fd; + } + return ret | (((u64)btf_obj_fd) << 32); + } + spin_lock_bh(&btf_idr_lock); + btf_put(mod_btf); + } + spin_unlock_bh(&btf_idr_lock); + } + return ret; +} + +const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = { + .func = bpf_btf_find_by_name_kind, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_ANYTHING, +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a81496c5d09f..638c7acad925 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4574,6 +4574,8 @@ syscall_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) switch (func_id) { case BPF_FUNC_sys_bpf: return &bpf_sys_bpf_proto; + case BPF_FUNC_btf_find_by_name_kind: + return &bpf_btf_find_by_name_kind_proto; default: return tracing_prog_func_proto(func_id, prog); } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6c8e178d8ffa..5841adb44de6 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4748,6 +4748,13 @@ union bpf_attr { * Execute bpf syscall with given arguments. * Return * A syscall result. + * + * long bpf_btf_find_by_name_kind(u32 btf_fd, char *name, u32 kind, int flags) + * Description + * Find given name with given type in BTF pointed to by btf_fd. + * If btf_fd is zero look for the name in vmlinux BTF and in module's BTFs. + * Return + * Returns btf_id and btf_obj_fd in lower and upper 32 bits. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -4917,6 +4924,7 @@ union bpf_attr { FN(for_each_map_elem), \ FN(snprintf), \ FN(sys_bpf), \ + FN(btf_find_by_name_kind), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper

[v2,bpf-next,10/16] bpf: Add bpf_btf_find_by_name_kind() helper.

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