From patchwork Wed Sep 20 15:59:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kui-Feng Lee X-Patchwork-Id: 13393064 X-Patchwork-Delegate: bpf@iogearbox.net 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 0D5233C6AA for ; Wed, 20 Sep 2023 16:01:00 +0000 (UTC) Received: from mail-yw1-x1130.google.com (mail-yw1-x1130.google.com [IPv6:2607:f8b0:4864:20::1130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F29B9B9 for ; Wed, 20 Sep 2023 09:00:57 -0700 (PDT) Received: by mail-yw1-x1130.google.com with SMTP id 00721157ae682-59be8a2099bso71417417b3.0 for ; Wed, 20 Sep 2023 09:00:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1695225656; x=1695830456; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=j5QreV6pWpdf4lxBYZjAA0RLHuYyklhaH4h2os7LIwo=; b=a47XlQxiOOsGT4+N4Fy9FOrC7NfVOLoo/gjvuRpJcRFUoQUoie/Kf1jaxU9Bn/4NlQ wcZlZyCx1eDNxak2OHM7vQ/lTusEee9EgasNniaLr4u+ShGMq2zy1SO6x0SbZz1suXmI v+kPbuMxYT3NaeI3l3Wgtti0POlgZ5uwQH6+A5tB/hj5H66uiPpxcTfpYrHGllKr/7EP bacMf1uD4mJ4sKQYAhKU1DmceTvSebfYNJi9fqyaK7v3aj9/jSanFSgIu03mNRmz5b6O TSE7MTe+HKHzWrtGX3w2zIzb3XoWREq7MdD4mpKPNR9qHmafWzpYG5RYvZG2O5XElbmH jT3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695225656; x=1695830456; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=j5QreV6pWpdf4lxBYZjAA0RLHuYyklhaH4h2os7LIwo=; b=oZnhH7N3Vx7fY9ve0RaXU7YFgwJ64ZMGECdds36ZxNToAj8/yfXwxsGn2fGDg1yhIK H9X4ptLsW/ASNp5+J/cZqh9zu7gwed30sdpTIba41W4nON4LnYFT/haY1RHiLAUv0E4s wWI+XD7+St07AxcDqm7RSWRq7ShA7jIwwCw52AXB0O7sY/mgNut5Ndtjp+bKy8rl0GnI DPyJRtQO4HDnaut8W4TIy1cQGqFE45NbqfVdq8UTow0L7gJk8g/hIvTJOKXr3BUShLnP LwD/1Ne/FLRDAhQeOsjwYP2YtDyPzLkmqanRz5fwgtKR/hhBJVrKdUYr1o0M3X0Wwwqe AsZw== X-Gm-Message-State: AOJu0YzidcUTPbdSfJMZzB81iUD76kg3hD2OOXSMxbsz6FHidFQ95R4H C31wa8N7i6gKRYSgOKTJxY6I9CetJZ0= X-Google-Smtp-Source: AGHT+IFKL/SbSBFHjSOCsTi3Z3cS/kjB2ffbQYf/ldPv5nH/DEVvuB+satZQ634n4hAACx+t1HIAuw== X-Received: by 2002:a81:4895:0:b0:589:d560:adaa with SMTP id v143-20020a814895000000b00589d560adaamr2835133ywa.7.1695225656135; Wed, 20 Sep 2023 09:00:56 -0700 (PDT) Received: from kickker.attlocal.net ([2600:1700:6cf8:1240:dcd2:9730:2c7c:239f]) by smtp.gmail.com with ESMTPSA id m131-20020a817189000000b00589dbcf16cbsm3860490ywc.35.2023.09.20.09.00.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Sep 2023 09:00:54 -0700 (PDT) From: thinker.li@gmail.com To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev, song@kernel.org, kernel-team@meta.com, andrii@kernel.org Cc: sinquersw@gmail.com, kuifeng@meta.com, Kui-Feng Lee Subject: [RFC bpf-next v3 09/11] libbpf: Find correct module BTFs for struct_ops maps and progs. Date: Wed, 20 Sep 2023 08:59:22 -0700 Message-Id: <20230920155923.151136-10-thinker.li@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230920155923.151136-1-thinker.li@gmail.com> References: <20230920155923.151136-1-thinker.li@gmail.com> 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_BLOCKED,SPF_HELO_NONE,SPF_PASS 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 X-Patchwork-State: RFC From: Kui-Feng Lee Find module BTFs for struct_ops maps and progs and pass them to the kernel. It ensures the kernel resolve type IDs from correct module BTFs. For the map of a struct_ops object, mod_btf is added to bpf_map to keep a reference to the module BTF. It's FD is passed to the kernel as mod_btf_fd when it is created. For a prog attaching to a struct_ops object, attach_btf_obj_fd of bpf_prog is the FD pointing to a module BTF in the kernel. Signed-off-by: Kui-Feng Lee --- tools/lib/bpf/bpf.c | 3 +- tools/lib/bpf/bpf.h | 4 +- tools/lib/bpf/libbpf.c | 121 ++++++++++++++++++++++++----------------- 3 files changed, 75 insertions(+), 53 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index b0f1913763a3..df4b7570ad92 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -169,7 +169,7 @@ int bpf_map_create(enum bpf_map_type map_type, __u32 max_entries, const struct bpf_map_create_opts *opts) { - const size_t attr_sz = offsetofend(union bpf_attr, map_extra); + const size_t attr_sz = offsetofend(union bpf_attr, mod_btf_fd); union bpf_attr attr; int fd; @@ -191,6 +191,7 @@ int bpf_map_create(enum bpf_map_type map_type, attr.btf_key_type_id = OPTS_GET(opts, btf_key_type_id, 0); attr.btf_value_type_id = OPTS_GET(opts, btf_value_type_id, 0); attr.btf_vmlinux_value_type_id = OPTS_GET(opts, btf_vmlinux_value_type_id, 0); + attr.mod_btf_fd = OPTS_GET(opts, mod_btf_fd, 0); attr.inner_map_fd = OPTS_GET(opts, inner_map_fd, 0); attr.map_flags = OPTS_GET(opts, map_flags, 0); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 74c2887cfd24..d18f75b0ccc9 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -51,8 +51,10 @@ struct bpf_map_create_opts { __u32 numa_node; __u32 map_ifindex; + + __u32 mod_btf_fd; }; -#define bpf_map_create_opts__last_field map_ifindex +#define bpf_map_create_opts__last_field mod_btf_fd LIBBPF_API int bpf_map_create(enum bpf_map_type map_type, const char *map_name, diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3a6108e3238b..df6ba5494adb 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -519,6 +519,7 @@ struct bpf_map { struct bpf_map_def def; __u32 numa_node; __u32 btf_var_idx; + struct module_btf *mod_btf; __u32 btf_key_type_id; __u32 btf_value_type_id; __u32 btf_vmlinux_value_type_id; @@ -893,6 +894,42 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, return 0; } +static int load_module_btfs(struct bpf_object *obj); + +static int find_kern_btf_id(struct bpf_object *obj, const char *kern_name, + __u16 kind, struct btf **res_btf, + struct module_btf **res_mod_btf) +{ + struct module_btf *mod_btf; + struct btf *btf; + int i, id, err; + + btf = obj->btf_vmlinux; + mod_btf = NULL; + id = btf__find_by_name_kind(btf, kern_name, kind); + + if (id == -ENOENT) { + err = load_module_btfs(obj); + if (err) + return err; + + for (i = 0; i < obj->btf_module_cnt; i++) { + /* we assume module_btf's BTF FD is always >0 */ + mod_btf = &obj->btf_modules[i]; + btf = mod_btf->btf; + id = btf__find_by_name_kind_own(btf, kern_name, kind); + if (id != -ENOENT) + break; + } + } + if (id <= 0) + return -ESRCH; + + *res_btf = btf; + *res_mod_btf = mod_btf; + return id; +} + static const struct btf_member * find_member_by_offset(const struct btf_type *t, __u32 bit_offset) { @@ -927,17 +964,23 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, const char *name, __u32 kind); static int -find_struct_ops_kern_types(const struct btf *btf, const char *tname, +find_struct_ops_kern_types(struct bpf_object *obj, const char *tname, + struct module_btf **mod_btf, const struct btf_type **type, __u32 *type_id, const struct btf_type **vtype, __u32 *vtype_id, const struct btf_member **data_member) { const struct btf_type *kern_type, *kern_vtype; const struct btf_member *kern_data_member; + struct btf *btf; __s32 kern_vtype_id, kern_type_id; __u32 i; - kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); + /* XXX: should search module BTFs as well. We need module name here + * to locate a correct BTF type. + */ + kern_type_id = find_kern_btf_id(obj, tname, BTF_KIND_STRUCT, + &btf, mod_btf); if (kern_type_id < 0) { pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", tname); @@ -992,13 +1035,15 @@ static bool bpf_map__is_struct_ops(const struct bpf_map *map) /* Init the map's fields that depend on kern_btf */ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, - const struct btf *btf, - const struct btf *kern_btf) + struct bpf_object *obj) { const struct btf_member *member, *kern_member, *kern_data_member; const struct btf_type *type, *kern_type, *kern_vtype; __u32 i, kern_type_id, kern_vtype_id, kern_data_off; struct bpf_struct_ops *st_ops; + const struct btf *kern_btf; + struct module_btf *mod_btf; + const struct btf *btf = obj->btf; void *data, *kern_data; const char *tname; int err; @@ -1006,16 +1051,19 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, st_ops = map->st_ops; type = st_ops->type; tname = st_ops->tname; - err = find_struct_ops_kern_types(kern_btf, tname, + err = find_struct_ops_kern_types(obj, tname, &mod_btf, &kern_type, &kern_type_id, &kern_vtype, &kern_vtype_id, &kern_data_member); if (err) return err; + kern_btf = mod_btf ? mod_btf->btf : obj->btf_vmlinux; + pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n", map->name, st_ops->type_id, kern_type_id, kern_vtype_id); + map->mod_btf = mod_btf; map->def.value_size = kern_vtype->size; map->btf_vmlinux_value_type_id = kern_vtype_id; @@ -1091,6 +1139,9 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, return -ENOTSUP; } + /* XXX: attach_btf_obj_fd is needed as well */ + if (mod_btf) + prog->attach_btf_obj_fd = mod_btf->fd; prog->attach_btf_id = kern_type_id; prog->expected_attach_type = kern_member_idx; @@ -1133,8 +1184,8 @@ static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) if (!bpf_map__is_struct_ops(map)) continue; - err = bpf_map__init_kern_struct_ops(map, obj->btf, - obj->btf_vmlinux); + /* XXX: should be a module btf if not vmlinux */ + err = bpf_map__init_kern_struct_ops(map, obj); if (err) return err; } @@ -5193,8 +5244,10 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b create_attr.numa_node = map->numa_node; create_attr.map_extra = map->map_extra; - if (bpf_map__is_struct_ops(map)) + if (bpf_map__is_struct_ops(map)) { create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id; + create_attr.mod_btf_fd = map->mod_btf ? map->mod_btf->fd : 0; + } if (obj->btf && btf__fd(obj->btf) >= 0) { create_attr.btf_fd = btf__fd(obj->btf); @@ -7700,40 +7753,6 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj) return libbpf_kallsyms_parse(kallsyms_cb, obj); } -static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name, - __u16 kind, struct btf **res_btf, - struct module_btf **res_mod_btf) -{ - struct module_btf *mod_btf; - struct btf *btf; - int i, id, err; - - btf = obj->btf_vmlinux; - mod_btf = NULL; - id = btf__find_by_name_kind(btf, ksym_name, kind); - - if (id == -ENOENT) { - err = load_module_btfs(obj); - if (err) - return err; - - for (i = 0; i < obj->btf_module_cnt; i++) { - /* we assume module_btf's BTF FD is always >0 */ - mod_btf = &obj->btf_modules[i]; - btf = mod_btf->btf; - id = btf__find_by_name_kind_own(btf, ksym_name, kind); - if (id != -ENOENT) - break; - } - } - if (id <= 0) - return -ESRCH; - - *res_btf = btf; - *res_mod_btf = mod_btf; - return id; -} - static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj, struct extern_desc *ext) { @@ -7744,7 +7763,7 @@ static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj, struct btf *btf = NULL; int id, err; - id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf); + id = find_kern_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf); if (id < 0) { if (id == -ESRCH && ext->is_weak) return 0; @@ -7798,7 +7817,7 @@ static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj, local_func_proto_id = ext->ksym.type_id; - kfunc_id = find_ksym_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf, + kfunc_id = find_kern_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf, &mod_btf); if (kfunc_id < 0) { if (kfunc_id == -ESRCH && ext->is_weak) @@ -9464,9 +9483,9 @@ static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) return err; } -static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, - enum bpf_attach_type attach_type, - int *btf_obj_fd, int *btf_type_id) +static int find_kernel_attach_btf_id(struct bpf_object *obj, const char *attach_name, + enum bpf_attach_type attach_type, + int *btf_obj_fd, int *btf_type_id) { int ret, i; @@ -9531,7 +9550,7 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac *btf_obj_fd = 0; *btf_type_id = 1; } else { - err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id); + err = find_kernel_attach_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id); } if (err) { pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n", @@ -12945,9 +12964,9 @@ int bpf_program__set_attach_target(struct bpf_program *prog, err = bpf_object__load_vmlinux_btf(prog->obj, true); if (err) return libbpf_err(err); - err = find_kernel_btf_id(prog->obj, attach_func_name, - prog->expected_attach_type, - &btf_obj_fd, &btf_id); + err = find_kernel_attach_btf_id(prog->obj, attach_func_name, + prog->expected_attach_type, + &btf_obj_fd, &btf_id); if (err) return libbpf_err(err); }