From patchwork Fri Oct 13 22:43:00 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: 13421808 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 CB0422C84B for ; Fri, 13 Oct 2023 22:43:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TRsS4KZn" Received: from mail-yw1-x112c.google.com (mail-yw1-x112c.google.com [IPv6:2607:f8b0:4864:20::112c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FB95BF for ; Fri, 13 Oct 2023 15:43:15 -0700 (PDT) Received: by mail-yw1-x112c.google.com with SMTP id 00721157ae682-5a7af20c488so31257817b3.1 for ; Fri, 13 Oct 2023 15:43:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697236994; x=1697841794; 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=zxMqaT8h6QY3nPgn2rnbtpHscHvTCIxN/Kv68wogCGY=; b=TRsS4KZn/2JSE3brtMgGC06nW1AD8Fp7Sp0y1iQT5Dn+xhSAHgeczaDjat9dhkWKVo OpfXQP8PrAWT2OpnglE0TysqSmc05kfw0JM7BesrF63/doxhbxgZEXaBRpeL/TD6CW+v lPymCchyh7BsXM7BezLoboaSJY/5lstwDMuqU9bZjd+3CUX/GM/ae8lsp6K48oyssEOw nH4cQ20RnyP+uEKPS11IqTdHaGuVJvP0bDxOpy/rzozvAjpkSMmoPm8dn3WoqfFGp7OX oaExBT46azWAA9SU21l78v8n3m5OjMxdMDHTdsdM3xhJnla3AAnglMCVGZBAfTBwmEuP 9OSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697236994; x=1697841794; 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=zxMqaT8h6QY3nPgn2rnbtpHscHvTCIxN/Kv68wogCGY=; b=e0e//wW7KrJk228nK2mf4I8gLWvvmp0JgiP5VSK4fXVsjitVG8k68Qne7F6F1xWQjY b8Wive2mS4bH4JwkLGDkmi+TEe3vfFR279jdOKOJVD7we5sMORZF9LkwORlBh5Qe2GOZ EToQerQesmAC4SaDNcIRlsMB+EwsicS9WobXw1WxUQk6yxNGmM7eG3+UPEvw9QxT+Tae Xd5X0Sg5NQEUrzlhWTvfarl20CobKu1Bn6MLOHdhBPRKEDTr/cMmi+qEim5GolRAI986 cgrGybDhChlIJRc0f1JSr1uPQurxlFZ95phti/AIRzXiZy+M14CiRRDjwZaatiE8psU0 s9dg== X-Gm-Message-State: AOJu0YyAEUKN/shLDj4wD2O0is5BzIybyk+j4DdVQNdYfSeB4ah03KBU +IpdDjCVWZ+QKodXAoFrwPQJ5uSzb+g= X-Google-Smtp-Source: AGHT+IG4AflsvHX0VhPyt/4Z5Aw4wzwGKy7DpTqDFJ3+IYWAZWfI3WXQs7ylkBxtSslx7XM/qlzKqg== X-Received: by 2002:a81:a083:0:b0:5a7:db09:5067 with SMTP id x125-20020a81a083000000b005a7db095067mr10590860ywg.20.1697236994529; Fri, 13 Oct 2023 15:43:14 -0700 (PDT) Received: from kickker.attlocal.net ([2600:1700:6cf8:1240:df89:3514:fdf4:ee2]) by smtp.gmail.com with ESMTPSA id g141-20020a0ddd93000000b00592548b2c47sm101989ywe.80.2023.10.13.15.43.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Oct 2023 15:43:14 -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, drosen@google.com Cc: sinquersw@gmail.com, kuifeng@meta.com, Kui-Feng Lee Subject: [PATCH bpf-next v4 5/9] bpf: pass attached BTF to the bpf_struct_ops subsystem Date: Fri, 13 Oct 2023 15:43:00 -0700 Message-Id: <20231013224304.187218-6-thinker.li@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231013224304.187218-1-thinker.li@gmail.com> References: <20231013224304.187218-1-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 From: Kui-Feng Lee Giving a BTF, the bpf_struct_ops knows the right place to look up type info associated with a type ID. This enables a user space program to load a struct_ops object linked to a struct_ops type defined by a module, by providing the module BTF (fd). The bpf_prog includes attach_btf in aux which is passed along with the bpf_attr when loading the program. The purpose of attach_btf is to determine the btf type of attach_btf_id. The attach_btf_id is then used to identify the traced function for a trace program. In the case of struct_ops programs, it is used to identify the struct_ops type of the struct_ops object that a program is attached to. Signed-off-by: Kui-Feng Lee --- include/uapi/linux/bpf.h | 5 +++++ kernel/bpf/bpf_struct_ops.c | 34 +++++++++++++++++++++++++++------- kernel/bpf/syscall.c | 2 +- kernel/bpf/verifier.c | 4 +++- tools/include/uapi/linux/bpf.h | 5 +++++ 5 files changed, 41 insertions(+), 9 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 73b155e52204..b5ef22f65f35 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1390,6 +1390,11 @@ union bpf_attr { * to using 5 hash functions). */ __u64 map_extra; + + __u32 value_type_btf_obj_fd; /* fd pointing to a BTF + * type data for + * btf_vmlinux_value_type_id. + */ }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */ diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 69703584fa4a..60445ff32275 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -677,6 +677,7 @@ static void __bpf_struct_ops_map_free(struct bpf_map *map) bpf_jit_uncharge_modmem(PAGE_SIZE); } bpf_map_area_free(st_map->uvalue); + btf_put(st_map->st_ops->btf); module_put(st_map->st_ops->owner); bpf_map_area_free(st_map); } @@ -718,23 +719,36 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) struct bpf_struct_ops_map *st_map; const struct btf_type *t, *vt; struct bpf_map *map; + struct btf *btf; int ret; - st_ops = bpf_struct_ops_find_value(btf_vmlinux, attr->btf_vmlinux_value_type_id); - if (!st_ops) + if (attr->value_type_btf_obj_fd) { + btf = btf_get_by_fd(attr->value_type_btf_obj_fd); + if (IS_ERR(btf)) + return ERR_PTR(PTR_ERR(btf)); + } else { + btf = btf_vmlinux; + btf_get(btf); + } + st_ops = bpf_struct_ops_find_value(btf, attr->btf_vmlinux_value_type_id); + if (!st_ops) { + btf_put(btf); return ERR_PTR(-ENOTSUPP); + } /* If st_ops->owner is NULL, it means the struct_ops is * statically defined in the kernel. We don't need to * take a refcount on it. */ - if (st_ops->owner && !btf_try_get_module(st_ops->btf)) + if (st_ops->owner && !btf_try_get_module(st_ops->btf)) { + btf_put(btf); return ERR_PTR(-EINVAL); + } vt = st_ops->value_type; if (attr->value_size != vt->size) { - module_put(st_ops->owner); - return ERR_PTR(-EINVAL); + ret = -EINVAL; + goto errout; } t = st_ops->type; @@ -747,8 +761,8 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) st_map = bpf_map_area_alloc(st_map_size, NUMA_NO_NODE); if (!st_map) { - module_put(st_ops->owner); - return ERR_PTR(-ENOMEM); + ret = -ENOMEM; + goto errout; } st_map->st_ops = st_ops; @@ -784,6 +798,12 @@ static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr) bpf_map_init_from_attr(map, attr); return map; + +errout: + btf_put(btf); + module_put(st_ops->owner); + + return ERR_PTR(ret); } static u64 bpf_struct_ops_map_mem_usage(const struct bpf_map *map) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 85c1d908f70f..5daf8a2c2bba 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1097,7 +1097,7 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, return ret; } -#define BPF_MAP_CREATE_LAST_FIELD map_extra +#define BPF_MAP_CREATE_LAST_FIELD value_type_btf_obj_fd /* called via syscall */ static int map_create(union bpf_attr *attr) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6564a03c425d..ce4df24eb03b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19623,6 +19623,7 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) const struct btf_member *member; struct bpf_prog *prog = env->prog; u32 btf_id, member_idx; + struct btf *btf; const char *mname; if (!prog->gpl_compatible) { @@ -19630,8 +19631,9 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) return -EINVAL; } + btf = prog->aux->attach_btf; btf_id = prog->aux->attach_btf_id; - st_ops = bpf_struct_ops_find(btf_vmlinux, btf_id); + st_ops = bpf_struct_ops_find(btf, btf_id); if (!st_ops) { verbose(env, "attach_btf_id %u is not a supported struct\n", btf_id); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 73b155e52204..b5ef22f65f35 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1390,6 +1390,11 @@ union bpf_attr { * to using 5 hash functions). */ __u64 map_extra; + + __u32 value_type_btf_obj_fd; /* fd pointing to a BTF + * type data for + * btf_vmlinux_value_type_id. + */ }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */