From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E49F41FAD for ; Fri, 5 Jan 2024 00:09:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uLbl6ihU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92C79C433C7; Fri, 5 Jan 2024 00:09:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704413364; bh=1AR3hgcJQGlnyqu5zNrIvgwAWVzLPVVbCrxAK82ulfY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uLbl6ihURNOPmq0g6I2FfZ96WcRWOHYHqBFez6XbkH9rX2ROTgR70IKPavgyajbIK i41QzRbTIUVunCtS5hwzmZNNe+01s5WLKoSR/wwOe5Q0Jj0xxZ/YYeFWmraiprxkQz pjU7BTJkdReqz7iO/V+yOEaUKeKiTS1FSb2P5I8weD3st6XKOauPnZGZY62UMeQal1 0mJhOd4rxUlkePQny85s7D1UyONrMW8IW0Bf68BK/Yf/JOIPPwx1KqxxygLeSn9ZXn a6a/4oPihYFka7PJxgs10EF7JBLKONWxA/I8iMH+UWPMvJwOBkcTnT9MOjcAkG7dAM xVuDOC12kIwvg== From: Andrii Nakryiko To: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org Cc: andrii@kernel.org, kernel-team@meta.com, Dave Marchevsky Subject: [PATCH bpf-next 4/8] bpf: support multiple tags per argument Date: Thu, 4 Jan 2024 16:09:05 -0800 Message-Id: <20240105000909.2818934-5-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240105000909.2818934-1-andrii@kernel.org> References: <20240105000909.2818934-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add ability to iterate multiple decl_tag types pointed to the same function argument. Use this to support multiple __arg_xxx tags per global subprog argument. We leave btf_find_decl_tag_value() intact, but change its implementation to use a new btf_find_next_decl_tag() which can be straightforwardly used to find next BTF type ID of a matching btf_decl_tag type. btf_prepare_func_args() is switched from btf_find_decl_tag_value() to btf_find_next_decl_tag() to gain multiple tags per argument support. Signed-off-by: Andrii Nakryiko --- include/linux/bpf.h | 2 ++ kernel/bpf/btf.c | 64 +++++++++++++++++++++++++++++---------------- 2 files changed, 43 insertions(+), 23 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7671530d6e4e..7ab4a290418a 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2471,6 +2471,8 @@ int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *pr struct btf *btf, const struct btf_type *t); const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt, int comp_idx, const char *tag_key); +int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt, + int comp_idx, const char *tag_key, int last_id); struct bpf_prog *bpf_prog_by_id(u32 id); struct bpf_link *bpf_link_by_id(u32 id); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index ccaf57e755fc..368d8fe19d35 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3310,30 +3310,48 @@ static int btf_find_kptr(const struct btf *btf, const struct btf_type *t, return BTF_FIELD_FOUND; } -const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt, - int comp_idx, const char *tag_key) +int btf_find_next_decl_tag(const struct btf *btf, const struct btf_type *pt, + int comp_idx, const char *tag_key, int last_id) { - const char *value = NULL; - int i; + int len = strlen(tag_key); + int i, n; - for (i = 1; i < btf_nr_types(btf); i++) { + for (i = last_id + 1, n = btf_nr_types(btf); i < n; i++) { const struct btf_type *t = btf_type_by_id(btf, i); - int len = strlen(tag_key); if (!btf_type_is_decl_tag(t)) continue; - if (pt != btf_type_by_id(btf, t->type) || - btf_type_decl_tag(t)->component_idx != comp_idx) + if (pt != btf_type_by_id(btf, t->type)) + continue; + if (btf_type_decl_tag(t)->component_idx != comp_idx) continue; if (strncmp(__btf_name_by_offset(btf, t->name_off), tag_key, len)) continue; - /* Prevent duplicate entries for same type */ - if (value) - return ERR_PTR(-EEXIST); - value = __btf_name_by_offset(btf, t->name_off) + len; + return i; } - if (!value) - return ERR_PTR(-ENOENT); + return -ENOENT; +} + +const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type *pt, + int comp_idx, const char *tag_key) +{ + const char *value = NULL; + const struct btf_type *t; + int len, id; + + id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0); + if (id < 0) + return ERR_PTR(id); + + t = btf_type_by_id(btf, id); + len = strlen(tag_key); + value = __btf_name_by_offset(btf, t->name_off) + len; + + /* Prevent duplicate entries for same type */ + id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, id); + if (id >= 0) + return ERR_PTR(-EEXIST); + return value; } @@ -6870,20 +6888,16 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) * Only PTR_TO_CTX and SCALAR are supported atm. */ for (i = 0; i < nargs; i++) { - const char *tag; u32 tags = 0; + int id = 0; - tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:"); - if (IS_ERR(tag) && PTR_ERR(tag) == -ENOENT) { - tag = NULL; - } else if (IS_ERR(tag)) { - bpf_log(log, "arg#%d type's tag fetching failure: %ld\n", i, PTR_ERR(tag)); - return PTR_ERR(tag); - } /* 'arg:' decl_tag takes precedence over derivation of * register type from BTF type itself */ - if (tag) { + while ((id = btf_find_next_decl_tag(btf, fn_t, i, "arg:", id)) > 0) { + const struct btf_type *tag_t = btf_type_by_id(btf, id); + const char *tag = __btf_name_by_offset(btf, tag_t->name_off) + 4; + /* disallow arg tags in static subprogs */ if (!is_global) { bpf_log(log, "arg#%d type tag is not supported in static functions\n", i); @@ -6899,6 +6913,10 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) return -EOPNOTSUPP; } } + if (id != -ENOENT) { + bpf_log(log, "arg#%d type tag fetching failure: %d\n", i, id); + return id; + } t = btf_type_by_id(btf, args[i].type); while (btf_type_is_modifier(t)) -- 2.34.1