From patchwork Mon Jul 31 07:30:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13333930 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 293F9C001DE for ; Mon, 31 Jul 2023 07:32:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231418AbjGaHcA (ORCPT ); Mon, 31 Jul 2023 03:32:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231433AbjGaHbe (ORCPT ); Mon, 31 Jul 2023 03:31:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DA7F2D7E; Mon, 31 Jul 2023 00:30:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B6C0560F1E; Mon, 31 Jul 2023 07:30:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22CCAC433C7; Mon, 31 Jul 2023 07:30:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690788629; bh=SVaKMsm5wi9MtePH615CD5h2bQfFDb6xVagKrZjtk0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LdZJ7fD3T+xhrnDmL+T7tHHUuFYDGmrM0yS8YzfN7su2DNxMmUwE6wd0weiynMwWM bZtsOuDuv09Q99o9hdOxijhLTUDclWHnM3cBEoOw5kIGaAZijCZrOpAqfIPG4ANZ+2 Lv62sx5inwIHaXGJYAc3vjj4m2SLW4vZH6LFTL6IWyz8Wd9AxUNb24y8xWLWRkKrXw md/vTfZyIR3H2GN3e9nsdrJsR0DqveTwZ+9uOOwPfF0/ScgqnrE/sIHs48vzdeZAgr 2SANoGKJTxFs+ncRbd5UV7l9YfrukVMYifnrtCenO1uU5LL3NlIv/oE0z2lcoM/6lL oqo1JY5YBc4OQ== From: "Masami Hiramatsu (Google)" To: linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steven Rostedt , mhiramat@kernel.org, Martin KaFai Lau , bpf@vger.kernel.org, Sven Schnelle , Alexei Starovoitov Subject: [PATCH v4 2/9] bpf/btf: tracing: Move finding func-proto API and getting func-param API to BTF Date: Mon, 31 Jul 2023 16:30:24 +0900 Message-Id: <169078862446.173706.13484451284649857042.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <169078860386.173706.3091034523220945605.stgit@devnote2> References: <169078860386.173706.3091034523220945605.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: Masami Hiramatsu (Google) Move generic function-proto find API and getting function parameter API to BTF library code from trace_probe.c. This will avoid redundant efforts on different feature. Signed-off-by: Masami Hiramatsu (Google) --- Changes in v3: - Remove perameter check. - Fix a typo. - Add a type check for btf_get_func_param() and add comment for that. - Use bpf_find_btf_id() and add bpf_put(). - Move the code before btf_show() related code. --- include/linux/btf.h | 4 ++++ kernel/bpf/btf.c | 47 +++++++++++++++++++++++++++++++++++++++++ kernel/trace/trace_probe.c | 50 +++++++++----------------------------------- 3 files changed, 61 insertions(+), 40 deletions(-) diff --git a/include/linux/btf.h b/include/linux/btf.h index dbfe41a09c4b..20e3a07eef8f 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -222,6 +222,10 @@ const struct btf_type * btf_resolve_size(const struct btf *btf, const struct btf_type *type, u32 *type_size); const char *btf_type_str(const struct btf_type *t); +const struct btf_type *btf_find_func_proto(const char *func_name, + struct btf **btf_p); +const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, + s32 *nr); #define for_each_member(i, struct_type, member) \ for (i = 0, member = btf_type_member(struct_type); \ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index b9b0eb1189bb..f7b25c615269 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -911,6 +911,53 @@ static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf, return t; } +/* + * Find a function proto type by name, and return the btf_type with its btf + * in *@btf_p. Return NULL if not found. + * Note that caller has to call btf_put(*@btf_p) after using the btf_type. + */ +const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **btf_p) +{ + const struct btf_type *t; + s32 id; + + id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p); + if (id < 0) + return NULL; + + /* Get BTF_KIND_FUNC type */ + t = btf_type_by_id(*btf_p, id); + if (!t || !btf_type_is_func(t)) + goto err; + + /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */ + t = btf_type_by_id(*btf_p, t->type); + if (!t || !btf_type_is_func_proto(t)) + goto err; + + return t; +err: + btf_put(*btf_p); + return NULL; +} + +/* + * Get function parameter with the number of parameters. + * This can return NULL if the function has no parameters. + * It can return -EINVAL if the @func_proto is not a function proto type. + */ +const struct btf_param *btf_get_func_param(const struct btf_type *func_proto, s32 *nr) +{ + if (!btf_type_is_func_proto(func_proto)) + return ERR_PTR(-EINVAL); + + *nr = btf_type_vlen(func_proto); + if (*nr > 0) + return (const struct btf_param *)(func_proto + 1); + else + return NULL; +} + #define BTF_SHOW_MAX_ITER 10 #define BTF_KIND_BIT(kind) (1ULL << kind) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index ecbe28f8d676..21a228d88ebb 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -361,38 +361,6 @@ static const char *type_from_btf_id(struct btf *btf, s32 id) return NULL; } -static const struct btf_type *find_btf_func_proto(const char *funcname, - struct btf **btf_p) -{ - const struct btf_type *t; - struct btf *btf = NULL; - s32 id; - - if (!funcname) - return ERR_PTR(-EINVAL); - - id = bpf_find_btf_id(funcname, BTF_KIND_FUNC, &btf); - if (id <= 0) - return ERR_PTR(-ENOENT); - - /* Get BTF_KIND_FUNC type */ - t = btf_type_by_id(btf, id); - if (!t || !btf_type_is_func(t)) - goto err; - - /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */ - t = btf_type_by_id(btf, t->type); - if (!t || !btf_type_is_func_proto(t)) - goto err; - - *btf_p = btf; - return t; - -err: - btf_put(btf); - return ERR_PTR(-ENOENT); -} - static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr, struct btf **btf_p, bool tracepoint) { @@ -403,12 +371,13 @@ static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr if (!funcname || !nr) return ERR_PTR(-EINVAL); - t = find_btf_func_proto(funcname, &btf); - if (IS_ERR(t)) + t = btf_find_func_proto(funcname, &btf); + if (!t) return (const struct btf_param *)t; - *nr = btf_type_vlen(t); - param = (const struct btf_param *)(t + 1); + param = btf_get_func_param(t, nr); + if (IS_ERR_OR_NULL(param)) + goto err; /* Hide the first 'data' argument of tracepoint */ if (tracepoint) { @@ -421,6 +390,7 @@ static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr return param; } +err: btf_put(btf); return NULL; } @@ -496,8 +466,8 @@ static const struct fetch_type *parse_btf_retval_type( if (ctx->funcname) { /* Do not use ctx->btf, because it must be used with ctx->param */ - t = find_btf_func_proto(ctx->funcname, &btf); - if (!IS_ERR(t)) { + t = btf_find_func_proto(ctx->funcname, &btf); + if (t) { typestr = type_from_btf_id(btf, t->type); btf_put(btf); } @@ -512,8 +482,8 @@ static bool is_btf_retval_void(const char *funcname) struct btf *btf; bool ret; - t = find_btf_func_proto(funcname, &btf); - if (IS_ERR(t)) + t = btf_find_func_proto(funcname, &btf); + if (!t) return false; ret = (t->type == 0);