From mboxrd@z Thu Jan 1 00:00:00 1970 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 25690C001DE for ; Tue, 18 Jul 2023 02:40:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230014AbjGRCkb (ORCPT ); Mon, 17 Jul 2023 22:40:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229541AbjGRCk3 (ORCPT ); Mon, 17 Jul 2023 22:40:29 -0400 Received: from mail-lf1-x12c.google.com (mail-lf1-x12c.google.com [IPv6:2a00:1450:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A70B9189; Mon, 17 Jul 2023 19:40:27 -0700 (PDT) Received: by mail-lf1-x12c.google.com with SMTP id 2adb3069b0e04-4fb9ae4cef6so8360208e87.3; Mon, 17 Jul 2023 19:40:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1689648026; x=1692240026; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=Cran8qgdQ9kbuzPnsHeCd+k7q1iRuxP3B3YP8nMjL34=; b=U/kWRP5EPDxi3j6sixpCB8+OuOPpd9nWrMYLmj9PwHbkg+iahW80idm3Ga5IgyP5t1 S+YjKI3tcP4ByLSaXlDPN4Z/hY+yfT8F4zVsI7xTrbiAE8M7ELEBT9Ur8Zix9BlqanRj Z2lKwQKNr9UXTEXmVQadJb9iAwJ9wi8PBk53lXkklL3dHFlJRmRxMxw6j/6wB3yzPQJY VSTpoKccWdU3kKv3a2u/DaLs01aaGHiHsJ0rPJjWIMNe2GVIJWj4P1911ZHhfyrTY/Xx Xw6PHRYmef3lIhSQQpcWYHun8CzMc4+gztbVP8b7L9WBByFbX0GIpYc8CA8xXh2Pn88B wzjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689648026; x=1692240026; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Cran8qgdQ9kbuzPnsHeCd+k7q1iRuxP3B3YP8nMjL34=; b=R+glik5MxoPB9ZNGqAgy2WPn4myu11zJdwmsBjoDpVTq41gTLnRtj0kHvm711WEGHp 2YoccWwKupm66Y5PLmOH1xZzr7aLUeXqr1V+K49MP0fTmd68amQZ7Uz9qXbyPU/hhua/ uj2+hbxU207InFNECMHiuopPCzqanUjiflHNFeWm+ag7PGkoJ0uCXcFsST4RVau4Kktd 5vmuiNobZk23eRZSVhSeZpj9StpViaNLcM+1Cj67EmYkh/xEi4FXnTETeFFaTTT/zpyG f15Z789v88ET6rjvWs6dDSPrflu17PmJlcafKq3MZ/DCAoEgMBfgcHUDYRFaqWBVGVx7 SAYw== X-Gm-Message-State: ABy/qLa2AY1znxgmN4tSLHBcgHAni4OGUmMqwET7Ftne6T+KT+4qsD7D mnz4s4lqI3hywh7YsrImteDkPsUVI47I/ngqEjs= X-Google-Smtp-Source: APBJJlGdZyV3Emffg0WnmEtnrU4uNkwMNeHhptUht0XrvrI3U4XBTQBd9vciTXhRsDxjLQXolD8bGNjqkf+TMbIGXl0= X-Received: by 2002:a05:6512:234a:b0:4fb:8b2a:5e09 with SMTP id p10-20020a056512234a00b004fb8b2a5e09mr9821535lfu.43.1689648025397; Mon, 17 Jul 2023 19:40:25 -0700 (PDT) MIME-Version: 1.0 References: <168960739768.34107.15145201749042174448.stgit@devnote2> <168960741686.34107.6330273416064011062.stgit@devnote2> In-Reply-To: <168960741686.34107.6330273416064011062.stgit@devnote2> From: Donglin Peng Date: Tue, 18 Jul 2023 10:40:09 +0800 Message-ID: Subject: Re: [PATCH v2 2/9] bpf/btf: tracing: Move finding func-proto API and getting func-param API to BTF To: "Masami Hiramatsu (Google)" Cc: linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt , Martin KaFai Lau , bpf@vger.kernel.org, Sven Schnelle , Alexei Starovoitov Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 17, 2023 at 11:24=E2=80=AFPM Masami Hiramatsu (Google) wrote: > > 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) > --- > include/linux/btf.h | 4 ++++ > kernel/bpf/btf.c | 45 ++++++++++++++++++++++++++++++++++++++= ++ > kernel/trace/trace_probe.c | 50 +++++++++++++-------------------------= ------ > 3 files changed, 64 insertions(+), 35 deletions(-) > > diff --git a/include/linux/btf.h b/include/linux/btf.h > index cac9f304e27a..98fbbcdd72ec 100644 > --- a/include/linux/btf.h > +++ b/include/linux/btf.h > @@ -221,6 +221,10 @@ 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(struct btf *btf, > + const char *func_name); > +const struct btf_param *btf_get_func_param(const struct btf_type *func_p= roto, > + s32 *nr); > > #define for_each_member(i, struct_type, member) \ > for (i =3D 0, member =3D btf_type_member(struct_type); \ > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 817204d53372..e015b52956cb 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -1947,6 +1947,51 @@ btf_resolve_size(const struct btf *btf, const stru= ct btf_type *type, > return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL,= NULL); > } > > +/* > + * Find a functio proto type by name, and return it. > + * Return NULL if not found, or return -EINVAL if parameter is invalid. > + */ > +const struct btf_type *btf_find_func_proto(struct btf *btf, const char *= func_name) > +{ > + const struct btf_type *t; > + s32 id; > + > + if (!btf || !func_name) > + return ERR_PTR(-EINVAL); > + > + id =3D btf_find_by_name_kind(btf, func_name, BTF_KIND_FUNC); > + if (id <=3D 0) > + return NULL; > + > + /* Get BTF_KIND_FUNC type */ > + t =3D btf_type_by_id(btf, id); > + if (!t || !btf_type_is_func(t)) > + return NULL; > + > + /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */ > + t =3D btf_type_by_id(btf, t->type); > + if (!t || !btf_type_is_func_proto(t)) > + return NULL; > + > + return t; > +} > + > +/* > + * Get function parameter with the number of parameters. > + * This can return NULL if the function has no parameters. > + */ > +const struct btf_param *btf_get_func_param(const struct btf_type *func_p= roto, s32 *nr) > +{ > + if (!func_proto || !nr) > + return ERR_PTR(-EINVAL); > + > + *nr =3D btf_type_vlen(func_proto); > + if (*nr > 0) > + return (const struct btf_param *)(func_proto + 1); > + else > + return NULL; > +} > + > static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id) > { > while (type_id < btf->start_id) > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index c68a72707852..cd89fc1ebb42 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -371,47 +371,23 @@ 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 =3D traceprobe_get_btf(); > - const struct btf_type *t; > - s32 id; > - > - if (!btf || !funcname) > - return ERR_PTR(-EINVAL); > - > - id =3D btf_find_by_name_kind(btf, funcname, BTF_KIND_FUNC); > - if (id <=3D 0) > - return ERR_PTR(-ENOENT); > - > - /* Get BTF_KIND_FUNC type */ > - t =3D btf_type_by_id(btf, id); > - if (!t || !btf_type_is_func(t)) > - return ERR_PTR(-ENOENT); > - > - /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */ > - t =3D btf_type_by_id(btf, t->type); > - if (!t || !btf_type_is_func_proto(t)) > - return ERR_PTR(-ENOENT); > - > - return t; > -} > - > static const struct btf_param *find_btf_func_param(const char *funcname,= s32 *nr, > bool tracepoint) > { > + struct btf *btf =3D traceprobe_get_btf(); I found that traceprobe_get_btf() only returns the vmlinux's btf. But if the function is defined in a kernel module, we should get the module's btf. -- Donglin > const struct btf_param *param; > const struct btf_type *t; > > - if (!funcname || !nr) > + if (!funcname || !nr || !btf) > return ERR_PTR(-EINVAL); > > - t =3D find_btf_func_proto(funcname); > - if (IS_ERR(t)) > + t =3D btf_find_func_proto(btf, funcname); > + if (IS_ERR_OR_NULL(t)) > return (const struct btf_param *)t; > > - *nr =3D btf_type_vlen(t); > - param =3D (const struct btf_param *)(t + 1); > + param =3D btf_get_func_param(t, nr); > + if (IS_ERR_OR_NULL(param)) > + return param; > > /* Hide the first 'data' argument of tracepoint */ > if (tracepoint) { > @@ -490,8 +466,8 @@ static const struct fetch_type *parse_btf_retval_type= ( > const struct btf_type *t; > > if (btf && ctx->funcname) { > - t =3D find_btf_func_proto(ctx->funcname); > - if (!IS_ERR(t)) > + t =3D btf_find_func_proto(btf, ctx->funcname); > + if (!IS_ERR_OR_NULL(t)) > typestr =3D type_from_btf_id(btf, t->type); > } > > @@ -500,10 +476,14 @@ static const struct fetch_type *parse_btf_retval_ty= pe( > > static bool is_btf_retval_void(const char *funcname) > { > + struct btf *btf =3D traceprobe_get_btf(); > const struct btf_type *t; > > - t =3D find_btf_func_proto(funcname); > - if (IS_ERR(t)) > + if (!btf) > + return false; > + > + t =3D btf_find_func_proto(btf, funcname); > + if (IS_ERR_OR_NULL(t)) > return false; > > return t->type =3D=3D 0; > >