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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A263C433ED for ; Tue, 27 Apr 2021 17:38:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C788613E5 for ; Tue, 27 Apr 2021 17:38:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238314AbhD0RjR (ORCPT ); Tue, 27 Apr 2021 13:39:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238282AbhD0RjQ (ORCPT ); Tue, 27 Apr 2021 13:39:16 -0400 Received: from mail-yb1-xb30.google.com (mail-yb1-xb30.google.com [IPv6:2607:f8b0:4864:20::b30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD189C061574; Tue, 27 Apr 2021 10:38:32 -0700 (PDT) Received: by mail-yb1-xb30.google.com with SMTP id j84so717626ybj.9; Tue, 27 Apr 2021 10:38:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mi3ASX57EUUORwgofsiMzfVhbo+tT5vFJSBQ/xFKHU8=; b=T1nlQOaNI87sRd+/1sOHA0gqLSVG520YDoFgDUi5aliaLMk7dBgJZ3r/W1PgR66wKi 9HhnR62iLPn1Y1cxlnZv4UOKEo740l8nsYyvNSFVMuo1CPsi540nIf0xqMTFKZpCGVLh cdNE3vUgVCLX3MdEGs0sr76bV/06fYtAvwEc7mXxTTp8WlEo/IZzVtorqDM2nvlIOwQs 0kaayrg5TTRQIc5DWvzajsPyDTgxyckdBtUffLydPfvdB/QZMRXHT1cFtJkVeVehTbgq pReTjXepVtLUH/el3jcuQPlEV2V8YP/Nu7EjK6QeHc3+3FnTl5sLMEH8PnbTpqmA2zSH FZEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mi3ASX57EUUORwgofsiMzfVhbo+tT5vFJSBQ/xFKHU8=; b=GNbT945TsCcC4gppgATwR8EBVkiWgPMtczHPQlseRNqkf6Ru6OFjXrXgvpxiLFF9Sh RbzHOUD64w/ll8FhpUsvIDIB4G0r/F4epynKEvLNDhzkF0lwiIHqtz2Vw79BSkAM/hmR 550YiI8DSVWumxISqYooSYu5YIvmklnq89F+k2q8FdD7M04WXC9/Kexp0aBiRd5PsCBb 1HsApON7pG54b3d71+0hz4InIvfVnfXccemnwKO4blDJPR9cKHGIlEbRVctS71y1AJLI ptX0q4RTKivmC8rZcg8SzA9dX4lv/nb0Ai/DzbgRaTTVsn0PDjF63c7zpqrTHCUbyLq9 BG6g== X-Gm-Message-State: AOAM530nVbJB2XyzW+Ri9vlhQBAPauUIIDUW2pl+XVHfiZFTMe+64uoT FXmEgEfgLv4bQCnIE/u+0qO/fmuabnOEN7lwi+nYpIA3 X-Google-Smtp-Source: ABdhPJxTB9XAHJ35LLUzZ/qlnVTp1HDQdBi3cnQST6VSSx+BUd0XoiuWF5J9Eoub+o5NKy4FpXs0XHCAA3zXWsRivq4= X-Received: by 2002:a05:6902:1144:: with SMTP id p4mr33911336ybu.510.1619545112132; Tue, 27 Apr 2021 10:38:32 -0700 (PDT) MIME-Version: 1.0 References: <20210423002646.35043-1-alexei.starovoitov@gmail.com> <20210423002646.35043-16-alexei.starovoitov@gmail.com> <20210427032837.mtaqbbptczd3dvck@ast-mbp.dhcp.thefacebook.com> In-Reply-To: <20210427032837.mtaqbbptczd3dvck@ast-mbp.dhcp.thefacebook.com> From: Andrii Nakryiko Date: Tue, 27 Apr 2021 10:38:21 -0700 Message-ID: Subject: Re: [PATCH v2 bpf-next 15/16] bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command. To: Alexei Starovoitov Cc: "David S. Miller" , Daniel Borkmann , Andrii Nakryiko , Networking , bpf , Kernel Team Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Apr 26, 2021 at 8:28 PM Alexei Starovoitov wrote: > > On Mon, Apr 26, 2021 at 03:35:16PM -0700, Andrii Nakryiko wrote: > > On Thu, Apr 22, 2021 at 5:27 PM Alexei Starovoitov > > wrote: > > > > > > From: Alexei Starovoitov > > > > > > Add -L flag to bpftool to use libbpf gen_trace facility and syscall/loader program > > > for skeleton generation and program loading. > > > > > > "bpftool gen skeleton -L" command will generate a "light skeleton" or "loader skeleton" > > > that is similar to existing skeleton, but has one major difference: > > > $ bpftool gen skeleton lsm.o > lsm.skel.h > > > $ bpftool gen skeleton -L lsm.o > lsm.lskel.h > > > $ diff lsm.skel.h lsm.lskel.h > > > @@ -5,34 +4,34 @@ > > > #define __LSM_SKEL_H__ > > > > > > #include > > > -#include > > > +#include > > > > > > The light skeleton does not use majority of libbpf infrastructure. > > > It doesn't need libelf. It doesn't parse .o file. > > > It only needs few sys_bpf wrappers. All of them are in bpf/bpf.h file. > > > In future libbpf/bpf.c can be inlined into bpf.h, so not even libbpf.a would be > > > needed to work with light skeleton. > > > > > > "bpftool prog load -L file.o" command is introduced for debugging of syscall/loader > > > program generation. Just like the same command without -L it will try to load > > > the programs from file.o into the kernel. It won't even try to pin them. > > > > > > "bpftool prog load -L -d file.o" command will provide additional debug messages > > > on how syscall/loader program was generated. > > > Also the execution of syscall/loader program will use bpf_trace_printk() for > > > each step of loading BTF, creating maps, and loading programs. > > > The user can do "cat /.../trace_pipe" for further debug. > > > > > > An example of fexit_sleep.lskel.h generated from progs/fexit_sleep.c: > > > struct fexit_sleep { > > > struct bpf_loader_ctx ctx; > > > struct { > > > struct bpf_map_desc bss; > > > } maps; > > > struct { > > > struct bpf_prog_desc nanosleep_fentry; > > > struct bpf_prog_desc nanosleep_fexit; > > > } progs; > > > struct { > > > int nanosleep_fentry_fd; > > > int nanosleep_fexit_fd; > > > } links; > > > struct fexit_sleep__bss { > > > int pid; > > > int fentry_cnt; > > > int fexit_cnt; > > > } *bss; > > > }; > > > > > > Signed-off-by: Alexei Starovoitov > > > --- > > > tools/bpf/bpftool/Makefile | 2 +- > > > tools/bpf/bpftool/gen.c | 313 +++++++++++++++++++++++++++--- > > > tools/bpf/bpftool/main.c | 7 +- > > > tools/bpf/bpftool/main.h | 1 + > > > tools/bpf/bpftool/prog.c | 80 ++++++++ > > > tools/bpf/bpftool/xlated_dumper.c | 3 + > > > 6 files changed, 382 insertions(+), 24 deletions(-) > > > > > > > [...] > > > > > @@ -268,6 +269,254 @@ static void codegen(const char *template, ...) > > > free(s); > > > } > > > > > > +static void print_hex(const char *obj_data, int file_sz) > > > +{ > > > + int i, len; > > > + > > > + /* embed contents of BPF object file */ > > > > nit: this comment should have stayed at the original place > > > > > + for (i = 0, len = 0; i < file_sz; i++) { > > > + int w = obj_data[i] ? 4 : 2; > > > + > > > > [...] > > > > > + bpf_object__for_each_map(map, obj) { > > > + const char * ident; > > > + > > > + ident = get_map_ident(map); > > > + if (!ident) > > > + continue; > > > + > > > + if (!bpf_map__is_internal(map) || > > > + !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE)) > > > + continue; > > > + > > > + printf("\tskel->%1$s =\n" > > > + "\t\tmmap(NULL, %2$zd, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED,\n" > > > + "\t\t\tskel->maps.%1$s.map_fd, 0);\n", > > > + ident, bpf_map_mmap_sz(map)); > > > > use codegen()? > > why? > codegen() would add extra early \n for no good reason. for consistency, seems like the rest of the code in that function uses codegen(). But not critical. > > > > + } > > > + codegen("\ > > > + \n\ > > > + return 0; \n\ > > > + } \n\ > > > + \n\ > > > + static inline struct %1$s * \n\ > > > > [...] > > > > > static int do_skeleton(int argc, char **argv) > > > { > > > char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")]; > > > @@ -277,7 +526,7 @@ static int do_skeleton(int argc, char **argv) > > > struct bpf_object *obj = NULL; > > > const char *file, *ident; > > > struct bpf_program *prog; > > > - int fd, len, err = -1; > > > + int fd, err = -1; > > > struct bpf_map *map; > > > struct btf *btf; > > > struct stat st; > > > @@ -359,7 +608,25 @@ static int do_skeleton(int argc, char **argv) > > > } > > > > > > get_header_guard(header_guard, obj_name); > > > - codegen("\ > > > + if (use_loader) > > > > please use {} for such a long if/else, even if it's, technically, a > > single-statement if > > I think it reads fine as-is, but, sure, I can add {} > > > > + codegen("\ > > > + \n\ > > > + /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ > > > + /* THIS FILE IS AUTOGENERATED! */ \n\ > > > + #ifndef %2$s \n\ > > > + #define %2$s \n\ > > > + \n\ > > > + #include \n\ > > > + #include \n\ > > > + #include \n\ > > > + \n\ > > > + struct %1$s { \n\ > > > + struct bpf_loader_ctx ctx; \n\ > > > + ", > > > + obj_name, header_guard > > > + ); > > > + else > > > + codegen("\ > > > \n\ > > > /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ > > > \n\ > > > > [...] > > --