From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: Re: [PATCH bpf-next v5 00/10] BTF: BPF Type Format Date: Tue, 12 Jun 2018 17:31:24 -0300 Message-ID: <20180612203124.GB22039@kernel.org> References: <20180607190510.qtj7gq4wbfewcn4g@kafai-mbp> <20180607193029.GG17292@kernel.org> <20180607200701.bvsjzoq56rnggwfd@kafai-mbp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , kernel-team@fb.com, Wang Nan , Jiri Olsa , Namhyung Kim , Ingo Molnar To: Martin KaFai Lau Return-path: Received: from mail.kernel.org ([198.145.29.99]:38110 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932787AbeFLUb3 (ORCPT ); Tue, 12 Jun 2018 16:31:29 -0400 Content-Disposition: inline In-Reply-To: <20180607200701.bvsjzoq56rnggwfd@kafai-mbp> Sender: netdev-owner@vger.kernel.org List-ID: Em Thu, Jun 07, 2018 at 01:07:01PM -0700, Martin KaFai Lau escreveu: > On Thu, Jun 07, 2018 at 04:30:29PM -0300, Arnaldo Carvalho de Melo wrote: > > So this must be available in a newer llvm version? Which one? > I should have put in the details in my last email or > in the commit message, my bad. > 1. The tools/testing/selftests/bpf/Makefile has the CLANG_FLAGS and > LLC_FLAGS needed to compile the bpf prog. It requires a new > "-mattr=dwarf" llc option which was added to the future > llvm 7.0. > Hence, I have been using the llvm's master in github which > also has the llvm-objcopy. > 2. The kernel's btf part only focus on the BPF map. > Hence, the testing bpf program should have the map's key > and map's value. e.g. tools/testing/selftests/bpf/test_btf_haskv.c So, with llvm and clang HEAD I get: [root@jouet bpf]# pahole -J hello.o [root@jouet bpf]# file hello.o hello.o: ELF 64-bit LSB relocatable, *unknown arch 0xf7* version 1 (SYSV), with debug_info, not stripped [root@jouet bpf]# llvm-readelf -s hello.o There are 26 section headers, starting at offset 0xe30: Section Headers: [Nr] Name Type Address Off Size ES Flg Lk Inf Al [ 0] NULL 0000000000000000 000000 000000 00 0 0 0 [ 1] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4 [ 2] syscalls:sys_enter_openat PROGBITS 0000000000000000 000040 000088 00 AX 0 0 8 [ 3] license PROGBITS 0000000000000000 0000c8 000004 00 WA 0 0 1 [ 4] version PROGBITS 0000000000000000 0000cc 000004 00 WA 0 0 4 [ 5] maps PROGBITS 0000000000000000 0000d0 000010 00 WA 0 0 4 [ 6] .rodata.str1.1 PROGBITS 0000000000000000 0000e0 00000e 01 AMS 0 0 1 [ 7] .debug_str PROGBITS 0000000000000000 0000ee 00010e 01 MS 0 0 1 [ 8] .debug_loc PROGBITS 0000000000000000 0001fc 000023 00 0 0 1 [ 9] .debug_abbrev PROGBITS 0000000000000000 00021f 0000e3 00 0 0 1 [10] .debug_info PROGBITS 0000000000000000 000302 00015e 00 0 0 1 [11] .debug_ranges PROGBITS 0000000000000000 000460 000030 00 0 0 1 [12] .debug_macinfo PROGBITS 0000000000000000 000490 000001 00 0 0 1 [13] .debug_pubnames PROGBITS 0000000000000000 000491 00006e 00 0 0 1 [14] .debug_pubtypes PROGBITS 0000000000000000 0004ff 00005a 00 0 0 1 [15] .debug_frame PROGBITS 0000000000000000 000560 000028 00 0 0 8 [16] .debug_line PROGBITS 0000000000000000 000588 00006e 00 0 0 1 [17] .symtab SYMTAB 0000000000000000 0005f8 000318 18 24 29 8 [18] .relsyscalls:sys_enter_openat REL 0000000000000000 000910 000010 10 17 2 8 [19] .rel.debug_info REL 0000000000000000 000920 0001e0 10 17 10 8 [20] .rel.debug_pubnames REL 0000000000000000 000b00 000010 10 17 13 8 [21] .rel.debug_pubtypes REL 0000000000000000 000b10 000010 10 17 14 8 [22] .rel.debug_frame REL 0000000000000000 000b20 000020 10 17 15 8 [23] .rel.debug_line REL 0000000000000000 000b40 000010 10 17 16 8 [24] .strtab STRTAB 0000000000000000 000b50 00018e 00 0 0 1 [25] .BTF PROGBITS 0000000000000000 000cde 00014e 00 0 0 1 Key to Flags: W (write), A (alloc), X (execute), M (merge), S (strings), l (large) I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown) O (extra OS processing required) o (OS specific), p (processor specific) [root@jouet bpf]# [root@jouet bpf]# pahole hello.o struct clang version 5.0.1 (tags/RELEASE_501/final) { clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1 (tags/RELEASE_501/final); /* 0 4 */ clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1 (tags/RELEASE_501/final); /* 4 4 */ clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1 (tags/RELEASE_501/final); /* 8 4 */ clang version 5.0.1 (tags/RELEASE_501/final) clang version 5.0.1 (tags/RELEASE_501/final); /* 12 4 */ /* size: 16, cachelines: 1, members: 4 */ /* last cacheline: 16 bytes */ }; [root@jouet bpf]# Ok, I guess I saw this case in the llvm/clang git logs, so this one was generated with the older clang, will regenerate and add that "-mattr=dwarf" part. - Arnaldo