From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8976 invoked by alias); 20 Nov 2017 08:09:01 -0000 Mailing-List: contact elfutils-devel-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: elfutils-devel-owner@sourceware.org Received: (qmail 8008 invoked by uid 48); 20 Nov 2017 08:08:52 -0000 From: "brueckner at linux dot vnet.ibm.com" To: elfutils-devel@sourceware.org Subject: [Bug libdw/22452] Failed to obtain CFI data for a OP_call_frame_CFA when looking for func entrypoc in an s390 kernel module Date: Mon, 20 Nov 2017 08:09:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: elfutils X-Bugzilla-Component: libdw X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: brueckner at linux dot vnet.ibm.com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2017-q4/txt/msg00060.txt.bz2 https://sourceware.org/bugzilla/show_bug.cgi?id=3D22452 --- Comment #10 from H. Brueckner --- (In reply to Mark Wielaard from comment #9) > (In reply to H. Brueckner from comment #8) > > (In reply to Mark Wielaard from comment #5) > > > (In reply to Mark Wielaard from comment #4) > > > > So, if you could provide the output of eu-readelf --relocs paes_s39= 0.ko (on > > > > your combined paes_s390.ko containing both code and debug) that wou= ld be > > > > helpful. > > >=20 > > > eu-readelf --debug-dump=3Dframes --relocs paes_s390.ko > > >=20 > >=20 > > Just attached the output; also the output of the binutils readelf comma= nd > > for comparision. I guess that there are some more issues because lots of > > invalid relocations are listed. >=20 > Is that eu-readelf from a distro install? Then there is something wrong w= ith > that install. If it is a build from source then make sure LD_LIBRARY_PATH > contains the backends directory that has libebl_s390.so. Otherwise > eu-readelf won't know about machine specific ELF/DWARF mappings (like the > relocation types/names). It was a local built and install, the LD_LIBRARY_PATH was not set properly. However, setting is correctly, the relocation are displayed like with reade= lf. Will update the attachment soon. >=20 > But the output does confirm what I feared. The R_390_PC32 .rela.eh_frame > relocations are not "simple". They are load based. So now it comes to that point I have feared, as it looks like the libdw just performs "simple" relocations. Your comment and the ebl_reloc_simple_type() call in libdwfl/relocate.c proofs that. Anyhow, do you plan to extend the relocation code to support more complex relocations tool? > It might not be too hard to add support for those. What needs to be done / is necessary for that? > But if there is any > possibility to generate .debug_frame based CFI for the s390x kernel modul= es > that would IMHO a much better/simpler solution because it makes things mo= re > in line with other arches. It should also make the kernel modules smaller. > Does anything actually use the loaded .eh_frame CFI on s390x? I will check the module usage on .eh_frame and will have a try on including= the CFI in the .debug_frame. Thanks. --=20 You are receiving this mail because: You are on the CC list for the bug.