From mboxrd@z Thu Jan 1 00:00:00 1970 From: Helge Deller Subject: Re: Out of order unwind entry warning Date: Tue, 03 Nov 2009 23:04:43 +0100 Message-ID: <4AF0A8FB.2000504@gmx.de> References: <20091103215408.7B0AD4E0B@hiauly1.hia.nrc.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: dave.anglin@nrc-cnrc.gc.ca, linux-parisc@vger.kernel.org, carlos@systemhalted.org, randolph@tausq.org To: John David Anglin Return-path: In-Reply-To: <20091103215408.7B0AD4E0B@hiauly1.hia.nrc.ca> List-ID: List-Id: linux-parisc.vger.kernel.org On 11/03/2009 10:54 PM, John David Anglin wrote: >> On 11/03/2009 10:36 PM, John David Anglin wrote: >>>> Unwind section '.PARISC.unwind' at offset 0x11c contains 3 entries: >>>> >>>> : [0x0-0x2c] >>>> Entry_GR=1 Save_SP Save_RP Total_frame_size=8 >>>> : [0x0-0x44] >>>> Entry_GR=1 Save_SP Save_RP Total_frame_size=8 >>>> : [0x0-0x6c] >>>> Entry_GR=2 Save_SP Save_RP Total_frame_size=8 >>> >>> What do you see for '.rela.PARISC.unwind'? >>> >>> I suspect that this is a problem in handling the R_PARISC_SEGREL32 >>> relocations is the kernel loader. The above would be fine if >>> libcrc32c_mod_fini and libcRc32c_mod_init are in different sections >>> (.exit.text and .inti.text). >> >> Relocation section '.rela.PARISC.unwind' at offset 0x9b8 contains 6 entries: >> Offset Info Type Sym.Value Sym. Name + Addend >> 00000000 00000231 R_PARISC_SEGREL32 00000000 .exit.text + 0 >> 00000004 00000231 R_PARISC_SEGREL32 00000000 .exit.text + 2c >> 00000010 00000331 R_PARISC_SEGREL32 00000000 .init.text + 0 >> 00000014 00000331 R_PARISC_SEGREL32 00000000 .init.text + 44 >> 00000020 00000431 R_PARISC_SEGREL32 00000000 .text.crc32c + 0 >> 00000024 00000431 R_PARISC_SEGREL32 00000000 .text.crc32c + 6c > > That's exactly what I expected. There's no overlap. The module > loader needs to sort the unwind entries after doing the relocations. It's already sorting the entries, but creating the relocation is currently a hack. See top of arch/parisc/kernel/module.c: * - SEGREL32 handling * We are not doing SEGREL32 handling correctly. According to the ABI, we * should do a value offset, like this: * if (in_init(me, (void *)val)) * val -= (uint32_t)me->module_init; * else * val -= (uint32_t)me->module_core; * However, SEGREL32 is used only for PARISC unwind entries, and we want * those entries to have an absolute address, and not just an offset. * * The unwind table mechanism has the ability to specify an offset for * the unwind table; however, because we split off the init functions into * a different piece of memory, it is not possible to do this using a * single offset. Instead, we use the above hack for now. If we change this, don't we require a binutils update then at the same time from the users? Helge