From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Thu, 4 Jan 2018 22:47:41 +0000 Subject: v4.14.9 on ARMv5: OK with gcc 4.8/5.4, NOK with gcc 7.2 In-Reply-To: References: <20180104180238.581b202c@windsurf.lan> <20180104171637.GP28752@n2100.armlinux.org.uk> Message-ID: <20180104224741.GA17719@n2100.armlinux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jan 04, 2018 at 07:19:45PM +0100, Andrea Adami wrote: > On Thu, Jan 4, 2018 at 6:16 PM, Russell King - ARM Linux > wrote: > > On Thu, Jan 04, 2018 at 06:02:38PM +0100, Thomas Petazzoni wrote: > >> Hello, > >> > >> I'm pretty sure it has already been reported, but just in case: I'm > >> testing v4.14.9 on an ARMv5 platform (Kirkwood-based OpenBlocks A7). > >> mvebu_v5_defconfig boots fine when built with gcc 4.8 (good old > >> Sourcery toolchain) or gcc 5.4 (some old Linaro toolchain), but doesn't > >> boot at all when built with gcc 7.2 (Fedora toolchain). Even when > >> configured and booted with earlyprintk, the kernel doesn't say anything. > >> > >> The toolchain being used is the default ARM toolchain provided by > >> Fedora 27. It says: > >> > >> gcc version 7.2.1 20170915 (Red Hat Cross 7.2.1-1) (GCC) > >> GNU ld version 2.29.1-1.fc27 > >> > >> So it's quite bleeding edge. > >> > >> Let me know if this has already been fixed, or if I should test a > >> patch. I have not tested 4.15-rc or next at this point, assuming that > >> if a fix had been made, it would have been backported to 4.14-stable. > > > > It's a known issue - > > > > http://archive.armlinux.org.uk/lurker/message/20171018.095713.a56a717b.en.html > > > > but so far no patches have been forthcoming for the kernel, because > > (I guess) it's deemed to be a gcc bug. > > > > It's one of those discussions that just seemed to die without any > > real conclusion. > > > > -- > > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ > > FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up > > According to speedtest.net: 8.21Mbps down 510kbps up > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel at lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > I am happy to report the gcc bug has been fixed in trunk. > I am as well dubious where they say this should also fix gcc6 where we > have no known issues with gcc6. > > " > This should also fix > incorrect generation of ldrd/strd with unaligned accesses that could > previously have occurred on ARMv5e where all such operations must be > 64-bit aligned." > > https://github.com/gcc-mirror/gcc/commit/f59996b56aaa1c1d62a16cbb4010775b624cbde0 > > In OpenEmbedded we backported the patch a while ago, see the > discussion about qemu booting where real hw doesn't: > http://lists.openembedded.org/pipermail/openembedded-core/2017-November/144045.html Thanks for reporting the update Andrea! -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up