On Thu, Feb 28, 2019 at 06:12:33PM +0000, Vineet Gupta wrote: > On 2/28/19 9:47 AM, Guenter Roeck wrote: > > On Wed, Jan 30, 2019 at 07:32:41PM +0300, Eugeniy Paltsev wrote: > >> As of today we enable unaligned access unconditionally on ARCv2. > >> Do this under a Kconfig option to allow disable it for test, benchmarking > >> etc. Also while at it > >> > >> - Select HAVE_EFFICIENT_UNALIGNED_ACCESS > >> - Although gcc defaults to unaligned access (since GNU 2018.03), add the > >> right toggles for enabling or disabling as appropriate > >> - update bootlog to prints both HW feature status (exists, enabled/disabled) > >> and SW status (used / not used). > >> - wire up the relaxed memcpy for unaligned access > >> > >> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx> > >> Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx> > >> [vgupta: squashed patches, handle gcc -mno-unaligned-access quick] > > Hi, > > > > with my brand-new gcc-8.3.0, built from upstream gcc, this patch > > results in > > > > arch/arc/kernel/setup.c: In function 'arc_cpu_mumbojumbo.constprop': > > include/linux/compiler.h:348:38: error: > > call to '__compiletime_assert_326' declared with attribute error: gcc doesn't support -mno-unaligned-access > > Sorry it broke ur build - but it did catch a deficiency in compiler as intended - > yay ! > > > when trying to build allnoconfig or tinyconfig. I get the same results > > with gcc-8.2.0. > > Unaligned access code gen was enabled by default in 7.x actually, but us OS folks > were late to find that which led to the recent patch to disable it which was > broken in gcc. > Claudiu fixed gcc promptly but that patch didn't make it to upstream, which I've > posted now. > > http://lists.infradead.org/pipermail/linux-snps-arc/2019-February/005522.html > > > Do I need some special compiler configuration flag when building the > > arcv2 toolchain ? Or am I simply out of luck for using upstream gcc ? > > Once the patch hits mainline you could use that. In the mean time I'll back out > the "detector" as it might trip other people too. > Can you possibly use $(cc-option,-mno-unaligned-access), or would that defeat the purpose ? > Many Thx for your testing service. My pleasure. Thanks, Guenter _______________________________________________ linux-snps-arc mailing list linux-snps-arc@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-snps-arc
