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Rozycki" To: David Laight cc: kernel test robot , oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, Andrew Morton , Linux Memory Management List , Nicolas Pitre , linux-mips@vger.kernel.org, Thomas Bogendoerfer Subject: Re: mips64-linux-ld: div64.c:undefined reference to `__multi3' In-Reply-To: <20260113200455.3dffe121@pumpkin> Message-ID: References: <202601140146.hMLODc6v-lkp@intel.com> <20260113200455.3dffe121@pumpkin> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspam-User: X-Stat-Signature: 4zx66hfo5tr7aassf994r1qd7ey73cyi X-Rspamd-Queue-Id: 011534000D X-Rspamd-Server: rspam04 X-HE-Tag: 1768371544-939792 X-HE-Meta: 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 bfq+re0B nVj16jjb/6FM3qPeq2WSKGwstQ1htbZrdvi5WLhUebwVsAfUTfgZA8a9Yz7RC2nhpwGcP1E3ZN/7Qi3v44e/Rv6Xxm0lMOahCjQqgKYmRDUPgDW0y1tfW+1x1vbtYV59fmRcyvaqjrH/WtnzR3VqHjU3FAPWQedpU/Qq3wEmAOBUYbI60K9OcfQofZD+hm10ra1Oeg/SrFdltWx54Pmb4hrVwriIHH39acV+HgkuRfVjHlu8FRSpjLiis1xwyBiX9vLa9wHsAi6/doXVkc+aKpI6aIhJDx+ZzVX5OZmP6IvD2Vbs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 13 Jan 2026, David Laight wrote: > > All errors (new ones prefixed by >>): > > > > mips64-linux-ld: lib/math/div64.o: in function `mul_u64_add_u64_div_u64': > > div64.c:(.text+0x84): undefined reference to `__multi3' > > >> mips64-linux-ld: div64.c:(.text+0x11c): undefined reference to `__multi3' > > > > This looks like a bug in the mips 'port'. > arch/mips/lib/multi3.c has the comment: > > /* > * GCC 7 & older can suboptimally generate __multi3 calls for mips64r6, so for > * that specific case only we implement that intrinsic here. > * > * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981 > */ > #if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ < 8) > > So this code is excluded for gcc 8.5 but the compiler is generating the call. > > Looking at the git log for that file there is a comment that includes: > "we wouldn't expect any calls to __multi3 to be generated from > kernel code". > Not true.... > Not sure why the link didn't fail before though, something subtle must > have changed. > > I think the fix is just to remove the gcc version check. Or rather fix the version check. The GCC fix went in with GCC 10: $ git log -1 --pretty=oneline 48b2123f6336 48b2123f6336ba6c06846d7c8b60bd14eaeae7ec re PR target/82981 (unnecessary __multi3 call for mips64r6 linux kernel) $ git show 48b2123f6336:gcc/BASE-VER 10.0.0 $ I don't know why the PR got it all wrong; I've fixed it now. Maciej