On Mon, Oct 19, 2026, at 11:49, Thomas Weißschuh wrote: > GCC may emit libcalls to __mulsi3(). As modpost is not aware that this > function is provided through the linked in libgcc, it fails: > > ERROR: modpost: kernel/locking/test-ww_mutex.ko: symbol '__mulsi3' undefined! > ERROR: modpost: kernel/time/test_udelay.ko: symbol '__mulsi3' undefined! > ERROR: modpost: kernel/resource_kunit.ko: symbol '__mulsi3' undefined! > ERROR: modpost: fs/fuse/virtiofs.ko: symbol '__mulsi3' undefined! > etc. > > Make sure modpost can see the symbol from libgcc. > > Reported-by: kernel test robot <[email protected]> > Closes: > https://lore.kernel.org/oe-kbuild-all/[email protected]/ > Fixes: 2fc8483fdcde ("nios2: Build infrastructure") > Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Arnd Bergmann <[email protected]> The patch looks correct to me, but it would also be nice to not use libgcc at all. What I see is that only arc, nios2, openrisc and parisc still link against the toolchain-provided libgcc, everything else uses the kernel's own runtime. It's probably not even that hard to do right, here is what I found is imported from libgcc. * Generic library helper exists, can be enabled through Kconfig: === __lshrdi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c arch/parisc/kernel/parisc_ksyms.c -> lib/lshrdi3.c === __ashldi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c arch/parisc/kernel/parisc_ksyms.c -> lib/ashldi3.c === __ashrdi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c arch/parisc/kernel/parisc_ksyms.c -> lib/ashrdi3.c === __cmpdi2 === arch/arc/kernel/arcksyms.c -> lib/cmpdi2.c === __muldi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c arch/parisc/kernel/parisc_ksyms.c -> lib/muldi3.c === __ucmpdi2 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c arch/parisc/kernel/parisc_ksyms.c -> lib/ucmpdi2.c * 64-bit division probably should not be provided on arc or nios2 (and sparc32, which has a private copy). parisc64 should get these from libgcc/libgcc2.c. === __divdi3 === arch/parisc/kernel/parisc_ksyms.c === __udivmoddi4 === arch/nios2/kernel/nios2_ksyms.c === __udivdi3 === arch/arc/kernel/arcksyms.c arch/parisc/kernel/parisc_ksyms.c === __umoddi3 === arch/nios2/kernel/nios2_ksyms.c arch/parisc/kernel/parisc_ksyms.c === __moddi3 === arch/nios2/kernel/nios2_ksyms.c arch/parisc/kernel/parisc_ksyms.c * floating-point math should not be provided by kernel: === __divdf3 === arch/arc/kernel/arcksyms.c === __divsf3 === arch/arc/kernel/arcksyms.c === __fixunsdfsi === arch/arc/kernel/arcksyms.c === __floatunsidf === arch/arc/kernel/arcksyms.c === __floatunsisf === arch/arc/kernel/arcksyms.c === __muldf3 === arch/arc/kernel/arcksyms.c * no generic implementation in kernel, need to copy from libgcc/lib1funcs.S code: === __divsi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c -> arch/arm/lib/lib1funcs.S arch/m68k/lib/divsi3.S arch/microblaze/lib/divsi3.S arch/xtensa/lib/divsi3.S === __modsi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c -> arch/m68k/lib/modsi3.S arch/microblaze/lib/modsi3.S arch/xtensa/lib/modsi3.S === __udivsi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c -> arch/arm/lib/lib1funcs.S arch/m68k/lib/udivsi3.S arch/microblaze/lib/udivsi3.S arch/sh/lib/udivsi3.S arch/xtensa/lib/udivsi3.S === __umodsi3 === arch/arc/kernel/arcksyms.c arch/nios2/kernel/nios2_ksyms.c arch/openrisc/kernel/or32_ksyms.c -> arch/arm/lib/lib1funcs.S arch/m68k/lib/umodsi3.S arch/microblaze/lib/umodsi3.S arch/xtensa/lib/umodsi3.S
