Hi Thiago, On 2024-04-10 5:21 PM, Thiago Jung Bauermann wrote: > Samuel Holland <samuel.holland@xxxxxxxxxx> writes: > >> Now that all previously-supported architectures select >> ARCH_HAS_KERNEL_FPU_SUPPORT, this code can depend on that symbol instead >> of the existing list of architectures. It can also take advantage of the >> common kernel-mode FPU API and method of adjusting CFLAGS. >> >> Acked-by: Alex Deucher <alexander.deucher@xxxxxxx> >> Reviewed-by: Christoph Hellwig <hch@xxxxxx> >> Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx> > > Unfortunately this patch causes build failures on arm with allyesconfig > and allmodconfig. Tested with next-20240410. > > Error with allyesconfig: > > $ make -j 8 \ > O=$HOME/.cache/builds/linux-cross-arm \ > ARCH=arm \ > CROSS_COMPILE=arm-linux-gnueabihf- > make[1]: Entering directory '/home/bauermann/.cache/builds/linux-cross-arm' > ⋮ > arm-linux-gnueabihf-ld: drivers/gpu/drm/amd/display/dc/dml/dcn20/dcn20_fpu.o: in function `dcn20_populate_dml_pipes_from_context': > dcn20_fpu.c:(.text+0x20f4): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: dcn20_fpu.c:(.text+0x210c): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: dcn20_fpu.c:(.text+0x2124): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: dcn20_fpu.c:(.text+0x213c): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: drivers/gpu/drm/amd/display/dc/dml/calcs/dcn_calcs.o: in function `pipe_ctx_to_e2e_pipe_params': > dcn_calcs.c:(.text+0x390): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: drivers/gpu/drm/amd/display/dc/dml/calcs/dcn_calcs.o:dcn_calcs.c:(.text+0x3a4): more undefined references to `__aeabi_l2d' follow > arm-linux-gnueabihf-ld: drivers/gpu/drm/amd/display/dc/dml2/dml2_wrapper.o: in function `optimize_configuration': > dml2_wrapper.c:(.text+0xcbc): undefined reference to `__aeabi_d2ulz' > arm-linux-gnueabihf-ld: drivers/gpu/drm/amd/display/dc/dml2/dml2_translation_helper.o: in function `populate_dml_plane_cfg_from_plane_state': > dml2_translation_helper.c:(.text+0x9e4): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: dml2_translation_helper.c:(.text+0xa20): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: dml2_translation_helper.c:(.text+0xa58): undefined reference to `__aeabi_l2d' > arm-linux-gnueabihf-ld: dml2_translation_helper.c:(.text+0xa90): undefined reference to `__aeabi_l2d' > make[3]: *** [/home/bauermann/src/linux/scripts/Makefile.vmlinux:37: vmlinux] Error 1 > make[2]: *** [/home/bauermann/src/linux/Makefile:1165: vmlinux] Error 2 > make[1]: *** [/home/bauermann/src/linux/Makefile:240: __sub-make] Error 2 > make[1]: Leaving directory '/home/bauermann/.cache/builds/linux-cross-arm' > make: *** [Makefile:240: __sub-make] Error 2 > > The error with allmodconfig is slightly different: > > $ make -j 8 \ > O=$HOME/.cache/builds/linux-cross-arm \ > ARCH=arm \ > CROSS_COMPILE=arm-linux-gnueabihf- > make[1]: Entering directory '/home/bauermann/.cache/builds/linux-cross-arm' > ⋮ > ERROR: modpost: "__aeabi_d2ulz" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined! > ERROR: modpost: "__aeabi_l2d" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined! > make[3]: *** [/home/bauermann/src/linux/scripts/Makefile.modpost:145: Module.symvers] Error 1 > make[2]: *** [/home/bauermann/src/linux/Makefile:1876: modpost] Error 2 > make[1]: *** [/home/bauermann/src/linux/Makefile:240: __sub-make] Error 2 > make[1]: Leaving directory '/home/bauermann/.cache/builds/linux-cross-arm' > make: *** [Makefile:240: __sub-make] Error 2 In both cases, the issue is that the toolchain requires runtime support to convert between `unsigned long long` and `double`, even when hardware FP is enabled. There was some past discussion about GCC inlining some of these conversions[1], but that did not get implemented. The short-term fix would be to drop the `select ARCH_HAS_KERNEL_FPU_SUPPORT` for 32-bit arm until we can provide these runtime library functions. Regards, Samuel [1]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91970
