Am 2021-03-08 um 2:33 p.m. schrieb Arnd Bergmann: > On Mon, Mar 8, 2021 at 8:11 PM Felix Kuehling <felix.kuehling@xxxxxxx> wrote: >> Am 2021-03-08 um 2:05 p.m. schrieb Arnd Bergmann: >>> On Mon, Mar 8, 2021 at 5:24 PM Felix Kuehling <felix.kuehling@xxxxxxx> wrote: >>>> The driver build should work without IOMMUv2. In amdkfd/Makefile, we >>>> have this condition: >>>> >>>> ifneq ($(CONFIG_AMD_IOMMU_V2),) >>>> AMDKFD_FILES += $(AMDKFD_PATH)/kfd_iommu.o >>>> endif >>>> >>>> In amdkfd/kfd_iommu.h we define inline stubs of the functions that are >>>> causing your link-failures if IOMMU_V2 is not enabled: >>>> >>>> #if defined(CONFIG_AMD_IOMMU_V2_MODULE) || defined(CONFIG_AMD_IOMMU_V2) >>>> ... function declarations ... >>>> #else >>>> ... stubs ... >>>> #endif >>> Right, that is the problem I tried to explain in my patch description. >>> >>> Should we just drop the 'imply' then and add a proper dependency like this? >>> >>> depends on DRM_AMDGPU && (X86_64 || ARM64 || PPC64) >>> depends on AMD_IOMMU_V2=y || DRM_AMDGPU=m >>> >>> I can send a v2 after some testing if you prefer this version. >> No. My point is, there should not be a hard dependency. The build should >> work without CONFIG_AMD_IOMMU_V2. I don't understand why it's not >> working for you. It looks like you're building kfd_iommu.o, which should >> not be happening when AMD_IOMMU_V2 is not enabled. The condition in >> amdkfd/Makefile should make sure that kfd_iommu.o doesn't get built with >> your kernel config. > Again, as I explained in the changelog text, AMD_IOMMU_V2 configured as > a loadable module, while AMDGPU is configured as built-in. I'm sorry, I didn't read it carefully. And I thought "imply" was meant to fix exactly this kind of issue. I don't want to create a hard dependency on AMD_IOMMU_V2 if I can avoid it, because it is only really needed for a small number of AMD APUs, and even there it is now optional for more recent ones. Is there a better way to avoid build failures without creating a hard dependency? The documentation in Documentation/kbuild/kconfig-language.rst suggests using if (IS_REACHABLE(CONFIG_AMD_IOMMU_V2)) to guard those problematic function calls. I think more generally, we could guard all of kfd_iommu.c with #if IS_REACHABLE(CONFIG_AMD_IOMMU_V2) And use the same condition to define the stubs in kfd_iommu.h. Regards, Felix > > The causes a link failure for the vmlinux file, because the linker cannot > resolve addresses of loadable modules at compile time -- they have > not been loaded yet. > > Arnd > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
