/usr/src/linux-headers-5.15.0-181/drivers/iommu/amd
Edit: /usr/src/linux-headers-5.15.0-181/drivers/iommu/amd/Makefile (190B)
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_AMD_IOMMU) += iommu.o init.o quirks.o io_pgtable.o
obj-$(CONFIG_AMD_IOMMU_DEBUGFS) += debugfs.o
obj-$(CONFIG_AMD_IOMMU_V2) += iommu_v2.o