arch/x86_64/kernel/built-in.o(.text+0x6265): In function `timer_resume':
: undefined reference to `is_hpet_enabled'
arch/x86_64/kernel/built-in.o(.init.text+0x862b): In function
`pci_iommu_init':
: undefined reference to `agp_amd64_init'
arch/x86_64/kernel/built-in.o(.init.text+0x8639): In function
`pci_iommu_init':
: undefined reference to `agp_copy_info'
make: *** [.tmp_vmlinux1] Error 1
Will debug later unless someone beats me to it.