device tree or ACPI table? and x0 register in arm64 kernel start

Hello, I saw the head.S file for arm64 assumes the x0 register contains the address of the device tree (dtb). But some systems use ACPI table for handing hardware configuration to the kernel. If the system firmware and bootloader uses UEFI and ACPI, (and bootloader like grub), does the bootloader set x0 with dtb too? In this case x0 is not use? Chan Kim