--- title: Porting to New Architectures category: Contributing layout: default SPDX-License-Identifier: LGPL-2.1-or-later --- # Porting systemd to New Architectures Here's a brief checklist of things to implement when porting systemd to a new architecture. 1. Patch [src/basic/architecture.h](https://github.com/systemd/systemd/blob/main/src/basic/architecture.h) and [src/basic/architecture.c](https://github.com/systemd/systemd/blob/main/src/basic/architecture.c) to make your architecture known to systemd. Besides an `ARCHITECTURE_XYZ` enumeration entry you need to provide an implementation of `native_architecture()` and `uname_architecture()`. 2. Patch [src/shared/gpt.h](https://github.com/systemd/systemd/blob/main/src/shared/gpt.h) and [src/shared/gpt.c](https://github.com/systemd/systemd/blob/main/src/shared/gpt.c) and define a new set of GPT partition type UUIDs for the root file system, `/usr/` file system, and the matching Verity and Verity signature partitions. Use `systemd-id128 new -p` to generate new suitable UUIDs you can use for this. Make sure to register your new types in the various functions in `gpt.c`. Also make sure to update the tables in [Discoverable Partitions Specification](https://uapi-group.org/specifications/specs/discoverable_partitions_specification) and `man/systemd-gpt-auto-generator.xml` accordingly. 3. If your architecture supports UEFI, make sure to update the `efi_arch` variable logic in `meson.build` to be set to the right architecture string as defined by the UEFI specification. (This ensures that `systemd-boot` will be built as the appropriately named `BOOT.EFI` binary.) Also, if your architecture uses a special boot protocol for the Linux kernel, make sure to implement it in `src/boot/efi/linux*.c`, so that the `systemd-stub` EFI stub can work. 4. Make sure to register the right system call numbers for your architecture in `src/basic/missing_syscall_def.h`. systemd uses various system calls the Linux kernel provides that are currently not wrapped by glibc (or are only in very new glibc), and we need to know the right numbers for them. It might also be necessary to tweak `src/basic/raw-clone.h`. 5. Make sure the code in `src/shared/seccomp-util.c` properly understands the local architecture and its system call quirks. 6. If your architecture uses a `/lib64/` library directory, then make sure that the `BaseFilesystem` table in `src/shared/base-filesystem.c` has an entry for it so that it can be set up automatically if missing. This is useful to support booting into OS trees that have an empty root directory with only `/usr/` mounted in. 7. If your architecture supports VM virtualization and provides CPU opcodes similar to x86' CPUID, consider adding native support for detecting VMs this way to `src/basic/virt.c`.