The Zither kernel backend is responsible for generating syscall-related glue logic for the kernel and vDSO, derived from the FIDL syscall specifications of library zx.
Most generated files are .inc files with legacy ‘macro template’ APIs, allowing for further, flexible, generation logic:
<lib/syscalls/category.inc>: a categorization of syscalls with macro helpers;<lib/syscalls/kernel-wrappers.inc>: kernel-side boilerplate for syscall definitions;<lib/syscalls/kernel.inc>: macro-templated enumeration of syscalls from the kernel's point of view;<lib/syscalls/syscalls.inc>: macro-templated enumeration of syscalls from userspace's point of view;<lib/syscalls/zx-syscall-numbers.h>: #defines of syscall numbers.${fidl_target}_zither.kernel generates a C++ library target aggregating the generated sources, and giving the headers and .inc files as public dependencies.
Any declaration type not mentioned below is ignored.
Each syscall declaration yields one ‘entry’ in each of the generated files.