Mason provides a Cargo build.rs primarily for Diosix components. It can automatically assemble low-level assembly code and package up binary objects so that they can be linked with and accessed by high-level Rust code.
It searches for a configuration file called mason.toml in the host file system tree from the current working directory up. This file controls how Mason works, and its format is described in build.rs. Exported symbols in code assembled by Mason can be referenced by the high-level code. Binary files will each be exported with the following symbols:
| Symbol | Description |
|---|---|
_binary_leafname_start |
Memory address of binary file's first byte |
_binary_leafname_end |
Memory address of first byte after file's end |
_binary_leafname_size |
Size of the file in memory in bytes |
Substitute leafname in the above for the binary file's leafname. A file's leafname must be unique within the build. Mason uses GNU binutils to assemble and archive files, so this must be present for the given build target architecture, which is determined from the environment variable TARGET set by Cargo. Here are the supported Cargo targets and the binutils executables expected:
| Cargo target | Binutils executable |
|---|---|
riscv64imac-* |
riscv64-linux-gnu-* |
riscv64gc-* |
riscv64-linux-gnu-* |
Eg, if you're targeting riscv64gc-unknown-none-elf, you'll need binutils' riscv64-linux-gnu-as, riscv64-linux-gnu-ld, etc, present on your build system.
Please email project lead Chris Williams if you have any questions or issues to raise, wish to get involved, have source to contribute, or have found a security flaw. You can, of course, submit pull requests or raise issues via GitHub, though please consider disclosing security-related matters privately. Please also observe the Diosix project's code of conduct if you wish to participate.
Copyright © Chris Williams, 2020-2021. See LICENSE for distribution and use of source code and binaries.