RISC-V Proxy Kernel and Boot Loader

About

The RISC-V Proxy Kernel, pk, is a lightweight application execution environment that can host statically-linked RISC-V ELF binaries. It is designed to support tethered RISC-V implementations with limited I/O capability and thus handles I/O-related system calls by proxying them to a host computer.

This package also contains the Berkeley Boot Loader, bbl, which is a supervisor execution environment for tethered RISC-V systems. It is designed to host the RISC-V Linux port.

Build Steps

We assume that the RISCV environment variable is set to the RISC-V tools install path, and that the riscv-gnu-toolchain package is installed. Please note that building the binaries directly inside the source directory is not supported; you need to use a separate build directory.

$ mkdir build
$ cd build
$ ../configure --prefix=$RISCV --host=riscv64-unknown-elf
$ make
$ make install

Alternatively, the GNU/Linux toolchain may be used to build this package, by setting --host=riscv64-unknown-linux-gnu.

By default, 64-bit (RV64) versions of pk and bbl are built. To built 32-bit (RV32) versions, supply a --with-arch=rv32i_zicsr_zifencei flag to the configure command. To process RVC binaries, supply a --with-arch=rv32ic_zicsr_zifencei flag, because the emulation code (floating point and miss-aligned load and store) is different in the RVC case.

The install step installs 64-bit build products into a directory matching your host (e.g. $RISCV/riscv64-unknown-elf). 32-bit versions are installed into a directory matching a 32-bit version of your host (e.g. $RISCV/riscv32-unknown-elf).

OpenBSD Build Steps

Install the riscv-gnu-toolchain, and follow generic build steps.

# pkg_add riscv-elf-binutils riscv-elf-gcc riscv-elf-newlib