Rust RISC-V Emulator (RV64IAC)

This project aims to provide a learning platform for RISC-V and Rust.

flowchart LR
    hart[HART] --> bus{bus}
    bus --> rom(ROM)
    bus --> ram(RAM)
    bus --> htif(HTIF)
    ram --> dt(DTB)
    bus --> rtc(RTC)
    hart --> csr(CSR)
    hart -->|SBI| see[SEE]
    see -..-> hart

Loading

• RAM is shared between one or more harts via the bus
• ROM is shared between one or more harts via the bus
• RTC is memory mapped and reachable from the bus
• SEE is global
• CSRs are per hart (or per core)
• The SEE can control all harts
• The device tree (DTB) is accessible via RAM

Glossary

	Definition
HART	Hardware Thread
CSR	Control and Status Registers
SBI	Supervisor Binary Interface
SEE	Supervisor Execution Environment
ISA	Instruction Set Architecture
M	Machine Mode
XLEN	RISC-V 32 or 64 flavour
EEI	Execution Environment Interface
ABI	Application Binary Interface
RTC	Real Time Clock
DTS	Device Tree Source
FTD	Flattened Device Tree
DTB	Device Tree Blob
HTIF	Deprecated Host Device
FESVR	RISC-V Frontend Server
PLIC	Platform-Level Interrupt Controller
AMO	Atomic Memory Operation

Development

make -C test
cargo test
cargo run

Verification

cd validation
podman build -t riscvvalidation .
podman run -it -v $PWD:/work:z -v $PWD/../target:/target riscvvalidation --verbose info arch-tests --clone
podman run -it -v $PWD:/work:z -v $PWD/../target:/target riscvvalidation

Licensing

Copyright 2023 Jonathan Buch

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Literature

Specs

• RISC-V ISA Volume 1
• RISC-V ISA Volume 2
• RISC-V Technical Specifications
• RISC-V SBI
• RISC-V ELF psABI
• The RISC-V Microcontroller Profile
• RISC-V Counters (Zinctr)
• RISC-V ACLINT
• RISC-V PLIC

Software

• RISC-V Online Assembler
• DarkRISCV
• RISC-V GNU Toolchain
• OpenHW Group CV32E40S User Manual
• rustsbi
• emuriscv
• Linux Kernel RISC-V architecture

Misc

• Misunderstanding RISC-V ecalls and syscalls
• Rust interior mutability
• UART Communications RISC-V OS In Rust
• RISC-V from scratch 3
• The Sodor Processor Collection
• An overview of OpenSBI
• Trivial RISC-V Linux Binary Bootloader
• Rare: Rust A RISC-V Emulator
• Writing a RISC-V Emulator in Rust
• Summit Bootflow
• Baremetal Timer
• RISC-V: A Bare-metal Introduction using C++. Machine Mode Timer
• Demystifying the RISC-V Linux software stack
• 6.S081: Interrupts
• RISC-V Bytes: Introduction to Instruction Formats

Device Trees

• example DTS for the HiFive Unleashed
• Device Node Requirements
• Device Tree Usage
• Introduction to Device Trees

Validation

• RISCOF
• HTIF
• Spike