Files

Martin Atkins 7d8fe2ab11 riscv: Expose privilege level as pseudo-register PRIV (#1989 )

Unlike some other architectures, RISC-V does not expose the current
privilege mode in any architecturally-defined register. That is intentional
to make it easier to implement virtualization in software, but a Unicorn
caller operates outside of the emulated hart and so it can and should be
able to observe and change the current privilege mode in order to properly
emulate certain behaviors of a real CPU.

The current privilege level is therefore now exposed as a new
pseudo-register using the name "priv", which matches the name of the
virtual register used by RISC-V's debug extension to allow the debugger
to read and change the privilege mode while the hart is halted. Unicorn's
use of it is conceptually similar to a debugger.

The bit encoding of this register is the same as specified in RISC-V Debug
Specification v1.0-rc3 Section 4.10.1. It's defined as a "virtual"
register exposing a subset of fields from the dcsr register, although here
it's implemented directly inside the Unicorn code because QEMU doesn't
currently have explicit support for the CSRs from the debug specification.
If it supports "dcsr" in a future release then this implementation could
change to wrap reading and writing that CSR and then projecting the "prv"
and "v" bitfields into the correct locations for the virtual register.

2024-11-11 21:09:45 +08:00

src

riscv: Expose privilege level as pseudo-register PRIV (#1989 )

2024-11-11 21:09:45 +08:00

build.rs

Fix dynamic linkage on msvc

2023-03-02 03:34:33 +08:00

COPYING

bindings: add Rust

2021-10-04 01:01:43 +08:00

README.md

Tag and release 2.1.1

2024-09-26 18:44:51 +08:00

README.md

Unicorn-engine

Rust bindings for the Unicorn emulator with utility functions.

Checkout Unicorn2 source code at dev branch.

use unicorn_engine::{Unicorn, RegisterARM};
use unicorn_engine::unicorn_const::{Arch, Mode, Permission, SECOND_SCALE};

fn main() {
    let arm_code32: Vec<u8> = vec![0x17, 0x00, 0x40, 0xe2]; // sub r0, #23

    let mut unicorn = Unicorn::new(Arch::ARM, Mode::LITTLE_ENDIAN).expect("failed to initialize Unicorn instance");
    let emu = &mut unicorn;
    emu.mem_map(0x1000, 0x4000, Permission::ALL).expect("failed to map code page");
    emu.mem_write(0x1000, &arm_code32).expect("failed to write instructions");

    emu.reg_write(RegisterARM::R0, 123).expect("failed write R0");
    emu.reg_write(RegisterARM::R5, 1337).expect("failed write R5");

    let _ = emu.emu_start(0x1000, (0x1000 + arm_code32.len()) as u64, 10 * SECOND_SCALE, 1000);
    assert_eq!(emu.reg_read(RegisterARM::R0), Ok(100));
    assert_eq!(emu.reg_read(RegisterARM::R5), Ok(1337));
}

Further sample code can be found in tests.

Usage

Add this to your Cargo.toml:

[dependencies]
unicorn-engine = "2.1.1"

Acknowledgements

These bindings are based on Sébastien Duquette's (@ekse) unicorn-rs. We picked up the project, as it is no longer maintained. Thanks to all contributors.