tg-kernel-context

Kernel context management for the rCore tutorial operating system.

Overview

This crate provides context switching primitives for RISC-V based kernel development. It handles the low-level details of saving and restoring CPU state during context switches between kernel and user space.

Features

• LocalContext: Thread context structure containing all general-purpose registers, program counter, and control flags
• Context switching: Assembly-based efficient context switch implementation
• Foreign address space support: Optional support for context switching across different address spaces (via foreign feature)
• no_std compatible: Designed for bare-metal kernel environments

Usage

use tg_kernel_context::LocalContext;

// Create a user-mode context with entry point
let ctx = LocalContext::user(entry_point);

// Create a kernel thread context
let ctx = LocalContext::thread(entry_point, true);

// Execute the context (unsafe - modifies CPU state)
unsafe {
    let sstatus = ctx.execute();
}

Features

• foreign - Enable support for context switching across different address spaces

Safety

The execute method is unsafe as it directly manipulates critical CSRs (sscratch, sepc, sstatus, stvec) and performs a privilege level switch.

License

Licensed under either of MIT license or Apache License, Version 2.0 at your option.