xv6-riscv-rust/theseus/src/spinlock.rs

// Mutual exclusion lock.
#[repr(C)]
pub struct SpinLock {
	// Is the lock held?
	pub locked: u32, // C boolean
	// For debugging:
	pub name: Option<*mut ()>, // Name of lock.
	pub cpu: Option<*mut ()>,  // The cpu holding the lock.
}