48 lines
1.6 KiB
Rust
48 lines
1.6 KiB
Rust
//! Spinner half of init's SMP self-test: one thread per hart, each
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//! incrementing its own counter in the page given in slot 0.
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#![no_std]
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#![no_main]
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extern crate libkos;
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use core::sync::atomic::{AtomicUsize, Ordering};
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use libkos::syscall;
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use types::address::{EntryPoint, StackPointer, VirtualAddress};
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use types::bounded::{CapSlot, PageCount};
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use types::mapping::PagePerms;
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/// Counter page layout (words): 0 next free counter index, 1..=THREADS counters.
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const COUNTERS_VA: usize = 0x0100_0000;
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const THREADS: usize = 4;
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#[unsafe(no_mangle)]
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extern "C" fn main() {
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let page = CapSlot::const_new(0);
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if syscall::map_region(page, VirtualAddress::from_raw(COUNTERS_VA), PagePerms::ReadWrite).is_err() {
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libkos::println!("smptest: cannot map the counter page");
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syscall::exit();
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}
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for _ in 1..THREADS {
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let Some(stack) = PageCount::new(1).and_then(syscall::request_pages) else {
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break;
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};
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let top = StackPointer::from_raw(stack.raw() + 4096);
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syscall::spawn_thread(EntryPoint::from_raw(spin as *const () as usize), top, 0);
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}
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spin();
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}
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extern "C" fn spin() -> ! {
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// SAFETY: COUNTERS_VA maps the counter page; every access is atomic.
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let word = |i: usize| unsafe { &*((COUNTERS_VA + i * 8) as *const AtomicUsize) };
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let mine = 1 + word(0).fetch_add(1, Ordering::Relaxed) % THREADS;
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loop {
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// Yield so a spinner sharing init's hart cannot starve it.
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for _ in 0..1024 {
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word(mine).fetch_add(1, Ordering::Relaxed);
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}
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syscall::yield_now();
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}
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}
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