refactor(userspace): split syscall/fat16/ext4 by concern; trim comments

crates/apps/smptest/src/main.rs

@@ -1,7 +1,5 @@
-//! The spinner half of init's SMP self-test (see init's `selftest`):
-//! maps the counter page it was given in slot 0 and runs one thread per
-//! hart, each incrementing its own counter for ever. Init watches the
-//! counters through its own mapping of the same page.
+//! Spinner half of init's SMP self-test: one thread per hart, each
+//! incrementing its own counter in the page given in slot 0.
 
 #![no_std]
 #![no_main]
@@ -14,8 +12,7 @@ use types::address::{EntryPoint, StackPointer, VirtualAddress};
 use types::bounded::{CapSlot, PageCount};
 use types::mapping::PagePerms;
 
-/// Where the counter page is mapped. Layout (words): 0 the next free
-/// counter index, 1..=THREADS the counters.
+/// Counter page layout (words): 0 next free counter index, 1..=THREADS counters.
 const COUNTERS_VA: usize = 0x0100_0000;
 const THREADS: usize = 4;
 
@@ -41,8 +38,7 @@ extern "C" fn spin() -> ! {
     let word = |i: usize| unsafe { &*((COUNTERS_VA + i * 8) as *const AtomicUsize) };
     let mine = 1 + word(0).fetch_add(1, Ordering::Relaxed) % THREADS;
     loop {
-        // Yield now and then: a spinner sharing init's hart would
-        // otherwise starve it until the next (1 s) timer tick.
+        // Yield so a spinner sharing init's hart cannot starve it.
         for _ in 0..1024 {
             word(mine).fetch_add(1, Ordering::Relaxed);
         }