Support toggling profiling.

src/arch/x86_64/interrupt/exception.rs

@@ -3,6 +3,7 @@ use core::sync::atomic::Ordering;
 use x86::irq::PageFaultError;
 
 use crate::memory::GenericPfFlags;
+use crate::scheme::serio::IS_PROFILING;
 use crate::{
     interrupt::stack_trace,
     paging::VirtualAddress,
@@ -50,6 +51,9 @@ interrupt_stack!(non_maskable, @paranoid, |stack| {
     let Some(profiling) = crate::percpu::PercpuBlock::current().profiling else {
         return;
     };
+    if !IS_PROFILING.load(Ordering::Relaxed) {
+        return;
+    }
     if stack.iret.cs & 0b00 == 0b11 {
         profiling.nmi_ucount.store(profiling.nmi_ucount.load(Ordering::Relaxed) + 1, Ordering::Relaxed);
         return;

src/scheme/serio.rs

@@ -1,7 +1,7 @@
 //! PS/2 unfortunately requires a kernel driver to prevent race conditions due
 //! to how status is utilized
 use core::str;
-use core::sync::atomic::{AtomicUsize, Ordering};
+use core::sync::atomic::{AtomicUsize, Ordering, AtomicBool};
 
 use spin::RwLock;
 
@@ -25,8 +25,20 @@ struct Handle {
 // Using BTreeMap as hashbrown doesn't have a const constructor.
 static HANDLES: RwLock<BTreeMap<usize, Handle>> = RwLock::new(BTreeMap::new());
 
+pub const PROFILE_TOGGLEABLE: bool = true;
+pub static IS_PROFILING: AtomicBool = AtomicBool::new(false);
+
 /// Add to the input queue
 pub fn serio_input(index: usize, data: u8) {
+    if PROFILE_TOGGLEABLE {
+        if index == 0 && data == 30 {
+            log::info!("Enabling profiling");
+            IS_PROFILING.store(true, Ordering::SeqCst);
+        } else if index == 0 && data == 48 {
+            log::info!("Disabling profiling");
+            IS_PROFILING.store(false, Ordering::SeqCst);
+        }
+    }
     INPUT[index].send(data);
 
     for (id, _handle) in HANDLES.read().iter() {