From ca8e7b40bc6817de79bf112b12263a6004526ad3 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Tue, 30 Jan 2024 01:07:06 +0200
Subject: [PATCH] Kernel: Implement SpinLock without CriticalScope

This actually is not even spinlock since it yields the current
thread. It will become one when I get to SMP though...
---
 kernel/include/kernel/SpinLock.h |  7 ++++---
 kernel/kernel/SpinLock.cpp       | 16 +---------------
 2 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/kernel/include/kernel/SpinLock.h b/kernel/include/kernel/SpinLock.h
index 82bd113867..c3fb8cafb7 100644
--- a/kernel/include/kernel/SpinLock.h
+++ b/kernel/include/kernel/SpinLock.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <BAN/Atomic.h>
 #include <BAN/NoCopyMove.h>
 
 #include <sys/types.h>
@@ -19,7 +20,7 @@ namespace Kernel
 		bool is_locked() const;
 
 	private:
-		volatile pid_t m_locker = -1;
+		BAN::Atomic<pid_t> m_locker = -1;
 	};
 
 	class RecursiveSpinLock
@@ -34,8 +35,8 @@ namespace Kernel
 		bool is_locked() const;
 
 	private:
-		pid_t m_locker = -1;
-		uint32_t m_lock_depth = 0;
+		BAN::Atomic<pid_t> m_locker = -1;
+		BAN::Atomic<uint32_t> m_lock_depth = 0;
 		SpinLock m_lock;
 	};
 
diff --git a/kernel/kernel/SpinLock.cpp b/kernel/kernel/SpinLock.cpp
index 905fa02160..e79c47f876 100644
--- a/kernel/kernel/SpinLock.cpp
+++ b/kernel/kernel/SpinLock.cpp
@@ -1,6 +1,5 @@
 #include <kernel/Scheduler.h>
 #include <kernel/SpinLock.h>
-#include <kernel/CriticalScope.h>
 
 namespace Kernel
 {
@@ -8,31 +7,18 @@ namespace Kernel
 	void SpinLock::lock()
 	{
 		pid_t tid = Scheduler::current_tid();
-		while (true)
-		{
-			{
-				CriticalScope _;
-				ASSERT(m_locker != tid);
-				if (m_locker == -1)
-				{
-					m_locker = tid;
-					break;
-				}
-			}
+		while (!m_locker.compare_exchange(-1, tid))
 			Scheduler::get().reschedule();
-		}
 	}
 
 	void SpinLock::unlock()
 	{
-		CriticalScope _;
 		ASSERT(m_locker == Scheduler::current_tid());
 		m_locker = -1;
 	}
 
 	bool SpinLock::is_locked() const
 	{
-		CriticalScope _;
 		return m_locker != -1;
 	}