Kernel: Move Arch/x86/Spinlock.h and add stubs for aarch64

The code in Spinlock.h has no architectural specific logic, thus can be
moved to the Arch directory. This contains no functional change.

Also add the Spinlock.cpp file for aarch64 which contains stubs for the
lock and unlock functions.

6 files changed, 103 insertions, 177 deletions

diff --git a/Kernel/Arch/Spinlock.h b/Kernel/Arch/Spinlock.h
index ac084e5e68..995dc36c37 100644
--- a/Kernel/Arch/Spinlock.h
+++ b/Kernel/Arch/Spinlock.h
@@ -1,17 +1,76 @@
 /*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
-#include <AK/Platform.h>
+#include <Kernel/Arch/Processor.h>
+#include <Kernel/Locking/LockRank.h>
 
-#if ARCH(X86_64) || ARCH(I386)
-#    include <Kernel/Arch/x86/Spinlock.h>
-#elif ARCH(AARCH64)
-#    include <Kernel/Arch/aarch64/Spinlock.h>
-#else
-#    error "Unknown architecture"
-#endif
+namespace Kernel {
+
+class Spinlock {
+    AK_MAKE_NONCOPYABLE(Spinlock);
+    AK_MAKE_NONMOVABLE(Spinlock);
+
+public:
+    Spinlock(LockRank rank = LockRank::None)
+        : m_rank(rank)
+    {
+    }
+
+    u32 lock();
+    void unlock(u32 prev_flags);
+
+    [[nodiscard]] ALWAYS_INLINE bool is_locked() const
+    {
+        return m_lock.load(AK::memory_order_relaxed) != 0;
+    }
+
+    ALWAYS_INLINE void initialize()
+    {
+        m_lock.store(0, AK::memory_order_relaxed);
+    }
+
+private:
+    Atomic<u8> m_lock { 0 };
+    const LockRank m_rank;
+};
+
+class RecursiveSpinlock {
+    AK_MAKE_NONCOPYABLE(RecursiveSpinlock);
+    AK_MAKE_NONMOVABLE(RecursiveSpinlock);
+
+public:
+    RecursiveSpinlock(LockRank rank = LockRank::None)
+        : m_rank(rank)
+    {
+    }
+
+    u32 lock();
+    void unlock(u32 prev_flags);
+
+    [[nodiscard]] ALWAYS_INLINE bool is_locked() const
+    {
+        return m_lock.load(AK::memory_order_relaxed) != 0;
+    }
+
+    [[nodiscard]] ALWAYS_INLINE bool is_locked_by_current_processor() const
+    {
+        return m_lock.load(AK::memory_order_relaxed) == FlatPtr(&Processor::current());
+    }
+
+    ALWAYS_INLINE void initialize()
+    {
+        m_lock.store(0, AK::memory_order_relaxed);
+    }
+
+private:
+    Atomic<FlatPtr> m_lock { 0 };
+    u32 m_recursions { 0 };
+    const LockRank m_rank;
+};
+
+}
diff --git a/Kernel/Arch/aarch64/Spinlock.cpp b/Kernel/Arch/aarch64/Spinlock.cpp
new file mode 100644
index 0000000000..fe549aa450
--- /dev/null
+++ b/Kernel/Arch/aarch64/Spinlock.cpp
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2022, Timon Kruiper <timonkruiper@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/Arch/Spinlock.h>
+
+namespace Kernel {
+
+u32 Spinlock::lock()
+{
+    VERIFY_NOT_REACHED();
+    return 0;
+}
+
+void Spinlock::unlock(u32)
+{
+    VERIFY_NOT_REACHED();
+}
+
+u32 RecursiveSpinlock::lock()
+{
+    VERIFY_NOT_REACHED();
+    return 0;
+}
+
+void RecursiveSpinlock::unlock(u32)
+{
+    VERIFY_NOT_REACHED();
+}
+
+}
diff --git a/Kernel/Arch/aarch64/Spinlock.h b/Kernel/Arch/aarch64/Spinlock.h
deleted file mode 100644
index ac763a55fc..0000000000
--- a/Kernel/Arch/aarch64/Spinlock.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <AK/Noncopyable.h>
-#include <AK/Types.h>
-#include <Kernel/Locking/LockRank.h>
-
-namespace Kernel {
-
-class Spinlock {
-    AK_MAKE_NONCOPYABLE(Spinlock);
-    AK_MAKE_NONMOVABLE(Spinlock);
-
-public:
-    Spinlock(LockRank rank = LockRank::None)
-    {
-        (void)rank;
-    }
-
-    ALWAYS_INLINE u32 lock()
-    {
-        VERIFY_NOT_REACHED();
-        return 0;
-    }
-
-    ALWAYS_INLINE void unlock(u32 /*prev_flags*/)
-    {
-        VERIFY_NOT_REACHED();
-    }
-
-    [[nodiscard]] ALWAYS_INLINE bool is_locked() const
-    {
-        VERIFY_NOT_REACHED();
-        return false;
-    }
-
-    ALWAYS_INLINE void initialize()
-    {
-        VERIFY_NOT_REACHED();
-    }
-};
-
-class RecursiveSpinlock {
-    AK_MAKE_NONCOPYABLE(RecursiveSpinlock);
-    AK_MAKE_NONMOVABLE(RecursiveSpinlock);
-
-public:
-    RecursiveSpinlock(LockRank rank = LockRank::None)
-    {
-        (void)rank;
-        VERIFY_NOT_REACHED();
-    }
-
-    ALWAYS_INLINE u32 lock()
-    {
-        VERIFY_NOT_REACHED();
-        return 0;
-    }
-
-    ALWAYS_INLINE void unlock(u32 /*prev_flags*/)
-    {
-        VERIFY_NOT_REACHED();
-    }
-
-    [[nodiscard]] ALWAYS_INLINE bool is_locked() const
-    {
-        VERIFY_NOT_REACHED();
-        return false;
-    }
-
-    [[nodiscard]] ALWAYS_INLINE bool is_locked_by_current_processor() const
-    {
-        VERIFY_NOT_REACHED();
-        return false;
-    }
-
-    ALWAYS_INLINE void initialize()
-    {
-        VERIFY_NOT_REACHED();
-    }
-};
-
-}
diff --git a/Kernel/Arch/x86/Spinlock.h b/Kernel/Arch/x86/Spinlock.h
deleted file mode 100644
index 54af902754..0000000000
--- a/Kernel/Arch/x86/Spinlock.h
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <Kernel/Arch/Processor.h>
-#include <Kernel/Locking/LockRank.h>
-
-#include <AK/Platform.h>
-VALIDATE_IS_X86()
-
-namespace Kernel {
-
-class Spinlock {
-    AK_MAKE_NONCOPYABLE(Spinlock);
-    AK_MAKE_NONMOVABLE(Spinlock);
-
-public:
-    Spinlock(LockRank rank = LockRank::None)
-        : m_rank(rank)
-    {
-    }
-
-    u32 lock();
-    void unlock(u32 prev_flags);
-
-    [[nodiscard]] ALWAYS_INLINE bool is_locked() const
-    {
-        return m_lock.load(AK::memory_order_relaxed) != 0;
-    }
-
-    ALWAYS_INLINE void initialize()
-    {
-        m_lock.store(0, AK::memory_order_relaxed);
-    }
-
-private:
-    Atomic<u8> m_lock { 0 };
-    const LockRank m_rank;
-};
-
-class RecursiveSpinlock {
-    AK_MAKE_NONCOPYABLE(RecursiveSpinlock);
-    AK_MAKE_NONMOVABLE(RecursiveSpinlock);
-
-public:
-    RecursiveSpinlock(LockRank rank = LockRank::None)
-        : m_rank(rank)
-    {
-    }
-
-    u32 lock();
-    void unlock(u32 prev_flags);
-
-    [[nodiscard]] ALWAYS_INLINE bool is_locked() const
-    {
-        return m_lock.load(AK::memory_order_relaxed) != 0;
-    }
-
-    [[nodiscard]] ALWAYS_INLINE bool is_locked_by_current_processor() const
-    {
-        return m_lock.load(AK::memory_order_relaxed) == FlatPtr(&Processor::current());
-    }
-
-    ALWAYS_INLINE void initialize()
-    {
-        m_lock.store(0, AK::memory_order_relaxed);
-    }
-
-private:
-    Atomic<FlatPtr> m_lock { 0 };
-    u32 m_recursions { 0 };
-    const LockRank m_rank;
-};
-
-}
diff --git a/Kernel/Arch/x86/common/Spinlock.cpp b/Kernel/Arch/x86/common/Spinlock.cpp
index 2da4509bea..e442377598 100644
--- a/Kernel/Arch/x86/common/Spinlock.cpp
+++ b/Kernel/Arch/x86/common/Spinlock.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <Kernel/Arch/x86/Spinlock.h>
+#include <Kernel/Arch/Spinlock.h>
 
 namespace Kernel {
 
diff --git a/Kernel/CMakeLists.txt b/Kernel/CMakeLists.txt
index acc4cbf13c..6619d410d0 100644
--- a/Kernel/CMakeLists.txt
+++ b/Kernel/CMakeLists.txt
@@ -421,6 +421,7 @@ else()
         Arch/aarch64/SafeMem.cpp
         Arch/aarch64/ScopedCritical.cpp
         Arch/aarch64/SmapDisabler.cpp
+        Arch/aarch64/Spinlock.cpp
         Arch/aarch64/init.cpp
         Arch/aarch64/vector_table.S