Kernel: Add the NonMaskableInterruptDisabler class

This class will be used later to disable NMIs when we
initialize the RTC timer.

2 files changed, 17 insertions, 0 deletions

diff --git a/Kernel/Arch/i386/CPU.cpp b/Kernel/Arch/i386/CPU.cpp
index cf4d2259ab..69e4b1db53 100644
--- a/Kernel/Arch/i386/CPU.cpp
+++ b/Kernel/Arch/i386/CPU.cpp
@@ -39,6 +39,7 @@
 #include <Kernel/KSyms.h>
 #include <Kernel/Process.h>
 #include <Kernel/VM/MemoryManager.h>
+#include <LibBareMetal/IO.h>
 #include <LibC/mallocdefs.h>
 
 //#define PAGE_FAULT_DEBUG
@@ -833,3 +834,13 @@ void __assertion_failed(const char* msg, const char* file, unsigned line, const
         ;
 }
 #endif
+
+NonMaskableInterruptDisabler::NonMaskableInterruptDisabler()
+{
+    IO::out8(0x70, IO::in8(0x70) | 0x80);
+}
+
+NonMaskableInterruptDisabler::~NonMaskableInterruptDisabler()
+{
+    IO::out8(0x70, IO::in8(0x70) & 0x7F);
+}
diff --git a/Kernel/Arch/i386/CPU.h b/Kernel/Arch/i386/CPU.h
index 80a08ebd79..87aebc3887 100644
--- a/Kernel/Arch/i386/CPU.h
+++ b/Kernel/Arch/i386/CPU.h
@@ -369,6 +369,12 @@ private:
     u32 m_flags;
 };
 
+class NonMaskableInterruptDisabler {
+public:
+    NonMaskableInterruptDisabler();
+    ~NonMaskableInterruptDisabler();
+};
+
 /* Map IRQ0-15 @ ISR 0x50-0x5F */
 #define IRQ_VECTOR_BASE 0x50