Added IO protection by setting IOPL to zero.

Makefile

@@ -4,6 +4,8 @@ all:
 	mkdir -p kernel/lib/interrupts/asm kernel/lib/interrupts/sycall kernel/lib/interrupts/syscall/asm
 	mkdir -p kernel/lib/drivers/ps2/x86_64
 	mkdir -p kernel/lib/userspace
+	mkdir -p kernel/lib/arch/protection/ 
+	mkdir -p kernel/lib/arch/protection/asm
 	bash builduserspace.sh
 	mv *.o kernel/lib/userspace
 	cd gnu-efi/; make; make bootloader; cd ../; cd kernel; make; make buildimg

kernel/src/arch/protection/asm/iopl.asm

@@ -0,0 +1,18 @@
+;; 2022 Ian Moffett <ian@kesscoin.com>
+
+global iopl_zero
+
+
+;; This will make sure IO operations can only operate in 
+;; ring zero.
+iopl_zero:
+    pushf                   ;; Push flags onto stack.
+    pop rax                 ;; Save it in RAX.
+    and rax, ~(1 << 12)     ;; Clear bit 12.
+    and rax, ~(1 << 13)     ;; Clear bit 13.
+
+    ;; Now it should be zero and can only be accessed 
+    ;; in ring zero.
+    push rax                ;; Push RAX back onto stack.
+    popf                    ;; Pop it into FLAGS.
+    retq

kernel/src/arch/protection/iopl.h

@@ -0,0 +1,10 @@
+#ifndef IOPL_H
+#define IOPL_H
+
+// 2022 Ian Moffett <ian@kesscoin.com>
+
+
+void iopl_zero();
+
+
+#endif

kernel/src/kernel.c

@@ -10,6 +10,7 @@
 #include <arch/memory/vmm.h>
 #include <arch/io/legacy-pic.h>
 #include <arch/io/io.h>
+#include <arch/protection/iopl.h>
 #include <interrupts/IDT.h>
 #include <interrupts/exceptions.h>
 #include <interrupts/syscall/syscall.h>
@@ -161,6 +162,7 @@ static void init(meminfo_t meminfo, void* rsdp) {
 // Stuff to init under init() before userspace.
 static void footer_init() {
     ps2_keyboard_init();
+    iopl_zero();
 }