Simple paging has been added for OpenKernel.

Author: OpenSoftware-World

Kernel/KernelServices/VirtualMem/vmem.c

@@ -0,0 +1,30 @@
+#include "vmem.h"
+
+static uint32_t page_dir[1024] __attribute__((aligned(4096)));
+static uint32_t first_page_table[1024] __attribute__((4096));
+
+void paging_init() {
+    for (int i = 0; i < 1024; i++) {
+        first_page_table[i] = 0;
+    }
+    for (int i = 0; i < 1024; i++) {
+        first_page_table[i] = (i * PAGE_SIZE) | PAGE_PRESENT | PAGE_RW;
+    }
+    for (int i = 0; i < 1024; i++) {
+        page_dir[i] = 0;
+    }
+    page_dir[0] = ((uint32_t)first_page_table) | PAGE_PRESENT | PAGE_RW;
+    load_page_dir(page_dir);
+    enable_paging();
+}
+
+void load_page_dir(uint32_t* pd) {
+    __asm__ __volatile__("mov %0, %%cr3" :: "r"(pd));
+}
+
+void enable_paging() {
+    uint32_t cr0;
+    __asm__ __volatile__("mov %%cr0, %0":"=r"(cr0));
+    cr0 |= 0x80000000;
+    __asm__ __volatile__("mov %0, %%cr0"::"r"(cr0));
+}

Kernel/KernelServices/VirtualMem/vmem.h

@@ -0,0 +1,14 @@
+#ifndef VMEM_H
+#define VMEM_H
+
+#include <OpenKernel/SystemLib/Std/types.h>
+
+#define PAGE_PRESENT 0x1
+#define PAGE_RW 0x2
+#define PAGE_USER 0x4
+
+void paging_init();
+void load_page_dir(uint32_t* pd);
+void enable_paging();
+
+#endif