From 356c3d72a2be0cdf968bf63e28337fb17d555617 Mon Sep 17 00:00:00 2001
From: "brice.boisson" <brice.boisson@epita.fr>
Date: Tue, 5 Sep 2023 16:47:54 +0900
Subject: [PATCH] Add: paging structure

---
 .gitignore   |  3 +-
 src/Makefile |  1 +
 src/paging.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/paging.h | 24 +++++++++++++++
 4 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 src/paging.c
 create mode 100644 src/paging.h

diff --git a/.gitignore b/.gitignore
index 89547ba..c03e5e6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
-log.txt
\ No newline at end of file
+log.txt
+.vscode
\ No newline at end of file
diff --git a/src/Makefile b/src/Makefile
index 10cdb72..9d4f0d3 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -13,6 +13,7 @@ OBJS	= \
 	  pic_controler.o \
 	  userland.o \
 	  launch_process.o \
+	  paging.o \
 
 DEPS = $(OBJS:.o=.d)
 
diff --git a/src/paging.c b/src/paging.c
new file mode 100644
index 0000000..dd728e4
--- /dev/null
+++ b/src/paging.c
@@ -0,0 +1,84 @@
+#include "paging.h"
+
+struct page_directory_entry page_dir[1024];
+struct page_table_entry page_table[1024];
+
+struct page_directory_param {
+    u8 P;
+    u8 R_W;
+    u8 U;
+    u8 PWT;
+    u8 PCD;
+    u8 A;
+    u8 PS;
+    u32 address;
+};
+
+struct page_table_param {
+    u8 P;
+    u8 R_W;
+    u8 U;
+    u8 PWT;
+    u8 PCD;
+    u8 A;
+    u8 D;
+    u8 PAT;
+    u8 G;
+    u32 address;
+};
+
+struct page_directory_entry create_page_directory_entry(struct page_directory_param param)
+{
+    struct page_directory_entry page_dir;
+
+    page_dir.flags = 2;
+
+    page_dir.available = (u8) 10;
+
+    page_dir.address = (u32) 24;
+
+    return page_dir;
+}
+
+struct page_table_entry create_page_table_entry(struct page_table_param param)
+{
+    struct page_table_entry page_table;
+
+    page_table.flags = 2;
+
+    page_table.g = (u8) 10;
+
+    page_table.available = (u8) 0;
+
+    page_table.address = (u32) 24;
+
+    return page_table;
+}
+
+int make_page(void)
+{
+    page_table[0] = create_page_table_entry((struct page_table_param) {
+                .P = 1, .R_W = 1, .U = 1, .PWT = 1, .PCD = 1,
+                .A = 0, .D = 0, .PAT = 0, .G = 0,
+                .address = 0});
+    
+    for (int i = 1; i < 1024; i++)
+    {
+        page_table[i] = create_page_table_entry((struct page_table_param) {
+                .P = 0, .R_W = 0, .U = 0, .PWT = 0, .PCD = 0,
+                .A = 0, .D = 0, .PAT = 0, .G = 0,
+                .address = 0});
+    }
+
+    page_dir[0] = create_page_directory_entry((struct page_directory_param) {
+                .P = 1, .R_W = 1, .U = 1, .PWT = 1, .PCD = 1,
+                .A = 0, .PS = 0, .address = page_table});
+    for (int i = 1; i < 1024; i++)
+    {
+        page_dir[i] = create_page_directory_entry((struct page_directory_param) {
+                        .P = 0, .R_W = 0, .U = 0, .PWT = 0, .PCD = 0,
+                        .A = 0, .PS = 0, .address = 0});
+    }
+
+    return 0;
+}
diff --git a/src/paging.h b/src/paging.h
new file mode 100644
index 0000000..af9c942
--- /dev/null
+++ b/src/paging.h
@@ -0,0 +1,24 @@
+#ifndef PAGING_H
+#define PAGING_H
+
+#include <types.h>
+
+struct page_directory_entry {
+    u8 flags;
+    u8 available : 4;
+    u32 address : 20;
+} __attribute__((packed));
+
+struct page_table_entry {
+    u8 flags;
+    u8 g : 1;
+    u8 available : 3;
+    u32 address : 20;
+} __attribute__((packed));
+
+int make_page(void);
+
+extern struct page_directory_entry page_dir[1024];
+extern struct page_table_entry page_table[1024];
+
+#endif  /*  !PAGING_H */