mem: add virtual memory mapping and enable paging

src/arch/i686/paging.asm

@@ -0,0 +1,24 @@
+global load_page_directory
+load_page_directory:
+	push ebp
+	mov ebp, esp
+
+	mov eax, [8+esp]
+	mov cr3, eax
+
+	mov esp, ebp
+	pop ebp
+	ret
+
+global enable_paging
+enable_paging:
+	push ebp
+	mov ebp, esp
+
+	mov eax, cr0
+	or eax, 0x80000000
+	mov cr0, eax
+
+	mov esp, ebp
+	pop ebp
+	ret

src/elsos.rs

@@ -5,14 +5,15 @@
 #![no_std]
 #![no_main]
 
-mod tools;
+mod ferramenta;
 mod vga;
 mod keyboard;
 mod tty;
 mod multiboot;
 mod serial;
 mod gdt;
 mod memory;
+mod libc;
 
 use core::panic::PanicInfo;
 
@@ -44,8 +45,7 @@ pub extern "C" fn kernel_main(magic: u32, address: u32)
 	vga::cursor::Cursor::init(0, 15);
 	if multiboot::check_magic(magic) && multiboot::parse(address)
 	{
-		let mut alloc: memory::pageframe::Allocator = memory::pageframe::Allocator::new();
-		unsafe { alloc.read_grub_mmap(MULTIBOOT_MMAP, MULTIBOOT_MMAP_ENTRIES); }
+		unsafe { crate::memory::init(MULTIBOOT_MMAP, MULTIBOOT_MMAP_ENTRIES); }
 		init_serial();
 		logln!("\n");
 		logln!("        :::      ::::::::    __       __       __ _  ____  ____  ");

src/tools.rs → src/ferramenta.rs

@@ -38,9 +38,9 @@ pub fn outb(port: u32, value: u8)
 	}
 }
 
-pub fn get_bit_at(input: u8, n: u8) -> bool
+pub fn get_bit_at(input: u32, n: u8) -> bool
 {
-	if n < 8
+	if n < 32
 	{
 		return input & (1 << n) != 0;
 	}
@@ -132,7 +132,7 @@ macro_rules! page_index
 {
 	($reg:expr) =>
 	{{
-		tools::divide_up($reg, 4096)
+		ferramenta::divide_up($reg, 4096)
 	}}
 }
 
@@ -227,3 +227,20 @@ impl Bitmap
 		}
 	}
 }
+
+pub fn set_bit(var: &mut u32, value: bool, bit: u8)
+{
+	if value
+	{
+		*var |= (value as u32) << bit;
+	}
+	else
+	{
+		*var &= !(!value as u32) << bit;
+	}
+}
+
+pub fn align(val: usize, bound: usize) -> usize
+{
+	val + bound - 1 & !(bound - 1)
+}

src/gdt.rs

@@ -1,6 +1,8 @@
 // using https://wiki.osdev.org/Global_Descriptor_Table#Segment_Descriptor to fill the values
 
 use core::mem::size_of;
+use core::ffi::c_void;
+use crate::libc;
 
 #[repr(C, packed)]
 struct gdt_ptr
@@ -102,7 +104,6 @@ static mut GDT_TABLE: gdt = gdt
 extern "C"
 {
 	fn _gdt_flush();
-	fn memcpy(dst: *const u8, src: *const u8, size: usize);
 }
 
 #[no_mangle]
@@ -117,7 +118,7 @@ pub fn init_gdt()
 	let size = size_of::<gdt>() - 1;
 	unsafe
 	{
-		memcpy(0x800 as *const u8, (&GDT_TABLE as *const _) as *const u8, size);
+		libc::memcpy(0x800 as *mut c_void, (&GDT_TABLE as *const _) as *const c_void, size);
 		_gp.limit = size as u16;
 		_gdt_flush();
 	}

src/keyboard/mod.rs

@@ -1,5 +1,5 @@
 use crate::tty;
-use crate::tools;
+use crate::ferramenta;
 
 mod azerty;
 mod qwerty;
@@ -54,7 +54,7 @@ pub fn get_scancodes()
 	let mut scancode: u8 = 0;
 	loop
     {
-		let new_scancode = tools::inb(KEYBOARD_DATA);
+		let new_scancode = ferramenta::inb(KEYBOARD_DATA);
 
 		if new_scancode == scancode
 		{

src/libc/libc.h

@@ -4,6 +4,6 @@
 void	*memset(void *b, int c, size_t len);
 void	*memcpy(void *dst, const void *src, size_t n);
 void	*memmove(void *dst, const void *src, size_t len);
-int 	memcmp(const void *s1, const void *s2, size_t n);
+int		memcmp(const void *s1, const void *s2, size_t n);
 
 #endif

src/libc/mod.rs

@@ -4,4 +4,5 @@ extern "C"
 {
 	pub fn memcpy(dest: *mut c_void, src: *const c_void, n: usize) -> *mut c_void;
 	pub fn memmove(dest: *mut c_void, src: *const c_void, n: usize) -> *mut c_void;
+	pub fn memset(dest: *mut c_void, val: usize, len: usize) -> *mut c_void;
 }

src/memory/mod.rs

@@ -1,13 +1,10 @@
-pub mod pageframe;
+mod pageframe;
+mod pagetable;
+mod page;
 
-use core::ffi::c_void;
 use crate::multiboot::MultibootTagMmap;
 
-extern "C"
-{
-	static _kernel_start: c_void;
-	static _kernel_end: c_void;
-}
+static PAGE_SIZE: usize = 4096;
 
 pub fn get_mem_size(mmap: *const MultibootTagMmap, mmap_size: usize) -> usize
 {
@@ -25,26 +22,47 @@ pub fn get_mem_size(mmap: *const MultibootTagMmap, mmap_size: usize) -> usize
 		}
 		if MEM_SIZE_BYTES > usize::MAX as u64
 		{
-			panic!("This version of ElsOS is in 32 bit, it only supports {}Mo of RAM, you have {}Mo installed", (usize::MAX / 1024) / 1024, (MEM_SIZE_BYTES / 1024) / 1024);
+			panic!("This version of elsOS is in 32 bit, it only supports {}MiB of RAM, you have {}MiB installed", (usize::MAX / 1024) / 1024, (MEM_SIZE_BYTES / 1024) / 1024);
 		}
 		return MEM_SIZE_BYTES as usize;
 	}
 }
 
-pub fn get_largest_mem_seg(mmap: *const MultibootTagMmap, mmap_size: usize) -> usize
+pub fn init(mmap: *const MultibootTagMmap, mmap_size: usize)
 {
-	let mut largest_free_mem_seg: usize = 0;
-	let mut largest_free_mem_seg_size: usize = 0;
+	let alloc: &mut pageframe::Allocator = pageframe::Allocator::shared();
+	alloc.read_grub_mmap(mmap, mmap_size);
+
+	let page_directory_addr = alloc.request_free_page();
+	let mut pt_manager = pagetable::Manager::new(page_directory_addr);
+
+	id_map(&mut pt_manager);
 	unsafe
 	{
-		for entry in (*mmap).entries(mmap_size)
-		{
-			if entry.len as usize > largest_free_mem_seg_size
-			{
-				largest_free_mem_seg_size = entry.len as usize;
-				largest_free_mem_seg = entry.addr as usize;
-			}
-		}
+		load_page_directory(page_directory_addr as *const page::DirectoryEntry);
+		enable_paging();
+	}
+}
+
+fn id_map(pt_manager: &mut pagetable::Manager)
+{
+	for i in 0..1024
+	{
+		pt_manager.memory_map(i * PAGE_SIZE, i * PAGE_SIZE);
+		pageframe::Allocator::shared().lock_page(i);
 	}
-	largest_free_mem_seg
+}
+
+extern "C"
+{
+	fn load_page_directory(address: *const page::DirectoryEntry);
+	fn enable_paging();
+}
+
+pub fn page_map_indexer(v_addr: usize) -> (usize, usize)
+{
+	let pdindex = v_addr >> 22;
+	let ptindex = v_addr >> 12 & 0x03FF;
+
+	return (pdindex, ptindex);
 }