stuck in the middle of paging

kernel-rs/Cargo.toml

@@ -5,3 +5,10 @@ authors = ["Jack Halford <jack@crans.org>"]
 
 [lib]
 crate-type = ["staticlib"]
+
+[dependencies]
+rlibc = "1.0"
+volatile = "0.1.0"
+spin = "0.4.5"
+multiboot2 = "0.1.0"
+bitflags = "0.9.1"

kernel-rs/Makefile

@@ -2,7 +2,7 @@ arch	?= x86_64
 kernel	:= build/kernel-$(arch).bin
 iso		:= build/os-$(arch).iso
 
-target	?= $(arch)-KFS
+target	?= $(arch)-kfs
 rust_os	:= target/$(target)/debug/libkfs.a
 
 linker_script		:= src/arch/$(arch)/linker.ld
@@ -16,9 +16,10 @@ asm_object_files	:= $(patsubst src/arch/$(arch)/%.asm, \
 all: $(kernel)
 
 clean:
+	@cargo clean
 	@rm -r build
 
-run: $(iso)
+run:
 	@qemu-system-x86_64 -cdrom $(iso)
 
 iso: $(iso)
@@ -31,11 +32,10 @@ $(iso): $(kernel) $(grub.cfg)
 	rm -r build/isofiles
 
 $(kernel): kernel $(asm_object_files) $(linker_script)
-	@ld -n -T $(linker_script) -o $(kernel) \
-		$(asm_object_files) $(rust_os)
+	@ld -n --gc-sections -T $(linker_script) -o $(kernel) $(asm_object_files) $(rust_os)
 
 kernel:
-	@xargo build --target $(target)
+	@RUST_TARGET_PATH="$(shell pwd)" xargo build --target $(target)
 
 # compile asm files
 build/arch/$(arch)/%.o: src/arch/$(arch)/%.asm

kernel-rs/src/arch/x86_64/boot.asm

@@ -6,6 +6,10 @@ bits 32
 start:
 	mov		esp, stack_top
 
+	; Move multiboot info pointer to edi 
+	; which is the first argument for the rust main
+	mov		edi, ebx
+
 	call	check_multiboot
 	call	check_cpuid
 	call	check_long_mode
@@ -86,14 +90,19 @@ check_long_mode:
 	jmp		error
 
 set_up_page_tables:
+	; map P4 511th byte recursively to P4
+	mov		eax, p4_table
+	or		eax, 0b11				; present + writable
+	mov		[p4_table + 511 * 8], eax
+
 	; map first P4 entry to P3 table
 	mov		eax, p3_table
-	or		eax, 0b11				; present + writeable
+	or		eax, 0b11				; present + writable
 	mov		[p4_table], eax
 	
 	; map first P3 entry to P2 table
 	mov		eax, p2_table
-	or		eax, 0b11				; present + writeable
+	or		eax, 0b11				; present + writable
 	mov		[p3_table], eax
 
 	mov		ecx, 0					;counter variable
@@ -142,7 +151,7 @@ p3_table:
 p2_table:
 	resb 4096
 stack_bottom:
-	resb	64
+	resb	4096 * 4
 stack_top:
 
 section .rodata

kernel-rs/src/arch/x86_64/linker.ld

@@ -6,11 +6,19 @@ SECTIONS {
 	.boot :
 	{
 		/* ensure that the multiboot header is at the beginning */
-		*(.multiboot_header)
+		KEEP(*(.multiboot_header))
 	}
 
 	.text :
 	{
-		*(.text)
+		*(.text .text.*)
+	}
+
+	.rodata : {
+		*(.rodata .rodata.*)
+	}
+
+	.data.rel.ro : {
+		*(.data.rel.ro.local*) *(.data.rel.ro .data.rel.ro.*)
 	}
 }

kernel-rs/src/arch/x86_64/long_mode_init.asm

@@ -14,7 +14,7 @@ long_mode_start:
 	extern	rust_main
 	call	rust_main
 
-	;print 'OKAY' to screen
-	mov		rax, 0x2f592f412f4b2f4f
-    mov		qword [0xb8000], rax
+	;;print 'OKAY' to screen
+	;mov		rax, 0x2f592f412f4b2f4f
+    ;mov		qword [0xb8000], rax
     hlt

kernel-rs/src/lib.rs

@@ -1,8 +1,71 @@
 #![feature(lang_items)]
+#![feature(const_fn)]
+#![feature(ptr_internals)]
 #![no_std]
 
+extern crate rlibc;
+extern crate volatile;
+extern crate spin;
+extern crate multiboot2;
+#[macro_use] extern crate bitflags;
+#[macro_use] mod vga_buffer;
+mod memory;
+
 #[no_mangle]
-pub extern fn rust_main() {}
+pub extern fn rust_main(multiboot_information_address: usize) {
+    use memory::FrameAllocator;
+
+    vga_buffer::clear_screen();
+    println!("Hello World {}", "!");
+
+    let boot_info = unsafe{ multiboot2::load(multiboot_information_address)};
+
+    let memory_map_tag = boot_info.memory_map_tag()
+        .expect("Memory map tag required");
+    println!("memory areas:");
+    for area in memory_map_tag.memory_areas() {
+        println!("    start: 0x{:x}, length: 0x{:x}",
+                 area.base_addr, area.length);
+    }
+
+    let elf_sections_tag = boot_info.elf_sections_tag()
+        .expect("ELF sections tag required");
+    println!("kernel sections:");
+    for section in elf_sections_tag.sections() {
+        println!("    addr: 0x{:x}, length: 0x{:x}, flags: 0x{:x}",
+                 section.addr, section.size, section.flags);
+    }
+
+    let kernel_start = elf_sections_tag.sections().map(|s| s.addr)
+        .min().unwrap();
+    let kernel_end = elf_sections_tag.sections().map(|s| s.addr + s.size)
+        .max().unwrap();
+
+    let multiboot_start = multiboot_information_address;
+    let multiboot_end = multiboot_start + (boot_info.total_size as usize);
+
+    let mut frame_allocator = memory::AreaFrameAllocator::new(
+        kernel_start as usize, kernel_end as usize, multiboot_start,
+        multiboot_end, memory_map_tag.memory_areas()
+        );
+
+    for i in 0.. {
+        if let None = frame_allocator.allocate_frame() {
+            println!("allocated {} frames", i);
+            break;
+        }
+    }
+
+    loop{};
+}
 
 #[lang = "eh_personality"] #[no_mangle] pub extern fn eh_personality() {}
-#[lang = "panic_fmt"] #[no_mangle] pub extern fn panic_fmt() -> ! {loop{}}
+
+#[lang = "panic_fmt"]
+#[no_mangle]
+pub extern fn panic_fmt(fmt: core::fmt::Arguments, file: &'static str,
+                        line: u32) -> ! {
+    println!("\n\nPANIC in {} at line {}:", file, line);
+    println!("    {}", fmt);
+    loop{}
+}

kernel-rs/src/memory/area_frame_allocator.rs

@@ -0,0 +1,92 @@
+use memory::{Frame, FrameAllocator};
+use multiboot2::{MemoryAreaIter, MemoryArea};
+
+pub struct AreaFrameAllocator {
+    next_free_frame: Frame,
+    current_area: Option<&'static MemoryArea>,
+    areas: MemoryAreaIter,
+    kernel_start: Frame,
+    kernel_end: Frame,
+    multiboot_start: Frame,
+    multiboot_end: Frame,
+}
+
+impl AreaFrameAllocator {
+    pub fn new(
+        kernel_start: usize,
+        kernel_end: usize,
+        multiboot_start: usize,
+        multiboot_end: usize,
+        memory_areas: MemoryAreaIter
+        ) -> AreaFrameAllocator {
+        let mut allocator = AreaFrameAllocator {
+            next_free_frame: Frame::containing_address(0),
+            current_area: None,
+            areas: memory_areas,
+            kernel_start: Frame::containing_address(kernel_start),
+            kernel_end: Frame::containing_address(kernel_end),
+            multiboot_start: Frame::containing_address(multiboot_start),
+            multiboot_end: Frame::containing_address(multiboot_end),
+        };
+        allocator.choose_next_area();
+        allocator
+    }
+
+    fn choose_next_area(&mut self) {
+        self.current_area = self.areas.clone().filter(|area| {
+            let address = area.base_addr + area.length - 1;
+            Frame::containing_address(address as usize) >= self.next_free_frame
+        }).min_by_key(|area| area.base_addr);
+
+        if let Some(area) = self.current_area {
+            let start_frame = Frame::containing_address(area.base_addr as usize);
+            if self.next_free_frame < start_frame {
+                self.next_free_frame = start_frame;
+            }
+        }
+    }
+}
+
+impl FrameAllocator for AreaFrameAllocator {
+    fn allocate_frame(&mut self) -> Option<Frame> {
+        if let Some(area) = self.current_area {
+            // "Clone" the frame to return it if it's free. Frame doesn't
+            // implement Clone, but we can construct an identical frame.
+            let frame = Frame{ number: self.next_free_frame.number };
+
+            // the last frame of the current area
+            let current_area_last_frame = {
+                let address = area.base_addr + area.length - 1;
+                Frame::containing_address(address as usize)
+            };
+
+            if frame > current_area_last_frame {
+                // all frames of current area are used, switch to next area
+                self.choose_next_area();
+            } else if frame >= self.kernel_start && frame <= self.kernel_end {
+                // 'frame' is used by the kernel
+                self.next_free_frame = Frame {
+                    number: self.kernel_end.number + 1
+                };
+            } else if frame >= self.multiboot_start && frame <= self.multiboot_end {
+                // 'frame' is used by the multiboot information structure
+                self.next_free_frame = Frame {
+                    number: self.multiboot_end.number + 1
+                };
+            } else {
+                // 'frame' is unused, increment next_free_frame and return it;
+                self.next_free_frame.number += 1;
+                return Some(frame)
+            };
+            // frame was not valid, try it again with the updated next_free_frame
+            self.allocate_frame()
+        } else {
+            None // no free frames left
+        }
+    }
+
+    fn deallocate_frame(&mut self, frame: Frame) {
+        unimplemented!()
+    }
+
+}

kernel-rs/src/memory/mod.rs

@@ -0,0 +1,28 @@
+pub use self::area_frame_allocator::AreaFrameAllocator;
+use self::paging::PhysicalAddress;
+
+mod area_frame_allocator;
+mod paging;
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Frame {
+    number: usize,
+}
+
+pub const PAGE_SIZE: usize = 4096;
+
+
+impl Frame {
+    fn containing_address(address: usize) -> Frame {
+        Frame{ number: address / PAGE_SIZE }
+    }
+    
+    fn start_address(&self) -> PhysicalAddress {
+        self.number * PAGE_SIZE
+    }
+}
+
+pub trait FrameAllocator {
+    fn allocate_frame(&mut self) -> Option<Frame>;
+    fn deallocate_frame(&mut self, frame: Frame);
+}

kernel-rs/src/memory/paging/entry.rs

@@ -0,0 +1,47 @@
+use memory::Frame;
+
+pub struct Entry(u64)
+
+bitflags! {
+    pub struct EntryFlags: u64 {
+        const PRESENT =         1 << 0;
+        const WRITABLE =        1 << 1;
+        const USER_ACCESSIBLE = 1 << 2;
+        const WRITE_THROUGH =   1 << 3;
+        const NO_CACHE =        1 << 4;
+        const ACCESSED =        1 << 5;
+        const DIRTY =           1 << 6;
+        const HUGE_PAGE =       1 << 7;
+        const GLOBAL =          1 << 8;
+        const NO_EXECUTE =      1 << 63;
+    }
+}
+
+impl Entry {
+    pub fn is_unused(&self) -> bool {
+        self.0 == 0;
+    }
+    
+    pub fn set_unused(&mut self) {
+        self.0 = 0;
+    }
+
+    pub fn flags(&self) -> EntryFlags {
+        EntryFlags::from_bits_truncate(self.0)
+    }
+    
+    pub fn pointed_frame(&self) -> Option<Frame> {
+        if self.flags().contains(PRESENT) {
+            Some(Frame::containing_address(
+                    self.0 as usize & 0x000fffff_fffff000
+                    ))
+        } else {
+            None
+        }
+    }
+
+    pub fn set(&mut self, frame: Frame, flags: EntryFlags) {
+        assert!(frame.start_address() & !0x000fffff_fffff000 == 0);
+        self.0 = (frame.start_address() as u64) | flags.bits();
+    }
+}

kernel-rs/src/memory/paging/mod.rs

@@ -0,0 +1,10 @@
+use memory::PAGE_SIZE;
+
+const ENTRY_COUNT: usize = 512;
+
+pub type PhysicalAddress = usize;
+pub type VirtualAddress = usize;
+
+pub struct Page {
+    number: usize,
+}

kernel-rs/src/memory/paging/table.rs

@@ -0,0 +1,51 @@
+use memory::paging::entry::*
+use memory::paging::ENTRY_COUNT;
+use core::ops::{Index, IndexMut};
+
+pub const P4: *mut Table = 0xffffffff_fffff000 as *mut _;
+
+pub struct Table {
+    entries: [Entry; ENTRY_COUNT],
+}
+
+impl Index<usize> for Table {
+    type Output = Entry;
+
+    fn index(&sef, index: usize) -> &Entry {
+        &self.entries[index]
+    }
+}
+
+impl IndexMut<usize> for Table {
+    fn index_mut(&mut self, index: usize) -> &mut Entry {
+        &mut self.entries[index]
+    }
+}
+
+impl Table {
+    pub fn zero(&mut self) {
+        for entry in self.entries.iter_mut() {
+            entry.set_unused();
+        }
+    }
+
+    pub fn next_table(&self, index: usize) -> Option<&Table> {
+        self.next_table_address(index)
+            .map(|address| unsafe { &*(address as *const _) })
+    }
+
+    pub fn next_table_mut(&self, index: usize) -> Option<&mut Table> {
+        self.next_table_address(index)
+            .map(|address| unsafe { &*(address as *mut _) })
+    }
+
+    fn next_table_address(&self, index: usize) -> Option<usize> {
+        let entry_flags = self[index].flags();
+        if entry_flags.contains(PRESENT) && !entry_flags.contains(HUGE_PAGE) {
+            let table_address = self as *const _ as usize;
+            Some((table_address << 9) | (index << 12))
+        } else {
+            None
+        }
+    }
+}

kernel-rs/src/vga_buffer.rs

@@ -0,0 +1,148 @@
+use core::ptr::Unique;
+use volatile::Volatile;
+use core::fmt;
+use spin::Mutex;
+
+pub static WRITER: Mutex<Writer> = Mutex::new(Writer {
+    column_position: 0,
+    color_code: ColorCode::new(Color::LightRed, Color::Black),
+    buffer: unsafe { Unique::new_unchecked(0xb8000 as *mut _) },
+});
+
+macro_rules! println {
+    ($fmt:expr) => (print!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => (print!(concat!($fmt, "\n"), $($arg)*));
+}
+
+macro_rules! print {
+    ($($arg:tt)*) => ({
+        $crate::vga_buffer::print(format_args!($($arg)*));
+    });
+}
+
+pub fn print(args: fmt::Arguments) {
+    use core::fmt::Write;
+    WRITER.lock().write_fmt(args).unwrap();
+}
+
+impl fmt::Write for Writer {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        for byte in s.bytes() {
+            self.write_byte(byte)
+        }
+        Ok(())
+    }
+}
+
+#[allow(dead_code)]
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+pub enum Color {
+    Black      = 0,
+    Blue       = 1,
+    Green      = 2,
+    Cyan       = 3,
+    Red        = 4,
+    Magenta    = 5,
+    Brown      = 6,
+    LightGray  = 7,
+    DarkGray   = 8,
+    LightBlue  = 9,
+    LightGreen = 10,
+    LightCyan  = 11,
+    LightRed   = 12,
+    Pink       = 13,
+    Yellow     = 14,
+    White      = 15,
+}
+
+#[derive(Debug, Clone, Copy)]
+struct ColorCode(u8);
+
+impl ColorCode {
+    const fn new(foreground: Color, background: Color) -> ColorCode {
+        ColorCode((background as u8) << 4 | (foreground as u8))
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+#[repr(C)]
+struct ScreenChar {
+    ascii_character: u8,
+    color_code: ColorCode,
+}
+
+const BUFFER_HEIGHT: usize = 25;
+const BUFFER_WIDTH: usize = 80;
+
+struct Buffer {
+    chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT]
+}
+
+pub struct Writer {
+    column_position: usize,
+    color_code: ColorCode,
+    buffer: Unique<Buffer>,
+}
+
+#[allow(dead_code)]
+impl Writer {
+    pub fn write_byte(&mut self, byte: u8) {
+        match byte {
+            b'\n' => self.new_line(),
+            byte => {
+                if self.column_position >= BUFFER_WIDTH {
+                    self.new_line();
+                }
+
+                let row = BUFFER_HEIGHT - 1;
+                let col = self.column_position;
+
+                let color_code = self.color_code;
+                self.buffer().chars[row][col].write(ScreenChar {
+                    ascii_character: byte,
+                    color_code: color_code,
+                });
+                self.column_position += 1;
+            }
+        }
+    }
+
+    pub fn write_str(&mut self, s: &str) {
+        for byte in s.bytes() {
+            self.write_byte(byte)
+        }
+    }
+    
+    fn buffer(&mut self) -> &mut Buffer {
+        unsafe{ self.buffer.as_mut()}
+    }
+
+    fn new_line(&mut self) {
+        for row in 1..BUFFER_HEIGHT {
+            for col in 0..BUFFER_WIDTH {
+                let buffer = self.buffer();
+                let character = buffer.chars[row][col].read();
+                buffer.chars[row - 1][col].write(character);
+            }
+        }
+        self.clear_row(BUFFER_HEIGHT - 1);
+        self.column_position = 0;
+    }
+
+    fn clear_row(&mut self, row: usize) {
+        let blank = ScreenChar {
+            ascii_character: b' ',
+            color_code: self.color_code,
+        };
+        for col in 0..BUFFER_WIDTH {
+            self.buffer().chars[row][col].write(blank);
+        }
+    }
+}
+
+pub fn clear_screen() {
+    for _ in 0..BUFFER_HEIGHT {
+        println!("");
+    }
+}

kernel-rs/x86_64-KFS.json

@@ -8,5 +8,6 @@
   "arch": "x86_64",
   "os": "none",
   "disable-redzone": true,
-  "features": "-mmx,-sse,+soft-float"
+  "features": "-mmx,-sse,+soft-float",
+  "panic-strategy": "abort"
 }