Paging basically done

Cargo.toml

@@ -17,13 +17,15 @@ panic ="abort"
 
 [dependencies]
 thiserror = { version = "2.0.9", default-features = false }
+lock_api = "0.4.12"
 spin = "0.9.8"
 
 bitfield-struct = "0.10.0"
 bitflags = "2.6.0"
 
 memory_addr = "0.3.1"
-lock_api = "0.4.12"
+lock_free_buddy_allocator = "0.1.0"
+talc = "4.4.2"
 
 [target.'cfg(any(target_arch = "x86_64", target_arch = "x86"))'.dependencies]
 multiboot2 = { version = "0.23.1", default-features = false }

README.md

@@ -9,3 +9,8 @@ Then, run the build script by issuing `./build.sh`
 | x86 (i486) |     Works     |                      |
 | x86 (i386) |  Unsupported  |     TLB flushing     |
 |   x86_64   |     TODO      |                      |
+
+## Help!!!
+Here are some things you could help with:
+- Find a way to make freeing in ZonedBuddy page allocator checked (you can free a random page rigth now and it won't even panic)
+- Find a way to also check freeing in NestedPageTable

bochsrc

@@ -0,0 +1,3 @@
+ata0-slave: type=cdrom, path=bin/os.iso, status=inserted
+boot: cdrom
+magic_break: enabled=1

build.sh

@@ -2,8 +2,9 @@
 
 # If this is not your path, kindly change it
 export CROSS_CC="${CROSS_CC:-$HOME/opt/cross/bin/i686-elf-gcc}"
-export ARCH=x86/x32
-export QEMU_SYSTEM=i386
+export ARCH="${ARCH:-x86/x32}"
+export QEMU_SYSTEM="${QEMU_SYSTEM:-i386}"
+export EMULATOR="${EMULATOR:-qemu}"
 
 # Colors
 if command -v tput &> /dev/null; then
@@ -27,7 +28,7 @@ fi
 # Utils
 build() {
 	if ! cargo build; then
-		return -1
+		return 1
 	fi
 
 	KERNEL="target/target/debug/satan"
@@ -44,12 +45,20 @@ build() {
 }
 
 run() {
-	qemu-system-$QEMU_SYSTEM -d guest_errors -no-reboot -cdrom bin/os.iso
+	if [ $EMULATOR = "bochs" ]; then
+		bochs -q
+	else
+		qemu-system-$QEMU_SYSTEM -d guest_errors -no-reboot -cdrom bin/os.iso
+	fi
 }
 
 debug() {
-	qemu-system-$QEMU_SYSTEM -d guest_errors -no-reboot -cdrom bin/os.iso -s -S &
-	rust-gdb target/target/debug/satan -x gdbinit
+	if [ $EMULATOR = "bochs" ]; then
+		bochs -q
+	else
+		qemu-system-$QEMU_SYSTEM -d guest_errors -no-reboot -cdrom bin/os.iso -s -S &
+		rust-gdb target/target/debug/satan -x gdbinit
+	fi
 }
 
 clean() {

flake.nix

@@ -18,7 +18,7 @@
         {
           devShell = pkgs.mkShell {
             buildInputs = with pkgs; [
-              qemu
+              qemu bochs
               libisoburn mtools
               pkgs-crosssystem.buildPackages.grub2
               pkgs-crosssystem.buildPackages.gcc

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2024-12-11"
+channel = "nightly"
 components = ["rust-src", "rust-analyzer"]

src/arch/mod.rs

@@ -2,4 +2,18 @@
 /// x86 and x86_64 architectures
 pub mod x86;
 #[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
-pub use x86::*;
+pub use x86 as current;
+
+// * Stub imports to make it easier to see required functions and types
+
+pub use current::{_panic, _print};
+
+/// Instructions like cpuid
+pub mod instructions {
+    pub use super::current::instructions::cpu_id;
+}
+
+/// Interrupt handling
+pub mod interrupts {
+    pub use super::current::interrupts::{disable, enable};
+}

src/arch/x86/instructions.rs

@@ -0,0 +1,4 @@
+/// Get a CPU identifier
+pub fn cpu_id() -> usize {
+    0
+}

src/arch/x86/interrupts.rs

@@ -31,24 +31,32 @@ struct InterruptStackFrame {
 
 /// Central interrupt handler, all interrupts come here specifying an interrupt number
 fn interrupt_handler(interrupt: u8, error_code: usize) {
+    if interrupt == 0x20 {
+        // Timer
+        return;
+    }
     if interrupt == 0x0E {
         // Page fault
         crate::println!("Page fault!\nError code:\n{:#032b}", error_code);
         crate::println!("                ^        ^^IRUWP");
         crate::println!("               SGX      SSPK    ");
-        return;
-    }
-    if interrupt == 0x20 {
-        // Timer
-        return;
+        panic!("Halt");
     }
     if interrupt == 0x21 {
         // Keyboard
         let scancode = u8::read(0x60);
         crate::println!("Keyboard: {}", scancode);
         return;
     }
-
+    if interrupt <= 0x08 {
+        panic!("Double fault!!!\nError code: {:#x}", error_code);
+    }
+    if interrupt <= 0x1F {
+        panic!(
+            "Unhandled exception: {:#x}\nError code: {:#x}",
+            interrupt, error_code
+        );
+    }
     loop {}
 }
 

src/arch/x86/mod.rs

@@ -1,21 +1,42 @@
 #[cfg(target_arch = "x86")]
 core::arch::global_asm!(include_str!("x32/bootstrap.S"), options(att_syntax));
 
+/// Instructions like cpuid
+pub mod instructions;
+
 /// Early logging facilities
 pub mod early_logger;
+pub use early_logger::{_panic, _print};
 
 /// Interrupts and IDT
 pub mod interrupts;
 
 /// Paging implementation
-/// I spent a lot of time here
+/// I spent a lot of time here.
+/// And I hate every single second of it.
 pub mod paging;
 
+mod allocator {
+    const SIZE: usize = 0x1000;
+    static mut ARENA: [u8; SIZE] = [0; SIZE];
+
+    // TODO: Use system allocator on OOM
+    #[global_allocator]
+    static ALLOCATOR: talc::Talck<spin::Mutex<()>, talc::ClaimOnOom> = talc::Talc::new(unsafe {
+        // if we're in a hosted environment, the Rust runtime may allocate before
+        // main() is called, so we need to initialize the arena automatically
+        talc::ClaimOnOom::new(talc::Span::from_slice(core::ptr::addr_of_mut!(ARENA)))
+    })
+    .lock();
+}
+
 /// Kernel setup function. First thing that is called
 /// after assembly bootstrap setus up GDT and higher-half address space
 #[no_mangle]
 pub extern "cdecl" fn ksetup(mb_magic: u32, mbi_ptr: u32) -> ! {
-    // loop {}
+    crate::println!("Hello, SATAN!");
+    interrupts::setup();
+
     let boot_info = if mb_magic == multiboot2::MAGIC {
         let boot_info = unsafe {
             multiboot2::BootInformation::load(mbi_ptr as *const multiboot2::BootInformationHeader)
@@ -34,8 +55,6 @@ pub extern "cdecl" fn ksetup(mb_magic: u32, mbi_ptr: u32) -> ! {
         );
     };
 
-    crate::println!("Hello, SATAN!");
-    interrupts::setup();
     paging::setup_paging(&boot_info);
 
     loop {}