don't rely on allocator for basic stuff

Makefile

@@ -44,7 +44,7 @@ $(final): $(kernel) $(linker_script) $(assembly_object_files)
 		--gc-sections
 
 $(kernel):
-	@RUST_TARGET_PATH=$(shell pwd) xargo build --target $(target) -Zbuild-std=core,alloc
+	@RUST_TARGET_PATH=$(shell pwd) xargo build --target $(target) -Zbuild-std=core --features "f_multiboot2"
 
 build/arch/$(arch)/%.o: arch/$(arch)/%.asm
 	@mkdir -p $(shell dirname $@)

serial.log

@@ -6,16 +6,19 @@ BdsDxe: starting Boot0001 "UEFI QEMU DVD-ROM QM00003 " from PciRoot(0x0)/Pci(0x1
 
 
WARNING: no console will be available to OS
 
error: no suitable video mode found.
-
-
-
-welcome to wukkOS!
-(c) 2022 Real Microsoft, LLC
-initialising memory maps...[OK]
-memory map:
-0 - a0000 : Available
-100000 - 800000 : Available
-808000 - 80b000 : Available
-80c000 - 810000 : Available
-900000 - 78ef000 : Available
-7bff000 - 7f58000 : Available
+
hello from wukkOS!
+
+
+welcome to wukkOS!
+(c) 2022 Real Microsoft, LLC
+initialising memory maps...[OK]
+memory map:
+0 - a0000 : available
+100000 - 800000 : available
+800000 - 808000 : reserved for hibernation
+808000 - 80b000 : available
+80b000 - 80c000 : reserved for hibernation
+80c000 - 810000 : available
+810000 - 900000 : reserved for hibernation
+900000 - 78ef000 : available
+78ef000 - 79ef000 : reserved

src/allocator/mod.rs

@@ -1,55 +0,0 @@
-use core::alloc::{GlobalAlloc, Layout};
-use core::cell::UnsafeCell;
-use core::ptr::null_mut;
-use core::sync::atomic::AtomicUsize;
-use core::sync::atomic::Ordering::SeqCst;
-
-const ARENA_SIZE: usize = 128 * 1024;
-const MAX_SUPPORTED_ALIGN: usize = 4096;
-#[repr(C, align(4096))] // 4096 == MAX_SUPPORTED_ALIGN
-struct SimpleAllocator {
-    arena: UnsafeCell<[u8; ARENA_SIZE]>,
-    remaining: AtomicUsize, // we allocate from the top, counting down
-}
-
-#[global_allocator]
-static ALLOCATOR: SimpleAllocator = SimpleAllocator {
-    arena: UnsafeCell::new([0x55; ARENA_SIZE]),
-    remaining: AtomicUsize::new(ARENA_SIZE),
-};
-
-unsafe impl Sync for SimpleAllocator {}
-
-unsafe impl GlobalAlloc for SimpleAllocator {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        let size = layout.size();
-        let align = layout.align();
-
-        // `Layout` contract forbids making a `Layout` with align=0, or align not power of 2.
-        // So we can safely use a mask to ensure alignment without worrying about UB.
-        let align_mask_to_round_down = !(align - 1);
-
-        if align > MAX_SUPPORTED_ALIGN {
-            return null_mut();
-        }
-
-        let mut allocated = 0;
-        if self
-            .remaining
-            .fetch_update(SeqCst, SeqCst, |mut remaining| {
-                if size > remaining {
-                    return None;
-                }
-                remaining -= size;
-                remaining &= align_mask_to_round_down;
-                allocated = remaining;
-                Some(remaining)
-            })
-            .is_err()
-        {
-            return null_mut();
-        };
-        (self.arena.get() as *mut u8).add(allocated)
-    }
-    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
-}

src/boot/mod.rs

@@ -1,27 +1,26 @@
-use alloc::vec::Vec;
+use core::marker::PhantomData;
 use crate::KernelArgs;
 
 #[cfg(feature = "f_multiboot2")]
-pub mod multiboot2;
+use multiboot2::{load, MemoryMapTag, BootInformation};
 
-pub enum MemoryType {
-    Available,
-    Reserved,
-    AcpiReclaimable,
-    Nvs,
-    BadMemory,
-    Kernel,
-    Bootloader,
-    Unknown(u32)
+pub struct KernelInfo {
+    #[cfg(feature = "f_multiboot2")]
+    boot_info: BootInformation,
 }
 
-pub struct MemoryArea {
-    pub start: usize,
-    pub end: usize,
-    pub area_type: MemoryType,
-}
+impl KernelInfo {
+    pub fn init_from_kernel_args(args: KernelArgs) -> Self {
+        let mut kernel_info = KernelInfo {
+            #[cfg(feature = "f_multiboot2")]
+            boot_info: unsafe { load(args.multiboot_information_address).expect("ERR ARGS BAD!") },
+        };
+        kernel_info
+    }
 
-pub trait KernelInfo {
-    fn init_from_kernel_args(&mut self, args: KernelArgs);
-    fn get_memory_areas(&self) -> Vec<MemoryArea>;
+    #[cfg(feature = "f_multiboot2")]
+    pub fn memory_areas(&self) -> impl Iterator<Item = &multiboot2::MemoryArea> {
+        let mm_tag = self.boot_info.memory_map_tag().expect("ERR NO MEM MAP TAG!");
+        mm_tag.all_memory_areas()
+    }
 }

src/boot/multiboot2/mod.rs

@@ -1,41 +0,0 @@
-extern crate multiboot2;
-
-use alloc::vec;
-use alloc::vec::Vec;
-use multiboot2::{BootInformation, load, MemoryAreaType};
-use crate::boot::{KernelInfo, MemoryArea, MemoryType};
-use crate::KernelArgs;
-
-#[derive(Default)]
-pub struct Multiboot2Bootloader {
-    pub boot_info: Option<BootInformation>,
-}
-
-impl KernelInfo for Multiboot2Bootloader {
-    fn init_from_kernel_args(&mut self, args: KernelArgs) {
-        let boot_info = unsafe {
-            load(args.multiboot_information_address)
-        }.expect("invalid kernel args!");
-        self.boot_info = Some(boot_info);
-    }
-
-    fn get_memory_areas(&self) -> Vec<MemoryArea> {
-        let mut memory_areas = vec![];
-        let boot_info = self.boot_info.as_ref().unwrap();
-        let memory_map_tag = boot_info.memory_map_tag().expect("memory map tag required but not found!");
-        for area in memory_map_tag.memory_areas() {
-            memory_areas.push(MemoryArea {
-                start: area.start_address() as usize,
-                end: area.end_address() as usize,
-                area_type: match area.typ() {
-                    MemoryAreaType::Available => MemoryType::Available,
-                    MemoryAreaType::Reserved => MemoryType::Reserved,
-                    MemoryAreaType::AcpiAvailable => MemoryType::AcpiReclaimable,
-                    MemoryAreaType::ReservedHibernate => MemoryType::Reserved,
-                    MemoryAreaType::Defective => MemoryType::BadMemory,
-                }
-            })
-        }
-        memory_areas
-    }
-}

src/internals/errors.rs

@@ -21,7 +21,7 @@ pub extern "x86-interrupt" fn double_fault(stack_frame: InterruptStackFrame, _er
     loop {}
 }
 
-pub extern "x86-interrupt" fn page_fault(stack_frame: InterruptStackFrame, error_code: PageFaultErrorCode) -> ! {
+pub extern "x86-interrupt" fn page_fault(stack_frame: InterruptStackFrame, error_code: PageFaultErrorCode) {
     println!("---KERNEL FUCKY WUKKY UWU---");
     println!("page fault!");
     println!("accessed address: {:?}", Cr2::read());

src/lib.rs

@@ -1,33 +1,23 @@
 #![feature(abi_x86_interrupt)]
 #![feature(default_alloc_error_handler)]
 #![feature(panic_info_message)]
+#![feature(asm_const)]
 #![no_std]
 #![no_main]
 
-use alloc::boxed::Box;
-use alloc::format;
-use alloc::string::ToString;
-use alloc::sync::Arc;
-use allocator::*;
-
-extern crate alloc;
 extern crate rlibc;
 
-use alloc::vec::Vec;
-use spin::Mutex;
-use core::arch::asm;
-use core::ops::Deref;
 use lazy_static::lazy_static;
 use core::panic::PanicInfo;
+use multiboot2::MemoryAreaType;
 use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
 use crate::boot::KernelInfo;
 use crate::internals::WhyDoTheyCallItOvenWhenYouOfInTheColdFoodOfOutHotEatTheFood::*;
-use crate::serial::{Port, potential_serial_ports, terminal_helpers, terminal::ST};
+use crate::serial::terminal::ST;
 
 mod font;
 mod serial;
 mod internals;
-mod allocator;
 mod security;
 mod boot;
 mod memory;
@@ -49,25 +39,26 @@ const RAINBOW : [Colour; 6] = [Colour{r:255,g:0,b:0}, Colour{r:255,g:127,b:0}, C
 
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
-    ST.logln("---KERNEL FUCKY WUKKY UWU (panic)---");
-    ST.logln(if let Some(s) = info.payload().downcast_ref::<&str>() {
-        format!("panic payload: {s:?}")
+    println!("---KERNEL FUCKY WUKKY UWU (panic)---");
+    if let Some(s) = info.payload().downcast_ref::<&str>() {
+        println!("panic payload: {s:?}")
     } else {
-        format!("no panic payload")
-    }.as_str());
-    ST.logln(if let Some(msg) = info.message() {
-        format!("panic msg: {}", msg.as_str().unwrap_or("no message"))
+        println!("no panic payload")
+    };
+   if let Some(msg) = info.message() {
+        println!("panic msg: {}", msg.as_str().unwrap_or("no message"))
     } else {
-        "no message".to_string()
-    }.as_str());
-    ST.logln(if let Some(location) = info.location() {
-        format!("location: file {} line {}", location.file(), location.line())
+        println!("no message");
+    }
+    if let Some(location) = info.location() {
+        println!("location: file {} line {}", location.file(), location.line());
     } else {
-        "no location".to_string()
-    }.as_str());
+        println!("no location");
+    };
     loop {}
 }
 
+#[repr(C)]
 pub struct KernelArgs {
     #[cfg(feature = "f_multiboot2")]
     multiboot_information_address: usize
@@ -89,14 +80,6 @@ pub extern fn kernel_main(args: KernelArgs) -> ! {
         ST.init_from_port(*port);
     }
 
-    let kern_info: Box<dyn boot::KernelInfo> = {
-        #[cfg(feature = "f_multiboot2")]
-        {
-            let mut kern_info = boot::multiboot2::Multiboot2Bootloader::default();
-            kern_info.init_from_kernel_args(args);
-            Box::new(kern_info)
-        }
-    };
 
     println!();
     println!();
@@ -104,19 +87,17 @@ pub extern fn kernel_main(args: KernelArgs) -> ! {
     println!("welcome to wukkOS!");
     println!("(c) 2022 Real Microsoft, LLC");
     print!("initialising memory maps...");
-    let mem_areas = kern_info.get_memory_areas();
+    let kern_info = KernelInfo::init_from_kernel_args(args);
+    let mut mem_areas = kern_info.memory_areas();
     println!("[OK]");
     println!("memory map:");
-    for area in mem_areas {
-        println!("{:x} - {:x} : {}", area.start, area.end, match area.area_type {
-            boot::MemoryType::Available => "Available",
-            boot::MemoryType::Reserved => "Reserved",
-            boot::MemoryType::AcpiReclaimable => "ACPI Reclaimable",
-            boot::MemoryType::Nvs => "NVS",
-            boot::MemoryType::BadMemory => "Bad Memory",
-            boot::MemoryType::Kernel => "Kernel",
-            boot::MemoryType::Bootloader => "Bootloader",
-            boot::MemoryType::Unknown(_) => "Unknown"
+    while let Some(area) = mem_areas.next() {
+        println!("{:x} - {:x} : {}", area.start_address(), area.end_address(), match area.typ() {
+            MemoryAreaType::Available => "available",
+            MemoryAreaType::Reserved => "reserved",
+            MemoryAreaType::AcpiAvailable => "ACPI available",
+            MemoryAreaType::ReservedHibernate => "reserved for hibernation",
+            MemoryAreaType::Defective => "defective",
         });
     }
 

src/macros/mod.rs

@@ -1,6 +1,4 @@
-use alloc::fmt::format;
 use core::fmt;
-use std::fmt::format;
 use crate::serial::terminal::ST;
 
 #[macro_export]
@@ -17,6 +15,5 @@ macro_rules! println {
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
-    let string = format(args);
-    ST.log(string.as_str());
+    ST.writer.lock().write_fmt(args).unwrap();
 }

src/memory/mod.rs

@@ -1,4 +0,0 @@
-#[repr(align(4096))]
-pub struct PageTable {
-    entries: [PageTableEntry; 512],
-}

src/serial/mod.rs

@@ -1,4 +1,4 @@
-#![feature(asm_const)]
+
 
 use core::arch::asm;
 use core::borrow::{Borrow, BorrowMut};

src/serial/terminal.rs

@@ -1,17 +1,25 @@
-use alloc::sync::Arc;
+use core::fmt;
 use core::ops::Deref;
 use lazy_static::lazy_static;
 use spin::Mutex;
 use crate::serial::Port;
 
 pub struct SerialTerminal {
-    pub port: Arc<Mutex<Option<Port>>>,
+    pub port: Mutex<Option<Port>>,
+    pub writer: Mutex<SerialTerminalWriter>,
+}
+
+pub struct SerialTerminalWriter {
+    pub port: Mutex<Option<Port>>,
 }
 
 lazy_static! {
     pub static ref ST: SerialTerminal = {
-        let mut serial_terminal = SerialTerminal {
-            port: Arc::new(Mutex::new(None)),
+        let serial_terminal: SerialTerminal = SerialTerminal {
+            port: Mutex::new(None),
+            writer: Mutex::new(SerialTerminalWriter {
+                port: Mutex::new(None),
+            }),
         };
         serial_terminal
     };
@@ -20,6 +28,7 @@ lazy_static! {
 impl SerialTerminal {
     pub fn init_from_port(&self, port: Port) {
         self.port.lock().replace(port);
+        self.writer.lock().port.lock().replace(port);
     }
 
     pub fn log(&self, message: &str) {
@@ -34,4 +43,13 @@ impl SerialTerminal {
             port.transmit_string("\r\n");
         }
     }
+}
+
+impl fmt::Write for SerialTerminalWriter {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        if let Some(port) = self.port.lock().deref() {
+            port.transmit_string(s);
+        }
+        Ok(())
+    }
 }