fixed interrupts (temporary, we need to do a real fix for this)

TODO:

* Debugging, tracing support.
* Logging infra so we can may pass a loglevel like on Linux.

.cargo/config.toml

@@ -17,8 +17,5 @@ runner = "scripts/run_debug.sh"
 [target.'cfg(all(target_arch = "x86_64", target_os = "none", not(debug_assertions)))']
 runner = "scripts/run_release.sh"
 
-[target.x86_64-kernel]
-rustflags = ["-C", "force-unwind-tables"]
-
 [registries.gitea]
 index = "sparse+https://git.zxq5.dev/api/packages/OsDev/cargo/" # Sparse index

Cargo.lock

@@ -99,18 +99,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "elf"
-version = "0.7.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4445909572dbd556c457c849c4ca58623d84b27c8fff1e74b0b4227d8b90d17b"
-
-[[package]]
-name = "fallible-iterator"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2acce4a10f12dc2fb14a218589d4f1f62ef011b2d0cc4b3cb1bba8e94da14649"
-
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -123,10 +111,7 @@ version = "0.1.0"
 dependencies = [
  "cc",
  "crossbeam",
- "elf",
- "fallible-iterator",
  "futures-util",
- "gimli",
  "libm",
  "limine",
  "linked_list_allocator",
@@ -160,12 +145,6 @@ dependencies = [
  "pin-utils",
 ]
 
-[[package]]
-name = "gimli"
-version = "0.31.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "07e28edb80900c19c28f1072f2e8aeca7fa06b23cd4169cefe1af5aa3260783f"
-
 [[package]]
 name = "ident_case"
 version = "1.0.1"

kernel/Cargo.toml

@@ -19,9 +19,11 @@ futures-util = { version = "0.3.31", default-features = false, features = [
     "alloc",
 ] }
 linked_list_allocator = { version = "0.10.5", features = ["use_spin"] }
-gimli = { version = "0.31.1", default-features = false, features = ["read"] }
-elf = { version = "0.7.4", default-features = false, features = ["nightly"] }
-fallible-iterator = "0.3.0"
+# gimli = { version = "0.31.1", default-features = false, features = ["read"] }
+# elf = { version = "0.7.4", default-features = false, features = ["nightly"] }
+# fallible-iterator = "0.3.0"
+# framehop = { version = "0.13.2", default-features = false }
+# object = { version = "0.36.7", default-features = false, features = ["read"] }
 
 [build-dependencies]
 cc = "1.2.14"

kernel/src/arch/x86_64/cpu/apic.rs

@@ -2,10 +2,13 @@
 
 use core::arch::x86_64::__cpuid;
 
-use crate::arch::x86_64::cpu::msr::*;
-use crate::arch::x86_64::memory::mapping::PHYSICAL_MEMORY_OFFSET;
-use crate::arch::x86_64::memory::{FRAME_ALLOCATOR, OFFSET_PAGE_TABLE};
-use crate::{debugln, serial_print, serial_println};
+use crate::arch::x86_64::{
+    cpu::msr::*,
+    memory::{
+        FRAME_ALLOCATOR, OFFSET_PAGE_TABLE, mapping::PHYSICAL_MEMORY_OFFSET,
+    },
+};
+
 use x86_64::structures::paging::Translate;
 use x86_64::{
     PhysAddr, VirtAddr,
@@ -28,7 +31,6 @@ const CPUID_FEAT_EDX_APIC: u64 = 1 << 9; // the cpuid instruction will return th
 
 fn set_apic_base_enable(apic: PhysAddr) {
     let rax = (apic.as_u64() & 0xfffff0000) | IA32_APIC_BASE_MSR_ENABLE;
-    debugln!("apic {:?}", PhysAddr::new(rax));
     cpu_set_msr(IA32_APIC_BASE_MSR, rax);
 }
 
@@ -42,8 +44,6 @@ fn get_apic_base() -> PhysAddr {
     let mut value: u64 = 0;
     cpu_get_msr(IA32_APIC_BASE_MSR, &mut value);
 
-    debugln!("apic base {:#x}", value);
-
     PhysAddr::new(value & 0xfffff0000)
 }
 
@@ -55,7 +55,6 @@ fn write_apic_register(apic_base: &PhysAddr, reg: u64, value: u32) {
 
     let phys_check =
         OFFSET_PAGE_TABLE.get().unwrap().lock().translate(virt_addr);
-    debugln!("{:?}", phys_check);
 
     unsafe { *(virt_addr.as_u64() as *mut u32) = value };
 }
@@ -76,14 +75,13 @@ pub fn check_apic() -> bool {
 unsafe fn phys_to_virt(phys: PhysAddr) -> VirtAddr {
     let phys = phys.as_u64();
     phys.checked_add(*PHYSICAL_MEMORY_OFFSET)
-        .map_or_else(|| panic!(" overflow"), VirtAddr::new)
+        .map_or_else(|| panic!("Overflow"), VirtAddr::new)
 }
 
 pub fn enable_apic() {
     let apic_base_physical_addr = get_apic_base();
     set_apic_base_enable(apic_base_physical_addr);
 
-    debugln!("{:?}", apic_base_physical_addr);
     enable_timer();
 
     write_apic_register(

kernel/src/arch/x86_64/drivers/ascii/mod.rs

@@ -1,4 +1,4 @@
-use core::fmt;
+use core::fmt::{self, Write};
 use spin::{Lazy, Mutex};
 use x86_64::instructions::interrupts;
 
@@ -7,6 +7,7 @@ use crate::arch::x86_64::drivers::framebuffer::{
 };
 
 use crate::resources::font::{FONT_SPLEEN_8X16, Font};
+use crate::std::maths::geometry::Vec2;
 
 static FONT_WIDTH: u32 = 8;
 static FONT_HEIGHT: u32 = 16;
@@ -25,11 +26,8 @@ pub struct Writer {
     screen_width: u32,
     /// Measured in chars not pixels.
     screen_height: u32,
-    /// 16 pixels tall.
     text_line: u32,
-    /// 8 pixels wide.
     text_col: u32,
-
     fg_color: Colour,
     bg_color: Colour,
 }
@@ -62,6 +60,15 @@ impl Writer {
         self.font = font;
     }
 
+    pub const fn set_pos(&mut self, coords: Vec2<u32>) {
+        self.text_col = coords.x();
+        self.text_line = coords.y();
+    }
+
+    pub const fn pos(&self) -> Vec2<u32> {
+        Vec2::new(self.text_col, self.text_line)
+    }
+
     /// This is sent when the user types a backspace.
     const BACKSPACE: u8 = 8;
 
@@ -206,6 +213,34 @@ pub fn clear_screen() {
     });
 }
 
+/// Prints a string at a given `coords` before returning to original position.
+///
+/// These are 0 based indices and refer to character position, not pixel
+/// positions.
+pub fn _print_oneshot(
+    fg: Colour,
+    bg: Colour,
+    coords: Vec2<u32>,
+    args: fmt::Arguments,
+) {
+    interrupts::without_interrupts(|| {
+        let mut writer = WRITER.lock();
+
+        // Save the old positions of `text_col` and `text_line`.
+        let old_pos = writer.pos();
+
+        // Also save the colors.
+        let old_fg_color = writer.fg_color;
+        let old_bg_color = writer.bg_color;
+
+        writer.set_pos(coords);
+        writer.set_colour(fg, bg);
+        writer.write_fmt(args).unwrap();
+        writer.set_colour(old_fg_color, old_bg_color);
+        writer.set_pos(old_pos);
+    });
+}
+
 pub fn reset_cursor() {
     interrupts::without_interrupts(|| {
         let mut writer = WRITER.lock();
@@ -214,6 +249,15 @@ pub fn reset_cursor() {
     });
 }
 
+#[macro_export]
+/// Prints a coloured string at a position before restoring previous position
+/// and colour.
+macro_rules! print_oneshot {
+    ($position:expr, $fg:expr, $bg:expr, $($arg:tt)*) => {
+        $crate::arch::x86_64::drivers::ascii::_print_oneshot($fg, $bg, $position, format_args!($($arg)*));
+    };
+}
+
 #[macro_export]
 macro_rules! println_log {
 	() => ($crate::print_log!("\n"));

kernel/src/arch/x86_64/interrupts.rs

@@ -127,7 +127,7 @@ extern "x86-interrupt" fn keyboard_interrupt_handler(
 extern "x86-interrupt" fn timer_interrupt_handler(
     _stack_frame: InterruptStackFrame,
 ) {
-    debug!("Timer Interrupt");
+    // debug!("Timer Interrupt");
     unsafe {
         PICS.lock()
             .notify_end_of_interrupt(InterruptIndex::Timer.as_u8());
@@ -138,10 +138,10 @@ extern "x86-interrupt" fn page_fault_handler(
     _stack_frame: InterruptStackFrame,
     _error_code: PageFaultErrorCode,
 ) {
-    serial_println!("Exception: Page Fault");
-    serial_println!("Accessed Address: {:?}", Cr2::read());
-    serial_println!("Error Code: {:?}", _error_code);
-    serial_println!("{:#?}", _stack_frame);
+    // serial_println!("Exception: Page Fault");
+    // serial_println!("Accessed Address: {:?}", Cr2::read());
+    // serial_println!("Error Code: {:?}", _error_code);
+    // serial_println!("{:#?}", _stack_frame);
 
     if let Some(frame_allocator) = FRAME_ALLOCATOR.get() {
         let mut f = frame_allocator.lock();

kernel/src/arch/x86_64/memory/allocation/heap_alloc.rs

@@ -3,8 +3,7 @@ use crate::arch::x86_64::memory::units::MemoryUnits;
 use crate::arch::x86_64::memory::{
     FRAME_ALLOCATOR, HEAP_SIZE, HEAP_VIRTUAL_SPACE,
 };
-use crate::serial_println;
-use crate::{debugln, serial_print};
+use crate::debugln;
 use core::alloc::{GlobalAlloc, Layout};
 use core::ptr;
 use spin::{Mutex, MutexGuard};

kernel/src/arch/x86_64/memory/mod.rs

@@ -11,12 +11,15 @@ use x86_64::{
     structures::paging::{OffsetPageTable, PageTable},
 };
 
-pub const STACK_VIRTUAL_SPACE: usize = 0x5555_5555_0000; // start address of the memory space where we store allocated stacks
-pub const HEAP_VIRTUAL_SPACE: usize = 0x4444_4444_0000; // start address of heap allocated memory
+/// Start address of the memory space where we store allocated stacks.
+pub const STACK_VIRTUAL_SPACE: usize = 0x5555_5555_0000;
+/// Start address of heap allocated memory.
+pub const HEAP_VIRTUAL_SPACE: usize = 0x4444_4444_0000;
 pub const HEAP_SIZE: usize = MiB(1).to_bytes();
 
 pub static FRAME_ALLOCATOR: Once<Mutex<FoundryOSFrameAllocator>> = Once::new();
 pub static OFFSET_PAGE_TABLE: Once<Mutex<OffsetPageTable>> = Once::new();
+
 /// Returns a mutable reference to the current level 4 page table.
 ///
 /// # Safety

kernel/src/lib.rs

@@ -1,5 +1,5 @@
 #![no_std]
-#![feature(abi_x86_interrupt)]
+#![feature(abi_x86_interrupt, breakpoint)]
 #![warn(
     clippy::correctness,
     clippy::nursery,
@@ -14,46 +14,40 @@
 extern crate alloc;
 
 use crate::{
-    // TODO: Fix nesting under `arch`. A lot of code does not NEED to run on
-    // x86_64. Note that the panic handler does.
     arch::x86_64::{
-        cpu::apic::enable_apic,
+        // cpu::apic::enable_apic,
         drivers::{
             ascii::screensize_chars, framebuffer::display::screensize_px,
         },
+        gdt,
+        interrupts,
         memory::{
             FRAME_ALLOCATOR,
             allocation::{
                 heap_alloc::init_heap, page_alloc::FoundryOSFrameAllocator,
             },
-            init_page_table,
+            init_page_table, mapping,
             units::MemoryUnits,
         },
     },
     prelude::*,
 };
 
-use arch::x86_64::memory::mapping;
+use alloc::{boxed::Box, format};
 use core::arch::asm;
 use limine::BaseRevision;
-use std::unwind::UNWINDER;
 use x86_64::VirtAddr;
 
 pub mod arch;
+/// Commonly used re-exports.
+pub mod prelude;
 pub mod resources;
-#[allow(unused)] // We aren't using much of this right now.
+// We aren't using much of this right now.
+#[allow(unused)]
 pub mod std;
+mod step;
 pub mod util;
 
-pub mod prelude {
-    pub use crate::{
-        debug, debugln, eprint, eprintln, print, print_log, println,
-        println_log, serial_print, serial_println,
-        std::debug::_debug,
-        std::io::{_print, _print_err, _print_log, _serial_write},
-    };
-}
-
 /// Sets the base revision to the latest revision supported by the crate.
 /// See specification for further info.
 /// Be sure to mark all limine requests with #[used], otherwise they may be
@@ -73,16 +67,28 @@ pub fn hcf() -> ! {
     }
 }
 
+#[derive(Debug)]
+pub struct NoError {}
+
+impl core::fmt::Display for NoError {
+    fn fmt(&self, _f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        Ok(())
+    }
+}
+
+pub struct NoTags;
+
+impl core::error::Error for NoError {}
+
 /// Panicking before this is initialised is unwise. We should probably extract
 /// very early init into it's own function because Stack Traces may require
 /// allocations etc.
-pub fn boot() -> Result<(), &'static str> {
+#[inline(never)]
+pub fn boot() -> Result<(), Box<dyn core::error::Error>> {
     if !BASE_REVISION.is_supported() {
-        return Err("Base revision not supported");
+        return Err("Base revision not supported.".into());
     }
 
-    use arch::x86_64::{gdt, interrupts};
-
     let memory_map = mapping::get_memory_map();
 
     print_log!("    Initialising Serial... ");
@@ -94,12 +100,11 @@ pub fn boot() -> Result<(), &'static str> {
         debugln!("[Success]");
     }
 
-    debugln!("    Display...");
-    let dimensions = screensize_chars();
-    let dimensions2 = screensize_px();
-    debugln!("      => (px)    : {}x{} ", dimensions2.0, dimensions2.1);
-    debugln!("      => (chars) : {}x{} ", dimensions.0, dimensions.1);
-    debugln!("    [Success]");
+    debugln!(
+        "Display is {:?} chars, {:?} px.",
+        screensize_chars(),
+        screensize_px()
+    );
 
     debug!("    Setting Up Global Descriptor Table... ");
     gdt::init();
@@ -116,36 +121,41 @@ pub fn boot() -> Result<(), &'static str> {
     FoundryOSFrameAllocator::init(memory_map);
     let available_bytes =
         FRAME_ALLOCATOR.get().unwrap().lock().available_memory();
+
     debugln!(
         "      => Available Memory: {}",
         MemoryUnits::from_bytes(available_bytes as usize)
     );
 
+    // Allocations should be all fine past this point.
+    debugln!("    Initialising Heap... ");
+    match unsafe { init_heap() } {
+        Ok(_) => debugln!("    [Success]"),
+        Err(why) => return Err(format!("{:?}", why).into()),
+    }
+
+    debug!("    Enabling PICs... ");
+    interrupts::enable_pic();
     debugln!("[Success]");
 
-    debugln!("    Initialising Heap... ");
-    if unsafe { init_heap() }.is_err() {
-        return Err("Failed to initialise heap: error");
-    }
-    debugln!("    [Success]");
-
-    // debug!("    Enabling PICs... ");
-    // interrupts::enable_pic();
+    // debug!("    Disabling PICs... ");
+    // interrupts::disable_pic();
     // debugln!("[Success]");
 
-    debug!("    Disabling PICs... ");
-    interrupts::disable_pic();
-    debugln!("[Success]");
-
-    debug!("    Initialising APIC... ");
-    enable_apic();
-    debugln!("[Success]");
+    // debug!("    Initialising APIC... ");
+    // enable_apic();
+    // debugln!("[Success]");
 
     debug!("    Enabling Interrupts... ");
     x86_64::instructions::interrupts::enable();
     debugln!("[Success]");
 
-    UNWINDER.lock(); // Initialises the Unwinder once and only once :fingers_crossed:.
-
     Ok(())
 }
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo<'_>) -> ! {
+    debugln!("{:?}", _info);
+
+    hcf()
+}

kernel/src/main.rs

@@ -3,9 +3,11 @@
 
 extern crate alloc;
 
-use foundry_os::arch::x86_64::processing::async_io::task::{Executor, Task};
-use foundry_os::prelude::*;
-use foundry_os::util::shell::shell;
+use foundry_os::{
+    arch::x86_64::processing::async_io::task::{Executor, Task},
+    prelude::*,
+    util::shell::shell,
+};
 
 #[unsafe(no_mangle)]
 extern "C" fn kmain() -> ! {
@@ -13,7 +15,6 @@ extern "C" fn kmain() -> ! {
     if let Err(err) = foundry_os::boot() {
         panic!("{}", err);
     }
-
     println_log!(" [ Kernel Initialised Successfully ] ");
 
     // println!("TESTING :: Allocation");
@@ -22,17 +23,9 @@ extern "C" fn kmain() -> ! {
     // println!("{}", somevec.len());
     // println!("PASSED!");
 
-    test1();
+    // test1();
 
     let mut executor = Executor::new();
     executor.spawn(Task::new(shell()));
     executor.run()
 }
-
-fn test1() {
-    test2()
-}
-
-fn test2() {
-    panic!("Test");
-}

kernel/src/prelude.rs

@@ -0,0 +1,7 @@
+pub use crate::{
+    arch::x86_64::drivers::framebuffer::colour::Colour,
+    debug, debugln, eprint, eprintln, hcf, print, print_log, print_oneshot,
+    println, println_log, serial_print, serial_println,
+    std::debug::_debug,
+    std::io::{_print, _print_err, _print_log, _serial_write},
+};

kernel/src/std/elf/mod.rs

@@ -11,14 +11,14 @@
 //! * Add support for loading binary programs (this should probably be written
 //!   in a different module)
 
-use alloc::format;
+use alloc::{format, vec::Vec};
 use elf::{
     ElfBytes, ParseError,
     endian::LittleEndian,
     parse::{ParseAt, ParsingTable},
     section::{SectionHeader, SectionHeaderTable},
     string_table::StringTable,
-    symbol::SymbolTable,
+    symbol::{Symbol, SymbolTable},
 };
 use limine::request::KernelFileRequest;
 
@@ -38,6 +38,8 @@ pub static KERNEL_FILE_REQUEST: KernelFileRequest = KernelFileRequest::new();
 pub enum ElfError {
     /// Returned if a section did not exist in [ElfReader::get_section_size].
     SectionNotExists,
+    /// Returned if we failed to fetch the symbol table.
+    Symtab,
     /// Parse errors returned by the `elf` crate.
     OtherParseError(elf::ParseError),
 }
@@ -49,8 +51,14 @@ impl From<elf::ParseError> for ElfError {
 }
 
 pub struct ElfReader {
+    /// The underlying bytes for the ELF file.
+    pub bytes: &'static [u8],
     /// Structure returned by the `elf` crate having parsed the ELF header.
-    elf: ElfBytes<'static, LittleEndian>,
+    pub elf: ElfBytes<'static, LittleEndian>,
+    /// A sorted list of symbols to binary search.
+    pub sorted_syms: Vec<Symbol>,
+    /// The string table for looking up symbol names.
+    pub symbol_strtab: StringTable<'static>,
 }
 
 impl ElfReader {
@@ -65,34 +73,35 @@ impl ElfReader {
     /// Both of these should be satisfied, but this function is marked unsafe
     /// just in case, because we are derefererencing arbitrary pointers.
     pub unsafe fn new() -> Result<Self, ElfError> {
-        let response = KERNEL_FILE_REQUEST
-            .get_response()
-            .expect("Didn't get the kernel file from Limine. That's odd.");
-
-        // We fetch these from Limine and use them to parse our own ELF file.
-        let file = response.file();
-        let file_start_ptr = file.addr();
-        let file_size = file.size() as usize;
-
-        // Safety: This slice should contain the whole bytes of the ELF file.
-        let elf_hdr_slice =
-            unsafe { core::slice::from_raw_parts(file_start_ptr, file_size) };
+        // Store this for use with other libraries.
+        let bytes = get_elf_slice();
 
         let elf: ElfBytes<'static, LittleEndian> =
-            elf::ElfBytes::minimal_parse(elf_hdr_slice)?;
+            elf::ElfBytes::minimal_parse(bytes)?;
 
-        Ok(Self { elf })
+        let Some((symtab, strtab)) = elf.symbol_table()? else {
+            return Err(ElfError::Symtab);
+        };
+
+        // Sort the symtab for later use and store the strtab.
+        let mut symbols = symtab.into_iter().collect::<Vec<Symbol>>();
+        symbols.sort_by_key(|sym| sym.st_value);
+
+        Ok(Self {
+            elf,
+            sorted_syms: symbols,
+            symbol_strtab: strtab,
+            bytes,
+        })
     }
 
-    #[warn(clippy::unwrap_used)]
     pub fn get_symbol_table(
         &self,
     ) -> Result<
         Option<(SymbolTable<'static, LittleEndian>, StringTable<'static>)>,
         ElfError,
     > {
-        // TODO: Remove .unwrap().
-        Ok(self.elf.symbol_table().unwrap())
+        Ok(self.elf.symbol_table()?)
     }
 
     /// Gets the section size of `section_name` in bytes.
@@ -114,7 +123,7 @@ impl ElfReader {
     /// Gets the section header of `section_name`.
     pub fn get_section_header(
         &self,
-        section_name: &'static str,
+        section_name: &str,
     ) -> Result<SectionHeader, ElfError> {
         let section_hdr = self
             .elf
@@ -123,4 +132,37 @@ impl ElfReader {
 
         section_hdr.ok_or(ElfError::SectionNotExists)
     }
+
+    pub fn search_symbol(&self, address: u64) -> Option<elf::symbol::Symbol> {
+        let entries = self.sorted_syms.iter().collect::<Vec<_>>();
+
+        let idx = entries
+            .as_slice()
+            .binary_search_by_key(&address, |sym| sym.st_value)
+            .ok()?;
+
+        Some(entries[idx].clone())
+    }
+
+    pub fn get_symbol_name(
+        &self,
+        sym: elf::symbol::Symbol,
+    ) -> Option<&'static str> {
+        self.symbol_strtab.get(sym.st_name as usize).ok()
+    }
+}
+
+/// Gets a slice of the bytes of the kernel ELF file.
+pub fn get_elf_slice() -> &'static [u8] {
+    let response = KERNEL_FILE_REQUEST
+        .get_response()
+        .expect("Didn't get the kernel file from Limine. That's odd.");
+
+    // We fetch these from Limine and use them to parse our own ELF file.
+    let file = response.file();
+    let file_start_ptr = file.addr();
+    let file_size = file.size() as usize;
+
+    // Safety: This slice should contain the whole bytes of the ELF file.
+    (unsafe { core::slice::from_raw_parts(file_start_ptr, file_size) }) as _
 }

kernel/src/std/maths/geometry.rs

@@ -42,6 +42,14 @@ impl<T: Coordinate> Vec2<T> {
     pub const fn y(&self) -> T {
         self.y
     }
+
+    pub const fn set_x(&mut self, x: T) {
+        self.x = x;
+    }
+
+    pub const fn set_y(&mut self, y: T) {
+        self.y = y;
+    }
 }
 
 impl<T: Coordinate> AddAssign for Vec2<T> {

kernel/src/std/mod.rs

@@ -1,7 +1,5 @@
 pub mod application;
 pub mod ascii;
 pub mod debug;
-pub mod elf;
 pub mod io;
 pub mod maths;
-pub mod unwind;

kernel/src/std/unwind/eh_info.rs

@@ -1,135 +0,0 @@
-//! Contains a [EhInfo] struct that contains the parsed DWARF exception header
-//! data from the ELF .eh_frame and .eh_frame_hdr sections.
-
-use alloc::{boxed::Box, slice};
-use gimli::{
-    BaseAddresses, EhFrame, EhFrameHdr, EhHdrTable, EndianSlice, LittleEndian,
-    ParsedEhFrameHdr,
-};
-use spin::Lazy;
-
-use crate::{println_log, std::elf::ElfReader};
-
-/// Contains useful data parsed from the ELF file in question. In the kernel
-/// this will be our own process.
-///
-/// We use this to implement stack traces and potential unwinding.
-///
-/// # Sources
-///
-/// This code is reproduced from [lesenchal.fr](https://lesenechal.fr/en/linux/unwinding-the-stack-the-hard-way#h5.1-parsing-eh_frame-and-eh_frame_hdr-with-gimli)
-/// and will later be extended as required.
-pub struct EhInfo {
-    /// A set of base addresses used for relative addressing.
-    pub base_addrs: BaseAddresses,
-    /// The parsed `.eh_frame_hdr` section.
-    pub hdr: &'static ParsedEhFrameHdr<EndianSlice<'static, LittleEndian>>,
-    /// The lookup table in the parsed `.eh_frame_hdr` section.
-    /// This is a binary search table, it is optional but should be present as
-    /// we are linking with LLD(?) \[needs citation].
-    pub hdr_table: EhHdrTable<'static, EndianSlice<'static, LittleEndian>>,
-    /// The parsed `.eh_frame` containing the CFIs (call frame information).
-    pub eh_frame: EhFrame<EndianSlice<'static, LittleEndian>>,
-}
-
-/// Stores the [ElfReader] struct for this ELF file.
-pub static ELF: Lazy<ElfReader> =
-    Lazy::new(|| unsafe { ElfReader::new().unwrap() });
-
-impl EhInfo {
-    /// Gets the `.eh_frame_hdr` size in bytes.
-    ///
-    /// # Panics
-    ///
-    /// If we can't get the size of `.eh_frame_hdr`.
-    pub fn eh_frame_hdr_size() -> usize {
-        ELF.get_section_size(".eh_frame_hdr")
-            .expect("Cannot get size of `.eh_frame_hdr`.") as usize
-    }
-
-    /// Gets the `.eh_frame` size in bytes.
-    ///
-    /// # Panics
-    ///
-    /// If we can't get the size of `.eh_frame`.
-    pub fn eh_frame_size() -> usize {
-        ELF.get_section_size(".eh_frame")
-            .expect("Cannot get size of `.eh_frame`.") as usize
-    }
-
-    /// Constructs a [EhInfo] from the base address. This is defined for a
-    /// symbol in the linker script so we can initialise stack traces and -- in
-    /// the future -- unwinding.
-    ///
-    /// # Safety
-    ///
-    /// Assumes the `.eh_frame_hdr` pointer to be valid, as well as the sizes of
-    /// the containing sections. These sizes are computed using [ElfReader].
-    ///
-    /// # Panics
-    ///
-    /// This function panics if Gimli throws parsing errors -- for example due
-    /// to a malformed or corrupted binary, or because this is called in
-    /// release-mode, or on a stripped binary.
-    ///
-    /// # TODOs
-    ///
-    /// * Support external System.map files which list symbols and contain
-    ///   debugging information.
-    pub unsafe fn from_hdr_ptr(eh_frame_hdr: *const u8) -> Self {
-        let mut base_addrs = BaseAddresses::default();
-        // We add the `.eh_frame_hdr` pointer to the set of base addresses which
-        // are used by Gimli for later parsing. This may be used to compute a
-        // pointer to `.eh_frame`.
-        base_addrs = base_addrs.set_eh_frame_hdr(eh_frame_hdr as u64);
-
-        // Leaking the Box gives us a reference with `'static` lifetime to use
-        // in Self.
-        let hdr = Box::leak(Box::new(
-            // We need to construct a slice as input for `EhFrameHdr::new`.
-            // This is sound if data pointer and length are known to be
-            // correct.
-            EhFrameHdr::new(
-                unsafe {
-                    core::slice::from_raw_parts(
-                        eh_frame_hdr,
-                        Self::eh_frame_hdr_size(),
-                    )
-                },
-                LittleEndian,
-            ) // Parse the header using the base address we provided (virtual
-            // memory). Address size is how many bytes make an
-            // address (64 bits).
-            .parse(&base_addrs, 8)
-            .expect(
-                "Could not parse `.eh_frame_hdr`. The ELF must be malformed.",
-            ),
-        ));
-
-        // Create a pointer to the `.eh_frame` ready to parse it.
-        let eh_frame = match hdr.eh_frame_ptr() {
-            gimli::Pointer::Direct(addr) => addr as *mut u8,
-            _ => unimplemented!(),
-        };
-
-        // Add the `.eh_frame` address for addresses relative to this section.
-        base_addrs = base_addrs.set_eh_frame(eh_frame as u64);
-
-        // Finally parse the `.eh_frame` section of our ELF.
-        let eh_frame = EhFrame::new(
-            unsafe {
-                core::slice::from_raw_parts(eh_frame, Self::eh_frame_size())
-            },
-            LittleEndian,
-        );
-
-        Self {
-            base_addrs,
-            hdr,
-            hdr_table: hdr.table().expect(
-                "The CFI binary search table was not present in this binary, oh dear.",
-            ),
-            eh_frame,
-        }
-    }
-}

kernel/src/std/unwind/mod.rs

@@ -1,23 +0,0 @@
-use core::arch::asm;
-
-use eh_info::ELF;
-use spin::{Lazy, Mutex};
-use unwinder::{RegisterSet, Unwinder};
-
-pub mod eh_info;
-pub mod panic;
-pub mod unwinder;
-
-/// We should initialise on program start.
-pub static UNWINDER: Lazy<Mutex<Unwinder>> = Lazy::new(|| {
-    // Setup stack traces and proper panic handler. TODO: Handle panics
-    // differently if not initialised.
-    let eh_frame_ptr = ELF
-        .get_section_addr(".eh_frame_hdr")
-        .expect("Could not get `.eh_frame_hdr` address.");
-
-    let eh_info = unsafe { eh_info::EhInfo::from_hdr_ptr(eh_frame_ptr) };
-    let mut registers = RegisterSet::default();
-
-    Mutex::new(Unwinder::new(eh_info, registers))
-});

kernel/src/std/unwind/panic.rs

@@ -1,55 +0,0 @@
-//! Defines a simple panic handler which handles stack traces as required.
-
-use core::{arch::asm, panic::PanicInfo};
-
-use alloc::string::ToString;
-use fallible_iterator::FallibleIterator;
-use gimli::{Register, X86_64};
-
-use super::unwinder::Unwinder;
-use crate::{
-    hcf,
-    prelude::*,
-    std::unwind::{UNWINDER, eh_info::ELF, unwinder::RegisterSet},
-};
-
-#[panic_handler]
-/// A basic panic handler which can produce a helpful stack trace.
-pub fn panic_handler(info: &PanicInfo<'_>) -> ! {
-    println!("Kernel panic: {}", info);
-    serial_println!("Kernel panic: {}", info);
-
-    let mut rip: u64;
-    let mut rsp: u64;
-    unsafe {
-        asm!("lea {0}, [rip]", 
-        "mov {1}, rsp",
-        out(reg) rip, out(reg) rsp);
-    }
-
-    let mut unwinder = UNWINDER.lock();
-    unwinder.regs.set_pc(rip);
-    unwinder.regs.set_stack_ptr(rsp);
-
-    while let Some(call_frame) = unwinder.next().unwrap_or_else(|err| {
-        // If an unwind error occurred.
-        eprintln!("{:?}", err);
-        hcf()
-    }) {
-        serial_println!("Got frame: {:x?}", call_frame);
-        let Some((symtab, strtab)) =
-            ELF.get_symbol_table().unwrap_or_else(|e| {
-                serial_println!("{:?}", e);
-                hcf()
-            })
-        else {
-            // TODO: Omit symbol names but just print addresses.
-            serial_println!("Didn't find symtab and strtab!");
-            hcf()
-        };
-
-        // let sym_name = symtab.get(call_frame.pc as usize).unwrap();
-    }
-
-    crate::hcf()
-}

kernel/src/std/unwind/unwinder.rs

@@ -1,229 +0,0 @@
-//! Implements the core stack unwinding logic.
-//!
-//! # TODOs
-//!
-//! * Support evaluation of DWARF expressions, this might not be required
-//!   however, because Rust doesn't tend to use this DWARF feature.
-
-use fallible_iterator::FallibleIterator;
-use gimli::{
-    CfaRule, EndianSlice, LittleEndian, Register, RegisterRule, StoreOnHeap,
-    UnwindContext, UnwindSection, X86_64,
-};
-
-use super::eh_info::EhInfo;
-
-/// Implements the core stack unwinding logic by parsing the call frame
-/// information. This also stores current (DWARF) register values.
-///
-/// # Sources
-///
-/// Taken from [lesenechal.fr](https://lesenechal.fr/en/linux/unwinding-the-stack-the-hard-way)
-/// with some additional features to be added soon.
-pub struct Unwinder {
-    /// The call frame information.
-    eh_info: EhInfo,
-    /// An [UnwindContext] used by Gimli for optimisations.
-    unwind_ctx: UnwindContext<usize, StoreOnHeap>,
-    /// The current values of ABI/architecture independent registers. There are
-    /// used by DWARF.
-    pub regs: RegisterSet,
-    /// The current CFA address.
-    cfa: u64,
-    /// Is this the first iteration?
-    is_first: bool,
-}
-
-// TODO: Use map_err et al.
-impl FallibleIterator for Unwinder {
-    type Item = CallFrame;
-    type Error = UnwinderError;
-
-    /// Returns call frames of calling functions. This may be called to produce
-    /// a stack trace or otherwise support physical unwinding.
-    fn next(&mut self) -> Result<Option<Self::Item>, Self::Error> {
-        // Gets the current program counter from the DWARF register set.
-        let Some(pc) = self.regs.get_pc() else {
-            return Err(UnwinderError::NoPcRegister);
-        };
-
-        if self.is_first {
-            self.is_first = false;
-
-            return Ok(Some(CallFrame { pc, symbol: 0 }));
-        }
-
-        // This is a row in the virtual unwind table AKA the CFI which will help
-        // us find the CFA (canonical frame address) for a given program
-        // counter.
-        let Ok(row) = self.eh_info.hdr_table.unwind_info_for_address(
-            &self.eh_info.eh_frame,
-            &self.eh_info.base_addrs,
-            &mut self.unwind_ctx,
-            pc,
-            |section, bases, offset|
-                                // Finds a DWARF CIE using an offset as given.
-                                section.cie_from_offset(bases, offset),
-        ) else {
-            return Err(UnwinderError::NoUnwindInfo);
-        };
-
-        // We compute the CFA (canonical frame address from its rule).
-        // TODO: Support other rules such as DWARF expressions.
-        match row.cfa() {
-            CfaRule::RegisterAndOffset { register, offset } => {
-                let Some(reg_val) = self.regs.get(*register) else {
-                    return Err(UnwinderError::CfaRuleUnknownRegister(
-                        *register,
-                    ));
-                };
-
-                self.cfa = (reg_val as i64 + offset) as u64;
-            }
-
-            // TODO: Support other rules for computing the CFA.
-            _ => return Err(UnwinderError::UnsupportedCfaRule),
-        }
-
-        for reg in RegisterSet::iter() {
-            match row.register(reg) {
-                RegisterRule::Undefined => self.regs.undef(reg),
-                RegisterRule::SameValue => (),
-                RegisterRule::Offset(offset) => {
-                    // Adds the given offset to the register contents and
-                    // retrieve the value from the stack at address CFA +
-                    // offset.
-                    let ptr = (self.cfa as i64 + offset) as u64 as *const usize;
-
-                    self.regs.set(reg, unsafe { ptr.read() } as u64)?
-                }
-
-                _ => {
-                    return Err(UnwinderError::UnimplementedRegisterRule);
-                }
-            }
-        }
-
-        // Get the new value for %rip from the function return value and
-        // subtract one from it, because the address actually points the the
-        // next instruction after the call.
-        let Some(pc) = self.regs.get_ret() else {
-            return Err(UnwinderError::NoReturnAddr);
-        };
-
-        // REVIEWME: Must be a nicer way of doing this.
-        let Some(pc) = pc.checked_sub(1) else {
-            // REVIEWME: This should handle underflow now.
-            return Ok(None);
-        };
-
-        self.regs.set_pc(pc);
-
-        // Set %rsp to the CFA. This simulates returning from the function,
-        // destroying the call frame, so we were able to virtually unwind (to
-        // the caller function).
-        self.regs.set_stack_ptr(self.cfa);
-
-        Ok(Some(CallFrame { pc, symbol: 0 }))
-    }
-    // fn next(&mut self) -> Option<Result<Option<CallFrame>, UnwinderError>> {}
-}
-
-impl Unwinder {
-    pub fn new(eh_info: EhInfo, regset: RegisterSet) -> Self {
-        Self {
-            eh_info,
-            regs: regset,
-            unwind_ctx: UnwindContext::new(),
-            cfa: 0,
-            is_first: true,
-        }
-    }
-}
-
-/// The set of registers used by DWARF. This struct allows future portability if
-/// we want to target other architectures than x86_64.
-#[derive(Debug, Default)]
-pub struct RegisterSet {
-    rip: Option<u64>,
-    rsp: Option<u64>,
-    rbp: Option<u64>,
-    /// The return address register.
-    ret: Option<u64>,
-}
-
-impl RegisterSet {
-    pub const fn get(&self, reg: Register) -> Option<u64> {
-        match reg {
-            X86_64::RSP => self.rsp,
-            X86_64::RBP => self.rbp,
-            X86_64::RA => self.ret,
-            _ => None,
-        }
-    }
-
-    pub const fn set(
-        &mut self,
-        reg: Register,
-        val: u64,
-    ) -> Result<(), UnwinderError> {
-        *match reg {
-            X86_64::RSP => &mut self.rsp,
-            X86_64::RBP => &mut self.rbp,
-            X86_64::RA => &mut self.ret,
-            _ => return Err(UnwinderError::UnexpectedRegister(reg)),
-        } = Some(val);
-
-        Ok(())
-    }
-
-    const fn undef(&mut self, reg: Register) {
-        *match reg {
-            X86_64::RSP => &mut self.rsp,
-            X86_64::RBP => &mut self.rbp,
-            X86_64::RA => &mut self.ret,
-            _ => return,
-        } = None;
-    }
-
-    const fn get_pc(&self) -> Option<u64> {
-        self.rip
-    }
-
-    pub const fn set_pc(&mut self, val: u64) {
-        self.rip = Some(val);
-    }
-
-    const fn get_ret(&self) -> Option<u64> {
-        self.ret
-    }
-
-    pub const fn set_stack_ptr(&mut self, val: u64) {
-        self.rsp = Some(val);
-    }
-
-    fn iter() -> impl Iterator<Item = Register> {
-        [X86_64::RSP, X86_64::RBP, X86_64::RA].into_iter()
-    }
-}
-
-/// The current instruction pointer.
-#[derive(Debug)]
-pub struct CallFrame {
-    /// The current instruction pointer.
-    pub pc: u64,
-    /// The symbol of the function.
-    pub symbol: usize,
-}
-
-#[derive(Debug)]
-/// A list of errors that could occur whilst unwinding the stack.
-pub enum UnwinderError {
-    UnexpectedRegister(Register),
-    UnsupportedCfaRule,
-    UnimplementedRegisterRule,
-    CfaRuleUnknownRegister(Register),
-    NoUnwindInfo,
-    NoPcRegister,
-    NoReturnAddr,
-}

kernel/src/step.rs

@@ -0,0 +1,104 @@
+/* //! Defines the [Step] struct which may be used when initialising the system.
+//!
+//! # Warning
+//!
+//! Use of alloc is currently required, so early initialisation will need a
+//! different method. We should possibly abstract some functionality so that
+//! consumers don't need to worry or care about the difference.
+use alloc::{borrow::ToOwned, boxed::Box, string::String, vec::Vec};
+
+use crate::{arch::x86_64::drivers::ascii::WRITER, prelude::*};
+
+/// Represents a [Step] when initialising the system.
+///
+/// Handles printing various information to the framebuffer using steps.
+///
+/// # Example
+///
+/// ```rs
+/// // Setup a Step for Foo.
+/// let foo_step: Step<Foo, FooError> = Step::new("foo", Foo::init()).register_tag(|foo| { foo.bar().to_string() });
+/// // This returns a Result<T, E>
+/// let foo = foo_step.run()?;
+/// ```
+///
+/// # TODOs
+///
+/// * If T = Option<T> and None is returned, we print `"[Not found]"`, otherwise
+///   `"[Success]`".
+pub struct Step<T: Clone + ToOwned> {
+    /// The initialisation function for the Step, usually this is a closure.
+    init_fn: fn() -> T,
+    /// A list of tag generator functions to display under the Step on success.
+    /// They are displayed like:
+    /// ```
+    ///     Initialising module... [Success]
+    ///         => Some information here.
+    /// ```
+    ///
+    /// # TODOs
+    ///
+    /// * Support tags without alloc being initialised.
+    tags: Vec<Box<dyn Fn(T) -> String>>,
+    /// The name of the module being initialised.
+    task: &'static str,
+}
+
+// This impl block might be so horrible it needs its own file.
+impl<T: ToOwned + Clone> Step<T> {
+    pub fn new(
+        task: &'static str,
+        init_fn: fn() -> T,
+        tags: Vec<Box<dyn Fn(T) -> String>>,
+    ) -> Self {
+        Self {
+            init_fn,
+            tags,
+            task,
+        }
+    }
+
+    /// Runs the initialisation function and logs where required.
+    ///
+    /// This function is a little messy but it just handles pretty printing the
+    /// [Step] to the terminal for us.
+    pub fn run(self) -> T {
+        print_log!("    {}", self.task);
+        let mut success_position = WRITER.lock().pos();
+        success_position.set_x(success_position.x() + 1);
+
+        let ret = (self.init_fn)();
+
+        println!();
+
+        for tag in &self.tags[..] {
+            // Calls the closure on the return value.
+            println_log!("      => {}", (tag)(ret.clone()));
+        }
+
+        // Print whether or not the step succeeded.
+        print_oneshot!(
+            success_position,
+            Colour::Green,
+            Colour::Black,
+            "[Success]"
+        );
+
+        ret
+    }
+
+    /// Registers a 'tag' or note to display under the line which says
+    /// `Initialising module... [Success]`.
+    ///
+    /// # Notes
+    ///
+    /// The tag is a closure taking in a reference to T and returning a
+    /// presumably formatted String.
+    #[allow(unused)]
+    pub fn register_tag(&mut self, tag: Box<dyn Fn(T) -> String>) -> &Self {
+        self.tags.push(tag);
+
+        self
+    }
+}
+ */

rustfmt.toml

@@ -2,3 +2,4 @@ wrap_comments = true
 max_width = 80
 comment_width = 80
 format_code_in_doc_comments = true
+doc_comment_code_block_width = 80

scripts/run_debug.sh

@@ -32,7 +32,7 @@ else
 fi
 
 # Set up test-specific flags
-if [ $is_test -eq 1 ]; then
+if [$is_test]; then
     test_flags="-device isa-debug-exit,iobase=0xf4,iosize=0x04 -display none"
     serial_flags="-serial stdio"
 else