Wrote stack unwinder. NEEDTO: fix NoUnwindInfo

Probably incorrect PC was set.

Cargo.lock

@@ -105,6 +105,12 @@ 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"
@@ -118,6 +124,7 @@ dependencies = [
  "cc",
  "crossbeam",
  "elf",
+ "fallible-iterator",
  "futures-util",
  "gimli",
  "libm",

kernel/Cargo.toml

@@ -21,6 +21,7 @@ futures-util = { version = "0.3.31", default-features = false, features = [
 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"
 
 [build-dependencies]
 cc = "1.2.14"

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

@@ -2,15 +2,15 @@
 
 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 x86_64::structures::paging::Translate;
 use x86_64::{
     PhysAddr, VirtAddr,
     structures::paging::{Mapper, Page, PageTableFlags, PhysFrame, Size4KiB},
 };
-use x86_64::structures::paging::Translate;
-use crate::arch::x86_64::cpu::msr::*;
-use crate::arch::x86_64::memory::{FRAME_ALLOCATOR, OFFSET_PAGE_TABLE};
 
 const IA32_APIC_BASE_MSR: u32 = 0x1b;
 const IA32_APIC_BASE_MSR_BSP: u64 = 0x100;
@@ -53,7 +53,8 @@ fn write_apic_register(apic_base: &PhysAddr, reg: u64, value: u32) {
 
     let virt_addr = unsafe { phys_to_virt(PhysAddr::new(reg_addr)) };
 
-    let phys_check = OFFSET_PAGE_TABLE.get().unwrap().lock().translate(virt_addr);
+    let phys_check =
+        OFFSET_PAGE_TABLE.get().unwrap().lock().translate(virt_addr);
     debugln!("{:?}", phys_check);
 
     unsafe { *(virt_addr.as_u64() as *mut u32) = value };
@@ -88,9 +89,8 @@ pub fn enable_apic() {
     write_apic_register(
         &apic_base_physical_addr,
         0xF0,
-        read_apic_register(&apic_base_physical_addr, 0xF0) | 0x1FF
+        read_apic_register(&apic_base_physical_addr, 0xF0) | 0x1FF,
     );
-
 }
 
 pub fn enable_timer() {

kernel/src/arch/x86_64/interrupts.rs

@@ -1,9 +1,13 @@
 use crate::{debug, serial_print};
 use pic8259::ChainedPics;
 use x86_64::registers::control::Cr2;
-use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame, PageFaultErrorCode};
+use x86_64::structures::idt::{
+    InterruptDescriptorTable, InterruptStackFrame, PageFaultErrorCode,
+};
 use x86_64::structures::paging::mapper::MapperFlushAll;
-use x86_64::structures::paging::{FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB};
+use x86_64::structures::paging::{
+    FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB,
+};
 
 use super::gdt;
 use crate::arch::x86_64::memory::{FRAME_ALLOCATOR, OFFSET_PAGE_TABLE};
@@ -25,7 +29,8 @@ static IDT: Lazy<InterruptDescriptorTable> = Lazy::new(|| {
     idt.page_fault.set_handler_fn(page_fault_handler);
 
     idt[InterruptIndex::Timer.as_u8()].set_handler_fn(timer_interrupt_handler);
-    idt[InterruptIndex::Keyboard.as_u8()].set_handler_fn(keyboard_interrupt_handler);
+    idt[InterruptIndex::Keyboard.as_u8()]
+        .set_handler_fn(keyboard_interrupt_handler);
     idt
 });
 
@@ -90,13 +95,16 @@ extern "x86-interrupt" fn double_fault_handler(
     panic!("Exception: Double Fault\n{:#?}", stack_frame);
 }
 
-extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: InterruptStackFrame) {
+extern "x86-interrupt" fn keyboard_interrupt_handler(
+    _stack_frame: InterruptStackFrame,
+) {
     use pc_keyboard::{HandleControl, Keyboard, ScancodeSet1, layouts};
     // use pc_keyboard::DecodedKey;
     use spin::Mutex;
     use x86_64::instructions::port::Port;
 
-    static KEYBOARD: Lazy<Mutex<Keyboard<layouts::Uk105Key, ScancodeSet1>>> = Lazy::new(|| {
+    static KEYBOARD: Lazy<Mutex<Keyboard<layouts::Uk105Key, ScancodeSet1>>> =
+        Lazy::new(|| {
             Mutex::new(Keyboard::new(
                 ScancodeSet1::new(),
                 layouts::Uk105Key,
@@ -116,7 +124,9 @@ extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: InterruptStac
     }
 }
 
-extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: InterruptStackFrame) {
+extern "x86-interrupt" fn timer_interrupt_handler(
+    _stack_frame: InterruptStackFrame,
+) {
     debug!("Timer Interrupt");
     unsafe {
         PICS.lock()

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

@@ -1,19 +1,25 @@
+use crate::arch::x86_64::memory::allocation::page_alloc::FoundryOSFrameAllocator;
+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 core::alloc::{GlobalAlloc, Layout};
 use core::ptr;
 use spin::{Mutex, MutexGuard};
-use x86_64::structures::paging::{Size4KiB, mapper::MapToError, PageTableFlags};
 use x86_64::VirtAddr;
-use crate::arch::x86_64::memory::{FRAME_ALLOCATOR, HEAP_SIZE, HEAP_VIRTUAL_SPACE};
+use x86_64::structures::paging::{
-use crate::arch::x86_64::memory::allocation::page_alloc::FoundryOSFrameAllocator;
+    PageTableFlags, Size4KiB, mapper::MapToError,
-use crate::arch::x86_64::memory::units::MemoryUnits;
+};
-use crate::serial_println;
 
-/// We are currently using a linked list heap allocator which uses our underlying page allocator.
+/// We are currently using a linked list heap allocator which uses our
+/// underlying page allocator.
 #[global_allocator]
-/// This is now Rust's global allocator, so we can use stuff requiring heap allocations.
+/// This is now Rust's global allocator, so we can use stuff requiring heap
-static ALLOCATOR: Locked<FoundryAllocator> = Locked::new(FoundryAllocator::new());
+/// allocations.
-
+static ALLOCATOR: Locked<FoundryAllocator> =
+    Locked::new(FoundryAllocator::new());
 
 /// Initializes the heap.
 ///
@@ -38,7 +44,8 @@ static ALLOCATOR: Locked<FoundryAllocator> = Locked::new(FoundryAllocator::new()
 /// initialized successfully.
 pub unsafe fn init_heap() -> Result<(), MapToError<Size4KiB>> {
     unsafe {
-        // code to allocate frames is now done in the page fault interrupt handler!
+        // code to allocate frames is now done in the page fault interrupt
+        // handler!
         ALLOCATOR.lock().init(HEAP_VIRTUAL_SPACE, HEAP_SIZE);
         Ok(())
     }
@@ -85,11 +92,13 @@ impl FoundryAllocator {
             fallback: Locked::new(FoundryFallbackAllocator::new()),
         }
     }
-    /// Initializes the fallback allocator with the given heap start address and size.
+    /// Initializes the fallback allocator with the given heap start address and
+    /// size.
     ///
     /// # Safety
     ///
-    /// This function is unsafe because it does not check whether the given heap start address and size are valid.
+    /// This function is unsafe because it does not check whether the given heap
+    /// start address and size are valid.
     pub unsafe fn init(&mut self, heap_start: usize, heap_size: usize) {
         debugln!("      => Start: {:?}", VirtAddr::new(heap_start as u64));
         debugln!("      => Size: {}", MemoryUnits::from_bytes(heap_size));
@@ -127,7 +136,9 @@ unsafe impl GlobalAlloc for Locked<FoundryAllocator> {
                         let block_size = BLOCK_SIZES[index];
                         // only works if all block sizes are a power of 2
                         let block_align = block_size;
-                        let layout = Layout::from_size_align(block_size, block_align).unwrap();
+                        let layout =
+                            Layout::from_size_align(block_size, block_align)
+                                .unwrap();
                         unsafe { allocator.fallback_alloc(layout) }
                     }
                 }
@@ -195,7 +206,8 @@ impl FoundryFallbackAllocator {
     ///
     /// # Safety
     ///
-    /// This function is unsafe because it does not check whether the given heap start address and size are valid.
+    /// This function is unsafe because it does not check whether the given heap
+    /// start address and size are valid.
     pub unsafe fn init(&mut self, heap_start: usize, heap_size: usize) {
         unsafe { self.add_region(heap_start, heap_size) };
     }
@@ -222,7 +234,9 @@ impl FoundryFallbackAllocator {
         let mut current = &mut self.head;
         // look for a large enough memory region in linked list
         while let Some(ref mut region) = current.next {
-            if let Ok(alloc_start) = Self::alloc_from_region(region, size, align) {
+            if let Ok(alloc_start) =
+                Self::alloc_from_region(region, size, align)
+            {
                 // region suitable for allocation -> remove node from list
                 let next = region.next.take();
                 let ret = Some((current.next.take().unwrap(), alloc_start));
@@ -275,7 +289,8 @@ unsafe impl GlobalAlloc for Locked<FoundryFallbackAllocator> {
         // perform layout adjustments
         let (size, align) = FoundryFallbackAllocator::size_align(layout);
 
-        if let Some((region, alloc_start)) = allocator.find_region(size, align) {
+        if let Some((region, alloc_start)) = allocator.find_region(size, align)
+        {
             let alloc_end = alloc_start.checked_add(size).expect("overflow");
             let excess_size = region.end_addr() - alloc_end;
             if excess_size > 0 {
@@ -301,6 +316,11 @@ unsafe impl GlobalAlloc for Locked<FoundryFallbackAllocator> {
 fn ensure_mapped(virt_addr: VirtAddr) {
     if !FoundryOSFrameAllocator::is_mapped(virt_addr) {
         let mut foundry_alloc = FRAME_ALLOCATOR.get().unwrap().lock();
-        foundry_alloc.allocate_page(virt_addr, PageTableFlags::PRESENT | PageTableFlags::WRITABLE).unwrap();
+        foundry_alloc
+            .allocate_page(
+                virt_addr,
+                PageTableFlags::PRESENT | PageTableFlags::WRITABLE,
+            )
+            .unwrap();
     }
 }

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

@@ -1,10 +1,13 @@
-use x86_64::structures::paging::{FrameAllocator, Mapper, Page, PageTableFlags, PhysFrame, Size4KiB, Translate};
+use crate::arch::x86_64::memory::{FRAME_ALLOCATOR, OFFSET_PAGE_TABLE};
+use limine::memory_map::EntryType;
 use limine::response::MemoryMapResponse;
 use spin::Mutex;
-use limine::memory_map::EntryType;
-use x86_64::{PhysAddr, VirtAddr};
 use x86_64::structures::paging::mapper::{MapToError, TranslateResult};
-use crate::arch::x86_64::memory::{FRAME_ALLOCATOR, OFFSET_PAGE_TABLE};
+use x86_64::structures::paging::{
+    FrameAllocator, Mapper, Page, PageTableFlags, PhysFrame, Size4KiB,
+    Translate,
+};
+use x86_64::{PhysAddr, VirtAddr};
 
 pub struct FoundryOSFrameAllocator {
     memory_map: &'static MemoryMapResponse,
@@ -36,7 +39,9 @@ impl FoundryOSFrameAllocator {
             .entries()
             .iter()
             .map(|region| region.base..region.base + region.length)
-            .flat_map(|r| r.step_by(4096)).count() as u64 * 4096
+            .flat_map(|r| r.step_by(4096))
+            .count() as u64
+            * 4096
     }
 
     /// An iterator over all usable frames in the memory map.
@@ -46,10 +51,14 @@ impl FoundryOSFrameAllocator {
     /// This function is used to allocate frames for the page map.
     fn usable_frames(&self) -> impl Iterator<Item = PhysFrame> + use<> {
         let regions = self.memory_map.entries().iter();
-        let usable_regions = regions.filter(|region| region.entry_type == EntryType::USABLE);
+        let usable_regions =
-        let addr_ranges = usable_regions.map(|region| region.base..region.base + region.length);
+            regions.filter(|region| region.entry_type == EntryType::USABLE);
+        let addr_ranges = usable_regions
+            .map(|region| region.base..region.base + region.length);
         let frame_addresses = addr_ranges.flat_map(|r| r.step_by(4096));
-        frame_addresses.map(|addr| PhysFrame::from_start_address(PhysAddr::new(addr)).unwrap())
+        frame_addresses.map(|addr| {
+            PhysFrame::from_start_address(PhysAddr::new(addr)).unwrap()
+        })
     }
 
     pub(crate) fn is_mapped(virt_addr: VirtAddr) -> bool {
@@ -57,14 +66,18 @@ impl FoundryOSFrameAllocator {
         matches!(mapper.translate(virt_addr), TranslateResult::Mapped { .. })
     }
 
-    pub(crate) fn allocate_page(&mut self, start_addr: VirtAddr, flags: PageTableFlags) -> Result<(), MapToError<Size4KiB>> {
+    pub(crate) fn allocate_page(
+        &mut self,
+        start_addr: VirtAddr,
+        flags: PageTableFlags,
+    ) -> Result<(), MapToError<Size4KiB>> {
         let page = Page::containing_address(start_addr);
-        let frame = self.allocate_frame().ok_or(MapToError::<Size4KiB>::FrameAllocationFailed)?;
+        let frame = self
+            .allocate_frame()
+            .ok_or(MapToError::<Size4KiB>::FrameAllocationFailed)?;
         let mut mapper = OFFSET_PAGE_TABLE.get().unwrap().lock();
 
-        unsafe {
+        unsafe { mapper.map_to(page, frame, flags, self)? }.flush();
-            mapper.map_to(page, frame, flags, self)?
-        }.flush();
 
         Ok(())
     }

kernel/src/lib.rs

@@ -12,23 +12,33 @@
 )]
 
 extern crate alloc;
-use crate::{arch::x86_64::memory::init_page_table, prelude::*};
+
-use arch::x86_64::memory::allocation::heap_alloc::init_heap;
+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,
+        drivers::{
+            ascii::screensize_chars, framebuffer::display::screensize_px,
+        },
+        memory::{
+            FRAME_ALLOCATOR,
+            allocation::{
+                heap_alloc::init_heap, page_alloc::FoundryOSFrameAllocator,
+            },
+            init_page_table,
+            units::MemoryUnits,
+        },
+    },
+    prelude::*,
+};
+
 use arch::x86_64::memory::mapping;
 use core::arch::asm;
 use limine::BaseRevision;
-use std::unwind;
-use std::unwind::eh_info::ELF;
 use x86_64::VirtAddr;
-use arch::x86_64::memory::allocation::page_alloc::FoundryOSFrameAllocator;
-use crate::arch::x86_64::cpu::apic::enable_apic;
-use crate::arch::x86_64::drivers::ascii::screensize_chars;
-use crate::arch::x86_64::drivers::framebuffer::display::screensize_px;
-use crate::arch::x86_64::memory::FRAME_ALLOCATOR;
-use crate::arch::x86_64::memory::units::MemoryUnits;
 
 pub mod arch;
-mod panic;
 pub mod resources;
 #[allow(unused)] // We aren't using much of this right now.
 pub mod std;
@@ -36,11 +46,10 @@ pub mod util;
 
 pub mod prelude {
     pub use crate::{
-        eprint, eprintln, print, print_log, println, println_log, serial_print,
+        debug, debugln, eprint, eprintln, print, print_log, println,
-        serial_println,
+        println_log, serial_print, serial_println,
-        debug, debugln,
-        std::io::{_print, _print_log, _serial_write, _print_err},
         std::debug::_debug,
+        std::io::{_print, _print_err, _print_log, _serial_write},
     };
 }
 
@@ -54,13 +63,6 @@ pub mod prelude {
 #[unsafe(link_section = ".requests")]
 static BASE_REVISION: BaseRevision = BaseRevision::new();
 
-#[panic_handler]
-fn rust_panic(_info: &core::panic::PanicInfo) -> ! {
-    println!("Kernel panic: {}", _info);
-    serial_println!("Kernel panic: {}", _info);
-    hcf();
-}
-
 pub fn hcf() -> ! {
     loop {
         unsafe {
@@ -70,6 +72,9 @@ pub fn hcf() -> ! {
     }
 }
 
+/// 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> {
     if !BASE_REVISION.is_supported() {
         return Err("Base revision not supported");
@@ -104,11 +109,16 @@ pub fn boot() -> Result<(), &'static str> {
     debugln!("[Success]");
 
     debugln!("    Initialising Memory Subsystem... ");
-    let physical_memory_offset = VirtAddr::new(*mapping::PHYSICAL_MEMORY_OFFSET);
+    let physical_memory_offset =
+        VirtAddr::new(*mapping::PHYSICAL_MEMORY_OFFSET);
     init_page_table(physical_memory_offset);
     FoundryOSFrameAllocator::init(memory_map);
-    let available_bytes = FRAME_ALLOCATOR.get().unwrap().lock().available_memory();
+    let available_bytes =
-    debugln!("      => Available Memory: {}", MemoryUnits::from_bytes(available_bytes as usize));
+        FRAME_ALLOCATOR.get().unwrap().lock().available_memory();
+    debugln!(
+        "      => Available Memory: {}",
+        MemoryUnits::from_bytes(available_bytes as usize)
+    );
 
     debugln!("[Success]");
 
@@ -134,16 +144,5 @@ pub fn boot() -> Result<(), &'static str> {
     x86_64::instructions::interrupts::enable();
     debugln!("[Success]");
 
-    debug!("    Setting up stack unwinder, panic handler... ");
-    // 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 { unwind::eh_info::EhInfo::from_hdr_ptr(eh_frame_ptr) };
-    debugln!("[Success]");
-
     Ok(())
 }

kernel/src/main.rs

@@ -2,11 +2,10 @@
 #![no_main]
 
 extern crate alloc;
-use foundry_os::arch::x86_64::drivers::ascii::screensize_chars;
+
-use foundry_os::arch::x86_64::drivers::framebuffer::display::screensize_px;
 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::{println, println_log};
 
 #[unsafe(no_mangle)]
 extern "C" fn kmain() -> ! {
@@ -23,7 +22,17 @@ extern "C" fn kmain() -> ! {
     // println!("{}", somevec.len());
     // println!("PASSED!");
 
+    test1();
+
     let mut executor = Executor::new();
     executor.spawn(Task::new(shell()));
     executor.run()
 }
+
+fn test1() {
+    test2()
+}
+
+fn test2() {
+    panic!("Test");
+}

kernel/src/panic.rs

@@ -1,75 +0,0 @@
-// //! Stack-unwinding code for the Kernel. This is a modified version of https://github.com/nbdd0121/unwinding/blob/trunk/src/panic_handler.rs
-// //! which does not support environment variables for obvious reasons, however we
-// //! may implement a cmdline similar to Linux in the near future.
-
-// #![expect(
-//     clippy::empty_loop,
-//     reason = "We don't yet have working power management. This is OK for now."
-// )]
-// use crate::prelude::*;
-// use alloc::boxed::Box;
-// use core::any::Any;
-// use core::cell::Cell;
-// use core::ffi::c_void;
-// use core::panic::{Location, PanicInfo};
-// use unwinding::abi::*;
-// use unwinding::panic::begin_panic;
-
-// #[thread_local]
-// static PANIC_COUNT: Cell<usize> = Cell::new(0);
-
-// #[link(name = "c")]
-// unsafe extern "C" {}
-
-// fn stack_trace() {
-//     struct CallbackData {
-//         counter: usize,
-//     }
-
-//     extern "C" fn callback(
-//         unwind_ctx: &UnwindContext<'_>,
-//         arg: *mut c_void,
-//     ) -> UnwindReasonCode {
-//         let data = unsafe { &mut *(arg as *mut CallbackData) };
-//         data.counter += 1;
-//         eprintln!(
-//             "{:4}:{:#19x} - <unknown>",
-//             data.counter,
-//             _Unwind_GetIP(unwind_ctx)
-//         );
-//         UnwindReasonCode::NO_REASON
-//     }
-//     let mut data = CallbackData { counter: 0 };
-//     _Unwind_Backtrace(callback, &mut data as *mut _ as _);
-// }
-
-// fn do_panic(msg: Box<dyn Any + Send>) -> ! {
-//     if PANIC_COUNT.get() >= 1 {
-//         stack_trace();
-//         eprintln!("Thread panicked while processing panic. aborting.");
-//         loop {}
-//     }
-
-//     PANIC_COUNT.set(1);
-//     stack_trace();
-
-//     let code = begin_panic(Box::new(msg));
-//     eprintln!("Failed to initiate panic: error {}", code.0);
-
-//     loop {}
-// }
-
-// #[panic_handler]
-// fn panic(info: &PanicInfo<'_>) -> ! {
-//     eprintln!("{}", info);
-
-//     struct NoPayload;
-//     do_panic(Box::new(NoPayload))
-// }
-
-// #[track_caller]
-// #[expect(unused, reason = "May still be used in the future.")]
-// pub fn panic_any<M: 'static + Any + Send>(msg: M) -> ! {
-//     eprintln!("Panicked at {}", Location::caller());
-//     do_panic(Box::new(msg))
-// }

kernel/src/std/debug.rs

@@ -1,6 +1,6 @@
+use crate::prelude::{_print_log, _serial_write};
 use core::fmt;
 use x86_64::instructions::interrupts;
-use crate::prelude::{_print_log, _serial_write};
 
 #[macro_export]
 macro_rules! debugln {
@@ -19,4 +19,3 @@ pub fn _debug(args: fmt::Arguments) {
         _serial_write(args);
     });
 }
-

kernel/src/std/mod.rs

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

kernel/src/std/unwind/eh_info.rs

@@ -21,15 +21,15 @@ use crate::{println_log, std::elf::ElfReader};
 /// and will later be extended as required.
 pub struct EhInfo {
     /// A set of base addresses used for relative addressing.
-    base_addrs: BaseAddresses,
+    pub base_addrs: BaseAddresses,
     /// The parsed `.eh_frame_hdr` section.
-    hdr: &'static ParsedEhFrameHdr<EndianSlice<'static, LittleEndian>>,
+    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].
-    hdr_table: EhHdrTable<'static, EndianSlice<'static, LittleEndian>>,
+    pub hdr_table: EhHdrTable<'static, EndianSlice<'static, LittleEndian>>,
     /// The parsed `.eh_frame` containing the CFIs (call frame information).
-    eh_frame: EhFrame<EndianSlice<'static, LittleEndian>>,
+    pub eh_frame: EhFrame<EndianSlice<'static, LittleEndian>>,
 }
 
 /// Stores the [ElfReader] struct for this ELF file.

kernel/src/std/unwind/mod.rs

@@ -1 +1,3 @@
 pub mod eh_info;
+pub mod panic;
+pub mod unwinder;

kernel/src/std/unwind/panic.rs

@@ -0,0 +1,52 @@
+//! 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::{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);
+
+    // 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 { super::eh_info::EhInfo::from_hdr_ptr(eh_frame_ptr) };
+    let mut registers = RegisterSet::default();
+
+    let mut rip: u64;
+    let mut rsp: u64;
+
+    unsafe {
+        asm!("lea {0}, [rip]", 
+        "mov {1}, rsp",
+        out(reg) rip, out(reg) rsp);
+    }
+    registers.set_pc(rip);
+    registers.set_stack_ptr(rsp);
+
+    let mut unwinder = Unwinder::new(eh_info, registers);
+    while let Some(call_frame) = unwinder.next().unwrap_or_else(|err| {
+        // If an unwind error occurred.
+        eprintln!("{:?}", err);
+        hcf()
+    }) {
+        eprintln!("Frame: {:x?}", call_frame);
+    }
+
+    crate::hcf()
+}

kernel/src/std/unwind/unwinder.rs

@@ -0,0 +1,223 @@
+//! 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.
+    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 }));
+        }
+
+        // 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 pc = pc - 1;
+
+        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 }))
+    }
+    // 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,
+}
+
+#[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,
+}