Fix CS in IDT

Makefile.toml

@@ -160,7 +160,7 @@ args = ["-display", "none", "-drive", "file=build/gila.iso,format=raw,index=0,me
 [tasks.debug_run]
 dependencies = ["iso"]
 command = "${QEMUCOMMAND}"
-args = ["-s", "-S", "-display", "none", "-drive", "file=build/gila.iso,format=raw,index=0,media=disk", "-no-reboot", "-no-shutdown", "-serial", "stdio", "-d", "int"]
+args = ["-s", "-S", "-display", "none", "-drive", "file=build/gila.iso,format=raw,index=0,media=disk", "-no-reboot", "-serial", "stdio", "-d", "int"]
 
 [tasks.debug_view]
 dependencies = ["iso"]

src/kernel/arch/x86_64/asm.rs

@@ -8,6 +8,7 @@ pub fn nop() {
     ::x86_64::instructions::nop();
 }
 
+#[allow(unused)]
 pub fn long_mode() -> bool {
     let mut output: u32;
     unsafe {
@@ -29,6 +30,7 @@ pub fn ltr(selector: u16) {
     }
 }
 
+#[allow(unused)]
 pub fn str() -> u16 {
     let result: u16;
     unsafe {

src/kernel/arch/x86_64/gdt.rs

@@ -59,9 +59,8 @@ pub struct Selectors {
     pub gdt: GlobalDescriptorTable<48>,
 }
 
-pub const TSS: TaskStateSegment = TaskStateSegment::new();
-
 lazy_static! {
+    pub static ref TSS: TaskStateSegment = TaskStateSegment::new();
     #[derive(Debug)]
     pub static ref SELECTORS: Selectors = {
         let mut gdt = GlobalDescriptorTable::empty();
@@ -79,7 +78,8 @@ lazy_static! {
         let sel_u_cs = gdt.append(Descriptor::user_code_segment());
         // DO NOT REORDER
         let sel_tss = gdt.append(
-            Descriptor::tss_segment(&TSS).set_flags(DescriptorFlags::from_bits_retain(0b1010)),
+            Descriptor::tss_segment(&TSS).set_flags(DescriptorFlags::from_bits_retain(0b1010))
+            //.set_access(0b10001011), // This would set the TSS to Busy, but it causes a GPF.
         );
         Selectors {
             sel_kernel_code: sel_k_cs,
@@ -134,6 +134,7 @@ pub fn read_gdt() -> GlobalDescriptorTable {
     GlobalDescriptorTable::from_raw_entries(gdt_raw)
 }
 
+#[allow(unused)]
 pub fn dump_gdt() {
     let gdt = crate::arch::x86_64::gdt::read_gdt();
     log_info!("GDT length: {}", gdt.limit() + 1);

src/kernel/arch/x86_64/interrupts.rs

@@ -1,12 +1,14 @@
 // Copyright (c) 2025 shibedrill
 // SPDX-License-Identifier: MIT
 
+use crate::arch::x86_64::gdt::SELECTORS;
 use crate::{LOGGER, format, log_info, log_trace};
 use crate::{LogLevel, log_error};
 use lazy_static::lazy_static;
 use x86_64::PhysAddr;
 use x86_64::structures::idt::*;
 
+#[allow(unused)]
 pub fn get_lapic_addr() -> PhysAddr {
     let apic_base = x86_64::registers::model_specific::ApicBase::read();
     let addr: PhysAddr = apic_base.0.start_address();
@@ -20,9 +22,11 @@ lazy_static! {
         // TODO: Rewrite using our own x86 interrupt wrapper
         // code. The x86_interrupt ABI is always breaking, and this
         // approach will fall apart once multiarch support is re-added.
-        idt.double_fault.set_handler_fn(double_fault);
-        idt.page_fault.set_handler_fn(page_fault);
-        idt.general_protection_fault.set_handler_fn(gen_prot_fault);
+        unsafe {
+            idt.double_fault.set_handler_fn(double_fault).set_code_selector(SELECTORS.sel_kernel_code).set_privilege_level(x86_64::PrivilegeLevel::Ring0);
+            idt.page_fault.set_handler_fn(page_fault).set_code_selector(SELECTORS.sel_kernel_code).set_privilege_level(x86_64::PrivilegeLevel::Ring0);
+            idt.general_protection_fault.set_handler_fn(gen_prot_fault).set_code_selector(SELECTORS.sel_kernel_code).set_privilege_level(x86_64::PrivilegeLevel::Ring0);
+        }
         idt
     };
 }

src/kernel/interrupt/mod.rs

@@ -1,7 +1,7 @@
 // Copyright (c) 2025 shibedrill
 // SPDX-License-Identifier: MIT
 
-use crate::{SERIAL_3F8, log::*};
+use crate::log::*;
 use crate::{format, log_error, memory::alloc::string::String};
 
 pub fn double_fault(info: String) -> ! {
@@ -13,6 +13,5 @@ pub fn page_fault_fatal(addr: usize, info: String) -> ! {
 }
 
 pub fn gen_prot_fault(info: String) {
-    SERIAL_3F8.lock().log_writeln("Ohhhhh shit double fault");
     log_error!("General protection fault: {}", info);
 }

src/kernel/main.rs

@@ -31,26 +31,18 @@ use limine::firmware::{
     FIRMWARE_TYPE_EFI32, FIRMWARE_TYPE_EFI64, FIRMWARE_TYPE_SBI, FIRMWARE_TYPE_X86BIOS,
 };
 use spin::mutex::Mutex;
-use x86_64::{
-    VirtAddr,
-    registers::rflags::RFlags,
-    structures::{
-        idt::InterruptStackFrameValue,
-        paging::{PageTableFlags, page_table::PageTableEntry},
-    },
-};
+use x86_64::{VirtAddr, registers::rflags::RFlags, structures::idt::InterruptStackFrameValue};
 
 use crate::{
     arch::{
-        asm::{self, ltr, str},
+        asm::ltr,
         x86_64::{
             cpuid::{CPUID, virt_supported},
-            gdt::{SELECTORS, dump_gdt},
-            interrupts::get_lapic_addr,
+            gdt::SELECTORS,
         },
     },
     boot::modules::MODULE_RESPONSE,
-    memory::paging::{self, active_root_table, map_page, phys_to_virt},
+    memory::paging::active_root_table,
 };
 
 lazy_static! {
@@ -95,19 +87,11 @@ unsafe extern "C" fn main() -> ! {
     // Initialize all statics so the bootloader memory can be reclaimed
     memory::init_statics();
 
-    log_info!(
-        "Long mode: {}",
-        if asm::long_mode() {
-            "enabled"
-        } else {
-            "disabled"
-        }
-    );
     // Ensure IDT exists
-    IDT.load();
-    log_info!("IDT loaded!");
     SELECTORS.gdt.load();
     log_info!("GDT loaded!");
+    IDT.load();
+    log_info!("IDT loaded!");
 
     log_info!(
         "Kernel cmdline: {}",
@@ -205,23 +189,12 @@ unsafe extern "C" fn main() -> ! {
             addr_of!(*root_ptable_info.0) as usize
         );
         // This is an expensive function. Only run it if we're actually logging the results.
-        let loglevel = LOGGER.lock().level;
-        if loglevel <= LogLevel::Trace {
-            paging::walk_tables();
-        }
+        //let loglevel = LOGGER.lock().level;
+        //if loglevel <= LogLevel::Trace {
+        //    paging::walk_tables();
+        //}
     }
 
-    dump_gdt();
-
-    let lapic = get_lapic_addr();
-    let mapping = {
-        let mut m = PageTableEntry::new();
-        m.set_addr(lapic, PageTableFlags::PRESENT);
-        m
-    };
-    let res = map_page(phys_to_virt(lapic), mapping);
-    log_info!("Map status: {:?}", res);
-
     if let Some(modules_list) = *MODULE_RESPONSE
         && modules_list.modules()[0].path().ends_with("/userboot.bin")
     {
@@ -232,23 +205,6 @@ unsafe extern "C" fn main() -> ! {
         let start_addr = VirtAddr::from_ptr(usermode_fn as *const fn());
         log_info!("Start address: 0x{:x}", start_addr);
 
-        // This does not work :/
-        /*unsafe {
-            InterruptStackFrameValue::new(
-                start_addr,
-                GDT_SELECTOR_USER_CODE,
-                RFlags::empty(),
-                phys_to_virt(PhysAddr::new(0x1000)),
-                GDT_SELECTOR_USER_DATA,
-            )
-            .iretq()
-        };*/
-        log_trace!("Segment offsets:");
-        log_trace!("GDT_SELECTOR_USER_CODE: {}", SELECTORS.sel_user_code.0);
-        log_trace!("GDT_SELECTOR_USER_DATA: {}", SELECTORS.sel_user_stack.0);
-        log_trace!("GDT_SELECTOR_KERNEL_CODE: {}", SELECTORS.sel_kernel_code.0);
-        log_trace!("GDT_SELECTOR_KERNEL_DATA: {}", SELECTORS.sel_kernel_stack.0);
-        log_trace!("GDT_SELECTOR_TSS: {}", SELECTORS.sel_tss.0);
         x86_64::registers::model_specific::Star::write(
             SELECTORS.sel_user_code,
             SELECTORS.sel_user_stack,
@@ -256,9 +212,7 @@ unsafe extern "C" fn main() -> ! {
             SELECTORS.sel_kernel_stack,
         )
         .expect("fuck");
-        log_trace!("STR before loading new TSS: {}", str());
-        ltr(SELECTORS.sel_tss.0);
-        log_trace!("STR after loading new TSS: {}", str());
+        ltr(SELECTORS.sel_tss.index());
         unsafe {
             InterruptStackFrameValue::new(
                 VirtAddr::from_ptr(usermode_fn as *const fn()),

src/kernel/memory/paging.rs

@@ -115,6 +115,7 @@ pub unsafe fn active_root_table() -> (&'static mut PageTable, usize) {
     )
 }
 
+#[allow(unused)]
 pub fn walk_tables() {
     iter_table(
         match control::Cr4::read().contains(Cr4Flags::L5_PAGING) {