Try spawning a process (doesn't work)

Makefile.toml

@@ -126,7 +126,7 @@ script = '''
 	cp -f ${LIMINEDIR}/${LIMINEBIN} build/iso/EFI/BOOT
 
 	cp -f ${ARTIFACTDIR}/kernel build/iso/boot/${ARCH}/kernel
-    cp -f ${ARTIFACTDIR}/userboot build/iso/boot/${ARCH}/userboot
+    cargo objcopy --release --bin userboot -- -O binary build/iso/boot/${ARCH}/userboot.bin
 
 	xorriso -as mkisofs \
     -b boot/limine/limine-bios-cd.bin \
@@ -147,6 +147,11 @@ dependencies = ["iso"]
 command = "${QEMUCOMMAND}"
 args = ["-drive", "file=build/gila.iso,format=raw,index=0,media=disk"]
 
+[tasks.monitor_run]
+dependencies = ["iso"]
+command = "${QEMUCOMMAND}"
+args = ["-display", "none", "-drive", "file=build/gila.iso,format=raw,index=0,media=disk", "-monitor", "stdio"]
+
 [tasks.run]
 dependencies = ["iso"]
 command = "${QEMUCOMMAND}"

configs/limine.conf

@@ -1,11 +1,32 @@
-timeout: 1
+timeout: 2
 wallpaper: boot():/wallpaper.png
 wallpaper_style: centered
+default_entry: Gila/Trace
+serial: yes
 
-/Gila
+/+Gila
+comment: The Gila microkernel.
+    
+    //Trace
     protocol: limine
     kernel_path: boot():/boot/${ARCH}/kernel
     cmdline: -loglevel=Trace -logdev=display,serial
-    module_path: boot():/boot/${ARCH}/userboot
+    module_path: boot():/boot/${ARCH}/userboot.bin
     kaslr: yes
     randomize_hhdm_base: yes
+
+    //Info
+    protocol: limine
+    kernel_path: boot():/boot/${ARCH}/kernel
+    cmdline: -loglevel=Info -logdev=display,serial
+    module_path: boot():/boot/${ARCH}/userboot.bin
+    kaslr: yes
+    randomize_hhdm_base: yes
+    
+    //Warn
+    protocol: limine
+    kernel_path: boot():/boot/${ARCH}/kernel
+    cmdline: -loglevel=Warning -logdev=display,serial
+    module_path: boot():/boot/${ARCH}/userboot.bin
+    kaslr: yes
+    randomize_hhdm_base: yes

shell.nix

@@ -12,6 +12,7 @@ pkgs.mkShell {
     rustup
     qemu
     cargo-make
+    cargo-binutils
   ];
 
   buildInputs = with pkgs; [

src/kernel/arch/x86_64/gdt.rs

@@ -5,6 +5,8 @@ use core::arch::asm;
 use core::ptr::addr_of_mut;
 
 use intbits::Bits;
+use lazy_static::lazy_static;
+use x86_64::PrivilegeLevel::{Ring0, Ring3};
 use x86_64::structures::gdt;
 use x86_64::structures::gdt::*;
 
@@ -12,6 +14,51 @@ use crate::log::*;
 use crate::memory::alloc::format;
 use crate::{log_info, log_trace};
 
+trait ModifyFlags {
+    fn set_flags(self, flags: DescriptorFlags) -> Self;
+}
+
+// All this is necessary because there's no fucking method to change the
+// flags in a segment descriptor. WHY??????
+impl ModifyFlags for Descriptor {
+    fn set_flags(self, flags: DescriptorFlags) -> Descriptor {
+        match self {
+            Descriptor::UserSegment(a) => {
+                Descriptor::UserSegment(a.with_bits(52..=55, flags.bits().bits(0..=3)))
+            }
+            Descriptor::SystemSegment(a, b) => {
+                log_trace!("0b{:b}", flags.bits().bits(0..=3));
+                Descriptor::SystemSegment(a.with_bits(52..=55, flags.bits().bits(0..=3)), b)
+            }
+        }
+    }
+}
+
+lazy_static! {
+    pub static ref TSS: x86_64::structures::tss::TaskStateSegment =
+        x86_64::structures::tss::TaskStateSegment::new();
+    pub static ref GDT: x86_64::structures::gdt::GlobalDescriptorTable<64> = {
+        let mut g = GlobalDescriptorTable::empty();
+        g.append(Descriptor::kernel_code_segment());
+        g.append(
+            Descriptor::kernel_data_segment().set_flags(DescriptorFlags::from_bits_retain(0b1010)),
+        );
+        g.append(Descriptor::user_code_segment());
+        g.append(
+            Descriptor::user_data_segment().set_flags(DescriptorFlags::from_bits_retain(0b1010)),
+        );
+        g.append(
+            Descriptor::tss_segment(&TSS).set_flags(DescriptorFlags::from_bits_retain(0b1010)),
+        );
+        g
+    };
+}
+pub const GDT_SELECTOR_KERNEL_CODE: SegmentSelector = SegmentSelector::new(1, Ring0);
+pub const GDT_SELECTOR_KERNEL_DATA: SegmentSelector = SegmentSelector::new(2, Ring0);
+pub const GDT_SELECTOR_USER_CODE: SegmentSelector = SegmentSelector::new(3, Ring3);
+pub const GDT_SELECTOR_USER_DATA: SegmentSelector = SegmentSelector::new(4, Ring3);
+pub const GDT_SELECTOR_TSS: SegmentSelector = SegmentSelector::new(5, Ring0);
+
 #[allow(dead_code)]
 pub trait GdtEntryRead {
     fn base(&self) -> usize;

src/kernel/interrupt/mod.rs

@@ -1,7 +1,7 @@
 // Copyright (c) 2025 shibedrill
 // SPDX-License-Identifier: MIT
 
-use crate::log::*;
+use crate::{SERIAL_3F8, log::*};
 use crate::{format, log_error, memory::alloc::string::String};
 
 pub fn double_fault(info: String) -> ! {
@@ -13,5 +13,6 @@ 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

@@ -31,19 +31,22 @@ use limine::firmware::{
     FIRMWARE_TYPE_EFI32, FIRMWARE_TYPE_EFI64, FIRMWARE_TYPE_SBI, FIRMWARE_TYPE_X86BIOS,
 };
 use spin::mutex::Mutex;
-use x86_64::structures::paging::{PageTableFlags, page_table::PageTableEntry};
+use x86_64::{
+    PhysAddr, VirtAddr,
+    registers::rflags::RFlags,
+    structures::{
+        gdt::SegmentSelector,
+        idt::InterruptStackFrameValue,
+        paging::{PageTableFlags, page_table::PageTableEntry},
+    },
+};
 
 use crate::{
     arch::{
-        asm,
+        asm, x86_64::{
-        x86_64::{
+            cpuid::{CPUID, virt_supported}, gdt::{GDT, GDT_SELECTOR_USER_CODE, GDT_SELECTOR_USER_DATA, dump_gdt}, interrupts::get_lapic_addr,
-            cpuid::{CPUID, virt_supported},
-            gdt::dump_gdt,
-            interrupts::get_lapic_addr,
         },
-    },
+    }, boot::modules::MODULE_RESPONSE, memory::paging::{self, active_root_table, map_page, phys_to_virt},
-    boot::modules::MODULE_RESPONSE,
-    memory::paging::{self, active_root_table, map_page, phys_to_virt},
 };
 
 lazy_static! {
@@ -88,8 +91,19 @@ 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!");
+    GDT.load();
+    log_info!("GDT loaded!");
 
     log_info!(
         "Kernel cmdline: {}",
@@ -188,12 +202,11 @@ unsafe extern "C" fn main() -> ! {
         );
         // This is an expensive function. Only run it if we're actually logging the results.
         let loglevel = LOGGER.lock().level;
-        if loglevel > LogLevel::Trace {
+        if loglevel <= LogLevel::Trace {
             paging::walk_tables();
         }
     }
 
-    log_info!("Long mode: {}", asm::long_mode());
     dump_gdt();
 
     let lapic = get_lapic_addr();
@@ -206,18 +219,29 @@ unsafe extern "C" fn main() -> ! {
     log_info!("Map status: {:?}", res);
 
     if let Some(modules_list) = *MODULE_RESPONSE
-        && modules_list.modules()[0].path().ends_with("/userboot")
+        && modules_list.modules()[0].path().ends_with("/userboot.bin")
     {
-        log_info!(
+        let ub = modules_list.modules()[0];
-            "Found userboot: {} {}",
+        log_info!("Found userboot: {} {}", ub.path(), ub.cmdline());
-            modules_list.modules()[0].path(),
+        let start_addr = VirtAddr::from_ptr(ub.data() as *const [u8]);
-            modules_list.modules()[0].cmdline()
+        log_info!("Start address: 0x{:x}", start_addr);
-        );
+
-        log_info!(
+        // This does not work :/
-            "Start address: 0x{:x}",
+        unsafe {
-            modules_list.modules()[0].data().as_ptr() as usize
+            InterruptStackFrameValue::new(
-        );
+                start_addr,
+                GDT_SELECTOR_USER_CODE,
+                RFlags::empty(),
+                phys_to_virt(PhysAddr::new(0x1000)),
+                GDT_SELECTOR_USER_DATA,
+            )
+            .iretq()
+        };
     }
 
+    // TODO:
+    // - Map APIC
+    // - Create an interrupt stack frame, push it to stack, and iret to userboot
+
     panic!("Finished boot, but cannot start init because processes not implemented!");
 }

src/kernel/memory/mod.rs

@@ -5,7 +5,6 @@ const PAGE_SIZE: usize = 4096;
 
 use crate::boot::modules::MODULE_RESPONSE;
 use crate::boot::params::EXECUTABLE_FILE_RESPONSE;
-use crate::memory::paging::virt_to_phys;
 use crate::{LOGGER, LogLevel, format};
 use alloc::string::String;
 
@@ -13,7 +12,6 @@ use lazy_static::lazy_static;
 use limine::request::{ExecutableAddressRequest, HhdmRepsonse, HhdmRequest};
 use limine::request::{MemmapRequest, MemmapResponse};
 use talc::*;
-use x86_64::VirtAddr;
 
 pub extern crate alloc;
 
@@ -90,10 +88,6 @@ pub fn log_address() {
     if let Some(resp) = ADDRESS_REQUEST.response() {
         log_info!("Kernel physical start address: 0x{:x}", resp.physical_base);
         log_info!("Kernel virtual start address: 0x{:x}", resp.virtual_base);
-        log_info!("Testing virt_to_phys(): 0x{:x}", resp.virtual_base);
-        let hhdm_vaddr = VirtAddr::new(resp.virtual_base);
-        let hhdm_paddr = virt_to_phys(hhdm_vaddr);
-        log_info!("Result: 0x{:x}", hhdm_paddr.unwrap());
     } else {
         log_warning!("No kernel address response provided.");
     }

src/kernel/memory/paging.rs

@@ -144,6 +144,7 @@ pub fn phys_to_virt(phys: PhysAddr) -> VirtAddr {
     VirtAddr::new(phys.as_u64() + HHDM_RESPONSE.offset)
 }
 
+#[allow(dead_code)]
 pub fn virt_to_phys(virt: VirtAddr) -> Option<PhysAddr> {
     let root_table = unsafe { active_root_table() };
     let mut current_table = root_table;

src/userboot/main.rs

@@ -5,6 +5,7 @@ use core::panic::PanicInfo;
 
 #[unsafe(no_mangle)]
 unsafe extern "C" fn main() -> ! {
+    unsafe { x86_64::instructions::port::Port::new(0x3f8).write(9u8) };
     panic!()
 }