Debugging triple fault

.gitignore

@@ -1,3 +1,4 @@
 /target
 /build
-.idea
+.idea
+/log

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", "-serial", "stdio"]
+args = ["-s", "-S", "-display", "none", "-drive", "file=build/gila.iso,format=raw,index=0,media=disk", "-no-reboot", "-no-shutdown", "-serial", "stdio", "-d", "int"]
 
 [tasks.debug_view]
 dependencies = ["iso"]

configs/limine.conf

@@ -12,21 +12,21 @@ comment: The Gila microkernel.
     kernel_path: boot():/boot/${ARCH}/kernel
     cmdline: -loglevel=Trace -logdev=display,serial
     module_path: boot():/boot/${ARCH}/userboot.bin
-    kaslr: yes
-    randomize_hhdm_base: yes
+    kaslr: no
+    randomize_hhdm_base: no
 
     //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
+    kaslr: no
+    randomize_hhdm_base: no
     
     //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
+    kaslr: no
+    randomize_hhdm_base: no

log.txt

@@ -1,46 +0,0 @@
-check_exception old: 0xffffffff new 0xe // Page Fault
-     0: v=0e e=0015 i=0 cpl=3 IP=001b:ffffffff800175b0 pc=ffffffff800175b0 SP=0023:ffffffff8f000000 CR2=ffffffff800175b0 // Correct address
-RAX=0000000000000200 RBX=0000000000000000 RCX=ffffffff800175b0 RDX=ffffffff8f000000
-RSI=000000000000001b RDI=ffffffff8f000023 RBP=0000000000000000 RSP=ffffffff8f000000
-R8 =ffffffff8f000000 R9 =ffffffff800175b0 R10=0000000000000000 R11=0000000000000000
-R12=0000000000000000 R13=0000000000000000 R14=0000000000000000 R15=0000000000000000
-RIP=ffffffff800175b0 RFL=00000202 [-------] CPL=3 II=0 A20=1 SMM=0 HLT=0
-ES =0000 0000000000000000 00000000 00001300
-CS =001b 0000000000000000 ffffffff 00affb00 DPL=3 CS64 [-RA]
-SS =0023 0000000000000000 ffffffff 00aff300 DPL=3 DS   [-WA]
-DS =0000 0000000000000000 00000000 00001300
-FS =0000 0000000000000000 00000000 00001300
-GS =0000 0000000000000000 00000000 00001300
-LDT=0000 0000000000000000 00000000 00008200 DPL=0 LDT
-TR =0038 0000000000000000 00000000 00008900 DPL=0 TSS64-avl
-GDT=     ffffffff80044498 00000037
-IDT=     ffffffff800433d0 00000fff
-CR0=80010011 CR2=ffffffff800175b0 CR3=0000000007d9e000 CR4=00000020
-DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
-DR6=00000000ffff0ff0 DR7=0000000000000400
-CCS=0000000000000000 CCD=ffff800007dad588 CCO=EFLAGS
-EFER=0000000000000d00
-check_exception old: 0xe new 0xd // General Protection Fault
-     1: v=08 e=0000 i=0 cpl=3 IP=001b:ffffffff800175b0 pc=ffffffff800175b0 SP=0023:ffffffff8f000000 env->regs[R_EAX]=0000000000000200
-RAX=0000000000000200 RBX=0000000000000000 RCX=ffffffff800175b0 RDX=ffffffff8f000000
-RSI=000000000000001b RDI=ffffffff8f000023 RBP=0000000000000000 RSP=ffffffff8f000000
-R8 =ffffffff8f000000 R9 =ffffffff800175b0 R10=0000000000000000 R11=0000000000000000
-R12=0000000000000000 R13=0000000000000000 R14=0000000000000000 R15=0000000000000000
-RIP=ffffffff800175b0 RFL=00000202 [-------] CPL=3 II=0 A20=1 SMM=0 HLT=0
-ES =0000 0000000000000000 00000000 00001300
-CS =001b 0000000000000000 ffffffff 00affb00 DPL=3 CS64 [-RA]
-SS =0023 0000000000000000 ffffffff 00aff300 DPL=3 DS   [-WA]
-DS =0000 0000000000000000 00000000 00001300
-FS =0000 0000000000000000 00000000 00001300
-GS =0000 0000000000000000 00000000 00001300
-LDT=0000 0000000000000000 00000000 00008200 DPL=0 LDT
-TR =0038 0000000000000000 00000000 00008900 DPL=0 TSS64-avl
-GDT=     ffffffff80044498 00000037
-IDT=     ffffffff800433d0 00000fff
-CR0=80010011 CR2=ffffffff800175b0 CR3=0000000007d9e000 CR4=00000020
-DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
-DR6=00000000ffff0ff0 DR7=0000000000000400
-CCS=0000000000000000 CCD=ffff800007dad588 CCO=EFLAGS
-EFER=0000000000000d00
-check_exception old: 0x8 new 0xd // Second General Protection Fault
-// Instead of calling the GPF handler again it's just a triple fault

src/kernel/arch/x86_64/asm.rs

@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: MIT
 
 use core::arch::asm;
-
 use intbits::Bits;
 
 pub fn nop() {
@@ -20,3 +19,23 @@ pub fn long_mode() -> bool {
     }
     output.bit(29)
 }
+
+pub fn ltr(selector: u16) {
+    unsafe {
+        asm!(
+            "ltr ax",
+            in("ax") selector
+        )
+    }
+}
+
+pub fn str() -> u16 {
+    let result: u16;
+    unsafe {
+        asm!(
+            "str ax",
+            out("ax") result,
+        )
+    }
+    result
+}

src/kernel/arch/x86_64/gdt.rs

@@ -33,6 +33,21 @@ impl ModifyFlags for Descriptor {
     }
 }
 
+trait ModifyAccess {
+    fn set_access(self, access: u8) -> Self;
+}
+
+impl ModifyAccess for Descriptor {
+    fn set_access(self, access: u8) -> Self {
+        match self {
+            Descriptor::UserSegment(_) => todo!(),
+            Descriptor::SystemSegment(a, b) => {
+                Descriptor::SystemSegment(a.with_bits(40..=47, access.bits(0..=7).into()), b)
+            },
+        }
+    }
+}
+
 pub struct Selectors {
     pub sel_kernel_code: SegmentSelector,
     pub sel_kernel_stack: SegmentSelector,
@@ -43,8 +58,10 @@ 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();
         // DO NOT REORDER
@@ -141,7 +158,7 @@ pub fn dump_gdt() {
 }
 
 #[derive(Debug)]
-enum SegmentType {
+pub enum SegmentType {
     Null,
     Code,
     Data,

src/kernel/main.rs

@@ -42,15 +42,10 @@ use x86_64::{
 
 use crate::{
     arch::{
-        asm,
-        x86_64::{
-            cpuid::{CPUID, virt_supported},
-            gdt::{SELECTORS, dump_gdt},
-            interrupts::get_lapic_addr,
+        asm::{self, ltr, str}, x86_64::{
+            cpuid::{CPUID, virt_supported}, gdt::{SELECTORS, SegmentType, TSS, 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! {
@@ -248,6 +243,7 @@ unsafe extern "C" fn main() -> ! {
         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,
@@ -255,12 +251,15 @@ 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());
         unsafe {
             InterruptStackFrameValue::new(
                 VirtAddr::from_ptr(usermode_fn as *const fn()),
                 SELECTORS.sel_user_code,
                 RFlags::INTERRUPT_FLAG,
-                VirtAddr::new(0xffffffff8f000000),
+                VirtAddr::new(0xffffffff80000000),
                 SELECTORS.sel_user_stack,
             )
             .iretq();