From 933abe8bc6f9480bcdea39c6bdd1a4e937402a06 Mon Sep 17 00:00:00 2001
From: Dennis Kobert <dennis@kobert.dev>
Date: Fri, 8 Nov 2019 22:50:13 +0100
Subject: Add InterruptStackTable

---
 kernel/src/interrupts/exceptions.rs | 15 ++++-----
 kernel/src/interrupts/gdt.rs        | 61 +++++++++++++++++++++++++++++++++++++
 kernel/src/interrupts/mod.rs        |  1 +
 kernel/src/interrupts/table.rs      | 11 +++++--
 4 files changed, 79 insertions(+), 9 deletions(-)
 create mode 100644 kernel/src/interrupts/gdt.rs

(limited to 'kernel/src/interrupts')

diff --git a/kernel/src/interrupts/exceptions.rs b/kernel/src/interrupts/exceptions.rs
index 08555c4..782dd16 100644
--- a/kernel/src/interrupts/exceptions.rs
+++ b/kernel/src/interrupts/exceptions.rs
@@ -4,6 +4,7 @@ use x86_64::structures::idt::{InterruptStackFrame, PageFaultErrorCode};
 pub extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
     let mut stdout = OStream::new();
     stdout.print(b"EXCEPTION: BREAKPOINT\n");
+    loop {}
 }
 
 pub extern "x86-interrupt" fn page_fault_handler(
@@ -13,11 +14,11 @@ pub extern "x86-interrupt" fn page_fault_handler(
     use x86_64::registers::control::Cr2;
 
     let mut stdout = OStream::new();
-    stdout.print(b"EXCEPTION: PAGEFAULT\n");
-    loop {}
-    panic!("PAGE FAULT");
-    //println!("Accessed Address: {:?}", Cr2::read());
-    //println!("Error Code: {:?}", error_code);
+    panic!(
+        "PAGE FAULT while accessing address: {:?}{:?}",
+        Cr2::read(),
+        error_code
+    );
     //println!("{:#?}", stack_frame);
 }
 
@@ -25,12 +26,12 @@ pub extern "x86-interrupt" fn segment_not_present_handler(
     stack_frame: &mut InterruptStackFrame,
     error_code: u64,
 ) {
-    loop {}
     let mut stdout = OStream::new();
     stdout.print(b"EXCEPTION: SEGMENT NOT PRESENT\n");
+    loop {}
 }
 
-extern "x86-interrupt" fn double_fault_handler(
+pub extern "x86-interrupt" fn double_fault_handler(
     stack_frame: &mut InterruptStackFrame,
     _error_code: u64,
 ) {
diff --git a/kernel/src/interrupts/gdt.rs b/kernel/src/interrupts/gdt.rs
new file mode 100644
index 0000000..8f20092
--- /dev/null
+++ b/kernel/src/interrupts/gdt.rs
@@ -0,0 +1,61 @@
+use lazy_static::lazy_static;
+use x86_64::structures::gdt::{Descriptor, GlobalDescriptorTable, SegmentSelector};
+use x86_64::structures::tss::TaskStateSegment;
+use x86_64::VirtAddr;
+
+pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
+pub const PAGE_FAULT_IST_INDEX: u16 = 1;
+
+lazy_static! {
+    static ref TSS: TaskStateSegment = {
+        let mut tss = TaskStateSegment::new();
+        tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
+            const STACK_SIZE: usize = 4096;
+            static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
+
+            let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
+            let stack_end = stack_start + STACK_SIZE;
+            stack_end
+        };
+        tss.interrupt_stack_table[PAGE_FAULT_IST_INDEX as usize] = {
+            const STACK_SIZE: usize = 4096;
+            static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
+
+            let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
+            let stack_end = stack_start + STACK_SIZE;
+            stack_end
+        };
+        tss
+    };
+}
+
+lazy_static! {
+    static ref GDT: (GlobalDescriptorTable, Selectors) = {
+        let mut gdt = GlobalDescriptorTable::new();
+        let code_selector = gdt.add_entry(Descriptor::kernel_code_segment());
+        let tss_selector = gdt.add_entry(Descriptor::tss_segment(&TSS));
+        (
+            gdt,
+            Selectors {
+                code_selector,
+                tss_selector,
+            },
+        )
+    };
+}
+
+struct Selectors {
+    code_selector: SegmentSelector,
+    tss_selector: SegmentSelector,
+}
+
+pub fn init() {
+    use x86_64::instructions::segmentation::set_cs;
+    use x86_64::instructions::tables::load_tss;
+
+    GDT.0.load();
+    unsafe {
+        set_cs(GDT.1.code_selector);
+        load_tss(GDT.1.tss_selector);
+    }
+}
diff --git a/kernel/src/interrupts/mod.rs b/kernel/src/interrupts/mod.rs
index ae21761..14de3f2 100644
--- a/kernel/src/interrupts/mod.rs
+++ b/kernel/src/interrupts/mod.rs
@@ -1,2 +1,3 @@
 mod exceptions;
+pub mod gdt;
 pub mod table;
diff --git a/kernel/src/interrupts/table.rs b/kernel/src/interrupts/table.rs
index 6472014..d417824 100644
--- a/kernel/src/interrupts/table.rs
+++ b/kernel/src/interrupts/table.rs
@@ -7,10 +7,17 @@ lazy_static! {
         let mut idt = InterruptDescriptorTable::new();
         idt.breakpoint
             .set_handler_fn(super::exceptions::breakpoint_handler);
-        idt.page_fault
-            .set_handler_fn(super::exceptions::page_fault_handler);
         idt.segment_not_present
             .set_handler_fn(super::exceptions::segment_not_present_handler);
+        unsafe {
+            idt.double_fault
+                .set_handler_fn(super::exceptions::double_fault_handler)
+                .set_stack_index(super::gdt::DOUBLE_FAULT_IST_INDEX);
+            idt.page_fault
+                .set_handler_fn(super::exceptions::page_fault_handler)
+                .set_stack_index(super::gdt::PAGE_FAULT_IST_INDEX);
+        }
+
         idt
     };
 }
-- 
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