Clean up global descriptor table initalization

1 files changed, 9 insertions, 14 deletions

diff --git a/arch/x86_64/src/context_switching/main.cpp b/arch/x86_64/src/context_switching/main.cpp
index 008da2f..db04b52 100644
--- a/arch/x86_64/src/context_switching/main.cpp
+++ b/arch/x86_64/src/context_switching/main.cpp
@@ -11,22 +11,16 @@ namespace teachos::arch::context_switching
   auto initialize_descriptor_tables() -> descriptor_tables
   {
     kernel::cpu::clear_interrupt_flag();
-    decltype(auto) global_descriptor_table = segment_descriptor_table::initialize_global_descriptor_table();
-    decltype(auto) interrupt_descriptor_table = interrupt_descriptor_table::initialize_interrupt_descriptor_table();
 
-    kernel::cpu::far_pointer pointer{&boot::reload_segment_register,
-                                     1 * sizeof(segment_descriptor_table::segment_descriptor)};
-    asm volatile("rex64 lcall *%[far_function_pointer]" : : [far_function_pointer] "m"(pointer));
+    segment_descriptor_table::update_global_descriptor_table_register();
+    interrupt_descriptor_table::update_interrupt_descriptor_table_register();
 
-    // Load task state segment descriptor from the last element in the global descriptor table, done by calculating
-    // offset in bytes to the start of the segment descriptor (5 * 16) = 80
-    uint16_t const tss_selector =
-        (global_descriptor_table.size() - 1) * sizeof(segment_descriptor_table::segment_descriptor);
-    kernel::cpu::load_task_register(tss_selector);
+    interrupt_descriptor_table::segment_selector segment_selector{
+        2U, interrupt_descriptor_table::segment_selector::REQUEST_LEVEL_KERNEL};
+    kernel::cpu::far_pointer pointer{&boot::reload_segment_register, segment_selector};
+    kernel::cpu::jmp(pointer);
 
-    auto const stored_task_register = kernel::cpu::store_task_register();
-    arch::exception_handling::assert(tss_selector == stored_task_register,
-                                     "[Global Descriptor Table] Loaded TR value is not the same as the stored value.");
+    segment_descriptor_table::update_task_state_segment_register();
 
     // FIXME: We currently cannot enable interrupts, since for some reason, we will later run into what looks like a GP
     // and triple fault.
@@ -34,7 +28,8 @@ namespace teachos::arch::context_switching
     // idt). NEVER happened when stepping through quickly. Can you reproduce this?
     kernel::cpu::set_interrupt_flag();
 
-    descriptor_tables tables = {global_descriptor_table, interrupt_descriptor_table};
+    descriptor_tables tables = {segment_descriptor_table::get_or_create_global_descriptor_table(),
+                                interrupt_descriptor_table::get_or_create_interrupt_descriptor_table()};
     return tables;
   }
 }  // namespace teachos::arch::context_switching