create TSS descriptor

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp b/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp
index c5554a7..6474739 100644
--- a/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp
+++ b/arch/x86_64/src/context_switching/descriptor_table/global_descriptor_table.cpp
@@ -12,6 +12,7 @@ namespace teachos::arch::context_switching::descriptor_table
     segment_descriptor null_segment{0};
 
     std::bitset<20U> limit{0xFFFFF};
+
     // Kernel space code segment
     access_byte kernel_code_access_byte{access_byte::PRESENT | access_byte::ACCESS_LEVEL_KERNEL |
                                         access_byte::CODE_OR_DATA_SEGMENT | access_byte::CODE_SEGMENT |
@@ -38,6 +39,15 @@ namespace teachos::arch::context_switching::descriptor_table
     gdt_flags user_data_gdt_flags{gdt_flags::GRANULARITY | gdt_flags::UPPER_BOUND, limit};
     segment_descriptor user_data_segment{user_data_access_byte, user_data_gdt_flags, 0, limit};
 
+    // Task state segment
+    // TODO: Create TSS
+    access_byte tss_access_byte{access_byte::PRESENT | access_byte::ACCESS_LEVEL_KERNEL |
+                                access_byte::TASK_STATE_SEGMENT_AVAILABLE};
+    gdt_flags tss_gdt_flags{0U, limit};
+    uint64_t tss_address = 0;  // &TSS
+    uint64_t tss_limit = 0U;   // sizeof(TSS) - 1
+    segment_descriptor task_state_segment{tss_access_byte, tss_gdt_flags, tss_address, tss_limit};
+
     stl::vector<segment_descriptor> global_descriptor_table{null_segment, kernel_code_segment, kernel_data_segment,
                                                             user_code_segment, user_data_segment};
     return global_descriptor_table;