create GDT and fix segment descriptor bit order

4 files changed, 72 insertions, 6 deletions

diff --git a/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp b/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp
index 7a2b0b0..4e5459f 100644
--- a/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp
+++ b/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp
@@ -2,9 +2,9 @@
 
 namespace teachos::arch::context_switching::descriptor_table
 {
-  access_byte::access_byte(uint8_t flags)
+  access_byte::access_byte(uint8_t flags, uint8_t type_field)
       : _flags(flags)
-      , _type(flags)
+      , _type(type_field)
   {
     // Nothing to do.
   }
diff --git a/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp b/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp
index 8fbf869..65f2e90 100644
--- a/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp
+++ b/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp
@@ -5,7 +5,7 @@
 namespace teachos::arch::context_switching::descriptor_table
 {
   gdt_flags::gdt_flags(uint8_t flags)
-      : _flags(flags << 5U)
+      : _flags(flags)
   {
     // Nothing to do.
   }
diff --git a/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp b/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
index 57564f2..ab8eaba 100644
--- a/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
+++ b/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
@@ -4,7 +4,7 @@ namespace teachos::arch::context_switching::descriptor_table
 {
   segment_descriptor::segment_descriptor(uint128_t flags)
       : _reserved(flags >> 96U)
-      , _access((flags >> 40U) << 80U)
+      , _access((flags >> 44U) << 80U, (flags >> 40U) << 84U)
       , _flag((flags >> 52U) << 72U)
       , _base(((flags >> 64U) << 32U) << 32U | ((flags >> 56U) << 64U) << 24U | (flags >> 16U) << 88U)
       , _limit(((flags >> 48U) << 72U) << 16U | flags << 112U)
@@ -12,13 +12,29 @@ namespace teachos::arch::context_switching::descriptor_table
     // Nothing to do.
   }
 
+  segment_descriptor::segment_descriptor(access_byte access_byte, gdt_flags flags, uint64_t base,
+                                         std::bitset<20U> limit)
+      : _reserved(0U)
+      , _access(access_byte)
+      , _flag(flags)
+      , _base(base)
+      , _limit(limit)
+  {
+    // Nothing to do
+  }
+
   auto segment_descriptor::get_segment_type() const -> segment_descriptor_type
   {
     if (!_access.contains_flags(access_byte::CODE_OR_DATA_SEGMENT))
     {
       return segment_descriptor_type::SYSTEM_SEGMENT;
     }
-    return _access.get_type_field().contains_flags(type_field::CODE_SEGMENT) ? segment_descriptor_type::CODE_SEGMENT
-                                                                             : segment_descriptor_type::DATA_SEGMENT;
+
+    if (_access.get_type_field().contains_flags(type_field::CODE_SEGMENT))
+    {
+      return segment_descriptor_type::CODE_SEGMENT;
+    }
+
+    return segment_descriptor_type::DATA_SEGMENT;
   }
 }  // namespace teachos::arch::context_switching::descriptor_table
diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 472aed5..d3938ed 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -1,9 +1,11 @@
 #include "arch/kernel/main.hpp"
 
+#include "arch/context_switching/descriptor_table/segment_descriptor.hpp"
 #include "arch/memory/heap/bump_allocator.hpp"
 #include "arch/memory/heap/global_heap_allocator.hpp"
 #include "arch/memory/main.hpp"
 #include "arch/memory/multiboot/reader.hpp"
+#include "arch/stl/vector.hpp"
 #include "arch/video/vga/text.hpp"
 
 namespace teachos::arch::kernel
@@ -57,5 +59,53 @@ namespace teachos::arch::kernel
     memory::heap::global_heap_allocator::register_heap_allocator(memory::heap::heap_allocator_type::LINKED_LIST);
 
     heap_test();
+
+    using context_switching::descriptor_table::access_byte;
+    using context_switching::descriptor_table::gdt_flags;
+    using context_switching::descriptor_table::segment_descriptor;
+    using context_switching::descriptor_table::segment_descriptor_type;
+    using context_switching::descriptor_table::type_field;
+
+    segment_descriptor null_segment{0};
+
+    // Kernel space code segment
+    access_byte kernel_code_access_byte{access_byte::PRESENT | access_byte::ACCESS_LEVEL_KERNEL |
+                                            access_byte::CODE_OR_DATA_SEGMENT,
+                                        type_field::CODE_SEGMENT | type_field::READABLE};
+    gdt_flags kernel_code_gdt_flags{gdt_flags::GRANULARITY | gdt_flags::LENGTH};
+    segment_descriptor kernel_code_segment{kernel_code_access_byte, kernel_code_gdt_flags, 0, 0xFFFFF};
+
+    // Kernel space data segment
+    access_byte kernel_data_access_byte{access_byte::PRESENT | access_byte::ACCESS_LEVEL_KERNEL |
+                                            access_byte::CODE_OR_DATA_SEGMENT,
+                                        type_field::WRITABLE};
+    gdt_flags kernel_data_gdt_flags{gdt_flags::GRANULARITY | gdt_flags::UPPER_BOUND};
+    segment_descriptor kernel_data_segment{kernel_data_access_byte, kernel_data_gdt_flags, 0, 0xFFFFF};
+
+    // User space code segment
+    access_byte user_code_access_byte{access_byte::PRESENT | access_byte::ACCESS_LEVEL_USER |
+                                          access_byte::CODE_OR_DATA_SEGMENT,
+                                      type_field::CODE_SEGMENT | type_field::READABLE};
+    gdt_flags user_code_gdt_flags{gdt_flags::GRANULARITY | gdt_flags::LENGTH};
+    segment_descriptor user_code_segment{user_code_access_byte, user_code_gdt_flags, 0, 0xFFFFF};
+
+    // User space data segment
+    access_byte user_data_access_byte{access_byte::PRESENT | access_byte::ACCESS_LEVEL_USER |
+                                          access_byte::CODE_OR_DATA_SEGMENT,
+                                      type_field::WRITABLE};
+    gdt_flags user_data_gdt_flags{gdt_flags::GRANULARITY | gdt_flags::UPPER_BOUND};
+    segment_descriptor user_data_segment{user_data_access_byte, user_data_gdt_flags, 0, 0xFFFFF};
+
+    stl::vector<segment_descriptor> global_descriptor_table{null_segment, kernel_code_segment, kernel_data_segment,
+                                                            user_code_segment, user_data_segment};
+
+    decltype(auto) x = global_descriptor_table.at(1);
+    if (global_descriptor_table.size() == 0)
+    {
+    }
+    if (x.get_segment_type() == segment_descriptor_type::CODE_SEGMENT)
+    {
+    }
+    video::vga::text::write("GDT FILLED", video::vga::text::common_attributes::green_on_black);
   }
 }  // namespace teachos::arch::kernel