Merge branch 'fmorgner/develop-BA-FS26/gdt_idt' into develop-BA-FS26

This patchset enables the use of interrupts. Specifically, it simplifies
debugging by printing the fault address in case of a page fault.

2 files changed, 61 insertions, 2 deletions

diff --git a/arch/x86_64/include/arch/cpu/initialization.hpp b/arch/x86_64/include/arch/cpu/initialization.hpp
index b2ce864..71186d4 100644
--- a/arch/x86_64/include/arch/cpu/initialization.hpp
+++ b/arch/x86_64/include/arch/cpu/initialization.hpp
@@ -3,4 +3,7 @@
 namespace arch::cpu
 {
   auto initialize_descriptors() -> void;
+
+  auto initialize_legacy_interrupts() -> void;
+
 }  // namespace arch::cpu
diff --git a/arch/x86_64/include/arch/cpu/interrupts.hpp b/arch/x86_64/include/arch/cpu/interrupts.hpp
index 92c5824..8f156a4 100644
--- a/arch/x86_64/include/arch/cpu/interrupts.hpp
+++ b/arch/x86_64/include/arch/cpu/interrupts.hpp
@@ -30,7 +30,7 @@ namespace arch::cpu
     //! Reserved
     std::uint8_t : 5;
     //! The type of this gate.
-    gate_type gate_type : 4;
+    enum gate_type gate_type : 4;
     //! Reserved
     std::uint8_t : 1;
     //! The privilege level required to enter through this gate.
@@ -48,14 +48,70 @@ namespace arch::cpu
   static_assert(sizeof(gate_descriptor) == 2 * sizeof(std::uint64_t));
   static_assert(std::is_aggregate_v<gate_descriptor>);
 
+  //! The stack frame as established by the low-level assembly interrupt stubs.
+  //!
+  //! @note The layout of this struct is reverse than what would reasonably be expected. The reason for this reversal is
+  //! that fact that it represents a stack frame. Stack frames on x86_64 grow towards lower addresses, meaning the first
+  //! item on the stack is the last item in C++ memory layout order.
+  struct interrupt_frame
+  {
+    struct
+    {
+      std::uint64_t r15;
+      std::uint64_t r14;
+      std::uint64_t r13;
+      std::uint64_t r12;
+      std::uint64_t r11;
+      std::uint64_t r10;
+      std::uint64_t r9;
+      std::uint64_t r8;
+      std::uint64_t rdi;
+      std::uint64_t rsi;
+      std::uint64_t rbp;
+      std::uint64_t rdx;
+      std::uint64_t rcx;
+      std::uint64_t rbx;
+      std::uint64_t rax;
+    } handler_saved;
+
+    struct
+    {
+      std::uint64_t number;
+      std::uint64_t error_code;
+    } interrupt;
+
+    struct
+    {
+      std::uint64_t rip;
+      std::uint64_t cs;
+      std::uint64_t rflags;
+      std::uint64_t rsp;
+      std::uint64_t ss;
+    } cpu_saved;
+  };
+
   struct interrupt_descriptor_table
   {
-    interrupt_descriptor_table();
+    interrupt_descriptor_table() noexcept;
+
+    auto load() const -> void;
 
   private:
     std::array<gate_descriptor, 256> m_descriptors{};
   };
 
+  struct [[gnu::packed]] interrupt_descriptor_table_register
+  {
+    std::uint16_t limit;
+    gate_descriptor const * base;
+
+    auto load() const -> void;
+    auto static read() -> interrupt_descriptor_table_register;
+  };
+
+  auto enable_interrupts() -> void;
+  auto disable_interrupts() -> void;
+
 }  // namespace arch::cpu
 
 #endif
\ No newline at end of file