x86_64/cpu: add basic interrupt support types

2 files changed, 81 insertions, 0 deletions

diff --git a/arch/x86_64/include/x86_64/cpu/interrupts.hpp b/arch/x86_64/include/x86_64/cpu/interrupts.hpp
new file mode 100644
index 0000000..88d0b78
--- /dev/null
+++ b/arch/x86_64/include/x86_64/cpu/interrupts.hpp
@@ -0,0 +1,61 @@
+#ifndef TEACHOS_X86_64_CPU_INTERRUPTS_HPP
+#define TEACHOS_X86_64_CPU_INTERRUPTS_HPP
+
+#include "x86_64/cpu/segment_selector.hpp"
+
+#include <array>
+#include <cstdint>
+#include <type_traits>
+
+namespace teachos::cpu::x86_64
+{
+
+  //! The types of supported gates.
+  enum struct gate_type : std::uint8_t
+  {
+    //! A gate entered through the @p INT instruction.
+    interrupt_gate = 0b1110,
+    //! A gate entered via an exception.
+    trap_gate = 0b1111,
+  };
+
+  struct alignas(std::uint64_t) gate_descriptor
+  {
+    //! The lowest 16 bits of the address of this gate's handler function.
+    std::uint16_t offset_low : 16;
+    //! The code segment used when handling the respective interrupt.
+    segment_selector m_code_segment;
+    //! The index into the Interrupt Stack Table naming the stack to use.
+    std::uint8_t interrupt_stack_table_selector : 3;
+    //! Reserved
+    std::uint8_t : 5;
+    //! The type of this gate.
+    gate_type gate_type : 4;
+    //! Reserved
+    std::uint8_t : 1;
+    //! The privilege level required to enter through this gate.
+    std::uint8_t descriptor_privilege_level : 2;
+    //! Whether this gate is present or not.
+    std::uint8_t present : 1;
+    //! The middle 16 bits of the address of this gate's handler function.
+    std::uint16_t offset_middle : 16;
+    //! The highest 32 bits of the address of this gate's handler function.
+    std::uint32_t offset_high : 32;
+    //! Reserved
+    std::uint32_t : 32;
+  };
+
+  static_assert(sizeof(gate_descriptor) == 2 * sizeof(std::uint64_t));
+  static_assert(std::is_aggregate_v<gate_descriptor>);
+
+  struct interrupt_descriptor_table
+  {
+    interrupt_descriptor_table();
+
+  private:
+    std::array<gate_descriptor, 256> m_descriptors{};
+  };
+
+}  // namespace teachos::cpu::x86_64
+
+#endif
\ No newline at end of file
diff --git a/arch/x86_64/include/x86_64/cpu/segment_selector.hpp b/arch/x86_64/include/x86_64/cpu/segment_selector.hpp
new file mode 100644
index 0000000..bb07e28
--- /dev/null
+++ b/arch/x86_64/include/x86_64/cpu/segment_selector.hpp
@@ -0,0 +1,20 @@
+#ifndef TEACHOS_X86_64_SEGMENT_SELECTOR_HPP
+#define TEACHOS_X86_64_SEGMENT_SELECTOR_HPP
+
+#include <cstdint>
+namespace teachos::cpu::x86_64
+{
+
+  struct segment_selector
+  {
+    std::uint16_t request_privilege_level : 2;
+    bool use_local_descriptor_table : 1;
+    std::uint16_t table_index : 13;
+  };
+
+  static_assert(sizeof(segment_selector) == sizeof(std::uint16_t));
+  static_assert(alignof(segment_selector) == alignof(std::uint16_t));
+
+}  // namespace teachos::cpu::x86_64
+
+#endif
\ No newline at end of file