x86-64/kapi: reimplement ia32_efer support

4 files changed, 119 insertions, 4 deletions

diff --git a/.vscode/settings.json b/.vscode/settings.json
index 8cee879..dcf1d1a 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -23,11 +23,14 @@
     },
     "cSpell.words": [
         "crtc",
+        "efer",
         "invlpg",
         "kapi",
         "kstd",
         "NOLINTNEXTLINE",
+        "rdmsr",
         "rvalues",
-        "TeachOS"
+        "TeachOS",
+        "wrmsr"
     ]
 }
\ No newline at end of file
diff --git a/arch/x86_64/include/x86_64/cpu/impl/model_specific_register.hpp b/arch/x86_64/include/x86_64/cpu/impl/model_specific_register.hpp
new file mode 100644
index 0000000..8a41a8a
--- /dev/null
+++ b/arch/x86_64/include/x86_64/cpu/impl/model_specific_register.hpp
@@ -0,0 +1,112 @@
+#ifndef TEACHOS_X86_64_CPU_IMPL_MODEL_SPECIFIC_REGISTER_HPP
+#define TEACHOS_X86_64_CPU_IMPL_MODEL_SPECIFIC_REGISTER_HPP
+
+#include <bit>
+#include <cstdint>
+#include <type_traits>
+
+namespace teachos::cpu::x86_64
+{
+  namespace impl
+  {
+    constexpr auto ia32_efer_number = 0xC000'0080u;
+
+    template<typename Derived, typename ValueType, typename = void>
+    struct model_specific_register_with_flags
+    {
+    };
+
+    template<typename Derived, typename ValueType>
+    struct model_specific_register_with_flags<Derived, ValueType, std::enable_if_t<std::is_enum_v<ValueType>>>
+    {
+      using flags = ValueType;
+
+      auto static set(flags flag) -> void
+      {
+        auto current = Derived::read();
+        current |= flag;
+        Derived::write(current);
+      }
+
+      auto static clear(flags flag) -> void
+      {
+        auto current = Derived::read();
+        current &= ~flag;
+        Derived::write(current);
+      }
+
+      auto test(flags flag) -> void
+      {
+        return Derived::read() & flag;
+      }
+    };
+
+    template<std::uint32_t Number, typename ValueType>
+    struct model_specific_register
+        : model_specific_register_with_flags<model_specific_register<Number, ValueType>, ValueType>
+    {
+      struct raw_value
+      {
+        std::uint32_t low_half;
+        std::uint32_t high_half;
+      };
+
+      auto static read() -> ValueType
+      {
+        auto raw = raw_value{};
+        asm volatile("rdmsr" : "=a"(raw.low_half), "=d"(raw.high_half) : "c"(Number));
+        return static_cast<ValueType>(std::bit_cast<std::uint64_t>(raw));
+      }
+
+      auto static write(ValueType value) -> void
+      {
+        auto raw = std::bit_cast<raw_value>(static_cast<std::uint64_t>(value));
+        asm volatile("wrmsr" : : "a"(raw.low_half), "d"(raw.high_half), "c"(Number));
+      }
+    };
+
+    enum struct ia32_efer_flags : std::uint64_t
+    {
+      syscall_enable = 1uz << 0,
+      ia32e_mode_enable = 1uz << 8,
+      ia32e_mode_active = 1uz << 10,
+      execute_disable_bit_enable = 1uz << 11,
+    };
+
+    constexpr auto operator|(ia32_efer_flags lhs, ia32_efer_flags rhs) -> ia32_efer_flags
+    {
+      return static_cast<ia32_efer_flags>(static_cast<std::underlying_type_t<ia32_efer_flags>>(lhs) |
+                                          static_cast<std::underlying_type_t<ia32_efer_flags>>(rhs));
+    }
+
+    constexpr auto operator|=(ia32_efer_flags & lhs, ia32_efer_flags rhs) -> ia32_efer_flags &
+    {
+      lhs = lhs | rhs;
+      return lhs;
+    }
+
+    constexpr auto operator&(ia32_efer_flags lhs, ia32_efer_flags rhs) -> ia32_efer_flags
+    {
+      return static_cast<ia32_efer_flags>(static_cast<std::underlying_type_t<ia32_efer_flags>>(lhs) &
+                                          static_cast<std::underlying_type_t<ia32_efer_flags>>(rhs));
+    }
+
+    constexpr auto operator&=(ia32_efer_flags & lhs, ia32_efer_flags rhs) -> ia32_efer_flags &
+    {
+      lhs = lhs & rhs;
+      return lhs;
+    }
+
+    constexpr auto operator~(ia32_efer_flags lhs) -> ia32_efer_flags
+    {
+      // NOLINTNEXTLINE(clang-analyzer-optin.core.EnumCastOutOfRange)
+      return static_cast<ia32_efer_flags>(~static_cast<std::underlying_type_t<ia32_efer_flags>>(lhs));
+    }
+
+  }  // namespace impl
+
+  using i32_efer = impl::model_specific_register<impl::ia32_efer_number, impl::ia32_efer_flags>;
+
+}  // namespace teachos::cpu::x86_64
+
+#endif
\ No newline at end of file
diff --git a/arch/x86_64/include/x86_64/cpu/registers.hpp b/arch/x86_64/include/x86_64/cpu/registers.hpp
index 7f71b95..97cba19 100644
--- a/arch/x86_64/include/x86_64/cpu/registers.hpp
+++ b/arch/x86_64/include/x86_64/cpu/registers.hpp
@@ -1,6 +1,7 @@
 #ifndef TEACHOS_X86_64_CPU_REGISTERS_HPP
 #define TEACHOS_X86_64_CPU_REGISTERS_HPP
 
-#include "x86_64/cpu/impl/control_registers.hpp"  // IWYU pragma: export
+#include "x86_64/cpu/impl/control_registers.hpp"        // IWYU pragma: export
+#include "x86_64/cpu/impl/model_specific_register.hpp"  // IWYU pragma: export
 
 #endif
\ No newline at end of file
diff --git a/arch/x86_64/src/kapi/memory.cpp b/arch/x86_64/src/kapi/memory.cpp
index 6102bee..d0d966b 100644
--- a/arch/x86_64/src/kapi/memory.cpp
+++ b/arch/x86_64/src/kapi/memory.cpp
@@ -6,7 +6,6 @@
 
 #include "x86_64/boot/boot.hpp"
 #include "x86_64/boot/ld.hpp"
-#include "x86_64/cpu/impl/control_registers.hpp"
 #include "x86_64/cpu/registers.hpp"
 #include "x86_64/memory/region_allocator.hpp"
 
@@ -50,7 +49,7 @@ namespace teachos::memory
     auto enable_cpu_protections() -> void
     {
       cpu::x86_64::cr0::set(cpu::x86_64::cr0::flags::write_protect);
-      // set_efer_bit(efer_flags::NXE);
+      cpu::x86_64::i32_efer::set(cpu::x86_64::i32_efer::flags::execute_disable_bit_enable);
     }
   }  // namespace