From a5ca21e45e9c8ead0b5895771c0b2f3fe3baf96b Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Fri, 21 Nov 2025 14:53:37 +0100
Subject: x86_64: rework control register access

---
 arch/x86_64/src/cpu/registers.cpp | 64 ---------------------------------------
 arch/x86_64/src/kapi/memory.cpp   |  3 +-
 arch/x86_64/src/memory/mmu.cpp    |  4 +--
 3 files changed, 4 insertions(+), 67 deletions(-)
 delete mode 100644 arch/x86_64/src/cpu/registers.cpp

(limited to 'arch/x86_64/src')

diff --git a/arch/x86_64/src/cpu/registers.cpp b/arch/x86_64/src/cpu/registers.cpp
deleted file mode 100644
index d59776b..0000000
--- a/arch/x86_64/src/cpu/registers.cpp
+++ /dev/null
@@ -1,64 +0,0 @@
-#include "x86_64/cpu/registers.hpp"
-
-#include <type_traits>
-
-namespace teachos::cpu::x86_64
-{
-  auto read_control_register(control_register cr) -> uint64_t
-  {
-    uint64_t current_value{};
-    switch (cr)
-    {
-      case control_register::cr0:
-        asm volatile("mov %%cr0, %[output]" : [output] "=r"(current_value));
-        break;
-      case control_register::cr2:
-        asm volatile("mov %%cr2, %[output]" : [output] "=r"(current_value));
-        break;
-      case control_register::cr3:
-        asm volatile("mov %%cr3, %[output]" : [output] "=r"(current_value));
-        break;
-      case control_register::cr4:
-        asm volatile("mov %%cr4, %[output]" : [output] "=r"(current_value));
-        break;
-    }
-    return current_value;
-  }
-
-  auto write_control_register(control_register cr, uint64_t new_value) -> void
-  {
-    switch (cr)
-    {
-      case control_register::cr0:
-        asm volatile("mov %[input], %%cr0"
-                     : /* no output from call */
-                     : [input] "r"(new_value)
-                     : "memory");
-        break;
-      case control_register::cr2:
-        asm volatile("mov %[input], %%cr2"
-                     : /* no output from call */
-                     : [input] "r"(new_value)
-                     : "memory");
-        break;
-      case control_register::cr3:
-        asm volatile("mov %[input], %%cr3"
-                     : /* no output from call */
-                     : [input] "r"(new_value)
-                     : "memory");
-        break;
-      case control_register::cr4:
-        asm volatile("mov %[input], %%cr4"
-                     : /* no output from call */
-                     : [input] "r"(new_value)
-                     : "memory");
-        break;
-    }
-  }
-
-  auto set_cr0_bit(cr0_flags flag) -> void
-  {
-    auto const cr0 = read_control_register(control_register::cr0);
-    write_control_register(control_register::cr0, static_cast<std::underlying_type_t<cr0_flags>>(flag) | cr0);
-  }
-}  // namespace teachos::cpu::x86_64
diff --git a/arch/x86_64/src/kapi/memory.cpp b/arch/x86_64/src/kapi/memory.cpp
index aa3eb58..4766bb3 100644
--- a/arch/x86_64/src/kapi/memory.cpp
+++ b/arch/x86_64/src/kapi/memory.cpp
@@ -6,6 +6,7 @@
 
 #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"
 
@@ -48,7 +49,7 @@ namespace teachos::memory
 
     auto enable_cpu_protections() -> void
     {
-      cpu::x86_64::set_cr0_bit(cpu::x86_64::cr0_flags::WRITE_PROTECT);
+      cpu::x86_64::cr0::clear(cpu::x86_64::cr0::flags::write_protect);
       // set_efer_bit(efer_flags::NXE);
     }
   }  // namespace
diff --git a/arch/x86_64/src/memory/mmu.cpp b/arch/x86_64/src/memory/mmu.cpp
index e573b4e..8ec8a2e 100644
--- a/arch/x86_64/src/memory/mmu.cpp
+++ b/arch/x86_64/src/memory/mmu.cpp
@@ -13,7 +13,7 @@ namespace teachos::memory::x86_64
 
   auto tlb_flush_all() -> void
   {
-    auto current_value = cpu::read_control_register(cpu::control_register::cr3);
-    cpu::write_control_register(cpu::control_register::cr3, current_value);
+    auto paging_root = cpu::cr3::read();
+    cpu::cr3::write(paging_root);
   }
 }  // namespace teachos::memory::x86_64
-- 
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