From eb8074e9003034ef2186b62fc66b1073455be5de Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Sat, 21 Mar 2026 08:48:26 +0100
Subject: x86_64/cpu: fixup 8259 interrupts

---
 arch/x86_64/include/arch/cpu/initialization.hpp |  3 ++
 arch/x86_64/include/arch/cpu/interrupts.hpp     |  3 ++
 arch/x86_64/kapi/system.cpp                     |  3 ++
 arch/x86_64/src/cpu/initialization.cpp          | 37 +++++++++++++++++++++++++
 arch/x86_64/src/cpu/interrupts.cpp              | 10 +++++++
 5 files changed, 56 insertions(+)

(limited to 'arch')

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 19358ac..8f156a4 100644
--- a/arch/x86_64/include/arch/cpu/interrupts.hpp
+++ b/arch/x86_64/include/arch/cpu/interrupts.hpp
@@ -109,6 +109,9 @@ namespace arch::cpu
     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
diff --git a/arch/x86_64/kapi/system.cpp b/arch/x86_64/kapi/system.cpp
index ffb6a46..301169f 100644
--- a/arch/x86_64/kapi/system.cpp
+++ b/arch/x86_64/kapi/system.cpp
@@ -1,6 +1,7 @@
 #include "kapi/system.hpp"
 
 #include "arch/cpu/initialization.hpp"
+#include "arch/cpu/interrupts.hpp"
 
 namespace kapi::system
 {
@@ -8,6 +9,8 @@ namespace kapi::system
   auto memory_initialized() -> void
   {
     arch::cpu::initialize_descriptors();
+    arch::cpu::initialize_legacy_interrupts();
+    arch::cpu::enable_interrupts();
   }
 
 }  // namespace kapi::system
\ No newline at end of file
diff --git a/arch/x86_64/src/cpu/initialization.cpp b/arch/x86_64/src/cpu/initialization.cpp
index 214687c..85da38d 100644
--- a/arch/x86_64/src/cpu/initialization.cpp
+++ b/arch/x86_64/src/cpu/initialization.cpp
@@ -4,6 +4,7 @@
 #include "arch/cpu/interrupts.hpp"
 #include "arch/cpu/segment_descriptor.hpp"
 #include "arch/cpu/task_state_segment.hpp"
+#include "arch/device_io/port_io.hpp"
 
 #include <kstd/print>
 
@@ -130,4 +131,40 @@ namespace arch::cpu
     idt.load();
   }
 
+  auto initialize_legacy_interrupts() -> void
+  {
+    using pic_master_control_port = io::port<0x20, std::uint8_t, io::port_read, io::port_write>;
+    using pic_master_data_port = io::port<0x21, std::uint8_t, io::port_read, io::port_write>;
+    using pic_slave_control_port = io::port<0xa0, std::uint8_t, io::port_read, io::port_write>;
+    using pic_slave_data_port = io::port<0xa1, std::uint8_t, io::port_read, io::port_write>;
+
+    constexpr auto pic_init_command = std::uint8_t{0x11};
+    constexpr auto pic_master_offset = std::uint8_t{0x20};
+    constexpr auto pic_slave_offset = std::uint8_t{0x28};
+    constexpr auto pic_cascade_address = std::uint8_t{0x04};
+    constexpr auto pic_cascade_slave_identity = std::uint8_t{0x02};
+    constexpr auto pic_use_8086_mode = std::uint8_t{0x01};
+    constexpr auto pic_master_mask = std::uint8_t{0xfb};
+    constexpr auto pic_slave_mask = std::uint8_t{0xff};
+    constexpr auto pic_timer_mask = std::uint8_t{0x01};
+
+    pic_master_control_port::write(pic_init_command);
+    pic_slave_control_port::write(pic_init_command);
+
+    pic_master_data_port::write(pic_master_offset);
+    pic_slave_data_port::write(pic_slave_offset);
+
+    pic_master_data_port::write(pic_cascade_address);
+    pic_slave_data_port::write(pic_cascade_slave_identity);
+
+    pic_master_data_port::write(pic_use_8086_mode);
+    pic_slave_data_port::write(pic_use_8086_mode);
+
+    pic_master_data_port::write(pic_master_mask);
+    pic_slave_data_port::write(pic_slave_mask);
+
+    auto const current_master_mask = pic_master_data_port::read();
+    pic_master_data_port::write<std::uint8_t>(current_master_mask | pic_timer_mask);
+  }
+
 }  // namespace arch::cpu
diff --git a/arch/x86_64/src/cpu/interrupts.cpp b/arch/x86_64/src/cpu/interrupts.cpp
index 08469c0..19cf6f4 100644
--- a/arch/x86_64/src/cpu/interrupts.cpp
+++ b/arch/x86_64/src/cpu/interrupts.cpp
@@ -91,4 +91,14 @@ namespace arch::cpu
     return idtr;
   }
 
+  auto enable_interrupts() -> void
+  {
+    asm volatile("sti");
+  }
+
+  auto disable_interrupts() -> void
+  {
+    asm volatile("cli");
+  }
+
 }  // namespace arch::cpu
\ No newline at end of file
-- 
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