From f456f1674d48932846eb7b5ec1df630ad67e7e3d Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 6 Apr 2026 17:24:36 +0200
Subject: kernel/acpi: discover local interrupt controllers

---
 kernel/kapi/acpi.cpp    | 43 ++++++++++++++++++++++++++++++++++++++++++-
 kernel/kapi/devices.cpp | 10 ++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)

(limited to 'kernel/kapi')

diff --git a/kernel/kapi/acpi.cpp b/kernel/kapi/acpi.cpp
index 998d7a0..1283d7e 100644
--- a/kernel/kapi/acpi.cpp
+++ b/kernel/kapi/acpi.cpp
@@ -5,6 +5,7 @@
 
 #include "kernel/acpi/manager.hpp"
 
+#include <kstd/memory>
 #include <kstd/units>
 
 #include <algorithm>
@@ -110,12 +111,47 @@ namespace kapi::acpi
     return {m_signature.data(), m_signature.size()};
   }
 
+  [[nodiscard]] auto madt_header::local_interrupt_controller_address() const noexcept -> memory::physical_address
+  {
+    return memory::physical_address{static_cast<std::uintptr_t>(m_local_interrupt_controller_address)};
+  }
+
+  [[nodiscard]] auto madt_header::flags() const noexcept -> std::uint32_t
+  {
+    return m_flags;
+  }
+
+  [[nodiscard]] auto madt_subtable_header::type() const noexcept -> std::uint8_t
+  {
+    return m_type;
+  }
+
+  [[nodiscard]] auto madt_subtable_header::length() const noexcept -> std::size_t
+  {
+    return m_length;
+  }
+
+  [[nodiscard]] auto madt_local_apic::apic_id() const noexcept -> std::uint8_t
+  {
+    return m_apic_id;
+  }
+
+  [[nodiscard]] auto madt_local_apic::flags() const noexcept -> std::uint32_t
+  {
+    return m_flags;
+  }
+
+  [[nodiscard]] auto madt_local_apic::processor_id() const noexcept -> std::uint32_t
+  {
+    return m_processor_id;
+  }
+
   auto init(root_system_description_pointer const & sdp) -> bool
   {
     auto static constinit initialized = std::atomic_flag{};
     if (initialized.test_and_set())
     {
-      system::panic("[OS::ACPI] The ACPI manager has already been initialized!");
+      system::panic("[OS:ACPI] The ACPI manager has already been initialized!");
     }
 
     manager.emplace(sdp);
@@ -130,4 +166,9 @@ namespace kapi::acpi
     return sum == 0;
   }
 
+  auto get_table(std::string_view signature) -> kstd::observer_ptr<system_description_table_header const>
+  {
+    return manager->get_table(signature);
+  }
+
 };  // namespace kapi::acpi
diff --git a/kernel/kapi/devices.cpp b/kernel/kapi/devices.cpp
index 031f2c9..b2911b0 100644
--- a/kernel/kapi/devices.cpp
+++ b/kernel/kapi/devices.cpp
@@ -1,7 +1,9 @@
 #include "kapi/devices.hpp"
 
+#include "kapi/acpi.hpp"
 #include "kapi/system.hpp"
 
+#include "kernel/devices/cpu.hpp"
 #include "kernel/devices/root_bus.hpp"
 
 #include <kstd/flat_map>
@@ -35,6 +37,14 @@ namespace kapi::devices
     auto & bus = root_bus.emplace();
     register_device(bus);
     bus.init();
+
+    auto madt = kapi::acpi::get_table("APIC");
+    if (madt)
+    {
+      auto cpu_major = allocate_major_number();
+      auto cpu = kstd::make_unique<kernel::devices::cpu>(cpu_major);
+      bus.add_child(std::move(cpu));
+    }
   }
 
   auto get_root_bus() -> bus &
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