1 files changed, 54 insertions, 0 deletions
diff --git a/arch/x86_64/kapi/cpu.cpp b/arch/x86_64/kapi/cpu.cpp
index 12edb0f..1382e08 100644
--- a/arch/x86_64/kapi/cpu.cpp
+++ b/arch/x86_64/kapi/cpu.cpp
@@ -1,14 +1,28 @@
 #include "kapi/cpu.hpp"
 
+#include "kapi/acpi.hpp"
+#include "kapi/devices.hpp"
 #include "kapi/system.hpp"
 
 #include "arch/cpu/initialization.hpp"
+#include "arch/devices/local_apic.hpp"
+
+#include <kstd/memory>
+#include <kstd/print>
 
 #include <atomic>
+#include <ranges>
+#include <utility>
 
 namespace kapi::cpu
 {
 
+  namespace
+  {
+    constexpr auto candidate_flags = acpi::processor_local_apic::flags::processor_enabled  //
+                                     | acpi::processor_local_apic::flags::online_capable;
+  }
+
   auto init() -> void
   {
     auto static constinit is_initialized = std::atomic_flag{};
@@ -28,4 +42,44 @@ namespace kapi::cpu
     __builtin_unreachable();
   }
 
+  auto discover_topology(kapi::devices::bus & bus) -> bool
+  {
+    auto static const core_major = kapi::devices::allocate_major_number();
+    auto static const interrupt_controller_major = kapi::devices::allocate_major_number();
+
+    auto madt = kapi::acpi::get_table<acpi::madt_table_signature>();
+    if (!madt)
+    {
+      kstd::println("[x86_64:PLT] Failed to find ACPI APIC table");
+      return false;
+    }
+
+    auto bsp_found = false;
+    auto core_count = 0uz;
+    auto local_apic_address = madt->local_interrupt_controller_address();
+
+    auto lapic_entries = *madt | std::views::filter([](auto const & entry) {
+      return entry.type() == acpi::multiple_apic_description_table_entry::types::processor_local_apic;
+    }) | std::views::transform([](auto const & entry) {
+      return static_cast<acpi::processor_local_apic const &>(entry);
+    }) | std::views::filter([](auto const & entry) {
+      return static_cast<bool>(entry.active_flags() & candidate_flags);
+    });
+
+    for (auto const & apic : lapic_entries)
+    {
+      auto is_bsp = !bsp_found;
+      bsp_found = true;
+      auto instance = kstd::make_unique<arch::devices::local_apic>(interrupt_controller_major, core_count,
+                                                                   apic.apic_id(), local_apic_address, is_bsp);
+      if (core_detected(bus, core_major, core_count, apic.processor_id(), is_bsp, std::move(instance)))
+      {
+        ++core_count;
+      }
+    }
+
+    kstd::println("[x86_64:PLT] Found {} CPU cores", core_count);
+    return core_count > 0;
+  }
+
 }  // namespace kapi::cpu