1 files changed, 97 insertions, 0 deletions
diff --git a/kernel/src/devices/cpu.cpp b/kernel/src/devices/cpu.cpp
new file mode 100644
index 0000000..7147368
--- /dev/null
+++ b/kernel/src/devices/cpu.cpp
@@ -0,0 +1,97 @@
+#include "kernel/devices/cpu.hpp"
+
+#include "kapi/acpi.hpp"
+#include "kapi/devices.hpp"
+
+#include <kstd/memory>
+#include <kstd/print>
+
+#include <cstddef>
+#include <cstdint>
+#include <utility>
+
+namespace kernel::devices
+{
+
+  namespace
+  {
+
+    auto process_madt(kstd::observer_ptr<kapi::acpi::madt_header const> madt, kapi::devices::bus & cpu) -> void
+    {
+      auto static const core_major = kapi::devices::allocate_major_number();
+      auto static const lapic_major = kapi::devices::allocate_major_number();
+
+      auto lapic_address = madt->local_interrupt_controller_address();
+
+      auto const * current = reinterpret_cast<std::byte const *>(madt.get()) + sizeof(kapi::acpi::madt_header);
+      auto const * end = reinterpret_cast<std::byte const *>(madt.get()) + madt->length();
+
+      auto bsp_found = false;
+      auto core_index = 0;
+
+      while (current < end)
+      {
+        auto const * sub_table = reinterpret_cast<kapi::acpi::madt_subtable_header const *>(current);
+        if (sub_table->type() == 0)
+        {
+          auto const * local_apic = reinterpret_cast<kapi::acpi::madt_local_apic const *>(sub_table);
+          if (local_apic->flags() & 0b11)
+          {
+            auto is_bsp = !bsp_found;
+            bsp_found = true;
+
+            auto apic_id = local_apic->apic_id();
+            auto core = kstd::make_unique<kernel::devices::cpu::core>(core_major, core_index, apic_id, is_bsp);
+            auto lapic = kapi::acpi::create_local_interrupt_controller(lapic_major, core_index, apic_id, lapic_address);
+
+            core->add_child(std::move(lapic));
+            cpu.add_child(std::move(core));
+
+            ++core_index;
+          }
+        }
+
+        current += sub_table->length();
+      }
+
+      kstd::println("[OS:DEV] Discovered {} CPU cores", core_index);
+    }
+
+  }  // namespace
+
+  cpu::core::core(std::size_t major_number, std::size_t minor_number, std::uint64_t hardware_id, bool is_bsp)
+      : kapi::devices::bus{major_number, minor_number, "cpu_core"}
+      , m_hardware_id{hardware_id}
+      , m_is_bsp{is_bsp}
+  {}
+
+  auto cpu::core::hardware_id() const -> std::uint64_t
+  {
+    return m_hardware_id;
+  }
+
+  auto cpu::core::is_bsp() const -> bool
+  {
+    return m_is_bsp;
+  }
+
+  cpu::cpu(std::size_t major_number)
+      : kapi::devices::bus{major_number, 0, "cpu"}
+  {}
+
+  auto cpu::probe() -> bool
+  {
+    auto madt = kapi::acpi::get_table("APIC");
+    if (!madt)
+    {
+      kstd::println("[OS:DEV] Failed to find ACPI APIC table");
+      return false;
+    }
+
+    auto madt_header = static_cast<kapi::acpi::madt_header const *>(madt.get());
+    process_madt(kstd::make_observer(madt_header), *this);
+
+    return true;
+  }
+
+}  // namespace kernel::devices
+\ No newline at end of file