Merge branch 'develop-BA-FS26' into 'develop'HEADdevelop

Merge of BA-FS26 branch into develop

See merge request teachos/kernel!49

1 files changed, 79 insertions, 1 deletions

diff --git a/arch/x86_64/kapi/cpu.cpp b/arch/x86_64/kapi/cpu.cpp
index 2a0f8f7..40dc228 100644
--- a/arch/x86_64/kapi/cpu.cpp
+++ b/arch/x86_64/kapi/cpu.cpp
@@ -1,12 +1,90 @@
-#include "kapi/cpu.hpp"
+#include <kapi/cpu.hpp>
+
+#include <arch/cpu/initialization.hpp>
+#include <arch/devices/local_apic.hpp>
+
+#include <kapi/acpi.hpp>
+#include <kapi/devices.hpp>
+#include <kapi/devices/cpu.hpp>
+#include <kapi/memory.hpp>
+#include <kapi/system.hpp>
+
+#include <acpi/acpi.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_entry::flags::processor_enabled  //
+                                     | ::acpi::processor_local_apic_entry::flags::online_capable;
+  }
+
+  auto init() -> void
+  {
+    auto static constinit is_initialized = std::atomic_flag{};
+
+    if (is_initialized.test_and_set())
+    {
+      system::panic("[x86_64] CPU has already been initialized.");
+    }
+
+    arch::cpu::initialize_descriptors();
+    arch::cpu::initialize_legacy_interrupts();
+  }
+
   auto halt() -> void
   {
     asm volatile("1: hlt\njmp 1b");
     __builtin_unreachable();
   }
 
+  auto discover_topology() -> bool
+  {
+    auto static const cpu_major = kapi::devices::allocate_major_number();
+    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::table_signature_v<::acpi::madt>>();
+    if (!madt)
+    {
+      kstd::println("[x86_64:PLT] Failed to find ACPI APIC table");
+      return false;
+    }
+
+    auto lapic_entries = *madt | std::views::filter([](auto const & entry) {
+      return entry.type() == ::acpi::madt_entry::type::processor_local_apic;
+    }) | std::views::transform([](auto const & entry) {
+      return static_cast<::acpi::processor_local_apic_entry const &>(entry);
+    }) | std::views::filter([](auto const & entry) { return static_cast<bool>(entry.flags() & candidate_flags); });
+
+    auto bsp_found = false;
+    auto core_count = 0uz;
+    auto local_apic_address = memory::physical_address{madt->local_interrupt_controller_address()};
+    auto cpu_bus = kstd::make_unique<devices::cpu>(cpu_major, 0);
+
+    for (auto const & apic : lapic_entries)
+    {
+      auto is_bsp = !bsp_found;
+      bsp_found = true;
+      auto core = kstd::make_unique<devices::cpu::core>(core_major, core_count, apic.processor_id(), is_bsp);
+      core->add_child(kstd::make_unique<arch::devices::local_apic>(interrupt_controller_major, core_count, apic.id(),
+                                                                   local_apic_address, is_bsp));
+      cpu_bus->add_child(std::move(core));
+      ++core_count;
+    }
+
+    devices::get_root_bus().add_child(std::move(cpu_bus));
+
+    kstd::println("[x86_64:PLT] Found {} CPU cores", core_count);
+    return core_count > 0;
+  }
+
 }  // namespace kapi::cpu