From f50815110789a0f8f6e5ca66ffd49b26578791a9 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 6 Apr 2026 18:43:28 +0200
Subject: kernel: generalize CPU discovery

---
 arch/x86_64/kapi/platform.cpp | 70 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 arch/x86_64/kapi/platform.cpp

(limited to 'arch/x86_64/kapi/platform.cpp')

diff --git a/arch/x86_64/kapi/platform.cpp b/arch/x86_64/kapi/platform.cpp
new file mode 100644
index 0000000..2e7c7e4
--- /dev/null
+++ b/arch/x86_64/kapi/platform.cpp
@@ -0,0 +1,70 @@
+#include "kapi/platform.hpp"
+
+#include "kapi/acpi.hpp"
+#include "kapi/devices.hpp"
+#include "kapi/memory.hpp"
+
+#include "arch/devices/local_apic.hpp"
+
+#include <kstd/memory>
+#include <kstd/print>
+
+#include <cstddef>
+#include <cstdint>
+
+namespace kapi::platform
+{
+
+  namespace
+  {
+    constexpr auto default_lapic_address = kapi::memory::physical_address{0xFEE0'0000};
+  }
+
+  auto discover_cpu_topology(kapi::devices::bus & bus) -> bool
+  {
+    auto madt = kapi::acpi::get_table("APIC");
+    if (!madt)
+    {
+      kstd::println("[x86_64:PLT] Failed to find ACPI APIC table");
+      return false;
+    }
+
+    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_count = 0uz;
+
+    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;
+
+          if (kapi::platform::cpu_detected(bus, local_apic->processor_id(), is_bsp))
+          {
+            ++core_count;
+          }
+        }
+      }
+
+      current += sub_table->length();
+    }
+
+    kstd::println("[x86_64:PLT] Found {} CPU cores", core_count);
+
+    return core_count > 0;
+  }
+
+  auto create_core_interrupt_controller(std::size_t major, std::size_t minor, std::uint64_t hardware_id)
+      -> kstd::unique_ptr<devices::device>
+  {
+    return kstd::make_unique<arch::devices::local_apic>(major, minor, hardware_id, default_lapic_address);
+  }
+
+}  // namespace kapi::platform
\ No newline at end of file
-- 
cgit v1.2.3


From d5c2e101d62f6b4b69c45c127e7a729d246da566 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 6 Apr 2026 19:04:16 +0200
Subject: kapi/platform: invert discovery dependencies

---
 arch/x86_64/kapi/platform.cpp | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

(limited to 'arch/x86_64/kapi/platform.cpp')

diff --git a/arch/x86_64/kapi/platform.cpp b/arch/x86_64/kapi/platform.cpp
index 2e7c7e4..380fc66 100644
--- a/arch/x86_64/kapi/platform.cpp
+++ b/arch/x86_64/kapi/platform.cpp
@@ -10,7 +10,7 @@
 #include <kstd/print>
 
 #include <cstddef>
-#include <cstdint>
+#include <utility>
 
 namespace kapi::platform
 {
@@ -22,6 +22,10 @@ namespace kapi::platform
 
   auto discover_cpu_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 static core_index = 0uz;
+
     auto madt = kapi::acpi::get_table("APIC");
     if (!madt)
     {
@@ -46,7 +50,10 @@ namespace kapi::platform
           auto is_bsp = !bsp_found;
           bsp_found = true;
 
-          if (kapi::platform::cpu_detected(bus, local_apic->processor_id(), is_bsp))
+          auto lapic = kstd::make_unique<arch::devices::local_apic>(interrupt_controller_major, core_index,
+                                                                    local_apic->apic_id(), default_lapic_address);
+          if (kapi::platform::cpu_detected(bus, core_major, core_index, local_apic->processor_id(), is_bsp,
+                                           std::move(lapic)))
           {
             ++core_count;
           }
@@ -61,10 +68,4 @@ namespace kapi::platform
     return core_count > 0;
   }
 
-  auto create_core_interrupt_controller(std::size_t major, std::size_t minor, std::uint64_t hardware_id)
-      -> kstd::unique_ptr<devices::device>
-  {
-    return kstd::make_unique<arch::devices::local_apic>(major, minor, hardware_id, default_lapic_address);
-  }
-
 }  // namespace kapi::platform
\ No newline at end of file
-- 
cgit v1.2.3