kernel/acpi: discover local interrupt controllers

8 files changed, 209 insertions, 3 deletions

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index fc01723..92e2bda 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -20,6 +20,7 @@ add_library("kernel_objs" OBJECT
     "src/memory.cpp"
     "src/devices/block_device.cpp"
     "src/devices/block_device_utils.cpp"
+    "src/devices/cpu.cpp"
     "src/devices/root_bus.cpp"
     "src/devices/storage/controller.cpp"
     "src/devices/storage/management.cpp"
diff --git a/kernel/include/kernel/acpi/manager.hpp b/kernel/include/kernel/acpi/manager.hpp
index 437d4c8..fae59a6 100644
--- a/kernel/include/kernel/acpi/manager.hpp
+++ b/kernel/include/kernel/acpi/manager.hpp
@@ -4,6 +4,7 @@
 #include "kapi/acpi.hpp"
 
 #include <kstd/flat_map>
+#include <kstd/memory>
 #include <kstd/vector>
 
 #include <string_view>
@@ -17,6 +18,8 @@ namespace kernel::acpi
 
     auto load_tables() -> bool;
 
+    auto get_table(std::string_view signature) -> kstd::observer_ptr<kapi::acpi::system_description_table_header const>;
+
   private:
     kapi::acpi::root_system_description_pointer const * m_sdp{};
     kapi::acpi::system_description_table_header const * m_rsdt{};
diff --git a/kernel/include/kernel/devices/cpu.hpp b/kernel/include/kernel/devices/cpu.hpp
new file mode 100644
index 0000000..b056665
--- /dev/null
+++ b/kernel/include/kernel/devices/cpu.hpp
@@ -0,0 +1,33 @@
+#ifndef TEACHOS_KERNEL_DEVICES_CPU_HPP
+#define TEACHOS_KERNEL_DEVICES_CPU_HPP
+
+#include "kapi/devices.hpp"
+
+#include <cstddef>
+#include <cstdint>
+
+namespace kernel::devices
+{
+
+  struct cpu final : kapi::devices::bus
+  {
+    struct core final : kapi::devices::bus
+    {
+      explicit core(std::size_t major_number, std::size_t minor_number, std::uint64_t hardware_id, bool is_bsp);
+
+      [[nodiscard]] auto hardware_id() const -> std::uint64_t;
+      [[nodiscard]] auto is_bsp() const -> bool;
+
+    private:
+      std::uint64_t m_hardware_id;
+      bool m_is_bsp;
+    };
+
+    explicit cpu(std::size_t major_number);
+
+    auto probe() -> bool final;
+  };
+
+}  // namespace kernel::devices
+
+#endif
\ No newline at end of file
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 &
diff --git a/kernel/src/acpi/manager.cpp b/kernel/src/acpi/manager.cpp
index 180d458..300b85e 100644
--- a/kernel/src/acpi/manager.cpp
+++ b/kernel/src/acpi/manager.cpp
@@ -4,10 +4,12 @@
 #include "kapi/memory.hpp"
 #include "kapi/system.hpp"
 
+#include <kstd/memory>
 #include <kstd/print>
 
 #include <cstddef>
 #include <cstdint>
+#include <string_view>
 
 namespace kernel::acpi
 {
@@ -80,8 +82,7 @@ namespace kernel::acpi
       }
       else
       {
-        kstd::println("[OS:ACPI] Found table: {}@{:#x}/{:#x} OEM: {} Rev: {}", table->signature(), linear_table_address,
-                      physical_table_address, table->oem_id(), table->creator_revision());
+        kstd::println("[OS:ACPI] Found '{}' ACPI table", table->signature());
         m_tables.emplace(table->signature(), table);
       }
     }
@@ -89,4 +90,14 @@ namespace kernel::acpi
     return !m_tables.empty();
   }
 
+  auto manager::get_table(std::string_view signature)
+      -> kstd::observer_ptr<kapi::acpi::system_description_table_header const>
+  {
+    if (m_tables.contains(signature))
+    {
+      return kstd::make_observer(m_tables.at(signature));
+    }
+    return nullptr;
+  }
+
 }  // namespace kernel::acpi
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
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index 2eaa2d8..e704955 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -1,3 +1,4 @@
+#include "kapi/acpi.hpp"
 #include "kapi/boot_modules.hpp"
 #include "kapi/cio.hpp"
 #include "kapi/cpu.hpp"
@@ -179,6 +180,15 @@ auto main() -> int
   kstd::println("[OS] Memory subsystem initialized.");
   kapi::system::memory_initialized();
 
+  auto acpi_root_pointer = kapi::acpi::get_root_pointer();
+  if (acpi_root_pointer && acpi_root_pointer->validate())
+  {
+    if (kapi::acpi::init(*acpi_root_pointer))
+    {
+      kstd::println("[OS] ACPI subsystem initialized.");
+    }
+  }
+
   kapi::devices::init();
   kstd::println("[OS] System root bus initialized.");