Merge branch 'fmorgner/develop-BA-FS26/apci' into develop-BA-FS26

This patchset introduces basic support for ACPI. Currently, the only
user of that support is the CPU discovery subsystem. It uses the
processed ACPI information to initialize CPU core devices and their
associated local APICs.

1 files changed, 174 insertions, 0 deletions

diff --git a/kernel/kapi/acpi.cpp b/kernel/kapi/acpi.cpp
new file mode 100644
index 0000000..1283d7e
--- /dev/null
+++ b/kernel/kapi/acpi.cpp
@@ -0,0 +1,174 @@
+#include "kapi/acpi.hpp"
+
+#include "kapi/memory.hpp"
+#include "kapi/system.hpp"
+
+#include "kernel/acpi/manager.hpp"
+
+#include <kstd/memory>
+#include <kstd/units>
+
+#include <algorithm>
+#include <atomic>
+#include <bit>
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <string_view>
+
+namespace kapi::acpi
+{
+
+  namespace
+  {
+    auto constinit manager = std::optional<kernel::acpi::manager>{};
+  }  // namespace
+
+  auto root_system_description_pointer::oem_id() const noexcept -> std::string_view
+  {
+    return {m_oem_id.data(), m_oem_id.size()};
+  }
+
+  auto root_system_description_pointer::revision() const noexcept -> std::uint8_t
+  {
+    return m_revision;
+  }
+
+  auto root_system_description_pointer::signature() const noexcept -> std::string_view
+  {
+    return {m_signature.data(), m_signature.size()};
+  }
+
+  auto root_system_description_pointer::table_address() const noexcept -> memory::physical_address
+  {
+    auto raw = std::bit_cast<std::uint32_t>(m_rsdt_address);
+    return memory::physical_address{static_cast<std::uintptr_t>(raw)};
+  }
+
+  auto root_system_description_pointer::validate() const noexcept -> bool
+  {
+    return validate_checksum({reinterpret_cast<std::byte const *>(this), sizeof(root_system_description_pointer)});
+  }
+
+  auto extended_system_description_pointer::length() const noexcept -> kstd::units::bytes
+  {
+    return kstd::units::bytes{m_length};
+  }
+
+  auto extended_system_description_pointer::table_address() const noexcept -> memory::physical_address
+  {
+    return memory::physical_address{std::bit_cast<std::uintptr_t>(m_xsdt_address)};
+  }
+
+  auto extended_system_description_pointer::validate() const noexcept -> bool
+  {
+    return validate_checksum({reinterpret_cast<std::byte const *>(this), m_length});
+  }
+
+  [[nodiscard]] auto system_description_table_header::checksum() const noexcept -> std::uint8_t
+  {
+    return m_checksum;
+  }
+
+  [[nodiscard]] auto system_description_table_header::creator_revision() const noexcept -> std::uint32_t
+  {
+    return m_creator_revision;
+  }
+
+  [[nodiscard]] auto system_description_table_header::creator_id() const noexcept -> std::uint32_t
+  {
+    return m_creator_id;
+  }
+
+  [[nodiscard]] auto system_description_table_header::length() const noexcept -> kstd::units::bytes
+  {
+    return kstd::units::bytes{m_length};
+  }
+
+  [[nodiscard]] auto system_description_table_header::oem_id() const noexcept -> std::string_view
+  {
+    return {m_oem_id.data(), m_oem_id.size()};
+  }
+
+  [[nodiscard]] auto system_description_table_header::oem_revision() const noexcept -> std::uint32_t
+  {
+    return m_oem_revision;
+  }
+
+  [[nodiscard]] auto system_description_table_header::oem_table_id() const noexcept -> std::string_view
+  {
+    return {m_oem_table_id.data(), m_oem_table_id.size()};
+  }
+
+  [[nodiscard]] auto system_description_table_header::revision() const noexcept -> std::uint8_t
+  {
+    return m_revision;
+  }
+
+  [[nodiscard]] auto system_description_table_header::signature() const noexcept -> std::string_view
+  {
+    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!");
+    }
+
+    manager.emplace(sdp);
+    return manager->load_tables();
+  }
+
+  auto validate_checksum(std::span<std::byte const> data) -> bool
+  {
+    auto sum = std::ranges::fold_left(data, std::uint8_t{}, [](auto acc, auto byte) {
+      return static_cast<std::uint8_t>(acc + static_cast<std::uint8_t>(byte));
+    });
+    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