kapi: add basic ACPI support

8 files changed, 205 insertions, 15 deletions

diff --git a/kapi/CMakeLists.txt b/kapi/CMakeLists.txt
index c9aa23f..eeda158 100644
--- a/kapi/CMakeLists.txt
+++ b/kapi/CMakeLists.txt
@@ -1,4 +1,6 @@
-add_library("kapi" INTERFACE)
+add_library("kapi" STATIC
+    "src/acpi.cpp"
+)
 add_library("os::kapi" ALIAS "kapi")
 
 file(GLOB_RECURSE KAPI_HEADERS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "include/**.hpp")
@@ -10,11 +12,11 @@ target_sources("kapi" PUBLIC
     ${KAPI_HEADERS}
 )
 
-target_include_directories("kapi" INTERFACE
+target_include_directories("kapi" PUBLIC
     "include"
 )
 
-target_link_libraries("kapi" INTERFACE
+target_link_libraries("kapi" PUBLIC
     "libs::kstd"
 
     "gcc"
diff --git a/kapi/include/kapi/acpi.hpp b/kapi/include/kapi/acpi.hpp
new file mode 100644
index 0000000..20e5e77
--- /dev/null
+++ b/kapi/include/kapi/acpi.hpp
@@ -0,0 +1,64 @@
+#ifndef TEACHOS_KAPI_ACPI_HPP
+#define TEACHOS_KAPI_ACPI_HPP
+
+#include "kapi/memory.hpp"
+#include <kstd/units>
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+
+namespace kapi::acpi
+{
+
+  //! @addtogroup kapi-acpi-api-defined
+  //! @{
+
+  struct [[gnu::packed]] root_system_description_pointer
+  {
+    [[nodiscard]] auto oem_id() const noexcept -> std::string_view;
+    [[nodiscard]] auto revision() const noexcept -> std::uint8_t;
+    [[nodiscard]] auto signature() const noexcept -> std::string_view;
+    [[nodiscard]] auto table_address() const noexcept -> memory::physical_address;
+    [[nodiscard]] auto validate() const noexcept -> bool;
+
+  private:
+    std::array<char, 8> m_signature;
+    [[maybe_unused]] std::uint8_t m_checksum;
+    std::array<char, 6> m_oem_id;
+    std::uint8_t m_revision;
+    std::array<std::byte, 4> m_rsdt_address;
+  };
+
+  struct [[gnu::packed]] extended_system_description_pointer : root_system_description_pointer
+  {
+    [[nodiscard]] auto length() const noexcept -> kstd::units::bytes;
+    [[nodiscard]] auto table_address() const noexcept -> memory::physical_address;
+    [[nodiscard]] auto validate() const noexcept -> bool;
+
+  private:
+    std::uint32_t m_length;
+    std::array<std::byte, 8> m_xsdt_address;
+    [[maybe_unused]] std::uint8_t m_extended_checksum;
+    [[maybe_unused]] std::array<std::byte, 3> m_reserved;
+  };
+
+  //! @}
+
+  struct [[gnu::packed]] system_description_table_header
+  {
+    std::array<char, 4> signature;
+    std::uint32_t length;
+    std::uint8_t revision;
+    std::uint8_t checksum;
+    std::array<char, 6> oem_id;
+    std::array<char, 8> oem_table_id;
+    std::uint32_t oem_revision;
+    std::uint32_t creator_id;
+    std::uint32_t create_revision;
+  };
+
+}  // namespace kapi::acpi
+
+#endif
diff --git a/kapi/src/acpi.cpp b/kapi/src/acpi.cpp
new file mode 100644
index 0000000..aa0066d
--- /dev/null
+++ b/kapi/src/acpi.cpp
@@ -0,0 +1,68 @@
+#include "kapi/acpi.hpp"
+
+#include "kapi/memory.hpp"
+
+#include <kstd/units>
+
+#include <algorithm>
+#include <bit>
+#include <cstddef>
+#include <cstdint>
+#include <span>
+#include <string_view>
+
+namespace kapi::acpi
+{
+
+  namespace
+  {
+    constexpr auto validate_checksum(std::span<std::byte const> data) -> bool
+    {
+      auto sum = std::ranges::fold_left(
+          data, std::uint8_t{}, [](std::uint8_t acc, auto byte) { return static_cast<std::uint8_t>(byte) + acc; });
+      return sum == 0;
+    }
+  }  // 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});
+  }
+
+};  // namespace kapi::acpi
diff --git a/kernel/include/kernel/memory/block_list_allocator.hpp b/kernel/include/kernel/memory/block_list_allocator.hpp
index f319097..de89f3b 100644
--- a/kernel/include/kernel/memory/block_list_allocator.hpp
+++ b/kernel/include/kernel/memory/block_list_allocator.hpp
@@ -43,10 +43,10 @@ namespace kernel::memory
   private:
     struct block_header final
     {
-      kstd::units::bytes usable_size;
-      bool free;
-      block_header * next;
-      block_header * prev;
+      kstd::units::bytes usable_size{};
+      bool free{};
+      block_header * next{};
+      block_header * prev{};
     };
 
     //! The size of the metadata required for each allocated block.
@@ -87,4 +87,4 @@ namespace kernel::memory
 
 }  // namespace kernel::memory
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/kstd/include/kstd/units b/libs/kstd/include/kstd/units
index f6dcdb1..bc7e1b9 100644
--- a/libs/kstd/include/kstd/units
+++ b/libs/kstd/include/kstd/units
@@ -14,6 +14,11 @@ namespace kstd
   {
     using value_type = ValueType;
 
+    constexpr basic_unit() noexcept
+      : value{}
+    {
+    }
+
     explicit constexpr basic_unit(value_type value) noexcept
         : value{value}
     {}
@@ -142,4 +147,4 @@ namespace kstd
 
 }  // namespace kstd
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/multiboot2/include/multiboot2/constants/information_id.hpp b/libs/multiboot2/include/multiboot2/constants/information_id.hpp
index be492eb..27c5300 100644
--- a/libs/multiboot2/include/multiboot2/constants/information_id.hpp
+++ b/libs/multiboot2/include/multiboot2/constants/information_id.hpp
@@ -57,10 +57,10 @@ namespace multiboot2
     smbios_tables,
 
     //! A copy of RSDP as defined per ACPI 1.0 specification.
-    acpi_old_rsdp,
+    acpi_rsdp,
 
-    //! A copy of RSDP as defined per ACPI 2.0 or later specification.
-    acpi_new_rsdp,
+    //! A copy of XSDP as defined per ACPI 2.0 or later specification.
+    acpi_xsdp,
 
     //! The network information specified specified as per DHCP.
     networking_information,
@@ -83,4 +83,4 @@ namespace multiboot2
 
 }  // namespace multiboot2
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/multiboot2/include/multiboot2/information.hpp b/libs/multiboot2/include/multiboot2/information.hpp
index d2fac2e..a2ded56 100644
--- a/libs/multiboot2/include/multiboot2/information.hpp
+++ b/libs/multiboot2/include/multiboot2/information.hpp
@@ -11,6 +11,7 @@
 #include <elf/section_header.hpp>
 
 #include <algorithm>
+#include <cstddef>
 #include <cstdint>
 #include <cstdlib>
 #include <optional>
@@ -128,6 +129,26 @@ namespace multiboot2
       return kstd::units::bytes{end_address - start_address};
     }
   };
+  
+  struct acpi_rsdp : vla_tag<data::acpi_rsdp, std::byte, std::span>
+  {
+    using vla_tag::vla_tag;
+
+    [[nodiscard]] auto pointer() const noexcept -> range_type
+    {
+      return {data(), size()};
+    }
+  };
+
+  struct acpi_xsdp : vla_tag<data::acpi_xsdp, std::byte, std::span>
+  {
+    using vla_tag::vla_tag;
+
+    [[nodiscard]] auto pointer() const noexcept -> range_type
+    {
+      return {data(), size()};
+    }
+  };
 
   struct information_view
   {
@@ -245,6 +266,26 @@ namespace multiboot2
              std::views::transform(transform_module);
     }
 
+    [[nodiscard]] auto maybe_acpi_rsdp() const noexcept -> std::optional<acpi_rsdp>
+    {
+      return get<multiboot2::acpi_rsdp>();
+    }
+
+    [[nodiscard]] auto acpi_rsdp() const noexcept -> acpi_rsdp
+    {
+      return maybe_acpi_rsdp().value();
+    }
+
+    [[nodiscard]] auto maybe_acpi_xsdp() const noexcept -> std::optional<acpi_xsdp>
+    {
+      return get<multiboot2::acpi_xsdp>();
+    }
+
+    [[nodiscard]] auto acpi_xsdp() const noexcept -> acpi_xsdp
+    {
+      return maybe_acpi_xsdp().value();
+    }
+
   private:
     template<typename Tag>
     [[nodiscard]] constexpr auto get() const noexcept -> std::optional<Tag>
@@ -264,4 +305,4 @@ namespace multiboot2
 
 }  // namespace multiboot2
 
-#endif
\ No newline at end of file
+#endif
diff --git a/libs/multiboot2/include/multiboot2/information/data.hpp b/libs/multiboot2/include/multiboot2/information/data.hpp
index 3b07d20..315eb39 100644
--- a/libs/multiboot2/include/multiboot2/information/data.hpp
+++ b/libs/multiboot2/include/multiboot2/information/data.hpp
@@ -167,8 +167,18 @@ namespace multiboot2
       std::uint32_t end_address;
     };
 
+    //! A copy of the ACPI RSDP
+    struct acpi_rsdp : tag_data<information_id::acpi_rsdp>
+    {
+    };
+
+    //! A copy of the ACPI XSDP
+    struct acpi_xsdp : tag_data<information_id::acpi_xsdp>
+    {
+    };
+
   }  // namespace data
 
 }  // namespace multiboot2
 
-#endif
\ No newline at end of file
+#endif