acpi: add basic MADT tests

10 files changed, 241 insertions, 5 deletions

diff --git a/libs/acpi/CMakeLists.txt b/libs/acpi/CMakeLists.txt
index b8face4..8ace42d 100644
--- a/libs/acpi/CMakeLists.txt
+++ b/libs/acpi/CMakeLists.txt
@@ -1,3 +1,11 @@
+cmake_minimum_required(VERSION "3.27.0")
+
+project("acpi"
+  DESCRIPTION "An ACPI parsing library"
+  VERSION "0.0.1"
+  LANGUAGES ASM CXX
+)
+
 add_library("acpi" STATIC)
 add_library("libs::acpi" ALIAS "acpi")
 
@@ -29,8 +37,34 @@ target_link_libraries("acpi" PUBLIC
 )
 
 if(NOT CMAKE_CROSSCOMPILING)
+  find_program(IASL_EXE NAMES "iasl" REQUIRED)
+
+  set(TEST_TABLES
+    "basic_madt"
+    "basic_rsdt"
+  )
+
+  foreach(TABLE IN LISTS TEST_TABLES)
+    add_custom_command(OUTPUT "test_data/${TABLE}.aml"
+      COMMAND "${IASL_EXE}" -p "test_data/${TABLE}.aml" "${CMAKE_CURRENT_SOURCE_DIR}/test_data/${TABLE}.asl"
+      DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/test_data/${TABLE}.asl"
+      COMMENT "Compiling test_data/${TABLE}.asl"
+      VERBATIM
+    )
+    list(APPEND GENERATED_TABLE_BLOBS "${CMAKE_CURRENT_BINARY_DIR}/test_data/${TABLE}.aml")
+  endforeach()
+
+  set_source_files_properties("test_data/tables.S" PROPERTIES OBJECT_DEPENDS "${GENERATED_TABLE_BLOBS}")
+
   add_executable("acpi_tests"
+    "acpi/madt.test.cpp"
     "acpi/pointers.test.cpp"
+
+    "test_data/tables.S"
+  )
+
+  target_include_directories("acpi_tests" PRIVATE
+    "${CMAKE_CURRENT_BINARY_DIR}/test_data"
   )
 
   target_link_libraries("acpi_tests" PRIVATE
diff --git a/libs/acpi/acpi/madt.cpp b/libs/acpi/acpi/madt.cpp
index 40289cf..6a62f07 100644
--- a/libs/acpi/acpi/madt.cpp
+++ b/libs/acpi/acpi/madt.cpp
@@ -1,3 +1,4 @@
+#include <acpi/acpi.hpp>
 #include <acpi/madt.hpp>
 
 #include <cstddef>
@@ -16,9 +17,14 @@ namespace acpi
     return m_flags;
   }
 
-  auto madt_entry::type() const noexcept -> types
+  auto madt::validate() const noexcept -> bool
   {
-    return static_cast<types>(m_type);
+    return signature() == madt_table_signature && sdt::validate();
+  }
+
+  auto madt_entry::type() const noexcept -> enum type
+  {
+    return static_cast<enum type>(m_type);
   }
 
   auto madt_entry::length() const noexcept -> std::size_t
diff --git a/libs/acpi/acpi/madt.hpp b/libs/acpi/acpi/madt.hpp
index f680430..8b75f58 100644
--- a/libs/acpi/acpi/madt.hpp
+++ b/libs/acpi/acpi/madt.hpp
@@ -4,6 +4,7 @@
 // IWYU pragma: private, include <acpi/acpi.hpp>
 
 #include <kstd/ext/bitfield_enum>
+#include <kstd/os/error.hpp>
 #include <kstd/units>
 
 #include <acpi/sdt.hpp>
@@ -11,6 +12,7 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <ranges>
 #include <type_traits>
 
 namespace acpi
@@ -18,7 +20,8 @@ namespace acpi
 
   struct [[gnu::packed]] madt_entry
   {
-    enum struct types : std::uint8_t
+    //! The type of an MADT entry.
+    enum struct type : std::uint8_t
     {
       processor_local_apic,
       io_apic,
@@ -29,28 +32,55 @@ namespace acpi
       processor_local_x2_apic,
     };
 
-    [[nodiscard]] auto type() const noexcept -> types;
+    //! Get the type of this entry.
+    [[nodiscard]] auto type() const noexcept -> enum type;
+
+    //! Get the length of this entry.
     [[nodiscard]] auto length() const noexcept -> std::size_t;
 
+    //! Cast this entry to the given concrete entry type.
+    //!
+    //! @warning This function will terminate execution if the desired target type does not match up with this entry's
+    //! actual type.
+    template<typename EntryType>
+    [[nodiscard]] auto as() const -> EntryType const &
+    {
+      if (type() != EntryType::this_type)
+      {
+        kstd::os::panic("Invalid cast");
+      }
+      return reinterpret_cast<EntryType const &>(*this);
+    }
+
   private:
     std::uint8_t m_type;
     std::uint8_t m_length;
   };
 
-  //! The common header for all
+  //! The Multiple APIC Description Table (MADT)
   struct [[gnu::packed]] madt : sdt
   {
     using iterator = sdt_iterator<madt_entry const>;
     using const_iterator = iterator;
 
+    //! Get the physical address of the local interrupt controllers described by this entry.
     [[nodiscard]] auto local_interrupt_controller_address() const noexcept -> std::uintptr_t;
+
     [[nodiscard]] auto flags() const noexcept -> std::uint32_t;
+    [[nodiscard]] auto validate() const noexcept -> bool;
 
     [[nodiscard]] auto begin() const noexcept -> iterator;
     [[nodiscard]] auto cbegin() const noexcept -> iterator;
     [[nodiscard]] auto end() const noexcept -> iterator;
     [[nodiscard]] auto cend() const noexcept -> iterator;
 
+    template<typename EntryType>
+    [[nodiscard]] auto only() const noexcept
+    {
+      return *this | std::views::filter([](auto const & e) { return e.type() == EntryType::this_type; }) |
+             std::views::transform([](auto const & e) { return e.template as<EntryType>(); });
+    }
+
   private:
     std::uint32_t m_local_interrupt_controller_address;
     std::uint32_t m_flags;
@@ -58,6 +88,8 @@ namespace acpi
 
   struct [[gnu::packed]] processor_local_apic : madt_entry
   {
+    constexpr auto static this_type = type::processor_local_apic;
+
     enum struct flags : std::uint32_t
     {
       processor_enabled = 1,
diff --git a/libs/acpi/acpi/madt.test.cpp b/libs/acpi/acpi/madt.test.cpp
new file mode 100644
index 0000000..8926192
--- /dev/null
+++ b/libs/acpi/acpi/madt.test.cpp
@@ -0,0 +1,55 @@
+#include <kstd/units>
+
+#include <acpi/madt.hpp>
+#include <catch2/catch_test_macros.hpp>
+#include <test_data/tables.hpp>
+
+#include <iterator>
+
+SCENARIO("MADT parsing", "[madt]")
+{
+  GIVEN("The basic compiled MADT containing a single LAPIC entry and the default x86 LAPIC address")
+  {
+    auto data = acpi::test_data::tables::basic_madt();
+
+    WHEN("parsing the table")
+    {
+      auto madt = reinterpret_cast<acpi::madt const *>(data.data());
+
+      THEN("the signature is correct")
+      {
+        REQUIRE(madt->signature() == "APIC");
+      }
+
+      THEN("validate returns true")
+      {
+        REQUIRE(madt->validate());
+      }
+
+      THEN("there is a single entry in the table")
+      {
+        REQUIRE(std::distance(madt->begin(), madt->end()) == 1);
+      }
+
+      THEN("the LAPIC address is 0xfee00000")
+      {
+        REQUIRE(madt->local_interrupt_controller_address() == 0xfee0'0000);
+      }
+
+      THEN("the length is sizeof(madt) + sizeof(processor_local_apic)")
+      {
+        REQUIRE(madt->length() == kstd::type_size<acpi::madt> + kstd::type_size<acpi::processor_local_apic>);
+      }
+
+      THEN("the first entry has type processor_local_apic")
+      {
+        REQUIRE(madt->cbegin()->type() == acpi::madt_entry::type::processor_local_apic);
+      }
+
+      THEN("`only` can be used to get a view of all processor_local_apic entries")
+      {
+        REQUIRE(std::ranges::distance(madt->only<acpi::processor_local_apic>()) == 1);
+      }
+    }
+  }
+}
diff --git a/libs/acpi/acpi/sdt.cpp b/libs/acpi/acpi/sdt.cpp
index c2b9d68..6c6cb47 100644
--- a/libs/acpi/acpi/sdt.cpp
+++ b/libs/acpi/acpi/sdt.cpp
@@ -1,7 +1,9 @@
 #include <kstd/units>
 
+#include <acpi/acpi.hpp>
 #include <acpi/sdt.hpp>
 
+#include <cstddef>
 #include <cstdint>
 #include <string_view>
 
@@ -48,4 +50,9 @@ namespace acpi
     return {m_signature.data(), m_signature.size()};
   }
 
+  auto sdt::validate() const noexcept -> bool
+  {
+    return acpi::validate_checksum({reinterpret_cast<std::byte const *>(this), length().value});
+  }
+
 }  // namespace acpi
diff --git a/libs/acpi/acpi/sdt.hpp b/libs/acpi/acpi/sdt.hpp
index 9e5ec89..72b3896 100644
--- a/libs/acpi/acpi/sdt.hpp
+++ b/libs/acpi/acpi/sdt.hpp
@@ -52,6 +52,11 @@ namespace acpi
       return *m_entry;
     }
 
+    constexpr auto operator->() const noexcept -> pointer
+    {
+      return m_entry;
+    }
+
     constexpr auto operator==(sdt_iterator const & other) const noexcept -> bool
     {
       return m_entry == other.m_entry || (is_end() && other.is_end());
@@ -94,6 +99,9 @@ namespace acpi
     //! Get the signature of this table.
     [[nodiscard]] auto signature() const noexcept -> std::string_view;
 
+    //! Valide this table's checksum
+    [[nodiscard]] auto validate() const noexcept -> bool;
+
   private:
     std::array<char, 4> m_signature;
     std::uint32_t m_length;
diff --git a/libs/acpi/test_data/basic_madt.asl b/libs/acpi/test_data/basic_madt.asl
new file mode 100644
index 0000000..cd6958a
--- /dev/null
+++ b/libs/acpi/test_data/basic_madt.asl
@@ -0,0 +1,29 @@
+/*
+ * Intel ACPI Component Architecture
+ * iASL Compiler/Disassembler version 20251212 (64-bit version)
+ * Copyright (c) 2000 - 2025 Intel Corporation
+ * 
+ * Template for [APIC] ACPI Table (static data table)
+ * Format: [ByteLength]  FieldName : HexFieldValue
+ */
+[0004]                          Signature : "APIC"    [Multiple APIC Description Table (MADT)]
+[0004]                       Table Length : 00000000
+[0001]                           Revision : 07
+[0001]                           Checksum : 00
+[0006]                             Oem ID : "INTEL "
+[0008]                       Oem Table ID : "Template"
+[0004]                       Oem Revision : 00000001
+[0004]                    Asl Compiler ID : "INTL"
+[0004]              Asl Compiler Revision : 20230628
+
+[0004]                 Local Apic Address : FEE00000
+[0004]              Flags (decoded below) : 00000001
+                      PC-AT Compatibility : 1
+
+[0001]                      Subtable Type : 00 [Processor Local APIC]
+[0001]                             Length : 08
+[0001]                       Processor ID : 00
+[0001]                      Local Apic ID : 00
+[0004]              Flags (decoded below) : 00000001
+                        Processor Enabled : 1
+                   Runtime Online Capable : 0
diff --git a/libs/acpi/test_data/basic_rsdt.asl b/libs/acpi/test_data/basic_rsdt.asl
new file mode 100644
index 0000000..6cf4c7a
--- /dev/null
+++ b/libs/acpi/test_data/basic_rsdt.asl
@@ -0,0 +1,26 @@
+/*
+ * Intel ACPI Component Architecture
+ * iASL Compiler/Disassembler version 20251212 (64-bit version)
+ * Copyright (c) 2000 - 2025 Intel Corporation
+ * 
+ * Template for [RSDT] ACPI Table (static data table)
+ * Format: [ByteLength]  FieldName : HexFieldValue
+ */
+[0004]                          Signature : "RSDT"    [Root System Description Table]
+[0004]                       Table Length : 00000000
+[0001]                           Revision : 01
+[0001]                           Checksum : 00
+[0006]                             Oem ID : "INTEL "
+[0008]                       Oem Table ID : "TEMPLATE"
+[0004]                       Oem Revision : 00000001
+[0004]                    Asl Compiler ID : "INTL"
+[0004]              Asl Compiler Revision : 20100528
+
+[0004]             ACPI Table Address   0 : 00000010
+[0004]             ACPI Table Address   1 : 00000020
+[0004]             ACPI Table Address   2 : 00000030
+[0004]             ACPI Table Address   3 : 00000040
+[0004]             ACPI Table Address   4 : 00000050
+[0004]             ACPI Table Address   5 : 00000060
+[0004]             ACPI Table Address   6 : 00000070
+[0004]             ACPI Table Address   7 : 00000080
diff --git a/libs/acpi/test_data/tables.S b/libs/acpi/test_data/tables.S
new file mode 100644
index 0000000..af58109
--- /dev/null
+++ b/libs/acpi/test_data/tables.S
@@ -0,0 +1,14 @@
+.section .rodata
+
+.balign 16
+
+#define TABLE(name, file)     \
+  .global name##_start;       \
+  .global name##_end;         \
+  name##_start: .incbin file; \
+  name##_end:
+
+TABLE(basic_madt, "basic_madt.aml")
+TABLE(basic_rsdt, "basic_rsdt.aml")
+
+#undef TABLE
diff --git a/libs/acpi/test_data/tables.hpp b/libs/acpi/test_data/tables.hpp
new file mode 100644
index 0000000..2b3874f
--- /dev/null
+++ b/libs/acpi/test_data/tables.hpp
@@ -0,0 +1,25 @@
+#ifndef ACPI_TEST_DATA_TABLES_HPP
+#define ACPI_TEST_DATA_TABLES_HPP
+
+#include <cstddef>
+#include <span>
+
+#define TABLE(name)                              \
+  extern "C" std::byte const name##_start;       \
+  extern "C" std::byte const name##_end;         \
+  auto inline name()->std::span<std::byte const> \
+  {                                              \
+    return {&name##_start, &name##_end};         \
+  }
+
+namespace acpi::test_data::tables
+{
+
+  TABLE(basic_madt);
+  TABLE(basic_rsdt);
+
+}  // namespace acpi::test_data::tables
+
+#undef TABLE
+
+#endif