Merge branch 'develop-BA-FS26' into 'develop'HEADdevelop

Merge of BA-FS26 branch into develop

See merge request teachos/kernel!49

10 files changed, 778 insertions, 0 deletions

diff --git a/kernel/src/devices/block_device.cpp b/kernel/src/devices/block_device.cpp
new file mode 100644
index 0000000..13d73ac
--- /dev/null
+++ b/kernel/src/devices/block_device.cpp
@@ -0,0 +1,42 @@
+#include <kernel/devices/block_device.hpp>
+
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/string>
+
+#include <cstddef>
+
+namespace kernel::devices
+{
+  block_device::block_device(size_t major, size_t minor, kstd::string const & name, size_t block_size)
+      : kapi::devices::device(major, minor, name)
+      , m_block_size(block_size)
+  {
+    if (m_block_size == 0)
+    {
+      kapi::system::panic("[DEVICES] block_device constructed with zero block size.");
+    }
+  }
+
+  auto block_device::calculate_transfer(size_t block_index) const -> transfer_info
+  {
+    size_t const offset = block_index * m_block_size;
+    size_t const limit = size();
+
+    size_t const available = (offset < limit) ? (limit - offset) : 0;
+    size_t const to_transfer = (available < m_block_size) ? available : m_block_size;
+
+    return {offset, to_transfer, m_block_size - to_transfer};
+  }
+
+  auto block_device::block_size() const -> size_t
+  {
+    return m_block_size;
+  }
+
+  auto block_device::capacity() const -> size_t
+  {
+    return size();
+  }
+}  // namespace kernel::devices
\ No newline at end of file
diff --git a/kernel/src/devices/block_device.tests.cpp b/kernel/src/devices/block_device.tests.cpp
new file mode 100644
index 0000000..a2ddd2b
--- /dev/null
+++ b/kernel/src/devices/block_device.tests.cpp
@@ -0,0 +1,46 @@
+#include <kernel/test_support/devices/block_device.hpp>
+
+#include <kernel/test_support/cpu.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/string>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+
+SCENARIO("Block device construction", "[devices][block_device]")
+{
+  GIVEN("parameters for a block device")
+  {
+    size_t major = 1;
+    size_t minor = 0;
+    kstd::string name = "test_block_device";
+    size_t block_size = 512;
+
+    WHEN("constructing a block device")
+    {
+      auto device =
+          kstd::make_shared<kernel::tests::devices::block_device>(major, minor, name, block_size, 3 * block_size);
+
+      THEN("the block device has the correct properties")
+      {
+        REQUIRE(device->major() == major);
+        REQUIRE(device->minor() == minor);
+        REQUIRE(device->name() == name);
+        REQUIRE(device->block_size() == block_size);
+        REQUIRE(device->capacity() == 3 * 512);
+      }
+    }
+
+    WHEN("constructing a block device with zero block size")
+    {
+      THEN("the constructor panics")
+      {
+        REQUIRE_THROWS_AS((kernel::tests::devices::block_device(major, minor, name, 0)), kernel::tests::cpu::halt);
+      }
+    }
+  }
+}
diff --git a/kernel/src/devices/block_device_utils.cpp b/kernel/src/devices/block_device_utils.cpp
new file mode 100644
index 0000000..18d1e9d
--- /dev/null
+++ b/kernel/src/devices/block_device_utils.cpp
@@ -0,0 +1,106 @@
+#include <kernel/devices/block_device_utils.hpp>
+
+#include <kernel/devices/block_device.hpp>
+
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/cstring>
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+
+namespace kernel::devices::block_device_utils
+{
+
+  using block_op = void (*)(size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
+                            std::byte * scratch, void * buffer);
+
+  auto process_blocks(kstd::shared_ptr<kapi::devices::device> const & device, size_t offset, size_t size, void * buffer,
+                      block_op op) -> size_t
+  {
+    if (buffer == nullptr)
+    {
+      kapi::system::panic("[FILESYSTEM] device_file::process_blocks called with null buffer.");
+    }
+
+    if (size == 0)
+    {
+      return 0;
+    }
+
+    if (!device->is_block_device())
+    {
+      kapi::system::panic("[FILESYSTEM] device_file: expected block_device.");
+    }
+
+    auto * block_dev = static_cast<devices::block_device *>(device.get());
+
+    size_t const block_size = block_dev->block_size();
+    size_t const capacity = block_dev->capacity();
+
+    if (offset >= capacity)
+    {
+      return 0;
+    }
+    size_t const total_to_process = std::min(size, capacity - offset);
+
+    kstd::vector<std::byte> scratch_buffer{block_size};
+    auto processed = 0uz;
+
+    while (processed < total_to_process)
+    {
+      size_t const absolute_offset = offset + processed;
+      size_t const block_index = absolute_offset / block_size;
+      size_t const in_block_offset = absolute_offset % block_size;
+      size_t const chunk_size = std::min(total_to_process - processed, block_size - in_block_offset);
+
+      op(block_index, in_block_offset, chunk_size, processed, block_dev, scratch_buffer.data(), buffer);
+
+      processed += chunk_size;
+    }
+
+    return processed;
+  }
+
+  auto read(kstd::shared_ptr<kapi::devices::device> const & device, void * buffer, size_t offset, size_t size) -> size_t
+  {
+    return process_blocks(device, offset, size, buffer,
+                          [](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
+                             std::byte * scratch, void * buffer) {
+                            auto * out = static_cast<std::byte *>(buffer);
+                            if (off == 0 && len == device->block_size())
+                            {
+                              device->read_block(idx, out + done);
+                            }
+                            else
+                            {
+                              device->read_block(idx, scratch);
+                              kstd::libc::memcpy(out + done, scratch + off, len);
+                            }
+                          });
+  }
+
+  auto write(kstd::shared_ptr<kapi::devices::device> const & device, void const * buffer, size_t offset, size_t size)
+      -> size_t
+  {
+    return process_blocks(device, offset, size, const_cast<void *>(buffer),
+                          [](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
+                             std::byte * scratch, void * buffer) {
+                            auto const * in = static_cast<std::byte const *>(buffer);
+                            if (off == 0 && len == device->block_size())
+                            {
+                              device->write_block(idx, in + done);
+                            }
+                            else
+                            {
+                              device->read_block(idx, scratch);
+                              kstd::libc::memcpy(scratch + off, in + done, len);
+                              device->write_block(idx, scratch);
+                            }
+                          });
+  }
+
+}  // namespace kernel::devices::block_device_utils
\ No newline at end of file
diff --git a/kernel/src/devices/block_device_utils.tests.cpp b/kernel/src/devices/block_device_utils.tests.cpp
new file mode 100644
index 0000000..e2e1e65
--- /dev/null
+++ b/kernel/src/devices/block_device_utils.tests.cpp
@@ -0,0 +1,219 @@
+#include <kernel/devices/block_device_utils.hpp>
+
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/devices/block_device.hpp>
+#include <kernel/test_support/devices/character_device.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+#include <cstdint>
+
+SCENARIO("reading from a block device with block_device_utils", "[devices][block_device_utils]")
+{
+  GIVEN("a block device with known data")
+  {
+    auto const block_size = 512;
+    auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", block_size);
+    kstd::vector<uint8_t> block_data(block_size);
+    for (size_t i = 0; i < block_data.size(); ++i)
+    {
+      block_data[i] = static_cast<uint8_t>(i % 256);
+    }
+    device->write_block(0, block_data.data());
+    device->write_block(1, block_data.data());
+
+    WHEN("reading from the block device using block_device_utils")
+    {
+      kstd::vector<uint8_t> read_buffer(block_size);
+      auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 0, read_buffer.size());
+
+      THEN("the correct number of bytes is read")
+      {
+        REQUIRE(bytes_read == read_buffer.size());
+      }
+
+      THEN("the data read matches the data written to the block device")
+      {
+        REQUIRE(read_buffer == block_data);
+      }
+    }
+
+    WHEN("reading over block boundaries")
+    {
+      kstd::vector<uint8_t> read_buffer(1024);
+      auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 256, read_buffer.size());
+
+      THEN("the correct number of bytes is read")
+      {
+        REQUIRE(bytes_read == 1.5 * block_size);
+      }
+
+      THEN("the data read matches the expected data across block boundaries")
+      {
+        for (size_t i = 0; i < bytes_read; ++i)
+        {
+          uint8_t expected_value = static_cast<uint8_t>((256 + i) % 256);
+          REQUIRE(read_buffer[i] == expected_value);
+        }
+      }
+    }
+
+    WHEN("reading beyond the device capacity")
+    {
+      kstd::vector<uint8_t> read_buffer(block_size);
+      auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 1024, read_buffer.size());
+
+      THEN("no bytes are read")
+      {
+        REQUIRE(bytes_read == 0);
+      }
+    }
+
+    WHEN("reading nothing")
+    {
+      kstd::vector<uint8_t> read_buffer(block_size);
+      auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 0, 0);
+
+      THEN("no bytes are read")
+      {
+        REQUIRE(bytes_read == 0);
+      }
+    }
+
+    WHEN("reading with a null buffer")
+    {
+      THEN("the system panics")
+      {
+        REQUIRE_THROWS_AS(kernel::devices::block_device_utils::read(device, nullptr, 0, 512), kernel::tests::cpu::halt);
+      }
+    }
+  }
+}
+
+SCENARIO("writing to a block device using block_device_utils", "[devices][block_device_utils]")
+{
+  GIVEN("a block device")
+  {
+    auto const block_size = 512;
+    auto device =
+        kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", block_size, 2 * block_size);
+
+    WHEN("writing to the block device using block_device_utils")
+    {
+      kstd::vector<uint8_t> write_buffer(block_size);
+      for (size_t i = 0; i < write_buffer.size(); ++i)
+      {
+        write_buffer[i] = static_cast<uint8_t>(i % 256);
+      }
+
+      auto bytes_written =
+          kernel::devices::block_device_utils::write(device, write_buffer.data(), 0, write_buffer.size());
+
+      THEN("the correct number of bytes is written")
+      {
+        REQUIRE(bytes_written == write_buffer.size());
+      }
+
+      THEN("the data written matches the data read back from the block device")
+      {
+        kstd::vector<uint8_t> read_buffer(block_size);
+        device->read_block(0, read_buffer.data());
+        REQUIRE(read_buffer == write_buffer);
+      }
+    }
+
+    WHEN("writing over block boundaries")
+    {
+      kstd::vector<uint8_t> write_buffer(2 * block_size);
+      for (size_t i = 0; i < write_buffer.size(); ++i)
+      {
+        write_buffer[i] = static_cast<uint8_t>(i % 256);
+      }
+
+      auto bytes_written =
+          kernel::devices::block_device_utils::write(device, write_buffer.data(), 256, write_buffer.size());
+
+      THEN("the correct number of bytes is written")
+      {
+        REQUIRE(bytes_written == 1.5 * block_size);
+      }
+
+      THEN("the data written matches the data read back from the block device across block boundaries")
+      {
+        kstd::vector<uint8_t> read_buffer(2 * block_size);
+        auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 256, 2 * block_size);
+
+        for (size_t i = 0; i < bytes_read; ++i)
+        {
+          REQUIRE(read_buffer[i] == write_buffer[i]);
+        }
+      }
+    }
+
+    WHEN("writing beyond the device capacity")
+    {
+      kstd::vector<uint8_t> write_buffer(block_size);
+      auto bytes_written =
+          kernel::devices::block_device_utils::write(device, write_buffer.data(), 1024, write_buffer.size());
+
+      THEN("no bytes are written")
+      {
+        REQUIRE(bytes_written == 0);
+      }
+    }
+
+    WHEN("writing nothing")
+    {
+      kstd::vector<uint8_t> write_buffer(block_size);
+      auto bytes_written = kernel::devices::block_device_utils::write(device, write_buffer.data(), 0, 0);
+
+      THEN("no bytes are written")
+      {
+        REQUIRE(bytes_written == 0);
+      }
+    }
+
+    WHEN("writing with a null buffer")
+    {
+      THEN("the system panics")
+      {
+        REQUIRE_THROWS_AS(kernel::devices::block_device_utils::write(device, nullptr, 0, block_size),
+                          kernel::tests::cpu::halt);
+      }
+    }
+  }
+}
+
+SCENARIO("block_device_utils with a non-block device", "[devices][block_device_utils]")
+{
+  GIVEN("a non-block device")
+  {
+    auto device = kstd::make_shared<kernel::tests::devices::character_device>(0, 0, "test_character_device");
+
+    WHEN("attempting to read from the non-block device using block_device_utils")
+    {
+      kstd::vector<uint8_t> read_buffer(512);
+      THEN("the system panics")
+      {
+        REQUIRE_THROWS_AS(kernel::devices::block_device_utils::read(device, read_buffer.data(), 0, read_buffer.size()),
+                          kernel::tests::cpu::halt);
+      }
+    }
+
+    WHEN("attempting to write to the non-block device using block_device_utils")
+    {
+      kstd::vector<uint8_t> write_buffer(512);
+      THEN("the system panics")
+      {
+        REQUIRE_THROWS_AS(
+            kernel::devices::block_device_utils::write(device, write_buffer.data(), 0, write_buffer.size()),
+            kernel::tests::cpu::halt);
+      }
+    }
+  }
+}
diff --git a/kernel/src/devices/root_bus.cpp b/kernel/src/devices/root_bus.cpp
new file mode 100644
index 0000000..1b754f2
--- /dev/null
+++ b/kernel/src/devices/root_bus.cpp
@@ -0,0 +1,12 @@
+#include <kernel/devices/root_bus.hpp>
+
+#include <kapi/devices.hpp>
+
+namespace kernel::devices
+{
+
+  root_bus::root_bus()
+      : kapi::devices::bus{0, 0, "system"}
+  {}
+
+}  // namespace kernel::devices
\ No newline at end of file
diff --git a/kernel/src/devices/storage/controller.cpp b/kernel/src/devices/storage/controller.cpp
new file mode 100644
index 0000000..171b918
--- /dev/null
+++ b/kernel/src/devices/storage/controller.cpp
@@ -0,0 +1,44 @@
+#include <kernel/devices/storage/controller.hpp>
+
+#include <kapi/devices/device.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+
+namespace kernel::devices::storage
+{
+  auto controller::set_ids(size_t major, size_t minors_per_dev) -> void
+  {
+    m_major = major;
+    m_minors_per_device = minors_per_dev;
+  }
+
+  auto controller::major() const -> size_t
+  {
+    return m_major;
+  }
+
+  auto controller::device_by_minor(size_t minor) const -> kstd::shared_ptr<kapi::devices::device>
+  {
+    auto it = std::ranges::find_if(m_devices, [minor](auto const & device) { return device->minor() == minor; });
+
+    if (it != m_devices.end())
+    {
+      return *it;
+    }
+    return nullptr;
+  }
+
+  auto controller::devices_count() const -> size_t
+  {
+    return m_devices.size();
+  }
+
+  auto controller::all_devices() const -> kstd::vector<kstd::shared_ptr<kapi::devices::device>> const &
+  {
+    return m_devices;
+  }
+}  // namespace kernel::devices::storage
\ No newline at end of file
diff --git a/kernel/src/devices/storage/management.cpp b/kernel/src/devices/storage/management.cpp
new file mode 100644
index 0000000..06efc27
--- /dev/null
+++ b/kernel/src/devices/storage/management.cpp
@@ -0,0 +1,95 @@
+#include <kernel/devices/storage/management.hpp>
+
+#include <kernel/devices/storage/controller.hpp>
+#include <kernel/devices/storage/ram_disk/controller.hpp>
+
+#include <kapi/boot_modules.hpp>
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+#include <optional>
+#include <ranges>
+
+namespace
+{
+  constexpr size_t static minors_per_device = 16;
+  constexpr size_t static start_major = 1;
+  constinit size_t static next_free_major = start_major;
+
+  constinit auto static storage_management = std::optional<kernel::devices::storage::management>{};
+}  // namespace
+
+namespace kernel::devices::storage
+{
+  auto management::init() -> void
+  {
+    if (storage_management)
+    {
+      kapi::system::panic("[DEVICES] Storage management has already been initialized.");
+    }
+    storage_management.emplace(management{});
+
+    auto ram_disk_controller = kstd::make_shared<ram_disk::controller>(&kapi::boot_modules::get_boot_module_registry());
+    storage_management->add_controller(ram_disk_controller);
+
+    std::ranges::for_each(storage_management->m_controllers, [](auto controller) { controller->probe(); });
+  }
+
+  auto management::get() -> management &
+  {
+    if (!storage_management)
+    {
+      kapi::system::panic("[DEVICES] Storage management has not been initialized.");
+    }
+
+    return *storage_management;
+  }
+
+  auto management::add_controller(kstd::shared_ptr<controller> const & controller) -> void
+  {
+    controller->set_ids(next_free_major++, minors_per_device);
+    m_controllers.push_back(controller);
+  }
+
+  auto management::all_controllers() const -> kstd::vector<kstd::shared_ptr<controller>> const &
+  {
+    return m_controllers;
+  }
+
+  auto management::device_by_major_minor(size_t major, size_t minor) -> kstd::shared_ptr<kapi::devices::device>
+  {
+    auto found = std::ranges::find_if(m_controllers, [=](auto const & controller) {
+      if (controller != nullptr && controller->major() == major)
+      {
+        return controller->device_by_minor(minor) != nullptr;
+      }
+      return false;
+    });
+
+    if (found != std::ranges::cend(m_controllers))
+    {
+      return found->get()->device_by_minor(minor);
+    }
+
+    return nullptr;
+  }
+
+  auto management::determine_boot_device() -> kstd::shared_ptr<kapi::devices::device>
+  {
+    return device_by_major_minor(start_major, 0);
+  }
+}  // namespace kernel::devices::storage
+
+namespace kernel::tests::devices::storage::management
+{
+  auto deinit() -> void
+  {
+    storage_management.reset();
+    next_free_major = start_major;
+  }
+}  // namespace kernel::tests::devices::storage::management
diff --git a/kernel/src/devices/storage/ram_disk/controller.cpp b/kernel/src/devices/storage/ram_disk/controller.cpp
new file mode 100644
index 0000000..30441fa
--- /dev/null
+++ b/kernel/src/devices/storage/ram_disk/controller.cpp
@@ -0,0 +1,27 @@
+#include <kernel/devices/storage/ram_disk/controller.hpp>
+
+#include <kernel/devices/storage/ram_disk/device.hpp>
+
+#include <kapi/boot_module/boot_module_registry.hpp>
+
+#include <kstd/memory>
+
+#include <algorithm>
+#include <cstddef>
+
+namespace kernel::devices::storage::ram_disk
+{
+  controller::controller(kapi::boot_modules::boot_module_registry const * registry)
+      : m_boot_module_registry(registry)
+  {}
+
+  auto controller::probe() -> void
+  {
+    size_t current_device_index = 0;
+
+    std::ranges::for_each(*m_boot_module_registry, [this, &current_device_index](auto const & module) {
+      auto const minor = current_device_index++ * m_minors_per_device;
+      m_devices.push_back(kstd::make_shared<device>(module, m_major, minor));
+    });
+  }
+}  // namespace kernel::devices::storage::ram_disk
\ No newline at end of file
diff --git a/kernel/src/devices/storage/ram_disk/device.cpp b/kernel/src/devices/storage/ram_disk/device.cpp
new file mode 100644
index 0000000..1557204
--- /dev/null
+++ b/kernel/src/devices/storage/ram_disk/device.cpp
@@ -0,0 +1,71 @@
+#include <kernel/devices/storage/ram_disk/device.hpp>
+
+#include <kernel/devices/block_device.hpp>
+
+#include <kapi/boot_module/boot_module.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/cstring>
+#include <kstd/string>
+
+#include <cstddef>
+
+namespace kernel::devices::storage::ram_disk
+{
+  namespace
+  {
+    constexpr size_t ram_disk_block_size = 512uz;
+  }  // namespace
+
+  device::device(kapi::boot_modules::boot_module const & module, size_t major, size_t minor)
+      : block_device(major, minor, "ram" + kstd::to_string(minor), ram_disk_block_size)
+      , m_boot_module(module)
+  {}
+
+  auto device::init() -> bool
+  {
+    return m_boot_module.start_address.raw() != 0 && m_boot_module.size > 0;
+  }
+
+  auto device::read_block(size_t block_index, void * buffer) const -> void
+  {
+    if (buffer == nullptr)
+    {
+      kapi::system::panic("[RAM DISK DEVICE] read_block called with null buffer.");
+    }
+
+    auto const info = calculate_transfer(block_index);
+
+    if (info.to_transfer > 0)
+    {
+      auto const src = static_cast<std::byte const *>(m_boot_module.start_address) + info.offset;
+      kstd::libc::memcpy(buffer, src, info.to_transfer);
+    }
+
+    if (info.remainder > 0)
+    {
+      kstd::libc::memset(static_cast<std::byte *>(buffer) + info.to_transfer, 0, info.remainder);
+    }
+  }
+
+  auto device::write_block(size_t block_index, void const * buffer) -> void
+  {
+    if (buffer == nullptr)
+    {
+      kapi::system::panic("[RAM DISK DEVICE] write_block called with null buffer.");
+    }
+
+    auto const info = calculate_transfer(block_index);
+
+    if (info.to_transfer > 0)
+    {
+      auto const dest = static_cast<std::byte *>(m_boot_module.start_address) + info.offset;
+      kstd::libc::memcpy(dest, buffer, info.to_transfer);
+    }
+  }
+
+  auto device::size() const -> size_t
+  {
+    return m_boot_module.size;
+  }
+}  // namespace kernel::devices::storage::ram_disk
\ No newline at end of file
diff --git a/kernel/src/devices/storage/ram_disk/device.tests.cpp b/kernel/src/devices/storage/ram_disk/device.tests.cpp
new file mode 100644
index 0000000..d0fab76
--- /dev/null
+++ b/kernel/src/devices/storage/ram_disk/device.tests.cpp
@@ -0,0 +1,116 @@
+#include <kernel/devices/storage/ram_disk/device.hpp>
+
+#include <kapi/boot_module/boot_module.hpp>
+#include <kapi/memory.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers.hpp>
+#include <catch2/matchers/catch_matchers_range_equals.hpp>
+
+#include <cstddef>
+#include <ranges>
+#include <stdexcept>
+#include <vector>
+
+SCENARIO("RAM Disk Device Construction and Initialization", "[ram_disk_device]")
+{
+  GIVEN("an empty boot module")
+  {
+    kapi::boot_modules::boot_module boot_module{};
+    boot_module.start_address = kapi::memory::linear_address{nullptr};
+    boot_module.size = 0;
+
+    WHEN("constructing the device")
+    {
+      kernel::devices::storage::ram_disk::device device{boot_module, 0, 0};
+
+      THEN("init return false")
+      {
+        REQUIRE_FALSE(device.init());
+      }
+    }
+  }
+
+  GIVEN("a boot module with a valid start address and size")
+  {
+    kapi::boot_modules::boot_module boot_module{};
+    boot_module.start_address = kapi::memory::linear_address{reinterpret_cast<std::byte *>(0x1000)};
+    boot_module.size = 512;
+
+    WHEN("constructing the device")
+    {
+      kernel::devices::storage::ram_disk::device device{boot_module, 0, 0};
+
+      THEN("init return true")
+      {
+        REQUIRE(device.init());
+      }
+    }
+  }
+}
+
+SCENARIO("RAM Disk Device Read and Write", "[ram_disk_device]")
+{
+  GIVEN("a device initialized with a valid boot module")
+  {
+    auto storage = std::vector{4096, std::byte{0xff}};
+    auto module =
+        kapi::boot_modules::boot_module{"test_module", kapi::memory::linear_address{storage.data()}, storage.size()};
+    auto device = kernel::devices::storage::ram_disk::device{module, 0, 0};
+    REQUIRE(device.init());
+
+    WHEN("reading a full block from the device")
+    {
+      auto buffer = std::vector<std::byte>(device.block_size());
+      device.read_block(0, buffer.data());
+
+      THEN("the buffer is filled with the module data")
+      {
+        REQUIRE_THAT(buffer, Catch::Matchers::RangeEquals(std::views::take(storage, device.block_size())));
+      }
+    }
+
+    WHEN("reading from a block index beyond the module size")
+    {
+      auto buffer = std::vector<std::byte>(device.block_size());
+      device.read_block(10, buffer.data());
+
+      THEN("the buffer is filled with zeros")
+      {
+        REQUIRE_THAT(buffer, Catch::Matchers::RangeEquals(std::vector<std::byte>(device.block_size(), std::byte{0})));
+      }
+    }
+
+    WHEN("reading into a null buffer")
+    {
+      REQUIRE_THROWS_AS(device.read_block(0, nullptr), std::runtime_error);
+    }
+
+    WHEN("writing to a full block")
+    {
+      auto buffer = std::vector<std::byte>(device.block_size(), std::byte{0x01});
+      device.write_block(0, buffer.data());
+
+      THEN("the module data is updated")
+      {
+        REQUIRE_THAT(std::views::take(storage, device.block_size()), Catch::Matchers::RangeEquals(buffer));
+      }
+    }
+
+    WHEN("writing to a block index beyond the module size")
+    {
+      auto buffer = std::vector<std::byte>(device.block_size(), std::byte{0x01});
+      device.write_block(10, buffer.data());
+
+      THEN("the module data is not updated")
+      {
+        REQUIRE_THAT(storage, Catch::Matchers::RangeEquals(std::vector{4096, std::byte{0xff}}));
+      }
+    }
+
+    WHEN("writing from a null buffer")
+    {
+      REQUIRE_THROWS_AS(device.write_block(0, nullptr), std::runtime_error);
+    }
+  }
+}
\ No newline at end of file