From 5ce5c28e0f0f034cb7c704f08e59089ef303ff7e Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Sat, 1 Aug 2026 00:33:56 +0200
Subject: kapi: add automatic driver registration

---
 kernel/kernel/drivers/init.cpp             | 31 +++++++++++++++++++++++-------
 kernel/kernel/drivers/pseudo/null.cpp      | 18 +++++++++++++++++
 kernel/kernel/drivers/pseudo/zero.cpp      | 17 ++++++++++++++++
 kernel/kernel/drivers/storage/ram_disk.cpp | 17 ++++++++++++++++
 4 files changed, 76 insertions(+), 7 deletions(-)

(limited to 'kernel')

diff --git a/kernel/kernel/drivers/init.cpp b/kernel/kernel/drivers/init.cpp
index cd196fa8..97d8f0bc 100644
--- a/kernel/kernel/drivers/init.cpp
+++ b/kernel/kernel/drivers/init.cpp
@@ -1,25 +1,42 @@
 #include <kernel/drivers/init.hpp>
 
-#include <kernel/drivers/pseudo/null.hpp>
-#include <kernel/drivers/pseudo/zero.hpp>
-#include <kernel/drivers/storage/ram_disk.hpp>
-
+#include <kapi/devices.hpp>
 #include <kapi/devices/driver_registry.hpp>
 
 #include <kstd/memory.hpp>
+#include <kstd/print.hpp>
+
+#include <ranges>
+#include <span>
 
 namespace kernel::drivers
 {
 
+  extern "C"
+  {
+    // We need to suppress clang-tidy linting warnings here, since these symbols are generated by the linker and we
+    // cannot choose their names, unless we wanted to extend the linker script needlessly.
+    // NOLINTBEGIN(readability-identifier-naming)
+    extern kstd::observer_ptr<kapi::devices::driver_descriptor> const __start_kernel_drivers;
+    extern kstd::observer_ptr<kapi::devices::driver_descriptor> const __stop_kernel_drivers;
+    // NOLINTEND(readability-identifier-naming)
+  }
+
   auto init() -> void
   {
     kapi::devices::driver_registry::init();
 
     auto & registry = kapi::devices::driver_registry::get();
 
-    registry.add(kstd::make_shared<kernel::drivers::pseudo::null>());
-    registry.add(kstd::make_shared<kernel::drivers::pseudo::zero>());
-    registry.add(kstd::make_shared<kernel::drivers::storage::ram_disk>());
+    auto descriptors = std::span{&__start_kernel_drivers, &__stop_kernel_drivers} |  //
+                       std::views::filter([](auto p) { return p != nullptr; });
+
+    for (auto driver : descriptors)
+    {
+      auto instance = driver->make_instance();
+      kstd::println("[OS:DRV] registering driver '{}' ({})", instance->name(), driver->name());
+      registry.add(driver->make_instance());
+    }
   }
 
 }  // namespace kernel::drivers
\ No newline at end of file
diff --git a/kernel/kernel/drivers/pseudo/null.cpp b/kernel/kernel/drivers/pseudo/null.cpp
index d0df9000..4995cc25 100644
--- a/kernel/kernel/drivers/pseudo/null.cpp
+++ b/kernel/kernel/drivers/pseudo/null.cpp
@@ -4,6 +4,7 @@
 #include <kernel/filesystem/reserved_numbers.hpp>
 
 #include <kapi/devices.hpp>
+#include <kapi/devices/driver_registry.hpp>
 #include <kapi/filesystem.hpp>
 
 #include <kstd/memory.hpp>
@@ -26,6 +27,23 @@ namespace kernel::drivers::pseudo
 
   namespace
   {
+    struct descriptor final : kapi::devices::driver_descriptor
+    {
+    public:
+      [[nodiscard("")]] auto name() const noexcept -> std::string_view override
+      {
+        return "dev_null";
+      }
+
+      [[nodiscard("")]] auto make_instance() const -> kstd::shared_ptr<kapi::devices::driver> override
+      {
+        return kstd::make_shared<null>();
+      }
+    };
+
+    [[gnu::used]]
+    constexpr auto registration = kapi::devices::kernel_driver<descriptor>{};
+
     struct null_node final : kapi::filesystem::character_special_file
     {
     public:
diff --git a/kernel/kernel/drivers/pseudo/zero.cpp b/kernel/kernel/drivers/pseudo/zero.cpp
index 550a97ff..724ff25c 100644
--- a/kernel/kernel/drivers/pseudo/zero.cpp
+++ b/kernel/kernel/drivers/pseudo/zero.cpp
@@ -27,6 +27,23 @@ namespace kernel::drivers::pseudo
 
   namespace
   {
+    struct descriptor final : kapi::devices::driver_descriptor
+    {
+    public:
+      [[nodiscard("")]] auto name() const noexcept -> std::string_view override
+      {
+        return "dev_zero";
+      }
+
+      [[nodiscard("")]] auto make_instance() const -> kstd::shared_ptr<kapi::devices::driver> override
+      {
+        return kstd::make_shared<zero>();
+      }
+    };
+
+    [[gnu::used]]
+    constexpr auto registration = kapi::devices::kernel_driver<descriptor>{};
+
     struct zero_node final : kapi::filesystem::character_special_file
     {
     public:
diff --git a/kernel/kernel/drivers/storage/ram_disk.cpp b/kernel/kernel/drivers/storage/ram_disk.cpp
index 987f4bbc..f7e73cd1 100644
--- a/kernel/kernel/drivers/storage/ram_disk.cpp
+++ b/kernel/kernel/drivers/storage/ram_disk.cpp
@@ -31,6 +31,23 @@ namespace kernel::drivers::storage
   {
     constexpr auto default_block_size = 512_B;
 
+    struct descriptor final : kapi::devices::driver_descriptor
+    {
+    public:
+      [[nodiscard("")]] auto name() const noexcept -> std::string_view override
+      {
+        return "ram_disk";
+      }
+
+      [[nodiscard("")]] auto make_instance() const -> kstd::shared_ptr<kapi::devices::driver> override
+      {
+        return kstd::make_shared<ram_disk>();
+      }
+    };
+
+    [[gnu::used]]
+    constexpr auto registration = kapi::devices::kernel_driver<descriptor>{};
+
     struct block_node final : kapi::filesystem::block_special_file
     {
       explicit block_node(kapi::boot_modules::module const & module)
-- 
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