Update kernel args to be module-based

- The old kernel_args structure is now mostly represented as a series of
  'modules' or memory ranges, tagged with a type. An arbitrary number
  can be passed to the kernel
- Update bootloader to allocate space for the args header and 10 module
  descriptors

src/include/kernel_args.h

@@ -4,44 +4,59 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#define DATA_HEADER_MAGIC     0x600dda7a
-#define DATA_HEADER_VERSION   1
+namespace kernel {
+namespace args {
 
-#define JSIX_FLAG_DEBUG    0x00000001
+constexpr uint32_t magic = 0x600dda7a;
+constexpr uint16_t version = 1;
+
+enum class flags : uint32_t
+{
+	debug = 0x00000001
+};
+
+enum class type : uint32_t {
+	unknown,
+
+	kernel,
+	initrd,
+
+	memory_map,
+	framebuffer,
+
+	max
+};
+
+enum class mode : uint8_t {
+	normal,
+	debug
+};
 
 #pragma pack(push, 1)
-struct kernel_args {
+struct module {
+	void *location;
+	size_t size;
+	type type;
+	flags flags;
+};
+
+struct header {
 	uint32_t magic;
 	uint16_t version;
-	uint16_t length;
 
-	uint16_t _reserved0;
-	uint16_t scratch_pages;
-	uint32_t flags;
+	mode mode;
 
-	void *initrd;
-	size_t initrd_length;
+	uint8_t _reserved0;
 
-	void *data;
-	size_t data_length;
-
-	void *memory_map;
-	size_t memory_map_length;
-	size_t memory_map_desc_size;
-
-	void *runtime;
-
-	void *acpi_table;
-
-	void *frame_buffer;
-	size_t frame_buffer_length;
-	uint32_t hres;
-	uint32_t vres;
-	uint32_t rmask;
-	uint32_t gmask;
-	uint32_t bmask;
 	uint32_t _reserved1;
+	uint32_t num_modules;
+	module *modules;
+
+	void *runtime_services;
+	void *acpi_table;
 }
 __attribute__((aligned(alignof(max_align_t))));
 #pragma pack(pop)
 
+} // namespace args
+} // namespace kernel