Add the beginning of support for kernel graphics to bootloader.

* Load a font file off disk to pass to kernel
* Expose a framebuffer to the kernel
* Currently the kernel just paints the screen red

src/boot/loader.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <efi.h>
+#include <stddef.h>
 
 #ifndef KERNEL_PHYS_ADDRESS
 #define KERNEL_PHYS_ADDRESS 0x100000
@@ -13,8 +14,12 @@
 #define KERNEL_MEMTYPE 0x80000000
 #endif
 
+#ifndef KERNEL_FONT_MEMTYPE
+#define KERNEL_FONT_MEMTYPE 0x80000001
+#endif
+
 #ifndef KERNEL_DATA_MEMTYPE
-#define KERNEL_DATA_MEMTYPE 0x80000001
+#define KERNEL_DATA_MEMTYPE 0x80000002
 #endif
 
 #ifndef KERNEL_DATA_PAGES
@@ -25,9 +30,19 @@
 #define KERNEL_FILENAME L"kernel.bin"
 #endif
 
-EFI_STATUS loader_load_kernel(
-	EFI_BOOT_SERVICES *bootsvc,
-	void **kernel_image,
-	uint64_t *kernel_length,
-	void **kernel_data,
-	uint64_t *data_length);
+#ifndef KERNEL_FONT
+#define KERNEL_FONT L"screenfont.psf"
+#endif
+
+struct loader_data {
+	void *kernel_image;
+	size_t kernel_image_length;
+
+	void *kernel_data;
+	size_t kernel_data_length;
+
+	void *screen_font;
+	size_t screen_font_length;
+};
+
+EFI_STATUS loader_load_kernel(EFI_BOOT_SERVICES *bootsvc, struct loader_data *data);