grub.cfg

@@ -1,4 +1,5 @@
 menuentry "Blank OS" {
-	multiboot /boot/kernel.elf
+	set gfxpayload=1024x768x32
+	multiboot2 /boot/kernel.elf
 	boot
 }

link.ld

@@ -1,28 +1,27 @@
 ENTRY(loader)
 
 SECTIONS {
-  /* Address to load at; 1MB */
+  /* Address to load at; 2MB */
 
-  . = 0x00100000;
+  /*. = 2M;*/
 
-  .__mbHeader : {
-	  *(.__mbHeader)
+  .multiboot_header ALIGN(4K) : {
+  	*(.multiboot_header)
   }
-
   /* Align relevant sections at 4KB  */
 
-  .text ALIGN (0x1000) :
+  .text ALIGN (4K) :
   {
     *(.text)
     *(.rodata)
   }
 
-  .data ALIGN (0x1000) :
+  .data ALIGN (4K) :
   {
     *(.data)
   }
 
-  .bss ALIGN (0x1000) :
+  .bss ALIGN (4K) :
   {
     *(COMMON)
     *(.bss)

src/kernel/kmain.c

@@ -5,6 +5,25 @@
 #include "system.h"
 #include "paging.h"
 #include "../drivers/ata.h"
+#include "../libc/stdint.h" 
+
+typedef struct {
+    uint32_t type;
+    uint32_t size;
+    uint64_t framebuffer_addr;
+    uint32_t framebuffer_pitch;
+    uint32_t framebuffer_width;
+    uint32_t framebuffer_height;
+    uint8_t framebuffer_bpp;
+    uint8_t framebuffer_type;
+    uint16_t reserved;
+} multiboot2_tag_framebuffer;
+
+typedef struct {
+    uint32_t total_size;
+    uint32_t reserved;
+    uint8_t tags[0];
+} multiboot2_info;
 
 char* ascii_title =
 "\n"
@@ -17,10 +36,52 @@ char* ascii_title =
 
 unsigned int g_multiboot_info_address;
 
-void kmain(unsigned int multiboot_info_address)
+void kmain(multiboot2_info *mb_info)
 {
-  g_multiboot_info_address = multiboot_info_address;
 
+	multiboot2_tag_framebuffer *fb_info = NULL;
+
+uint8_t *tags = mb_info->tags;
+    while (1) {
+        uint32_t tag_type = *((uint32_t*) tags);
+        uint32_t tag_size = *((uint32_t*) (tags + 4));
+
+        if (tag_type == 0) break;
+        if (tag_type == 8) {
+            fb_info = (multiboot2_tag_framebuffer*) tags;
+        }
+
+        tags += ((tag_size + 7) & ~7);
+    }
+
+    serial_printf(3, "Framebuffer Address: 0x%x\r\n", fb_info->framebuffer_addr);
+serial_printf(3, "Framebuffer Width: %u\r\n", fb_info->framebuffer_width);
+serial_printf(3, "Framebuffer Height: %u\r\n", fb_info->framebuffer_height);
+serial_printf(3, "Framebuffer Pitch: %u\r\n", fb_info->framebuffer_pitch);
+serial_printf(3, "Framebuffer BPP: %u\r\n", fb_info->framebuffer_bpp);
+
+
+    if (fb_info) {
+	log("Entered fb_info\r\n", 3);
+        uint32_t *framebuffer = (uint32_t *) fb_info->framebuffer_addr;
+        uint32_t width = fb_info->framebuffer_width;
+        uint32_t height = fb_info->framebuffer_height;
+        uint32_t pitch = fb_info->framebuffer_pitch;
+        uint32_t bpp = fb_info->framebuffer_bpp;
+
+        for (uint32_t y = 0; y < 100; y++) {
+            for (uint32_t x = 0; x < 100; x++) {
+                framebuffer[y * (pitch / 4) + x] = 0xFF0000; // Rouge
+            }
+        }
+	log("Drew to framebuffer.\r\n", 3);
+    }
+    puts("This should NOT work.");
+
+    while (1);
+
+
+  /*
   init_serial();
   log("serial connection established\n", 3);
   gdt_install();
@@ -51,4 +112,5 @@ void kmain(unsigned int multiboot_info_address)
   serial_printf(2, "%d\tinitialized keyboard handler", global_ticks); 
   shell_install();
   serial_printf(2, "%d\tstarted system shell", global_ticks); 
+  */
 }

src/kernel/loader.s

@@ -1,19 +1,45 @@
 global loader
 
-section .__mbHeader
+section .multiboot_header
 
-align 0x4
-section .text:
+align 8
 
-MAGIC_NUMBER      equ 0x1BADB002   ; multiboot magic 
-FLAGS             equ 0x0 
-CHECKSUM          equ -MAGIC_NUMBER
-KERNEL_STACK_SIZE equ 4096
+; ASM macros
 
-  dd MAGIC_NUMBER
-  dd FLAGS
+MAGIC_NUMBER      equ 0xe85250d6  ; multiboot2 magic 
+FLAGS             equ 0x0	  ; 32-bit protected mode for i386
+HEADER_LEN	  equ 44 	  ;  Tags=2+2+4+4+4+4+2+2+4=28
+CHECKSUM          equ -(MAGIC_NUMBER + FLAGS + HEADER_LEN)
+
+; Multiboot 2 header, according to specification (16bytes)
+
+  dd MAGIC_NUMBER		; dd = 4 bytes = 32bits = u32
+  dd FLAGS			
+  dd HEADER_LEN
   dd CHECKSUM
 
+; Tags? (28bytes)
+
+; Tag 1 : set graphics mode (only recommended, can be overriden by GRUB)
+
+  dw 5			; 2
+  dw 0			; 2
+  dd 20			; 4
+  dd 1920		; 4
+  dd 1080		; 4
+  dd 32			; 4
+
+; End of tags
+
+  dw 0			; 2
+  ;dw 0			; 2
+  dd 8			; 4
+
+; End of Multiboot 2 header
+
+section .text:
+
+KERNEL_STACK_SIZE equ 4096
 extern kmain
 
 loader: