From 284a012509ce982559a34703b0976551a169e626 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Sat, 9 Dec 2023 17:33:58 +0200
Subject: [PATCH] Kernel: Add framebuffer information to kernel image

---
 kernel/arch/x86_64/boot.S    | 22 ++++++++++++++++++----
 kernel/arch/x86_64/linker.ld |  1 +
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/kernel/arch/x86_64/boot.S b/kernel/arch/x86_64/boot.S
index f2dd6ad4..331cefab 100644
--- a/kernel/arch/x86_64/boot.S
+++ b/kernel/arch/x86_64/boot.S
@@ -2,6 +2,10 @@
 .set PG_READ_WRITE,	1<<1
 .set PG_PAGE_SIZE,	1<<7
 
+.set FB_WIDTH,	800
+.set FB_HEIGHT,	600
+.set FB_BPP,	32
+
 #define KERNEL_OFFSET 0xFFFFFFFF80000000
 #define V2P(vaddr) ((vaddr) - KERNEL_OFFSET)
 
@@ -9,8 +13,8 @@
 
 # multiboot2 header
 .section .multiboot, "aw"
-multiboot2_start:
 	.align 8
+multiboot2_start:
 	.long 0xE85250D6
 	.long 0
 	.long multiboot2_end - multiboot2_start
@@ -21,9 +25,9 @@ multiboot2_start:
 	.short 5
 	.short 0
 	.long 20
-	.long 800
-	.long 600
-	.long 32
+	.long FB_WIDTH
+	.long FB_HEIGHT
+	.long FB_BPP
 
 	# legacy start
 	.align 8
@@ -38,6 +42,16 @@ multiboot2_start:
 	.long 8
 multiboot2_end:
 
+.section .bananboot, "aw"
+	.align 8
+bananboot_start:
+	.long 0xBABAB007
+	.long -(0xBABAB007 + FB_WIDTH + FB_HEIGHT + FB_BPP)
+	.long FB_WIDTH
+	.long FB_HEIGHT
+	.long FB_BPP
+bananboot_end:
+
 .section .bss, "aw", @nobits
  	# Create stack
 	.global g_boot_stack_bottom
diff --git a/kernel/arch/x86_64/linker.ld b/kernel/arch/x86_64/linker.ld
index 14dbf389..e8c3d9d0 100644
--- a/kernel/arch/x86_64/linker.ld
+++ b/kernel/arch/x86_64/linker.ld
@@ -11,6 +11,7 @@ SECTIONS
 	{
 		g_kernel_execute_start = .;
 		*(.multiboot)
+		*(.bananboot)
 		*(.text.*)
 	}
 	.userspace ALIGN(4K) : AT(ADDR(.userspace) - KERNEL_OFFSET)