From 3e80780859c4cbe5223ca4329bfd6176f5c2c879 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Mon, 15 Aug 2022 20:48:23 +0200
Subject: kernel: port to multiboot2

---
 src/kernel/arch/amd64/boot.c | 56 ++++++++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 23 deletions(-)

(limited to 'src/kernel/arch/amd64/boot.c')

diff --git a/src/kernel/arch/amd64/boot.c b/src/kernel/arch/amd64/boot.c
index 1041c7d..a03c21d 100644
--- a/src/kernel/arch/amd64/boot.c
+++ b/src/kernel/arch/amd64/boot.c
@@ -6,25 +6,27 @@
 #include <kernel/arch/amd64/driver/video.h>
 #include <kernel/arch/amd64/interrupts/idt.h>
 #include <kernel/arch/amd64/interrupts/irq.h>
-#include <kernel/arch/amd64/multiboot.h>
+#include <kernel/arch/amd64/3rdparty/multiboot2.h>
 #include <kernel/arch/amd64/tty/tty.h>
 #include <kernel/arch/generic.h>
 #include <kernel/main.h>
 #include <kernel/mem/alloc.h>
 #include <kernel/panic.h>
 
-static void find_init(struct multiboot_info *multiboot, struct kmain_info *info)
-{
-	struct multiboot_mod *module = (void*)(long)multiboot->mods;
-	if (multiboot->mods_count != 1) {
-		kprintf("unexpected amount of multiboot modules\n");
-		panic_invalid_state();
+static void *mbi_tag(void *mbi, uint32_t type) {
+	struct multiboot_tag *tag;
+	for (tag = mbi + 8;
+		tag->type != MULTIBOOT_TAG_TYPE_END;
+		tag = ((void*)tag) + ((tag->size + 7) & ~7))
+	{
+		if (tag->type == type)
+			return tag;
 	}
-	info->init.at   = (void*)(long)module->start;
-	info->init.size = module->end - module->start;
+	kprintf("bootloader didn't pass required tag type %u\n", type);
+	panic_invalid_state();
 }
 
-void kmain_early(struct multiboot_info *multiboot) {
+void kmain_early(void *mbi) {
 	struct kmain_info info;
 	struct fb_info vid;
 
@@ -34,10 +36,27 @@ void kmain_early(struct multiboot_info *multiboot) {
 	kprintf("irq...");
 	irq_init();
 
-	info.memtop = (void*)(long)(multiboot->mem_upper * 1024);
-	find_init(multiboot, &info);
-	info.fb.at   = (void*)multiboot->framebuffer_addr;
-	info.fb.size = multiboot->framebuffer_pitch * multiboot->framebuffer_height;
+	struct multiboot_tag_basic_meminfo *meminfo;
+	meminfo = mbi_tag(mbi, MULTIBOOT_TAG_TYPE_BASIC_MEMINFO);
+	info.memtop = (void*)(long)(meminfo->mem_upper * 1024);
+
+	struct multiboot_tag_framebuffer *framebuf;
+	framebuf = mbi_tag(mbi, MULTIBOOT_TAG_TYPE_FRAMEBUFFER);
+	vid.b      = (void*)framebuf->common.framebuffer_addr;
+	vid.pitch  = framebuf->common.framebuffer_pitch;
+	vid.width  = framebuf->common.framebuffer_width;
+	vid.height = framebuf->common.framebuffer_height;
+	vid.bpp    = framebuf->common.framebuffer_bpp;
+	vid.size   = vid.pitch * vid.height;
+	// TODO framebuffer doesn't need to be part of kmain_info
+	info.fb.at   = vid.b;
+	info.fb.size = vid.size;
+
+	struct multiboot_tag_module *init;
+	init = mbi_tag(mbi, MULTIBOOT_TAG_TYPE_MODULE);
+	info.init.at = (void*)(long)init->mod_start;
+	info.init.size = init->mod_end - init->mod_start;
+
 	kprintf("mem...\n");
 	mem_init(&info);
 
@@ -49,21 +68,12 @@ void kmain_early(struct multiboot_info *multiboot) {
 	kprintf("ata...\n");
 	pata_init();
 
-	vid.b      = (void*)multiboot->framebuffer_addr;
-	vid.pitch  = multiboot->framebuffer_pitch;
-	vid.width  = multiboot->framebuffer_width;
-	vid.height = multiboot->framebuffer_height;
-	vid.bpp    = multiboot->framebuffer_bpp;
-	vid.size   = vid.pitch * vid.height;
-
 	kprintf("kernel %8x -> %8x\n", 0, &_bss_end);
 	kprintf("init   %8x -> %8x\n", info.init.at, info.init.at + info.init.size);
 	kprintf("video  %8x -> %8x\n", vid.b, vid.b + vid.size);
 	kprintf("limit  %8x\n", info.memtop);
-
 	kprintf("framebuffer at 0x%x, %ux%u bpp %u\n", vid.b, vid.width, vid.height, vid.bpp);
 	video_init(vid);
 
-
 	kmain(info);
 }
-- 
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