From 354339e8312758162bca93d1997b1795231ba221 Mon Sep 17 00:00:00 2001
From: Tomas <kubecekt@gmail.com>
Date: Mon, 14 Apr 2025 20:15:05 +0200
Subject: [PATCH] Began using Limine as a bootloader instead of QEMUs mb1
 bootloader.

---
 .gitignore          |  1 +
 README              | 10 ++++++++++
 TODO                |  8 +++++---
 defaults.mk         |  4 ++++
 docs/filesys.txt    | 17 +++++++++++++++++
 kernel/makefile     |  2 +-
 kernel/src/gdt.c    |  2 ++
 kernel/src/idt.c    |  3 +++
 kernel/src/isr.c    |  2 ++
 kernel/src/paging.c |  2 ++
 makefile            | 41 +++++++++++++++++++++++++++++++++++------
 11 files changed, 82 insertions(+), 10 deletions(-)
 create mode 100644 docs/filesys.txt

diff --git a/.gitignore b/.gitignore
index 55d593a..131199e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,7 @@
 *.sys
 *.dtb
 *~
+sysroot
 
 # Local
 DS_Store
diff --git a/README b/README
index e81e2d2..d35394f 100644
--- a/README
+++ b/README
@@ -24,5 +24,15 @@ Features
 * Virtual memory manager
 * System calls
 
+Dependencies
+------------
+* binutils that can target i386-elf
+* sfdisk
+* GCC that can target i386-elf
+* Limine
+* make
+* Mtools
+* NASM
+
 Old Version: https://github.com/Tom-on64/old-kern
 
diff --git a/TODO b/TODO
index 9bf771a..597f102 100644
--- a/TODO
+++ b/TODO
@@ -45,12 +45,13 @@ Todos
     - [ ] dup()
     - [ ] pipe()
   - [ ] Memory
-    - [ ] Physical MM
-    - [ ] Virtual MM
-    - [ ] Paging
+    - [x] Physical MM
+    - [x] Virtual MM
+    - [x] Paging
     - [ ] Kernel Heap
   - [ ] Drivers
     - [x] tty
+    - [ ] ATA PIO
     - [x] serial
     - [ ] Timer
     - [ ] VFS
@@ -102,5 +103,6 @@ Todos
   - [ ] doom
 
 - [ ] Write an OS in kern.
+- [ ] Paradox
 - [ ] Finish all the TODOs
 
diff --git a/defaults.mk b/defaults.mk
index 86110d7..5b7e0c7 100644
--- a/defaults.mk
+++ b/defaults.mk
@@ -16,6 +16,10 @@ LDFLAGS = -melf_i386
 ASFLAGS = 
 ARFLAGS =
 
+# Disk image
+IMG_NAME = kern.img
+IMG_SIZE = 256	# 256MB
+
 # Qemu
 AUDIODEV = pipewire
 
diff --git a/docs/filesys.txt b/docs/filesys.txt
new file mode 100644
index 0000000..ea0a32b
--- /dev/null
+++ b/docs/filesys.txt
@@ -0,0 +1,17 @@
+Filesystem
+==========
+
+Here's how the filesystem is layed out:
+	/
+	|- bin/		Administrator binaries
+	|- boot/	Files required to boot, like the kernel
+	|- dev/		Device nodes
+	|- etc/		Configuration files
+	|- lib/		Shared libraties
+	|- sbin/	System binaries
+	|- usr/		Regular user stuff
+	|  |- bin/	User binaries
+	|  |- include/	Headers
+	|  '- share/	"Constant" stuff, same across systems
+	'- tmp/		Temporary filesystem, cleared on reboot
+
diff --git a/kernel/makefile b/kernel/makefile
index 2f2e59d..9466b40 100644
--- a/kernel/makefile
+++ b/kernel/makefile
@@ -7,7 +7,7 @@ SRCS_C = $(wildcard $(SRC)/*.c)
 SRCS_S = $(wildcard $(SRC)/*.s)
 OBJS_C = $(patsubst $(SRC)/%.c, $(BIN)/%.c.o, $(SRCS_C))
 OBJS_S = $(patsubst $(SRC)/%.s, $(BIN)/%.s.o, $(SRCS_S))
-OUT = ./kernel.elf
+OUT = $(SYSROOT)/boot/kernel.elf
 LINKER = ./linker.ld
 
 .PHONY: all clean
diff --git a/kernel/src/gdt.c b/kernel/src/gdt.c
index be24365..47a415b 100644
--- a/kernel/src/gdt.c
+++ b/kernel/src/gdt.c
@@ -61,6 +61,8 @@ int gdt_init(void) {
 	gdt_reload();
 	tss_reload();
 
+	debugf("[gdt] GDT loaded.\n");
+
 	return 0;
 }
 
diff --git a/kernel/src/idt.c b/kernel/src/idt.c
index 2c5b204..4d18fdb 100644
--- a/kernel/src/idt.c
+++ b/kernel/src/idt.c
@@ -22,7 +22,10 @@ int idt_init(void) {
 	idtp.limit = sizeof(idt);
 	idtp.base = (uint32_t)&idt;
 
+	// Load IDT instruction
 	__asm__ volatile ("lidt %0" : : "m"(idtp));
+
+	debugf("[idt] IDT initalized.\n");
 	return 0;
 }
 
diff --git a/kernel/src/isr.c b/kernel/src/isr.c
index 2089a57..f4afa33 100644
--- a/kernel/src/isr.c
+++ b/kernel/src/isr.c
@@ -70,6 +70,8 @@ int isr_init(void) {
 
 	// Let interrupts interrupt
 	__asm__ volatile ("sti");
+
+	debugf("[isr] ISR initialized.\n");
 	return 0;
 }
 
diff --git a/kernel/src/paging.c b/kernel/src/paging.c
index 9c5a1fd..a709980 100644
--- a/kernel/src/paging.c
+++ b/kernel/src/paging.c
@@ -43,6 +43,8 @@ int pag_init(void) {
 	memset(pagedirs, 0, PAGE_SIZE * PAGE_DIR_COUNT);
 	memset(pagedirUsed, 0, PAGE_DIR_COUNT);
 
+	debugf("[pag] Paging initalized.\n");
+
 	return 0;
 }
 
diff --git a/makefile b/makefile
index f2df9be..1f66d39 100644
--- a/makefile
+++ b/makefile
@@ -1,22 +1,51 @@
 include defaults.mk
 
-KERNEL = ./kernel
+TARGET = ./$(IMG_NAME)
+OFFSET = 1048576
+SYSROOT = ./sysroot
 
+# Modules
+KERNEL = ./kernel
 MODULES = $(KERNEL)
 
+# Treat these targets as names and not files
 .PHONY: all clean $(MODULES) qemu
 
-all: $(MODULES)
+all: $(TARGET)
+$(TARGET): $(SYSROOT) $(MODULES)
+	cp /usr/share/limine/limine-bios.sys $(SYSROOT)/boot
+	echo -e 'timeout: 5\n\n/kern.\n\tprotocol: multiboot1\n\tpath: boot():/boot/kernel.elf\n' > $(SYSROOT)/boot/limine.conf
+	dd if=/dev/zero of=$(TARGET) bs=1M count=$(IMG_SIZE)
+	echo ',,c,*' | sfdisk $(TARGET) >/dev/null
+	mformat -F -i $(TARGET)@@$(OFFSET) ::/
+	mcopy -i $(TARGET)@@$(OFFSET) $(SYSROOT)/* ::
+	limine bios-install $(TARGET)
+	
+# Build out base directory structure
+$(SYSROOT):
+	@mkdir $(SYSROOT)
+	@mkdir $(SYSROOT)/bin
+	@mkdir $(SYSROOT)/boot
+	@mkdir $(SYSROOT)/dev
+	@mkdir $(SYSROOT)/etc
+	@mkdir $(SYSROOT)/lib
+	@mkdir $(SYSROOT)/sbin
+	@mkdir $(SYSROOT)/usr
+	@mkdir $(SYSROOT)/usr/bin
+	@mkdir $(SYSROOT)/usr/include
+	@mkdir $(SYSROOT)/usr/share
+	@mkdir $(SYSROOT)/tmp
+
 $(MODULES):
-	$(MAKE) -C $@
+	$(MAKE) -C $@ SYSROOT=$(abspath $(SYSROOT))
 
 clean:
-	rm -f $(IMG)
+	rm -f $(TARGET)
+	rm -fr $(SYSROOT)
 	for m in $(MODULES); do $(MAKE) -C $$m clean; done
 
 qemu:
-	qemu-system-x86_64\
-		-kernel ./kernel/kernel.elf\
+	qemu-system-x86_64 $(TARGET)\
 		-m 256M -accel tcg -monitor stdio -net none\
 		-rtc base=localtime,clock=host,driftfix=slew\
 		-audiodev $(AUDIODEV),id=audio0 -machine pcspk-audiodev=audio0