Kernel debug shell

Reviewed-on: #15

.gitignore

@@ -10,3 +10,7 @@ iso_root
 .gdb_history
 symbols.map
 symbols.S
+*.log
+build/
+compile_commands.json
+.cache/

DOOM.txt

@@ -1,24 +0,0 @@
-up to doom:
-
-- Return from pedicel_main() normally (to idle)
-
-** Checkpoint: ring0 process working
-
-- VFS layer (open/read/write/...) with USTar filesystem (for initrd)
-
-** Checkpoint: files not linked to but accessible by the kernel
-
-- Ring3 memory mappings 
-- Ring3 privilege switch
-
-** Checkpoint: welcome to userland
-
-- Syscall interface
-- Implement syscalls needed for doom
-
-** Checkpoint: can run simple programs, ring 3, loaded from filesystem 
-
-- Properly handle the keyboard interrupt (keyboard buffer)
-- Port DOOMgeneric (few functions with Framebuffer/ticks/etc.)
-
-** Achievement: It runs doom!

Makefile

@@ -1,28 +1,41 @@
-SOURCES = src/debug/panic.c src/debug/stacktrace.c src/boot/boot.c src/sched/scheduler.c src/sched/process.c src/mem/heap/kheap.c src/mem/paging/vmm.c src/mem/paging/paging.c src/mem/paging/pmm.c src/string/string.c src/io/kbd/ps2.c src/io/serial/serial.c src/io/term/printf.c src/io/term/term.c src/idt/idt.c src/mem/gdt/gdt.c src/mem/misc/utils.c src/time/timer.c src/kmain.c
 
-PROBLEMATIC_FLAGS=-Wno-unused-parameter -Wno-unused-variable
+BUILDDIR := build
+ELFFILE := pepperk
+SRC := src
+SOURCES := $(shell find src -name '*.c')
+OBJFILES := $(patsubst $(SRC)/%.c, $(BUILDDIR)/%.o, $(SOURCES))
 
-build:
-	rm -f *.o
-	x86_64-elf-gcc -g -c -Isrc $(SOURCES) $(PROBLEMATIC_FLAGS) -Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-omit-frame-pointer -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel
-	objcopy -O elf64-x86-64 -B i386 -I binary zap-light16.psf zap-light16.o
-	nasm -f elf64 src/idt/idt.S -o idt_stub.o
-	nasm -f elf64 src/entry.S -o entry.o
-	x86_64-elf-ld -o pepperk -T linker.ld *.o
-	nm -n pepperk | awk '$$2 ~ /[TtDdBbRr]/ {print $$1, $$3}' > symbols.map
+CC := x86_64-elf-gcc
+CC_FLAGS=-Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-omit-frame-pointer -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel
+CC_PROBLEMATIC_FLAGS=-Wno-unused-parameter -Wno-unused-variable
+
+LD := x86_64-elf-ld
+
+$(ELFFILE): $(BUILDDIR) $(OBJFILES)
+	nasm -f elf64 src/arch/x86/idt.S -o $(BUILDDIR)/idt_stub.o
+	$(LD) -o $(ELFFILE) -T linker.ld $(OBJFILES) $(BUILDDIR)/idt_stub.o
+	# Get the symbols for debugging
+	nm -n $(ELFFILE) | awk '$$2 ~ /[TtDdBbRr]/ {print $$1, $$3}' > symbols.map
 	python3 symbols.py
-	nasm -f elf64 symbols.S -o symbols.o
-	x86_64-elf-ld -o pepperk -T linker.ld *.o
+	nasm -f elf64 symbols.S -o $(BUILDDIR)/symbols.o
+	$(LD) -o $(ELFFILE) -T linker.ld $(OBJFILES) $(BUILDDIR)/idt_stub.o $(BUILDDIR)/symbols.o
+
+$(BUILDDIR):
+	@mkdir -p $(BUILDDIR)
+
+$(BUILDDIR)/%.o: $(SRC)/%.c
+	mkdir -p $(dir $@)
+	$(CC) -g -c -Iinclude $< $(CC_PROBLEMATIC_FLAGS) $(CC_FLAGS) -o $@
 
 limine/limine:
 	rm -rf limine
 	git clone https://github.com/limine-bootloader/limine.git --branch=v9.x-binary --depth=1
 	$(MAKE) -C limine
 
-build-iso: limine/limine build
+build-iso: limine/limine $(ELFFILE)
 	rm -rf iso_root
 	mkdir -p iso_root/boot
-	cp -v pepperk iso_root/boot
+	cp -v $(ELFFILE) iso_root/boot
 	mkdir -p iso_root/boot/limine
 	cp -v limine.conf iso_root/boot/limine
 	mkdir -p iso_root/EFI/BOOT
@@ -36,16 +49,20 @@ build-iso: limine/limine build
 		iso_root -o pepper.iso
 	./limine/limine bios-install pepper.iso
 
+.PHONY: debug
 debug:
-	/usr/bin/qemu-system-x86_64 -drive file=pepper.iso -s -S -d int -no-reboot -no-shutdown &
-	gdb pepperk --command=debug.gdb
+	/usr/bin/qemu-system-x86_64 -drive file=pepper.iso -s -S -d int -D qemu.log -no-reboot -no-shutdown &
+	gdb $(ELFFILE) --command=debug.gdb
 
+.PHONY: debug2
 debug2:
 	/usr/bin/qemu-system-x86_64 -drive file=pepper.iso -s -S -d int -no-reboot -no-shutdown &
-	pwndbg pepperk --command=debug.gdb
+	pwndbg $(ELFFILE) --command=debug.gdb
 
+.PHONY: run
 run: build-iso
 	/usr/bin/qemu-system-x86_64 -cdrom pepper.iso -serial stdio
 
+.PHONY: clean
 clean:
-	rm -rf *.o symbols.map symbols.S pepperk iso_root pepper.iso limine
+	rm -rf $(BUILDDIR) symbols.map symbols.S $(ELFFILE) iso_root pepper.iso limine

README.md

@@ -1,11 +1,38 @@
 # <img width="40" height="40" alt="red-pepper" src="https://i.ibb.co/mrHH6d1m/pixil-frame-0-4.png" /> pepperOS: "will never be done"
 
-## Trying the kernel
+## Description
 
-First install the dependencies: `sudo apt install python3 xorriso make qemu-system`
+PepperOS is a 64-bit freely-licensed monolithic kernel for x86 processors, with round-robin preemptive scheduling and 4-level paging. See the [manual](docs/MANUAL.md) for more.
 
-Then, to compile the kernel and make an ISO image file: `make build-iso`
-To run it with QEMU, `make run`
+## Trying the kernel in QEMU
+
+### Debian-based distributions
+
+First, install the dependencies: `sudo apt install nasm python3 xorriso make qemu-system`
+
+Then, you can get an x86_64 toolchain for compilation. The easiest way to do that on most systems is to install it from Homebrew:
+
+```
+brew install x86_64-elf-gcc
+```
+
+If you're already on a 64-bit machine (which you probably are), and don't want to install a cross-compiler, you can just override `CC` and `LD` variables in the Makefile, like so:
+
+```
+CC := gcc
+LD := ld
+```
+
+Then, to compile the kernel and make an ISO image file, run: `make build-iso`
+To run it with QEMU, do: `make run`
+
+## Trying the kernel on real hardware
+
+Compile the kernel and generate an ISO image like described above, then burn the image to a USB stick, `/dev/sdX` being the device name (you can get it using `lsblk`):
+
+```
+sudo dd if=pepper.iso of=/dev/sdX
+```
 
 ## TODO
 
@@ -13,11 +40,10 @@ The basics that I'm targeting are:
 
 ### Basic utility of what we call a "kernel"
 
-- Fix terminal driver (backspace issues, scrolling) OR add Flanterm or equivalent
 - Implement tasks, and task switching + context switching and spinlock acquire/release
 - Load an executable
 - Filesystem (TAR for read-only initfs, then maybe read-write using FAT12/16/32 or easier fs) w/ VFS layer
-- Getting to userspace (syscalls)
+- Getting to userspace (ring 3 switching, syscall interface)
 - Porting musl libc or equivalent
 
 ### Scalability/maintenance/expansion features
@@ -26,7 +52,6 @@ The basics that I'm targeting are:
 - SOME error handling in functions
 - Unit tests
 - Good error codes (like Linux kernel: ENOMEM, ENOENT, ...)
-- Make the panic function work within itself without dependencies + error message (and still get cpu context?)
 
 ### Optional features
 
@@ -40,9 +65,12 @@ In the future, maybe?
 PepperOS wouldn't be possible without the following freely-licensed software:
 
 - the [Limine](https://codeberg.org/Limine/Limine) portable bootloader
-- Marco Paland's freestanding [printf implementation](https://github.com/mpaland)
-- the [ZAP](https://www.zap.org.au/projects/console-fonts-zap/) PSF console fonts
+- Charles Nicholson's [nanoprintf](https://github.com/charlesnicholson/nanoprintf)
+- Mintuski's [Flanterm](https://codeberg.org/Mintsuki/Flanterm) terminal emulator
 
 ...and without these amazing resources:
 
 - the [OSDev](https://osdev.org) wiki & forums
+- Intel 64 and IA-32 Architectures Software Developer's Manual
+- Documentation for the [GNU Compiler Collection](https://gcc.gnu.org/onlinedocs/gcc/)
+- dreamos82's [OSDev Notes](https://github.com/dreamportdev/Osdev-Notes/tree/master)

debug.gdb

@@ -1,3 +1,7 @@
 target remote localhost:1234
 set disassembly-flavor intel
 display/4i $rip
+
+# Trying to debug that flanterm page fault
+
+# b plot_char_unscaled_uncanvas if $rdi == 0 || $rsi == 0 || $rdx == 0 || $r10 == 0

docs/MANUAL.md

@@ -0,0 +1,40 @@
+# PepperOS Manual
+
+# Table of Contents
+
+- [Overview](#i-overview)
+    - [Supported Hardware](#a-supported-hardware)
+    - [Features](#b-features)
+- [Kernel architecture](#ii-kernel-architecture)
+    - [Boot process](#a-boot-process)
+    - [Memory management](#b-memory-management)
+    - [Scheduling](#c-scheduling)
+    - [Input/output](#d-inputoutput)
+- [Syscall table](#iii-syscall-table)
+
+## I. Overview
+
+## a. Supported Hardware
+
+The recommended hardware to run PepperOS is the following:
+
+- UEFI/BIOS
+- Any x86 processor, 64-bits only
+- PS/2 Keyboard
+- Minimum 128MB of memory
+
+## b. Features
+
+## II. Kernel architecture
+
+### a. Boot process
+
+### b. Memory management
+
+### c. Scheduling
+
+### d. Input/Output
+
+## III. Syscall table
+
+Not yet implemented.

docs/STYLE.md

@@ -0,0 +1,93 @@
+# Pepper kernel coding style
+
+This document describes the coding style for the Pepper kernel. It is used as a guideline across all source files.
+
+## Indentation
+
+Indentations should be 4 characters long.
+
+## Line length
+
+Lines should not be more than 100 characters long. Exceptions is made for printing strings.
+
+## Variables
+
+Variables should be declared at most once per line.
+
+## Braces
+
+Non-function statement blocks should have an opening brace last on the line, and a closing brace first. Exception is made for `else`, `else if` statements and the like:
+
+```c
+if (something) {
+    do_something();
+} else if (something_else) {
+    do_something_else();
+}
+```
+
+Having no braces for a single statement structure is fine.
+
+Functions should have their opening brace on a separate line, and the same goes for the closing brace:
+
+```c
+void function()
+{
+    do_something();
+}
+```
+
+## Spaces
+
+Use a space after `if, switch, case, for, do, while` keywords, but not for `sizeof, typeof, alignof, __attribute__` and the like.
+
+For pointers, the asterisk should always be placed adjacent to the type name, like `char* str;`.
+
+## Naming
+
+Functions should be named with whole words, beginning with the corresponding name of the module in the kernel (the parent folder). Words should be spaced with underscores, like so:
+
+```c
+serial_init(void* ptr, char* str, int foo);
+```
+
+Constants should be named in all caps, separated by underscores:
+
+```c
+#define MAX_HEAP_SIZE 0x1000
+```
+
+Global variables need to have descriptive names. Local variables can be kept short (especially for loop counters).
+
+## Typedefs
+
+Structures should not be `typedef`'d. However using `typedef` for an enumeration is fine.
+
+## Functions
+
+Functions should be short, simple, and only do one thing.
+
+Function prototypes should include parameter names and their data types.
+
+## Commenting
+
+Comments should describe what a function does and why, not how it does it. The preferred way of commenting functions is the following:
+
+```c
+/*
+ * function_name - Function brief description
+ * @arg1: Argument 1 description
+ * @arg2: Argument 2 description
+ *
+ * A longer description can be featured here, explaining more
+ * in detail what the function does and why it does it.
+ */
+```
+
+## Kernel messages
+
+When printing kernel messages with the `DEBUG` macro, they should start with a capital letter.
+
+### Resources
+
+Some of the elements here are inspired by the [Linux kernel coding style](https://www.kernel.org/doc/html/v4.10/process/coding-style.html).

include/arch/x86.h

@@ -1,18 +1,20 @@
-/*
- * @author  xamidev <xamidev@riseup.net>
- * @brief   Interrupt Descriptor Table setup and dispatching
- * @license GPL-3.0-only
- */
-
-#ifndef IDT_H
-#define IDT_H
+#ifndef X86_H
+#define X86_H
 
+#include <stdbool.h>
 #include <stdint.h>
 
-void idt_init();
+uint64_t rdmsr(uint32_t msr);
+void cpuid(uint32_t leaf, uint32_t* eax, uint32_t* ebx, uint32_t* ecx, uint32_t* edx);
+void wrmsr(uint32_t msr, uint64_t value);
+bool x86_has_msr();
+void x86_arch_init();
 
-struct interrupt_descriptor
-{
+/* Interrupt Descriptor Table */
+
+void idt_init(void);
+
+struct interrupt_descriptor {
     uint16_t address_low;
     uint16_t selector;
     uint8_t ist;
@@ -22,8 +24,7 @@ struct interrupt_descriptor
     uint32_t reserved;
 } __attribute__((packed));
 
-struct idtr 
-{
+struct idtr {
     uint16_t limit;
     uint64_t base;
 } __attribute__((packed));
@@ -31,8 +32,7 @@ struct idtr
 // All general-purpose registers (except rsp) as stored on the stack,
 // plus the values we pushed (vector number, error code) and the iret frame
 // In reverse order because the stack grows downwards.
-struct cpu_status_t
-{
+struct cpu_status_t {
     uint64_t r15;
     uint64_t r14;
     uint64_t r13;
@@ -42,7 +42,6 @@ struct cpu_status_t
     uint64_t r9;
     uint64_t r8;
     uint64_t rbp;
-    //uint64_t rsp;
     uint64_t rdi;
     uint64_t rsi;
     uint64_t rdx;
@@ -60,4 +59,6 @@ struct cpu_status_t
     uint64_t iret_ss;
 };
 
+struct cpu_status_t* syscall_handler(struct cpu_status_t* regs);
+
 #endif

include/config.h

@@ -0,0 +1,59 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PepperOS configuration file
+ * @license GPL-3.0-only
+ */
+
+#ifndef CONFIG_H
+#define CONFIG_H
+
+/* version */
+#define PEPPEROS_VERSION_MAJOR "0"
+#define PEPPEROS_VERSION_MINOR "0"
+#define PEPPEROS_VERSION_PATCH "58"
+#define PEPPEROS_SPLASH \
+"\x1b[38;5;196m                                      \x1b[38;5;231m____  _____\r\n\x1b[0m"\
+"\x1b[38;5;196m    ____  ___  ____  ____  ___  _____\x1b[38;5;231m/ __ \\/ ___/\r\n\x1b[0m"\
+"\x1b[38;5;196m   / __ \\/ _ \\/ __ \\/ __ \\/ _ \\/ ___\x1b[38;5;231m/ / / /\\__ \\ \r\n\x1b[0m"\
+"\x1b[38;5;196m  / /_/ /  __/ /_/ / /_/ /  __/ /  \x1b[38;5;231m/ /_/ /___/ / \r\n\x1b[0m"\
+"\x1b[38;5;196m / .___/\\___/ .___/ .___/\\___/_/   \x1b[38;5;231m\\____//____/  \r\n\x1b[0m"\
+"\x1b[38;5;196m/_/        /_/   /_/                             \r\n\x1b[0m"\
+"     --- version \x1b[38;5;220m"PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\x1b[0m built on \x1b[38;5;40m"__DATE__" "__TIME__"\x1b[0m\r\n"
+
+/* pedicel */
+#define PEDICEL_PROMPT "pedicel$ "
+#define PEDICEL_INPUT_SIZE 128
+
+/* process */
+#define PROCESS_NAME_MAX 64
+#define PROCESS_STACK_SIZE 0x10000 // 64kb
+#define PROCESS_BASE 0x400000
+#define PROCESS_STACK_BASE 0x1000000
+
+/* sched */
+// 1 tick = 1 ms => quantum = 10ms
+#define SCHEDULER_QUANTUM 10
+
+/* kernel */
+#define KERNEL_BASE 0xFFFFFFFF80000000ULL
+// 2 MB should be enough (as of now, the whole kernel ELF is around 75kb)
+#define KERNEL_SIZE 0x200000
+#define KERNEL_STACK_SIZE 65536
+#define KERNEL_IDT_ENTRIES 33
+
+/* paging */
+#define PAGING_MAX_PHYS 0x200000000
+
+/* heap */
+#define KHEAP_SIZE (32*1024*1024)
+
+/* term */
+#define TERM_HISTORY_MAX_LINES 256
+
+/* kbd */
+#define KBD_BUFFER_MAX 256
+
+/* time */
+#define TIMER_FREQUENCY 1000
+
+#endif

include/io/kbd/ps2.h

@@ -7,21 +7,24 @@
 #ifndef PS2_H
 #define PS2_H
 
-void keyboard_handler();
+#include <stddef.h>
+
+void keyboard_handler(void);
+char keyboard_getchar();
+int keyboard_putchar(char c);
+int keyboard_getline(char* output, size_t size);
 
 #define SHIFT_PRESSED_BIT 0b00000001
 #define ALT_PRESSED_BIT   0b00000010
 #define CTRL_PRESSED_BIT  0b00000100
 
-enum SpecialKeys
-{
+enum SpecialKeys {
     SHIFT = 255,
     ALT = 254,
     CTRL = 253
 };
 
-enum SpecialScancodes
-{
+enum SpecialScancodes {
     LEFT_SHIFT_PRESSED = 0x2A,
     LEFT_SHIFT_RELEASED = 0xAA,
     RIGHT_SHIFT_PRESSED = 0x36,
@@ -32,8 +35,7 @@ enum SpecialScancodes
     ALT_RELEASED = 0xB8  
 };
 
-enum KeyboardLayout
-{
+enum KeyboardLayout {
     US,
     FR  
 };

include/io/serial/serial.h

@@ -7,10 +7,13 @@
 #ifndef SERIAL_H
 #define SERIAL_H
 
+// COM1
+#define PORT 0x3F8
+
 void outb(int port, unsigned char data);
 unsigned char inb(int port);
 
-int serial_init();
+int serial_init(void);
 void skputs(const char* str);
 void skputc(char c);
 

include/io/term/flanterm.h

@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_H
+#define FLANTERM_H 1
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define FLANTERM_CB_DEC 10
+#define FLANTERM_CB_BELL 20
+#define FLANTERM_CB_PRIVATE_ID 30
+#define FLANTERM_CB_STATUS_REPORT 40
+#define FLANTERM_CB_POS_REPORT 50
+#define FLANTERM_CB_KBD_LEDS 60
+#define FLANTERM_CB_MODE 70
+#define FLANTERM_CB_LINUX 80
+#define FLANTERM_CB_OSC 90
+
+#ifdef FLANTERM_IN_FLANTERM
+
+#include "flanterm_private.h"
+
+#else
+
+struct flanterm_context;
+
+#endif
+
+void flanterm_write(struct flanterm_context *ctx, const char *buf, size_t count);
+void flanterm_flush(struct flanterm_context *ctx);
+void flanterm_full_refresh(struct flanterm_context *ctx);
+void flanterm_deinit(struct flanterm_context *ctx, void (*_free)(void *ptr, size_t size));
+
+void flanterm_get_dimensions(struct flanterm_context *ctx, size_t *cols, size_t *rows);
+void flanterm_set_autoflush(struct flanterm_context *ctx, bool state);
+void flanterm_set_callback(struct flanterm_context *ctx, void (*callback)(struct flanterm_context *, uint64_t, uint64_t, uint64_t, uint64_t));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/io/term/flanterm_backends/fb.h

@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_FB_H
+#define FLANTERM_FB_H 1
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "../flanterm.h"
+
+#ifdef FLANTERM_IN_FLANTERM
+
+#include "fb_private.h"
+
+#endif
+
+#define FLANTERM_FB_ROTATE_0 0
+#define FLANTERM_FB_ROTATE_90 1
+#define FLANTERM_FB_ROTATE_180 2
+#define FLANTERM_FB_ROTATE_270 3
+
+struct flanterm_context *flanterm_fb_init(
+    /* If _malloc and _free are nulled, use the bump allocated instance (1 use only). */
+    void *(*_malloc)(size_t size),
+    void (*_free)(void *ptr, size_t size),
+    uint32_t *framebuffer, size_t width, size_t height, size_t pitch,
+    uint8_t red_mask_size, uint8_t red_mask_shift,
+    uint8_t green_mask_size, uint8_t green_mask_shift,
+    uint8_t blue_mask_size, uint8_t blue_mask_shift,
+    uint32_t *canvas, /* If nulled, no canvas. */
+    uint32_t *ansi_colours, uint32_t *ansi_bright_colours, /* If nulled, default. */
+    uint32_t *default_bg, uint32_t *default_fg, /* If nulled, default. */
+    uint32_t *default_bg_bright, uint32_t *default_fg_bright, /* If nulled, default. */
+    /* If font is null, use default font and font_width and font_height ignored. */
+    void *font, size_t font_width, size_t font_height, size_t font_spacing,
+    /* If scale_x and scale_y are 0, automatically scale font based on resolution. */
+    size_t font_scale_x, size_t font_scale_y,
+    size_t margin,
+    /* One of FLANTERM_FB_ROTATE_* values. */
+    int rotation
+);
+
+void flanterm_fb_set_flush_callback(struct flanterm_context *ctx, void (*flush_callback)(volatile void *address, size_t length));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/io/term/flanterm_backends/fb_private.h

@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_FB_PRIVATE_H
+#define FLANTERM_FB_PRIVATE_H 1
+
+#ifndef FLANTERM_IN_FLANTERM
+#error "Do not use fb_private.h. Use interfaces defined in fb.h only."
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define FLANTERM_FB_FONT_GLYPHS 256
+
+struct flanterm_fb_char {
+    uint32_t c;
+    uint32_t fg;
+    uint32_t bg;
+};
+
+struct flanterm_fb_queue_item {
+    size_t x, y;
+    struct flanterm_fb_char c;
+};
+
+struct flanterm_fb_context {
+    struct flanterm_context term;
+
+    void (*plot_char)(struct flanterm_context *ctx, struct flanterm_fb_char *c, size_t x, size_t y);
+    void (*flush_callback)(volatile void *address, size_t length);
+
+    size_t font_width;
+    size_t font_height;
+    size_t glyph_width;
+    size_t glyph_height;
+
+    size_t font_scale_x;
+    size_t font_scale_y;
+
+    size_t offset_x, offset_y;
+
+    volatile uint32_t *framebuffer;
+    size_t pitch;
+    size_t width;
+    size_t height;
+    size_t phys_height;
+    size_t bpp;
+
+    uint8_t red_mask_size, red_mask_shift;
+    uint8_t green_mask_size, green_mask_shift;
+    uint8_t blue_mask_size, blue_mask_shift;
+
+    int rotation;
+
+    size_t font_bits_size;
+    uint8_t *font_bits;
+    size_t font_bool_size;
+    bool *font_bool;
+
+    uint32_t ansi_colours[8];
+    uint32_t ansi_bright_colours[8];
+    uint32_t default_fg, default_bg;
+    uint32_t default_fg_bright, default_bg_bright;
+
+    size_t canvas_size;
+    uint32_t *canvas;
+
+    size_t grid_size;
+    size_t queue_size;
+    size_t map_size;
+
+    struct flanterm_fb_char *grid;
+
+    struct flanterm_fb_queue_item *queue;
+    size_t queue_i;
+
+    struct flanterm_fb_queue_item **map;
+
+    uint32_t text_fg;
+    uint32_t text_bg;
+    size_t cursor_x;
+    size_t cursor_y;
+
+    uint32_t saved_state_text_fg;
+    uint32_t saved_state_text_bg;
+    size_t saved_state_cursor_x;
+    size_t saved_state_cursor_y;
+
+    size_t old_cursor_x;
+    size_t old_cursor_y;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/io/term/flanterm_private.h

@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_PRIVATE_H
+#define FLANTERM_PRIVATE_H 1
+
+#ifndef FLANTERM_IN_FLANTERM
+#error "Do not use flanterm_private.h. Use interfaces defined in flanterm.h only."
+#endif
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define FLANTERM_MAX_ESC_VALUES 16
+
+struct flanterm_context {
+    /* internal use */
+
+    size_t tab_size;
+    bool autoflush;
+    bool cursor_enabled;
+    bool scroll_enabled;
+    bool wrap_enabled;
+    bool origin_mode;
+    bool control_sequence;
+    bool escape;
+    bool osc;
+    bool osc_escape;
+    size_t osc_buf_i;
+    uint8_t osc_buf[256];
+    bool rrr;
+    bool discard_next;
+    bool bold;
+    bool bg_bold;
+    bool reverse_video;
+    bool dec_private;
+    bool insert_mode;
+    bool csi_unhandled;
+    uint64_t code_point;
+    size_t unicode_remaining;
+    uint8_t g_select;
+    uint8_t charsets[2];
+    size_t current_charset;
+    size_t escape_offset;
+    size_t esc_values_i;
+    size_t saved_cursor_x;
+    size_t saved_cursor_y;
+    size_t current_primary;
+    size_t current_bg;
+    size_t scroll_top_margin;
+    size_t scroll_bottom_margin;
+    uint32_t esc_values[FLANTERM_MAX_ESC_VALUES];
+    uint8_t last_printed_char;
+    bool last_was_graphic;
+    bool saved_state_bold;
+    bool saved_state_bg_bold;
+    bool saved_state_reverse_video;
+    bool saved_state_origin_mode;
+    bool saved_state_wrap_enabled;
+    size_t saved_state_current_charset;
+    uint8_t saved_state_charsets[2];
+    size_t saved_state_current_primary;
+    size_t saved_state_current_bg;
+
+    /* to be set by backend */
+
+    size_t rows, cols;
+
+    void (*raw_putchar)(struct flanterm_context *, uint8_t c);
+    void (*clear)(struct flanterm_context *, bool move);
+    void (*set_cursor_pos)(struct flanterm_context *, size_t x, size_t y);
+    void (*get_cursor_pos)(struct flanterm_context *, size_t *x, size_t *y);
+    void (*set_text_fg)(struct flanterm_context *, size_t fg);
+    void (*set_text_bg)(struct flanterm_context *, size_t bg);
+    void (*set_text_fg_bright)(struct flanterm_context *, size_t fg);
+    void (*set_text_bg_bright)(struct flanterm_context *, size_t bg);
+    void (*set_text_fg_rgb)(struct flanterm_context *, uint32_t fg);
+    void (*set_text_bg_rgb)(struct flanterm_context *, uint32_t bg);
+    void (*set_text_fg_default)(struct flanterm_context *);
+    void (*set_text_bg_default)(struct flanterm_context *);
+    void (*set_text_fg_default_bright)(struct flanterm_context *);
+    void (*set_text_bg_default_bright)(struct flanterm_context *);
+    void (*move_character)(struct flanterm_context *, size_t new_x, size_t new_y, size_t old_x, size_t old_y);
+    void (*scroll)(struct flanterm_context *);
+    void (*revscroll)(struct flanterm_context *);
+    void (*swap_palette)(struct flanterm_context *);
+    void (*save_state)(struct flanterm_context *);
+    void (*restore_state)(struct flanterm_context *);
+    void (*double_buffer_flush)(struct flanterm_context *);
+    void (*full_refresh)(struct flanterm_context *);
+    void (*deinit)(struct flanterm_context *, void (*)(void *, size_t));
+
+    /* to be set by client */
+
+    void (*callback)(struct flanterm_context *, uint64_t, uint64_t, uint64_t, uint64_t);
+};
+
+void flanterm_context_reinit(struct flanterm_context *ctx);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/io/term/term.h

@@ -0,0 +1,16 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Framebuffer-based terminal driver
+ * @license GPL-3.0-only
+ */
+
+#ifndef TERM_H
+#define TERM_H
+
+void kputs(const char* str);
+void term_init(void);
+int printf(const char* fmt, ...);
+void internal_putc(int c, void *_);
+int kprintf(const char* fmt, ...);
+
+#endif

include/kernel.h

@@ -7,8 +7,7 @@
 #ifndef KERNEL_H
 #define KERNEL_H
 
-enum ErrorCodes
-{
+enum ErrorCodes {
 	ENOMEM,
 	EIO
 };
@@ -16,33 +15,52 @@ enum ErrorCodes
 #define CLEAR_INTERRUPTS __asm__ volatile("cli")
 #define SET_INTERRUPTS __asm__ volatile("sti")
 
-#include "io/serial/serial.h"
-#include "io/term/printf.h"
-#include "idt/idt.h"
+#include <io/serial/serial.h>
+#include <io/term/term.h>
+#include <arch/x86.h>
+#include <stdbool.h>
 
-#define DEBUG(log, ...) fctprintf((void*)&skputc, 0, "debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__)
+extern volatile uint64_t ticks;
+#define DEBUG(log, ...) kprintf("[%8u] debug: <%s>: " log "\r\n", ticks, __func__, ##__VA_ARGS__)
 
-#define DIE_DEBUG(str) fctprintf((void*)&skputc, 0, str)
+/* #define DEBUG(log, ...) \
+	printf("debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__); \
+	fctprintf((void*)&skputc, 0, "debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__)
+ */
+
+#define DIE_DEBUG(str) printf(str)
 
 #define CHECK_BIT(var,pos) ((var) & (1<<(pos)))
 
 // printf("debug: [%s]: " log "\n", __FILE__, ##__VA_ARGS__);
 
 void panic(struct cpu_status_t* ctx, const char* str);
-void hcf();
-void idle();
+void hcf(void);
+void idle(void);
 
+void pedicel_main(void* arg);
+
+/* debug */
 void debug_stack_trace(unsigned int max_frames);
 const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset);
+void boot_mem_display(void);
 
 #define assert(check) do { if(!(check)) hcf(); } while(0)
 
-struct boot_context
-{
+struct boot_context {
 	struct limine_framebuffer* fb;
 	struct limine_memmap_response* mmap;
 	struct limine_hhdm_response* hhdm;
 	struct limine_kernel_address_response* kaddr;
 };
 
+// Are these modules initialized yet?
+struct init_status {
+	bool terminal;
+	bool serial;
+	bool keyboard;
+	bool timer;
+	bool all;
+};
+
 #endif

include/mem/gdt.h

@@ -21,12 +21,11 @@
 #define USER_CODE_SEGMENT 0x18
 #define USER_DATA_SEGMENT 0x20
 
-struct GDTR 
-{
+struct GDTR {
     uint16_t limit;
     uint64_t address;
 } __attribute__((packed));
 
-void gdt_init();
+void gdt_init(void);
 
 #endif

include/mem/kheap.h

@@ -14,18 +14,19 @@
 
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 
-struct heap_block_t
-{
+struct heap_block_t {
     size_t size;
-    bool free;
+    bool free; // 1byte
+    uint8_t reserved[7]; // (7+1 = 8 bytes)
     struct heap_block_t* next;
-};
+} __attribute__((aligned(16)));
 
-void kheap_init();
+void kheap_init(void);
 void* kmalloc(size_t size);
 void kfree(void* ptr);
-void* kalloc_stack();
-void kheap_map_page();
+void* kalloc_stack(void);
+void kheap_map_page(void);
 
 #endif

include/mem/paging.h

@@ -11,9 +11,10 @@
 
 #include <stdint.h>
 #include <limine.h>
-#include "mem/heap/kheap.h"
+#include <mem/kheap.h>
+#include <kernel.h>
 
-void paging_init();
+void paging_init(struct boot_context boot_ctx);
 void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_t flags);
 
 // To swap root page tables
@@ -40,12 +41,15 @@ extern uint64_t hhdm_off;
 
 // Page entry special bits
 // Bits set on a parent (directory, table) fall back to their children
-#define PTE_PRESENT     (1ULL << 0)
-#define PTE_WRITABLE    (1ULL << 1)
-#define PTE_USER        (1ULL << 2)
-#define PTE_PWT         (1ULL << 3)
-#define PTE_PCD         (1ULL << 4)
-#define PTE_HUGE        (1ULL << 7)
-#define PTE_NOEXEC      (1ULL << 63)
+enum PTE_FLAGS
+{
+    PTE_PRESENT = (1ULL << 0),
+    PTE_WRITABLE = (1ULL << 1),
+    PTE_USER = (1ULL << 2),
+    PTE_PWT = (1ULL << 3),
+    PTE_PCD = (1ULL << 4),
+    PTE_HUGE = (1ULL << 7),
+    PTE_NOEXEC = (1ULL << 63)
+};
 
 #endif

include/mem/pmm.h

@@ -8,9 +8,10 @@
 #define PAGING_PMM_H
 
 #include <limine.h>
+#include <kernel.h>
 
-void pmm_init(struct limine_memmap_response* memmap, struct limine_hhdm_response* hhdm);
+void pmm_init(struct boot_context boot_ctx);
 void pmm_free(uintptr_t addr);
-uintptr_t pmm_alloc();
+uintptr_t pmm_alloc(void);
 
 #endif

include/mem/vmm.h

@@ -16,8 +16,7 @@ Flags here aren't x86 flags, they are platform-agnostic
 kernel-defined flags.
 */
 
-struct vm_object
-{
+struct vm_object {
     uintptr_t base;
     size_t length;
     size_t flags;
@@ -30,6 +29,6 @@ struct vm_object
 #define VM_FLAG_EXEC (1 << 1)
 #define VM_FLAG_USER (1 << 2)
 
-void vmm_init();
+void vmm_init(void);
 
 #endif

include/sched/process.h

@@ -8,18 +8,16 @@
 #define PROCESS_H
 
 #include <stddef.h>
-#include "config.h"
+#include <config.h>
 #include <stdint.h>
 
-typedef enum 
-{
+typedef enum {
     READY,
     RUNNING,
     DEAD
 } status_t;
 
-struct process_t
-{
+struct process_t {
     size_t pid;
     char name[PROCESS_NAME_MAX];
 
@@ -29,13 +27,12 @@ struct process_t
     struct process_t* next;
 };
 
-void process_init();
+void process_init(void);
 struct process_t* process_create(char* name, void(*function)(void*), void* arg);
 void process_add(struct process_t** processes_list, struct process_t* process);
 void process_delete(struct process_t** processes_list, struct process_t* process);
 struct process_t* process_get_next(struct process_t* process);
-void process_switch(uint64_t stack_addr, uint64_t code_addr);
-void process_exit();
+void process_exit(void);
 
 void process_display_list(struct process_t* processes_list);
 

include/sched/scheduler.h

@@ -8,6 +8,6 @@
 #define SCHEDULER_H
 
 struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context);
-void scheduler_init();
+void scheduler_init(void);
 
 #endif

include/sched/spinlock.h

@@ -0,0 +1,22 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Spinlock implementation
+ * @license GPL-3.0-only
+ */
+
+#ifndef SPINLOCK_H
+#define SPINLOCK_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+struct spinlock_t
+{
+    bool locked;
+    uint64_t rflags;
+};
+
+void spinlock_acquire(struct spinlock_t* lock);
+void spinlock_release(struct spinlock_t* lock);
+
+#endif

include/string/string.h

@@ -7,8 +7,11 @@
 #ifndef STRING_H
 #define STRING_H
 
+#include <stddef.h>
+
 char *strcpy(char *dest, const char *src);
 char *strcat(char *dest, const char *src);
 void strncpy(char* dst, const char* src, size_t n);
+int strncmp(const char* s1, const char* s2, size_t n);
 
 #endif

include/time/timer.h

@@ -7,7 +7,7 @@
 #ifndef TIMER_H
 #define TIMER_H
 
-void timer_init();
+void timer_init(void);
 void timer_wait(unsigned int wait_ticks);
 
 #endif

limine.conf

@@ -1,6 +1,8 @@
 timeout: 3
+interface_branding: Welcome to the PepperOS disk!
 
 /PepperOS
 	protocol: limine
 	
+	comment: Default configuration (warning: spicy)
 	path: boot():/boot/pepperk

linker.ld

@@ -1,6 +1,6 @@
 OUTPUT_FORMAT(elf64-x86-64)
 
-ENTRY(_start)
+ENTRY(kmain)
 
 PHDRS
 {

src/arch/x86/cpuid.c

@@ -0,0 +1,21 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   x86 CPU identification
+ * @license GPL-3.0-only
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+
+/*
+ * cpuid - Wrapper for CPUID instruction
+ * @leaf: Requested leaf (input EAX)
+ * @eax: EAX register value (output)
+ * @ebx: EBX register value (output)
+ * @ecx: ECX register value (output)
+ * @edx: EDX register value (output)
+*/
+void cpuid(uint32_t leaf, uint32_t* eax, uint32_t* ebx, uint32_t* ecx, uint32_t* edx)
+{
+    __asm__ volatile("cpuid" : "=a"(*eax), "=b"(*ebx), "=c"(*ecx), "=d"(*edx) : "a"(leaf));
+}

src/arch/x86/idt.S

@@ -151,12 +151,13 @@ vector_7_handler:
 align 16
 vector_8_handler:
     ; No error code, we only push vector number
-    push qword 1
+    push qword 8
     jmp interrupt_stub
 
 ; Coprocessor Segment Overrun
 align 16
 vector_9_handler:
+    push qword 0
     push qword 9
     jmp interrupt_stub
 

src/arch/x86/idt.c

@@ -4,16 +4,16 @@
  * @license GPL-3.0-only
  */
 
-#include "idt.h"
+#include <arch/x86.h>
 #include <stdint.h>
 #include <stddef.h>
-#include "io/serial/serial.h"
-#include "io/kbd/ps2.h"
+#include <io/serial/serial.h>
+#include <io/kbd/ps2.h>
 #include <kernel.h>
 #include <stdbool.h>
-#include "sched/scheduler.h"
-#include "config.h"
-#include "sched/process.h"
+#include <sched/scheduler.h>
+#include <config.h>
+#include <sched/process.h>
 
 struct interrupt_descriptor idt[256];
 struct idtr idt_reg;
@@ -22,8 +22,16 @@ struct idtr idt_reg;
 extern char vector_0_handler[];
 
 // Timer ticks
-extern uint64_t ticks;
+extern volatile uint64_t ticks;
 
+extern struct init_status init;
+
+/*
+ * idt_set_entry - Sets an Interrupt Descriptor Table entry
+ * @vector:  Vector number in the IDT
+ * @handler: Pointer to the executable Interrupt Service Routine
+ * @dpl:     Desired privilege level
+ */
 void idt_set_entry(uint8_t vector, void* handler, uint8_t dpl)
 {
     uint64_t handler_addr = (uint64_t)handler;
@@ -42,6 +50,10 @@ void idt_set_entry(uint8_t vector, void* handler, uint8_t dpl)
     entry->ist = 0;
 }
 
+/*
+ * idt_load - Loads the Interrupt Descriptor Table
+ * @idt_addr: Address to the IDT
+ */
 void idt_load(void* idt_addr)
 {
     // "limit" = "size" = Size of the IDT - 1 byte = (16*256)-1 = 0xFFF
@@ -50,19 +62,34 @@ void idt_load(void* idt_addr)
     asm volatile("lidt %0" :: "m"(idt_reg));
 }
 
+/*
+ * idt_init - Initializes the Interrupt Descriptor Table
+ *
+ * Sets all IDT entries and their corresponding service routines,
+ * then loads it.
+ */
 void idt_init()
 {
-    // We set 256 entries, but we have only the first few stubs.
-    // Undefined behavior?
-    for (size_t i=0; i<256; i++)
-    {
+    for (size_t i=0; i<=KERNEL_IDT_ENTRIES; i++) {
         // Each vector handler is 16-byte aligned, so <vector_no>*16 = address of that handler
         idt_set_entry(i, vector_0_handler + (i*16), 0);
     }
+
+    idt_set_entry(0x80, syscall_handler, 0);
+
     idt_load(&idt);
     DEBUG("IDT initialized");
 }
 
+/*
+ * read_cr2 - Reads the CR2 register
+ *
+ * This function is useful because it gets the address
+ * that the CPU tried to access in the case of a #PF.
+ *
+ * Return:
+ * %val - CR2 register value
+ */
 static inline uint64_t read_cr2(void)
 {
     uint64_t val;
@@ -70,6 +97,15 @@ static inline uint64_t read_cr2(void)
     return val;
 }
 
+/*
+ * page_fault_handler - Handler for #PF
+ * @ctx: CPU context
+ *
+ * Shows detail about a #PF, especially what instruction (RIP)
+ * caused it, and what address access (CR2) caused it.
+ * Also displays an interpretation of the thrown error code.
+ * Then halts the system. We could implement demand paging later.
+ */
 static void page_fault_handler(struct cpu_status_t* ctx)
 {
     // It could be used to remap pages etc. to fix the fault, but right now what I'm more
@@ -88,9 +124,29 @@ static void page_fault_handler(struct cpu_status_t* ctx)
     CHECK_BIT(ctx->error_code, 7) ? " SGX_VIOLATION" : "",
     cr2);
 
+    if (init.all) {
+        printf("\x1b[38;5;231mPage Fault at rip=0x%p, err=%u (%s%s%s%s%s%s%s%s) when accessing addr=0x%p\x1b[0m", ctx->iret_rip, ctx->error_code,
+        CHECK_BIT(ctx->error_code, 0) ? "PAGE_PROTECTION_VIOLATION " : "PAGE_NOT_PRESENT ",
+        CHECK_BIT(ctx->error_code, 1) ? "ON_WRITE " : "ON_READ ",
+        CHECK_BIT(ctx->error_code, 2) ? "IN_USER_MODE" : "IN_KERNEL_MODE",
+        CHECK_BIT(ctx->error_code, 3) ? " WAS_RESERVED" : "",
+        CHECK_BIT(ctx->error_code, 4) ? " ON_INSTRUCTION_FETCH" : "",
+        CHECK_BIT(ctx->error_code, 5) ? " PK_VIOLATION" : "",
+        CHECK_BIT(ctx->error_code, 6) ? " ON_SHADOWSTACK_ACCESS" : "",
+        CHECK_BIT(ctx->error_code, 7) ? " SGX_VIOLATION" : "",
+        cr2);
+    }
+
     panic(ctx, "page fault");
 }
 
+/*
+ * gp_fault_handler - Handler for #GP
+ * @ctx: CPU context
+ *
+ * Shows detail about a General Protection Fault,
+ * and what may have caused it. Halts the system.
+ */
 static void gp_fault_handler(struct cpu_status_t* ctx)
 {
     DEBUG("\x1b[38;5;231mGeneral Protection Fault at rip=0x%p, err=%u (%s)\x1b[0m",
@@ -99,8 +155,7 @@ static void gp_fault_handler(struct cpu_status_t* ctx)
     (ctx->error_code == 0) ? "NOT_SEGMENT_RELATED" : "SEGMENT_RELATED");
 
     // Segment-related
-    if (ctx->error_code != 0)
-    {
+    if (ctx->error_code != 0) {
         bool is_external = CHECK_BIT(ctx->error_code, 0);
         // is it IDT, GDT, LDT?
         uint8_t table = ctx->error_code & 0x6; // 0b110 (isolate table)
@@ -117,82 +172,89 @@ static void gp_fault_handler(struct cpu_status_t* ctx)
     panic(ctx, "gp fault");
 }
 
+/*
+ * interrupt_dispatch - Interrupt dispatcher
+ * @context: CPU context
+ *
+ * This function is where all interrupt routines go, after they passed
+ * through their corresponding vector handler in the IDT assembly stub.
+ * It catches all exceptions.
+ *
+ * Return:
+ * <context> - CPU context after interrupt
+ */
 struct cpu_status_t* interrupt_dispatch(struct cpu_status_t* context)
 {
-    if (context == NULL)
-    {
+    if (context == NULL) {
         panic(NULL, "Interrupt dispatch recieved NULL context!");
     }
 
-    switch(context->vector_number)
-    {
+    switch(context->vector_number) {
         case 0:
-            DEBUG("Divide Error!");
+            panic(context, "Divide Error");
             break;
         case 1:
-            DEBUG("Debug Exception!");
+            panic(context, "Debug Exception");
             break;
         case 2:
-            DEBUG("NMI Interrupt!");
+            panic(context, "NMI Interrupt");
             break;
         case 3:
-            DEBUG("Breakpoint Interrupt!");
+            panic(context, "Breakpoint Interrupt");
             break;
         case 4:
-            DEBUG("Overflow Trap!");
+            panic(context, "Overflow Trap");
             break;
         case 5:
-            DEBUG("BOUND Range Exceeded!");
+            panic(context, "BOUND Range Exceeded");
             break;
         case 6:
-            DEBUG("Invalid Opcode!");
-            panic(context, "Invalid Opcode!");
+            panic(context, "Invalid Opcode");
             break;
         case 7:
-            DEBUG("Device Not Available!");
+            panic(context, "Device Not Available");
             break;
         case 8:
-            DEBUG("Double Fault!");
+            panic(context, "Double Fault");
             break;
         case 9:
-            DEBUG("Coprocessor Segment Overrun!");
+            panic(context, "Coprocessor Segment Overrun");
             break;
         case 10:
-            DEBUG("Invalid TSS!");
+            panic(context, "Invalid TSS");
             break;
         case 11:
-            DEBUG("Segment Not Present!");
+            panic(context, "Segment Not Present");
             break;
         case 12:
-            DEBUG("Stack-Segment Fault!");
+            panic(context, "Stack-Segment Fault");
             break;
         case 13:
             gp_fault_handler(context);
             break;
         case 14:
-            // Better debugging for page faults...
             page_fault_handler(context);
             break;
         case 15:
-            DEBUG("Intel Reserved Interrupt! (Achievement unlocked: How Did We Get Here?)");
+            panic(context, "Intel Reserved Interrupt (Achievement unlocked: How Did We Get Here?)");
             break;
         case 16:
-            DEBUG("x87 Floating-Point Error!");
+            panic(context, "x87 Floating-Point Error");
             break;
         case 17:
-            DEBUG("Alignment Check Fault!");
+            panic(context, "Alignment Check Fault");
             break;
         case 18:
-            DEBUG("Machine Check!");
+            panic(context, "Machine Check");
             break;
         case 19:
-            DEBUG("SIMD Floating-Point Exception!");
+            panic(context, "SIMD Floating-Point Exception");
             break;
         case 20:
-            DEBUG("Virtualization Exception!");
+            panic(context, "Virtualization Exception");
             break;
         case 21:
-            DEBUG("Control Protection Exception!");
+            panic(context, "Control Protection Exception");
             break;
 
         case 32: // Timer Interrupt
@@ -200,23 +262,20 @@ struct cpu_status_t* interrupt_dispatch(struct cpu_status_t* context)
             // Send an EOI so that we can continue having interrupts
             outb(0x20, 0x20);
 
-            if (ticks % SCHEDULER_QUANTUM == 0)
-            {
+            if (ticks % SCHEDULER_QUANTUM == 0) {
                 return scheduler_schedule(context);
-                //struct cpu_status_t* current_ctx = scheduler_schedule(context);
-                //process_switch(current_ctx->iret_rsp, current_ctx->iret_rip);
-                //SET_INTERRUPTS;
             }
 
             break;
 
-        case 33:
-            DEBUG("Keyboard Interrupt");
+        case 33: // Keyboard Interrupt
             keyboard_handler();
+            //process_create("keyboard-initiated", kbdproc_main, NULL); // DEBUG
+            outb(0x20, 0x20);
             break;
 
         default:
-            DEBUG("Unexpected interrupt");
+            DEBUG("Unexpected Interrupt");
             break;
     }
 

src/arch/x86/init.c

@@ -0,0 +1,46 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   x86 architecture-dependant initialization
+ * @license GPL-3.0-only
+ */
+
+#include <mem/gdt.h>
+#include <stdint.h>
+#include <arch/x86.h>
+#include <kernel.h>
+
+/*
+ * x86_overwrite_pat - Set PAT to WC
+ *
+ * This function overwrites the 1st Page Attribute
+ * Table entry, to enable the Write-Combining property
+ * when we map memory regions later on.
+ * The framebuffer will be mapped with WC, which makes
+ * memory access significantly faster by using burst
+ * operations. 
+*/
+
+static void x86_overwrite_pat()
+{
+    uint64_t pat = rdmsr(0x277);
+    pat &= ~(0xFFULL << 8); // Clear PAT1
+    pat |= (0x01ULL << 8); // PAT1 = 0x01 (WC)
+    wrmsr(0x277, pat);
+}
+
+/*
+ * x86_arch_init - Initialize x86 CPU structures
+ *
+ * This function is responsible for overriding a PAT entry
+ * (to put the framebuffer area in WC mode) only.
+ *
+ * Later, all architecture-dependant init (GDT, IDT, TSS, ...)
+ * should be initialized here, and separate function pointers
+ * should be set up for each arch.
+ */
+void x86_arch_init()
+{
+    x86_overwrite_pat();
+    idt_init();
+    gdt_init();
+}

src/arch/x86/msr.c

@@ -0,0 +1,66 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   x86 MSR C wrappers
+ * @description
+ * Wrapper functions to access Model Specific Registers
+ *
+ * @license GPL-3.0-only
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <arch/x86.h>
+
+/*
+ * rdmsr - Read from MSR
+ * @msr: model specific register number 
+ *
+ * Read a 64-bit word from a Model Specific Register.
+ * Wrapper for the "rdmsr" instruction. It originally
+ * outputs to two 32-bit registers (EDX:EAX), so the
+ * function does the job of uniting them as a 64-bit
+ * value for us.
+ *
+ * Return:
+ * <value> - value read from MSR
+ */
+uint64_t rdmsr(uint32_t msr)
+{
+    uint32_t low;
+    uint32_t high;
+
+    __asm__ volatile("rdmsr" : "=a"(low), "=d"(high) : "c"(msr));
+
+    return ((uint64_t)high << 32) | low;
+}
+
+/*
+ * wrmsr - Write to MSR
+ * @msr: model specific register number 
+ *
+ * Write a 64-bit value to a Model Specific Register.
+ */
+void wrmsr(uint32_t msr, uint64_t value)
+{
+    uint32_t low = (uint32_t)(value & 0xFFFFFFFF);
+    uint32_t high = (uint32_t)(value >> 32);
+
+    __asm__ volatile("wrmsr" : : "c"(msr), "a"(low), "d"(high) : "memory");
+}
+
+/*
+ * x86_has_msr - Test for MSR support
+ *
+ * Checks if CPU supports Model Specific Registers
+ * using CPUID.01h:EDX[bit 5].
+ *
+ * Return:
+ * true  - MSR are supported
+ * false - MSR are not supported 
+ */
+bool x86_has_msr()
+{
+    uint32_t eax, ebx, ecx, edx;
+    cpuid(1, &eax, &ebx, &ecx, &edx);
+    return (edx & (1 << 5)) != 0;
+}

src/arch/x86/syscall.c

@@ -0,0 +1,26 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   System call handling
+ * @license GPL-3.0-only
+ */
+
+#include <arch/x86.h>
+#include <kernel.h>
+
+struct cpu_status_t* syscall_handler(struct cpu_status_t* regs)
+{
+    DEBUG("Syscall %lx with argument %lx", regs->rdi, regs->rsi);
+
+    switch (regs->rdi)
+    {
+        case 0:
+            break;
+        case 1:
+            break;
+        default:
+            regs->rsi = 0xdeadbeef;
+            break;
+    }
+
+    return regs;
+}

src/boot/boot.c

@@ -1,33 +1,34 @@
 /*
  * @author  xamidev <xamidev@riseup.net>
  * @brief   Limine requests for boot
+ * @description
+ * The kernel makes a few requests to the Limine bootloader
+ * in order to get precious information about the system.
+ * We get a framebuffer, a memory map, the address of the
+ * kernel in memory, and the Higher Half Direct Map offset.
  * @license GPL-3.0-only
  */
 
 #include <limine.h>
 
-// Framebuffer request
 __attribute__((used, section(".limine_requests")))
 volatile struct limine_framebuffer_request framebuffer_request = {
 	.id = LIMINE_FRAMEBUFFER_REQUEST,
 	.revision = 0
 };
 
-// Memory map request
 __attribute__((used, section(".limine_requests")))
 volatile struct limine_memmap_request memmap_request = {
 	.id = LIMINE_MEMMAP_REQUEST,
 	.revision = 0
 };
 
-// Higher Half Direct Map
 __attribute__((used, section(".limine_requests")))
 volatile struct limine_hhdm_request hhdm_request = {
 	.id = LIMINE_HHDM_REQUEST,
 	.revision = 0
 };
 
-// Executable Address/Kernel Address (find base phys/virt address of kernel)
 __attribute__((used, section(".limine_requests")))
 volatile struct limine_kernel_address_request kerneladdr_request = {
 	.id = LIMINE_KERNEL_ADDRESS_REQUEST,

src/config.h

@@ -1,38 +0,0 @@
-/*
- * @author  xamidev <xamidev@riseup.net>
- * @brief   PepperOS configuration file
- * @license GPL-3.0-only
- */
-
-#ifndef CONFIG_H
-#define CONFIG_H
-
-/* version */
-#define PEPPEROS_VERSION_MAJOR "0"
-#define PEPPEROS_VERSION_MINOR "0"
-#define PEPPEROS_VERSION_PATCH "58"
-#define PEPPEROS_SPLASH "pepperOS version "PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\n"
-
-/* process */
-#define PROCESS_NAME_MAX 64
-#define PROCESS_STACK_SIZE 0x10000 // 64kb
-#define PROCESS_BASE 0x400000
-#define PROCESS_STACK_BASE 0x1000000
-
-/* sched */
-// 1 tick = 1 ms => quantum = 10ms
-#define SCHEDULER_QUANTUM 10
-
-/* kernel */
-#define KERNEL_BASE 0xFFFFFFFF80000000ULL
-// 2 MB should be enough (as of now, the whole kernel ELF is around 75kb)
-#define KERNEL_SIZE 0x200000
-#define KERNEL_STACK_SIZE 65536
-
-/* heap */
-#define KHEAP_SIZE (16*1024*1024)
-
-/* term */
-#define TERM_HISTORY_MAX_LINES 256
-
-#endif

src/debug/misc.c

@@ -0,0 +1,79 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Miscellaneous debug features
+ * @license GPL-3.0-only
+ */
+
+#include <kernel.h>
+#include <limine.h>
+#include <string/string.h>
+#include <stddef.h>
+
+extern struct boot_context boot_ctx;
+
+/*
+ * memmap_display - displays a memory map
+ * @response: Limine memory map response
+ *
+ * Displays the memory map we get from Limine
+ * to see different regions, their sizes, and
+ * how the memory is laid out at handoff.
+ */
+void memmap_display(struct limine_memmap_response* response)
+{
+	DEBUG("Got memory map from Limine: revision %u, %u entries", response->revision, response->entry_count);
+
+	for (size_t i=0; i<response->entry_count; i++) {
+		struct limine_memmap_entry* entry = response->entries[i];
+		char type[32] = {0};
+		switch(entry->type) {
+			case LIMINE_MEMMAP_USABLE:
+				strcpy(type, "USABLE");
+				break;
+			case LIMINE_MEMMAP_RESERVED:
+				strcpy(type, "RESERVED");
+				break;
+			case LIMINE_MEMMAP_ACPI_RECLAIMABLE:
+				strcpy(type, "ACPI_RECLAIMABLE");
+				break;
+			case LIMINE_MEMMAP_ACPI_NVS:
+				strcpy(type, "ACPI_NVS");
+				break;
+			case LIMINE_MEMMAP_BAD_MEMORY:
+				strcpy(type, "BAD_MEMORY");
+				break;
+			case LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE:
+				strcpy(type, "BOOTLOADER_RECLAIMABLE");
+				break;
+			case LIMINE_MEMMAP_KERNEL_AND_MODULES:
+				strcpy(type, "KERNEL_AND_MODULES");
+				break;
+			case LIMINE_MEMMAP_FRAMEBUFFER:
+				strcpy(type, "FRAMEBUFFER");
+				break;
+			default:
+				strcpy(type, "UNKNOWN");
+				break;
+		}
+		DEBUG("Entry %02u: [0x%016x | %016u bytes] - %s", i, entry->base, entry->length, type);
+	}
+}
+
+/*
+ * hhdm_display - displays the HHDM offset
+ * @hhdm: Limine HHDM offset response
+ */
+void hhdm_display(struct limine_hhdm_response* hhdm)
+{
+	DEBUG("Got HHDM revision=%u offset=0x%p", hhdm->revision, hhdm->offset);
+}
+
+/*
+ * boot_mem_display - displays all memory info
+ */
+void boot_mem_display()
+{
+	memmap_display(boot_ctx.mmap);
+	hhdm_display(boot_ctx.hhdm);
+	DEBUG("Kernel is at phys_base=0x%p virt_base=0x%p", boot_ctx.kaddr->physical_base, boot_ctx.kaddr->virtual_base);
+}

src/debug/panic.c

@@ -1,23 +1,71 @@
-#include <stddef.h>
-#include "idt/idt.h"
-#include "io/serial/serial.h"
-#include "kernel.h"
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Kernel panic
+ * @license GPL-3.0-only
+ */
 
+#include <stddef.h>
+#include <arch/x86.h>
+#include <io/serial/serial.h>
+#include <kernel.h>
+
+extern struct init_status init;
+extern int panic_count;
+
+/*
+ * reaf_rflags - provide easy reading of the RFLAGS register
+ * @rflags: RFLAGS register value
+ */
+void read_rflags(uint64_t rflags)
+{
+	DEBUG("\x1b[38;5;226m%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\x1b[38;5;231m",
+		CHECK_BIT(rflags, 0) ? "CF " : "", /*carry flag*/
+		CHECK_BIT(rflags, 2) ? "PF " : "", /*parity flag*/
+		CHECK_BIT(rflags, 4) ? "AF " : "", /*auxiliary carry flag*/
+		CHECK_BIT(rflags, 6) ? "ZF " : "", /*zero flag*/
+		CHECK_BIT(rflags, 7) ? "SF " : "", /*sign flag*/
+		CHECK_BIT(rflags, 8) ? "TF " : "", /*trap flag*/
+		CHECK_BIT(rflags, 9) ? "IF " : "", /*interrupt enable flag*/
+		CHECK_BIT(rflags, 10) ? "DF " : "", /*direction flag*/
+		CHECK_BIT(rflags, 11) ? "OF " : "", /*overflow flag*/
+		(CHECK_BIT(rflags, 12) && CHECK_BIT(rflags, 13)) ? "IOPL3 " : "IOPL0 ", /*io privilege lvl*/
+		CHECK_BIT(rflags, 14) ? "NT " : "", /*nested task*/
+		CHECK_BIT(rflags, 16) ? "RF " : "", /*resume flag*/
+		CHECK_BIT(rflags, 17) ? "VM " : "", /*virtual 8086 mode*/
+		CHECK_BIT(rflags, 18) ? "AC " : "", /*alignment check/access control*/
+		CHECK_BIT(rflags, 19) ? "VIF " : "", /*virtual interrupt flag*/
+		CHECK_BIT(rflags, 20) ? "VIP " : "", /*virtual interrupt pending*/
+		CHECK_BIT(rflags, 21) ? "ID " : ""); /*id flag*/
+}
+
+/*
+ * panic - Kernel panic
+ * @ctx: CPU context (optional)
+ * @str: Error message 
+ *
+ * Ends execution of the kernel in case of an unrecoverable error.
+ * Will display to terminal if it is initialized, otherwise serial only.
+ * Can be called with or without a CPU context.
+ */
 void panic(struct cpu_status_t* ctx, const char* str)
 {
 	CLEAR_INTERRUPTS;
-	if (ctx == NULL)
-	{
-		DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m Something went horribly wrong! (no cpu ctx)");
-		DIE_DEBUG(str);
-		skputc('\n');
-		DEBUG("\x1b[38;5;231m\x1b[48;5;196mend Kernel panic - halting...\x1b[0m");
-		hcf();
-	}
-	DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m at rip=%p\nSomething went horribly wrong! vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p\n\rHalting...",
-		ctx->iret_rip,
-		ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
-		ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags);
+	panic_count += 1;
+	if (ctx == NULL) {
+		printf("\r\n\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[48;5;232m Something went horribly wrong! (no cpu ctx)");
+		printf("\r\n%s\r\n\x1b[38;5;231m\x1b[0m", str);
 		debug_stack_trace(100);
+		hcf();
+	}
+
+	printf("\r\n\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[48;5;232mat rip=%p\r\nSomething went horribly wrong! (%s) vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p ",
+	ctx->iret_rip,
+	str,
+	ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
+	ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags);
+
+	read_rflags(ctx->iret_flags);
+	debug_stack_trace(100);
+	
 	hcf();
 }

src/debug/stacktrace.c

@@ -1,35 +1,50 @@
-#include <stdint.h>
-#include "kernel.h"
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Stack trace tools
+ * @license GPL-3.0-only
+ */
 
+#include <stdint.h>
+#include <kernel.h>
+#include <stddef.h>
+
+extern struct init_status init;
+
+/*
+ * debug_stack_trace - Prints the stack trace
+ * @max_frames: Maximum amount of stack frames to walk
+ *
+ * Walks back the stack and gets all return values (RIP)
+ * and prints them to the DEBUG interface.
+ */
 void debug_stack_trace(unsigned int max_frames)
 {
-    DEBUG("*** begin stack trace ***");
+    printf("\r\n\x1b[48;5;232m\x1b[38;5;231m*** begin stack trace ***\r\n");
+
     // Thanks GCC :)
     uintptr_t* rbp = (uintptr_t*)__builtin_frame_address(0);
 
-    for (unsigned int frame=0; frame<max_frames && rbp != NULL; frame++)
-    {
+    for (unsigned int frame=0; frame<max_frames && rbp != NULL; frame++) {
         // Return address, 1 word above saved rbp
         uintptr_t rip = rbp[1];
         uintptr_t offset = 0;
         const char* name = debug_find_symbol(rip, &offset);
-        DEBUG("[%u] <0x%p> (%s+0x%x)", frame, (void*)rip, name, offset);
+        printf("[%u] <0x%p> (%s+0x%x)\r\n", frame, (void*)rip, name, offset);
 
         uintptr_t* next_rbp = (uintptr_t*)rbp[0];
 
-        // invalid rbp or we're at the end
-        if (next_rbp <= rbp || next_rbp == NULL)
-        {
+        // Invalid rbp or we're at the end
+        if (next_rbp <= rbp || next_rbp == NULL) {
             break;
         }
 
         rbp = next_rbp;
     }
-    DEBUG("*** end stack trace ***");
+
+    printf("*** end stack trace ***\r\n[end Kernel panic]\r\nHalting system...\x1b[0m");
 }
 
-typedef struct
-{
+typedef struct {
     uint64_t addr;
     const char *name;
 } __attribute__((packed)) kernel_symbol_t;
@@ -37,11 +52,19 @@ typedef struct
 __attribute__((weak)) extern kernel_symbol_t symbol_table[];
 __attribute__((weak)) extern uint64_t symbol_count;
 
-// binary search
+/*
+ * debug_find_symbol - Finds the symbol name associated to an address
+ * @rip:    Pointer to executable code
+ * @offset: Out pointer to reference the offset in the found function, if any
+ *
+ * Return:
+ * <symbol name> - symbol name
+ * "???"         - no symbol table found
+ * "unknown"     - symbol table found, but address isn't in the table
+ */
 const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset)
 {
-    if (!symbol_table || symbol_count == 0)
-    {
+    if (!symbol_table || symbol_count == 0) {
         if (offset) *offset = 0;
         return "???";
     }
@@ -49,11 +72,9 @@ const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset)
     int low = 0, high = (int)symbol_count - 1;
     int best = -1;
 
-    while (low <= high)
-    {
+    while (low <= high) {
         int mid = (low + high) / 2;
-        if (symbol_table[mid].addr <= rip)
-        {
+        if (symbol_table[mid].addr <= rip) {
             best = mid;
             low = mid + 1;
         } else {
@@ -61,15 +82,15 @@ const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset)
         }
     }
 
-    if (best != -1)
-    {
-        if (offset)
-        {
+    if (best != -1) {
+        if (offset) {
             *offset = rip - symbol_table[best].addr;
         }
         return symbol_table[best].name;
     }
 
-    if (offset) *offset = 0;
+    if (offset) {
+        *offset = 0;
+    }
     return "unknown";
 }

src/entry.S

@@ -1,23 +0,0 @@
-bits 64
-global _start
-
-extern kmain
-extern kernel_stack
-
-KERNEL_STACK_SIZE equ 65536
-
-section .text
-
-_start:
-    cli
-
-    ; load kernel stack
-    lea rsp, [kernel_stack+KERNEL_STACK_SIZE]
-
-    ; rbp=0 so last frame in stack trace
-    xor rbp, rbp
-
-    ; 16 byte align
-    and rsp, -16
-
-    call kmain

src/io/kbd/ps2.c

@@ -4,11 +4,13 @@
  * @license GPL-3.0-only
  */
 
-#include "io/serial/serial.h"
-#include "ps2.h"
+#include "config.h"
+#include <io/serial/serial.h>
+#include <io/kbd/ps2.h>
 #include <stdint.h>
-#include "io/term/term.h"
+#include <io/term/term.h>
 #include <kernel.h>
+#include <stddef.h>
 
 // The key status bitfield will be used to see if ALT, CONTROL, or SHIFT is pressed
 uint8_t key_status = 0b00000000;
@@ -17,6 +19,13 @@ uint8_t key_status = 0b00000000;
 unsigned char* keymap;
 unsigned char* keymap_shifted;
 
+// Keyboard buffer
+char keyboard_buffer[KBD_BUFFER_MAX] = {0};
+int write_index = 0;
+int read_index = 0;
+
+extern struct init_status init;
+
 unsigned char kbdus[128] =
 {
     0,  27, '1', '2', '3', '4', '5', '6', '7', '8',	/* 9 */
@@ -154,16 +163,22 @@ unsigned char kbdfr_shifted[128] =
     0
 };
 
+/*
+ * keyboard_handler - Keyboard event handler
+ *
+ * Is called from the interrupt dispatcher.
+ * When a key is pressed or released, we get a scancode, and
+ * it is then translated to an ASCII character.
+ * Left Shift, Ctrl, and Alt keys are also taken into consideration. 
+ */
 void keyboard_handler()
 {
     unsigned char scancode = inb(0x60);
 
     // Key release (bit 7 set)
-    if (scancode & 0x80)
-    {
+    if (scancode & 0x80) {
         unsigned char code = scancode & 0x7F;
-        switch (code)
-        {
+        switch (code) {
             // Clear the corresponding bit if corresponding key is released
             case LEFT_SHIFT_PRESSED:
             case RIGHT_SHIFT_PRESSED:
@@ -176,16 +191,10 @@ void keyboard_handler()
                 key_status &= ~ALT_PRESSED_BIT;
                 break;
         }
-
-        // Send EOI
-        outb(0x20, 0x20);
         return;
-    }
-    else
-    {
+    } else {
         // Key press
-        switch (scancode)
-        {
+        switch (scancode) {
             // Set bits for corresponding special key press
             case LEFT_SHIFT_PRESSED:
             case RIGHT_SHIFT_PRESSED:
@@ -200,29 +209,110 @@ void keyboard_handler()
 
             default:
             {
+                // Avoiding buffer overflow from extended keys lol
+                if (scancode < 128) {
                     // Should we get a SHIFTED char or a regular one?
                     unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];
 
-                if (c)
-                {
-                    // Should probably have a keyboard buffer here... instead of this
-                    putchar(c);
-                }
-            }
-        }
+                    if (c) {
+                        if (c == '\n') {
+                            internal_putc('\r', NULL);
                         }
 
-    // End of Interrupt (to master PIC)
-    outb(0x20, 0x20);
+                        internal_putc(c, NULL);
+                        keyboard_putchar(c);
+                    }
+                }
+            }
+        }
+    }
 }
 
+/*
+ * keyboard_getchar - Get a character from keyboard
+ *
+ * This function reads one character from the keyboard buffer.
+ * If the keyboard buffer is empty, it will block until a key
+ * is pressed.
+ *
+ * Return:
+ * <char> - character from keyboard buffer
+ */
+char keyboard_getchar()
+{
+    while (read_index == write_index); // Empty buffer
+
+    char c = keyboard_buffer[read_index];
+    read_index = (read_index+1) % KBD_BUFFER_MAX;
+    return c;
+}
+
+/*
+ * keyboard_putchar - Puts a character in the keyboard buffer
+ * @c: character to add
+ *
+ * This function is used in the keyboard handler to add new
+ * characters to the keyboard buffer.
+ *
+ * Return:
+ * %-1 - keyboard buffer is full
+ * %0 - operation completed successfully
+ */
+int keyboard_putchar(char c)
+{
+    if ((write_index+1) % KBD_BUFFER_MAX == read_index) {
+        // Full buffer
+        return -1;
+   }
+   
+   keyboard_buffer[write_index] = c;
+   write_index = (write_index+1) % KBD_BUFFER_MAX;
+   return 0;
+}
+
+/*
+ * keyboard_getline - Gets a line of input from keyboard
+ * @output: Output string
+ * @size:   Size of output string
+ *
+ * Read a line of characters from the keyboard, until the
+ * buffer fills or a newline character is read.
+ * The output string is NULL-terminated.
+ *
+ * Return:
+ * <num> - the number of characters read
+ */
+int keyboard_getline(char* output, size_t size)
+{
+    char c;
+    size_t index = 0;
+    
+    // Read until Enter is pressed
+    while ((c = keyboard_getchar()) != 0x0A) {
+        if (index == size-1) {
+            output[index] = c;
+            output[index+1] = '\0';
+            return index;
+        }
+        output[index] = c;
+        index++;
+    }
+    output[index+1] = '\0';
+    return index;
+}
+
+/*
+ * keyboard_init - Keyboard initialization
+ * @layout: Desired layout
+ *
+ * Prepares the PS/2 keyboard to recieve input.
+ */
 void keyboard_init(unsigned char layout)
 {
     // Here we might go and select PS/2, USB, or other... (once we implement multiple keyboard protocols)
 
     // Keyboard layout selection
-    switch (layout)
-    {
+    switch (layout) {
         case US:
             keymap = kbdus;
             keymap_shifted = kbdus_shifted;
@@ -233,14 +323,20 @@ void keyboard_init(unsigned char layout)
             break;
         
         default:
-            skputs("Unsupported layout.");
+            panic(NULL, "Unsupported keyboard layout");
             return;
     }
 
+    // Flush keyboard buffer
+    while (inb(0x64) & 1) {
+        inb(0x60);
+    }
+
     // Unmask IRQ1
     uint8_t mask = inb(0x21);
     mask &= ~(1 << 1);
     outb(0x21, mask);
 
     DEBUG("PS/2 Keyboard initialized");
+    init.keyboard = true;
 }

src/io/serial/serial.c

@@ -5,13 +5,33 @@
  */
  
 #include <kernel.h>
-#include "serial.h"
+#include <io/serial/serial.h>
+#include <sched/spinlock.h>
 
+extern struct init_status init;
+
+extern int panic_count;
+struct spinlock_t serial_lock = {0};
+
+/*
+ * outb - Writes a byte to a CPU port
+ * @port: CPU port to write to
+ * @data: Byte to write
+ *
+ * Writes a single byte to the serial interface.
+ */
 void outb(int port, unsigned char data)
 {
     __asm__ __volatile__("outb %%al, %%dx" :: "a" (data),"d" (port));
 }
 
+/*
+ * inb - Gets a byte in through a CPU port
+ * @port: The CPU port to get a byte from
+ *
+ * Return:
+ * <data> - byte got from port
+ */
 unsigned char inb(int port)
 {
     unsigned char data = 0;
@@ -19,9 +39,13 @@ unsigned char inb(int port)
     return data;
 }
 
-// COM1
-#define PORT 0x3F8
-
+/*
+ * serial_init - Initializes serial interface
+ * 
+ * Return:
+ * %-EIO - Input/output error
+ * %0    - Success
+ */
 int serial_init()
 {
     outb(PORT + 1, 0x00);      // Disable all interrupts
@@ -34,36 +58,58 @@ int serial_init()
     outb(PORT + 4, 0x1E);    // Set in loopback mode, test the serial chip
     outb(PORT + 0, 0xAE);    // Test serial chip (send byte 0xAE and check if serial returns same byte)
 
-    if (inb(PORT) != 0xAE)
-    {
+    if (inb(PORT) != 0xAE) {
         return -EIO;
     }
 
     // Set normal operation mode
     outb(PORT + 4, 0x0F);
 
-    DEBUG("serial initialized");
+    init.serial = true;
+    DEBUG("*** Welcome to PepperOS! (built @ %s %s) ***", __DATE__, __TIME__);
     return 0;
 }
 
+/*
+ * is_transmit_empty - Check if the serial transmit register is empty
+ *
+ * Return: Non-zero if the transmit register is empty and a new
+ * byte can be written to the serial port, 0 otherwise.
+ */
 static int is_transmit_empty()
 {
     return inb(PORT + 5) & 0x20;
 }
 
-// Serial kernel putchar
+/*
+ * skputc - Serial kernel putchar
+ * @c: character to write
+ *
+ * Writes a single character to the serial interface.
+ */
 void skputc(char c)
 {
+    if (panic_count == 0) {
+        spinlock_acquire(&serial_lock);
         while (!is_transmit_empty()); // wait for free spot
         outb(PORT, c);
+        spinlock_release(&serial_lock);
+    } else {
+        while (!is_transmit_empty());
+        outb(PORT, c);
+    }
 }
 
-// Serial kernel putstring
+/*
+ * skputs - Serial kernel puts
+ * @str: Message to write
+ *
+ * Writes a non-formatted string to serial output.
+ */
 void skputs(const char* str)
 {
     unsigned int i=0;
-    while (str[i])
-    {
+    while (str[i]) {
         skputc(str[i]);
         i++;
     }

src/io/term/printf.c

@@ -1,914 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-// \author (c) Marco Paland (info@paland.com)
-//             2014-2019, PALANDesign Hannover, Germany
-//
-// \license The MIT License (MIT)
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-// \brief Tiny printf, sprintf and (v)snprintf implementation, optimized for speed on
-//        embedded systems with a very limited resources. These routines are thread
-//        safe and reentrant!
-//        Use this instead of the bloated standard/newlib printf cause these use
-//        malloc for printf (and may not be thread safe).
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#include <stdbool.h>
-#include <stdint.h>
-
-#include "printf.h"
-
-
-// define this globally (e.g. gcc -DPRINTF_INCLUDE_CONFIG_H ...) to include the
-// printf_config.h header file
-// default: undefined
-#ifdef PRINTF_INCLUDE_CONFIG_H
-#include "printf_config.h"
-#endif
-
-
-// 'ntoa' conversion buffer size, this must be big enough to hold one converted
-// numeric number including padded zeros (dynamically created on stack)
-// default: 32 byte
-#ifndef PRINTF_NTOA_BUFFER_SIZE
-#define PRINTF_NTOA_BUFFER_SIZE    32U
-#endif
-
-// 'ftoa' conversion buffer size, this must be big enough to hold one converted
-// float number including padded zeros (dynamically created on stack)
-// default: 32 byte
-#ifndef PRINTF_FTOA_BUFFER_SIZE
-#define PRINTF_FTOA_BUFFER_SIZE    32U
-#endif
-
-// support for the floating point type (%f)
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_FLOAT
-#define PRINTF_SUPPORT_FLOAT
-#endif
-
-// support for exponential floating point notation (%e/%g)
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_EXPONENTIAL
-#define PRINTF_SUPPORT_EXPONENTIAL
-#endif
-
-// define the default floating point precision
-// default: 6 digits
-#ifndef PRINTF_DEFAULT_FLOAT_PRECISION
-#define PRINTF_DEFAULT_FLOAT_PRECISION  6U
-#endif
-
-// define the largest float suitable to print with %f
-// default: 1e9
-#ifndef PRINTF_MAX_FLOAT
-#define PRINTF_MAX_FLOAT  1e9
-#endif
-
-// support for the long long types (%llu or %p)
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_LONG_LONG
-#define PRINTF_SUPPORT_LONG_LONG
-#endif
-
-// support for the ptrdiff_t type (%t)
-// ptrdiff_t is normally defined in <stddef.h> as long or long long type
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_PTRDIFF_T
-#define PRINTF_SUPPORT_PTRDIFF_T
-#endif
-
-///////////////////////////////////////////////////////////////////////////////
-
-// internal flag definitions
-#define FLAGS_ZEROPAD   (1U <<  0U)
-#define FLAGS_LEFT      (1U <<  1U)
-#define FLAGS_PLUS      (1U <<  2U)
-#define FLAGS_SPACE     (1U <<  3U)
-#define FLAGS_HASH      (1U <<  4U)
-#define FLAGS_UPPERCASE (1U <<  5U)
-#define FLAGS_CHAR      (1U <<  6U)
-#define FLAGS_SHORT     (1U <<  7U)
-#define FLAGS_LONG      (1U <<  8U)
-#define FLAGS_LONG_LONG (1U <<  9U)
-#define FLAGS_PRECISION (1U << 10U)
-#define FLAGS_ADAPT_EXP (1U << 11U)
-
-
-// import float.h for DBL_MAX
-#if defined(PRINTF_SUPPORT_FLOAT)
-#include <float.h>
-#endif
-
-
-// output function type
-typedef void (*out_fct_type)(char character, void* buffer, size_t idx, size_t maxlen);
-
-
-// wrapper (used as buffer) for output function type
-typedef struct {
-  void  (*fct)(char character, void* arg);
-  void* arg;
-} out_fct_wrap_type;
-
-
-// internal buffer output
-static inline void _out_buffer(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  if (idx < maxlen) {
-    ((char*)buffer)[idx] = character;
-  }
-}
-
-
-// internal null output
-static inline void _out_null(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  (void)character; (void)buffer; (void)idx; (void)maxlen;
-}
-
-
-// internal _putchar wrapper
-static inline void _out_char(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  (void)buffer; (void)idx; (void)maxlen;
-  if (character) {
-    _putchar(character);
-  }
-}
-
-
-// internal output function wrapper
-static inline void _out_fct(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  (void)idx; (void)maxlen;
-  if (character) {
-    // buffer is the output fct pointer
-    ((out_fct_wrap_type*)buffer)->fct(character, ((out_fct_wrap_type*)buffer)->arg);
-  }
-}
-
-
-// internal secure strlen
-// \return The length of the string (excluding the terminating 0) limited by 'maxsize'
-static inline unsigned int _strnlen_s(const char* str, size_t maxsize)
-{
-  const char* s;
-  for (s = str; *s && maxsize--; ++s);
-  return (unsigned int)(s - str);
-}
-
-
-// internal test if char is a digit (0-9)
-// \return true if char is a digit
-static inline bool _is_digit(char ch)
-{
-  return (ch >= '0') && (ch <= '9');
-}
-
-
-// internal ASCII string to unsigned int conversion
-static unsigned int _atoi(const char** str)
-{
-  unsigned int i = 0U;
-  while (_is_digit(**str)) {
-    i = i * 10U + (unsigned int)(*((*str)++) - '0');
-  }
-  return i;
-}
-
-
-// output the specified string in reverse, taking care of any zero-padding
-static size_t _out_rev(out_fct_type out, char* buffer, size_t idx, size_t maxlen, const char* buf, size_t len, unsigned int width, unsigned int flags)
-{
-  const size_t start_idx = idx;
-
-  // pad spaces up to given width
-  if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD)) {
-    for (size_t i = len; i < width; i++) {
-      out(' ', buffer, idx++, maxlen);
-    }
-  }
-
-  // reverse string
-  while (len) {
-    out(buf[--len], buffer, idx++, maxlen);
-  }
-
-  // append pad spaces up to given width
-  if (flags & FLAGS_LEFT) {
-    while (idx - start_idx < width) {
-      out(' ', buffer, idx++, maxlen);
-    }
-  }
-
-  return idx;
-}
-
-
-// internal itoa format
-static size_t _ntoa_format(out_fct_type out, char* buffer, size_t idx, size_t maxlen, char* buf, size_t len, bool negative, unsigned int base, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  // pad leading zeros
-  if (!(flags & FLAGS_LEFT)) {
-    if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
-      width--;
-    }
-    while ((len < prec) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = '0';
-    }
-    while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = '0';
-    }
-  }
-
-  // handle hash
-  if (flags & FLAGS_HASH) {
-    if (!(flags & FLAGS_PRECISION) && len && ((len == prec) || (len == width))) {
-      len--;
-      if (len && (base == 16U)) {
-        len--;
-      }
-    }
-    if ((base == 16U) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = 'x';
-    }
-    else if ((base == 16U) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = 'X';
-    }
-    else if ((base == 2U) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = 'b';
-    }
-    if (len < PRINTF_NTOA_BUFFER_SIZE) {
-      buf[len++] = '0';
-    }
-  }
-
-  if (len < PRINTF_NTOA_BUFFER_SIZE) {
-    if (negative) {
-      buf[len++] = '-';
-    }
-    else if (flags & FLAGS_PLUS) {
-      buf[len++] = '+';  // ignore the space if the '+' exists
-    }
-    else if (flags & FLAGS_SPACE) {
-      buf[len++] = ' ';
-    }
-  }
-
-  return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
-}
-
-
-// internal itoa for 'long' type
-static size_t _ntoa_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, unsigned long value, bool negative, unsigned long base, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  char buf[PRINTF_NTOA_BUFFER_SIZE];
-  size_t len = 0U;
-
-  // no hash for 0 values
-  if (!value) {
-    flags &= ~FLAGS_HASH;
-  }
-
-  // write if precision != 0 and value is != 0
-  if (!(flags & FLAGS_PRECISION) || value) {
-    do {
-      const char digit = (char)(value % base);
-      buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
-      value /= base;
-    } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
-  }
-
-  return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags);
-}
-
-
-// internal itoa for 'long long' type
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-static size_t _ntoa_long_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, unsigned long long value, bool negative, unsigned long long base, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  char buf[PRINTF_NTOA_BUFFER_SIZE];
-  size_t len = 0U;
-
-  // no hash for 0 values
-  if (!value) {
-    flags &= ~FLAGS_HASH;
-  }
-
-  // write if precision != 0 and value is != 0
-  if (!(flags & FLAGS_PRECISION) || value) {
-    do {
-      const char digit = (char)(value % base);
-      buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
-      value /= base;
-    } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
-  }
-
-  return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags);
-}
-#endif  // PRINTF_SUPPORT_LONG_LONG
-
-
-#if defined(PRINTF_SUPPORT_FLOAT)
-
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-// forward declaration so that _ftoa can switch to exp notation for values > PRINTF_MAX_FLOAT
-static size_t _etoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags);
-#endif
-
-
-// internal ftoa for fixed decimal floating point
-static size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  char buf[PRINTF_FTOA_BUFFER_SIZE];
-  size_t len  = 0U;
-  double diff = 0.0;
-
-  // powers of 10
-  static const double pow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 };
-
-  // test for special values
-  if (value != value)
-    return _out_rev(out, buffer, idx, maxlen, "nan", 3, width, flags);
-  if (value < -DBL_MAX)
-    return _out_rev(out, buffer, idx, maxlen, "fni-", 4, width, flags);
-  if (value > DBL_MAX)
-    return _out_rev(out, buffer, idx, maxlen, (flags & FLAGS_PLUS) ? "fni+" : "fni", (flags & FLAGS_PLUS) ? 4U : 3U, width, flags);
-
-  // test for very large values
-  // standard printf behavior is to print EVERY whole number digit -- which could be 100s of characters overflowing your buffers == bad
-  if ((value > PRINTF_MAX_FLOAT) || (value < -PRINTF_MAX_FLOAT)) {
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-    return _etoa(out, buffer, idx, maxlen, value, prec, width, flags);
-#else
-    return 0U;
-#endif
-  }
-
-  // test for negative
-  bool negative = false;
-  if (value < 0) {
-    negative = true;
-    value = 0 - value;
-  }
-
-  // set default precision, if not set explicitly
-  if (!(flags & FLAGS_PRECISION)) {
-    prec = PRINTF_DEFAULT_FLOAT_PRECISION;
-  }
-  // limit precision to 9, cause a prec >= 10 can lead to overflow errors
-  while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9U)) {
-    buf[len++] = '0';
-    prec--;
-  }
-
-  int whole = (int)value;
-  double tmp = (value - whole) * pow10[prec];
-  unsigned long frac = (unsigned long)tmp;
-  diff = tmp - frac;
-
-  if (diff > 0.5) {
-    ++frac;
-    // handle rollover, e.g. case 0.99 with prec 1 is 1.0
-    if (frac >= pow10[prec]) {
-      frac = 0;
-      ++whole;
-    }
-  }
-  else if (diff < 0.5) {
-  }
-  else if ((frac == 0U) || (frac & 1U)) {
-    // if halfway, round up if odd OR if last digit is 0
-    ++frac;
-  }
-
-  if (prec == 0U) {
-    diff = value - (double)whole;
-    if ((!(diff < 0.5) || (diff > 0.5)) && (whole & 1)) {
-      // exactly 0.5 and ODD, then round up
-      // 1.5 -> 2, but 2.5 -> 2
-      ++whole;
-    }
-  }
-  else {
-    unsigned int count = prec;
-    // now do fractional part, as an unsigned number
-    while (len < PRINTF_FTOA_BUFFER_SIZE) {
-      --count;
-      buf[len++] = (char)(48U + (frac % 10U));
-      if (!(frac /= 10U)) {
-        break;
-      }
-    }
-    // add extra 0s
-    while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) {
-      buf[len++] = '0';
-    }
-    if (len < PRINTF_FTOA_BUFFER_SIZE) {
-      // add decimal
-      buf[len++] = '.';
-    }
-  }
-
-  // do whole part, number is reversed
-  while (len < PRINTF_FTOA_BUFFER_SIZE) {
-    buf[len++] = (char)(48 + (whole % 10));
-    if (!(whole /= 10)) {
-      break;
-    }
-  }
-
-  // pad leading zeros
-  if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) {
-    if (width && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
-      width--;
-    }
-    while ((len < width) && (len < PRINTF_FTOA_BUFFER_SIZE)) {
-      buf[len++] = '0';
-    }
-  }
-
-  if (len < PRINTF_FTOA_BUFFER_SIZE) {
-    if (negative) {
-      buf[len++] = '-';
-    }
-    else if (flags & FLAGS_PLUS) {
-      buf[len++] = '+';  // ignore the space if the '+' exists
-    }
-    else if (flags & FLAGS_SPACE) {
-      buf[len++] = ' ';
-    }
-  }
-
-  return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
-}
-
-
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-// internal ftoa variant for exponential floating-point type, contributed by Martijn Jasperse <m.jasperse@gmail.com>
-static size_t _etoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  // check for NaN and special values
-  if ((value != value) || (value > DBL_MAX) || (value < -DBL_MAX)) {
-    return _ftoa(out, buffer, idx, maxlen, value, prec, width, flags);
-  }
-
-  // determine the sign
-  const bool negative = value < 0;
-  if (negative) {
-    value = -value;
-  }
-
-  // default precision
-  if (!(flags & FLAGS_PRECISION)) {
-    prec = PRINTF_DEFAULT_FLOAT_PRECISION;
-  }
-
-  // determine the decimal exponent
-  // based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c)
-  union {
-    uint64_t U;
-    double   F;
-  } conv;
-
-  conv.F = value;
-  int exp2 = (int)((conv.U >> 52U) & 0x07FFU) - 1023;           // effectively log2
-  conv.U = (conv.U & ((1ULL << 52U) - 1U)) | (1023ULL << 52U);  // drop the exponent so conv.F is now in [1,2)
-  // now approximate log10 from the log2 integer part and an expansion of ln around 1.5
-  int expval = (int)(0.1760912590558 + exp2 * 0.301029995663981 + (conv.F - 1.5) * 0.289529654602168);
-  // now we want to compute 10^expval but we want to be sure it won't overflow
-  exp2 = (int)(expval * 3.321928094887362 + 0.5);
-  const double z  = expval * 2.302585092994046 - exp2 * 0.6931471805599453;
-  const double z2 = z * z;
-  conv.U = (uint64_t)(exp2 + 1023) << 52U;
-  // compute exp(z) using continued fractions, see https://en.wikipedia.org/wiki/Exponential_function#Continued_fractions_for_ex
-  conv.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14)))));
-  // correct for rounding errors
-  if (value < conv.F) {
-    expval--;
-    conv.F /= 10;
-  }
-
-  // the exponent format is "%+03d" and largest value is "307", so set aside 4-5 characters
-  unsigned int minwidth = ((expval < 100) && (expval > -100)) ? 4U : 5U;
-
-  // in "%g" mode, "prec" is the number of *significant figures* not decimals
-  if (flags & FLAGS_ADAPT_EXP) {
-    // do we want to fall-back to "%f" mode?
-    if ((value >= 1e-4) && (value < 1e6)) {
-      if ((int)prec > expval) {
-        prec = (unsigned)((int)prec - expval - 1);
-      }
-      else {
-        prec = 0;
-      }
-      flags |= FLAGS_PRECISION;   // make sure _ftoa respects precision
-      // no characters in exponent
-      minwidth = 0U;
-      expval   = 0;
-    }
-    else {
-      // we use one sigfig for the whole part
-      if ((prec > 0) && (flags & FLAGS_PRECISION)) {
-        --prec;
-      }
-    }
-  }
-
-  // will everything fit?
-  unsigned int fwidth = width;
-  if (width > minwidth) {
-    // we didn't fall-back so subtract the characters required for the exponent
-    fwidth -= minwidth;
-  } else {
-    // not enough characters, so go back to default sizing
-    fwidth = 0U;
-  }
-  if ((flags & FLAGS_LEFT) && minwidth) {
-    // if we're padding on the right, DON'T pad the floating part
-    fwidth = 0U;
-  }
-
-  // rescale the float value
-  if (expval) {
-    value /= conv.F;
-  }
-
-  // output the floating part
-  const size_t start_idx = idx;
-  idx = _ftoa(out, buffer, idx, maxlen, negative ? -value : value, prec, fwidth, flags & ~FLAGS_ADAPT_EXP);
-
-  // output the exponent part
-  if (minwidth) {
-    // output the exponential symbol
-    out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen);
-    // output the exponent value
-    idx = _ntoa_long(out, buffer, idx, maxlen, (expval < 0) ? -expval : expval, expval < 0, 10, 0, minwidth-1, FLAGS_ZEROPAD | FLAGS_PLUS);
-    // might need to right-pad spaces
-    if (flags & FLAGS_LEFT) {
-      while (idx - start_idx < width) out(' ', buffer, idx++, maxlen);
-    }
-  }
-  return idx;
-}
-#endif  // PRINTF_SUPPORT_EXPONENTIAL
-#endif  // PRINTF_SUPPORT_FLOAT
-
-
-// internal vsnprintf
-static int _vsnprintf(out_fct_type out, char* buffer, const size_t maxlen, const char* format, va_list va)
-{
-  unsigned int flags, width, precision, n;
-  size_t idx = 0U;
-
-  if (!buffer) {
-    // use null output function
-    out = _out_null;
-  }
-
-  while (*format)
-  {
-    // format specifier?  %[flags][width][.precision][length]
-    if (*format != '%') {
-      // no
-      out(*format, buffer, idx++, maxlen);
-      format++;
-      continue;
-    }
-    else {
-      // yes, evaluate it
-      format++;
-    }
-
-    // evaluate flags
-    flags = 0U;
-    do {
-      switch (*format) {
-        case '0': flags |= FLAGS_ZEROPAD; format++; n = 1U; break;
-        case '-': flags |= FLAGS_LEFT;    format++; n = 1U; break;
-        case '+': flags |= FLAGS_PLUS;    format++; n = 1U; break;
-        case ' ': flags |= FLAGS_SPACE;   format++; n = 1U; break;
-        case '#': flags |= FLAGS_HASH;    format++; n = 1U; break;
-        default :                                   n = 0U; break;
-      }
-    } while (n);
-
-    // evaluate width field
-    width = 0U;
-    if (_is_digit(*format)) {
-      width = _atoi(&format);
-    }
-    else if (*format == '*') {
-      const int w = va_arg(va, int);
-      if (w < 0) {
-        flags |= FLAGS_LEFT;    // reverse padding
-        width = (unsigned int)-w;
-      }
-      else {
-        width = (unsigned int)w;
-      }
-      format++;
-    }
-
-    // evaluate precision field
-    precision = 0U;
-    if (*format == '.') {
-      flags |= FLAGS_PRECISION;
-      format++;
-      if (_is_digit(*format)) {
-        precision = _atoi(&format);
-      }
-      else if (*format == '*') {
-        const int prec = (int)va_arg(va, int);
-        precision = prec > 0 ? (unsigned int)prec : 0U;
-        format++;
-      }
-    }
-
-    // evaluate length field
-    switch (*format) {
-      case 'l' :
-        flags |= FLAGS_LONG;
-        format++;
-        if (*format == 'l') {
-          flags |= FLAGS_LONG_LONG;
-          format++;
-        }
-        break;
-      case 'h' :
-        flags |= FLAGS_SHORT;
-        format++;
-        if (*format == 'h') {
-          flags |= FLAGS_CHAR;
-          format++;
-        }
-        break;
-#if defined(PRINTF_SUPPORT_PTRDIFF_T)
-      case 't' :
-        flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
-        format++;
-        break;
-#endif
-      case 'j' :
-        flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
-        format++;
-        break;
-      case 'z' :
-        flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
-        format++;
-        break;
-      default :
-        break;
-    }
-
-    // evaluate specifier
-    switch (*format) {
-      case 'd' :
-      case 'i' :
-      case 'u' :
-      case 'x' :
-      case 'X' :
-      case 'o' :
-      case 'b' : {
-        // set the base
-        unsigned int base;
-        if (*format == 'x' || *format == 'X') {
-          base = 16U;
-        }
-        else if (*format == 'o') {
-          base =  8U;
-        }
-        else if (*format == 'b') {
-          base =  2U;
-        }
-        else {
-          base = 10U;
-          flags &= ~FLAGS_HASH;   // no hash for dec format
-        }
-        // uppercase
-        if (*format == 'X') {
-          flags |= FLAGS_UPPERCASE;
-        }
-
-        // no plus or space flag for u, x, X, o, b
-        if ((*format != 'i') && (*format != 'd')) {
-          flags &= ~(FLAGS_PLUS | FLAGS_SPACE);
-        }
-
-        // ignore '0' flag when precision is given
-        if (flags & FLAGS_PRECISION) {
-          flags &= ~FLAGS_ZEROPAD;
-        }
-
-        // convert the integer
-        if ((*format == 'i') || (*format == 'd')) {
-          // signed
-          if (flags & FLAGS_LONG_LONG) {
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-            const long long value = va_arg(va, long long);
-            idx = _ntoa_long_long(out, buffer, idx, maxlen, (unsigned long long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
-#endif
-          }
-          else if (flags & FLAGS_LONG) {
-            const long value = va_arg(va, long);
-            idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
-          }
-          else {
-            const int value = (flags & FLAGS_CHAR) ? (char)va_arg(va, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(va, int) : va_arg(va, int);
-            idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned int)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
-          }
-        }
-        else {
-          // unsigned
-          if (flags & FLAGS_LONG_LONG) {
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-            idx = _ntoa_long_long(out, buffer, idx, maxlen, va_arg(va, unsigned long long), false, base, precision, width, flags);
-#endif
-          }
-          else if (flags & FLAGS_LONG) {
-            idx = _ntoa_long(out, buffer, idx, maxlen, va_arg(va, unsigned long), false, base, precision, width, flags);
-          }
-          else {
-            const unsigned int value = (flags & FLAGS_CHAR) ? (unsigned char)va_arg(va, unsigned int) : (flags & FLAGS_SHORT) ? (unsigned short int)va_arg(va, unsigned int) : va_arg(va, unsigned int);
-            idx = _ntoa_long(out, buffer, idx, maxlen, value, false, base, precision, width, flags);
-          }
-        }
-        format++;
-        break;
-      }
-#if defined(PRINTF_SUPPORT_FLOAT)
-      case 'f' :
-      case 'F' :
-        if (*format == 'F') flags |= FLAGS_UPPERCASE;
-        idx = _ftoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags);
-        format++;
-        break;
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-      case 'e':
-      case 'E':
-      case 'g':
-      case 'G':
-        if ((*format == 'g')||(*format == 'G')) flags |= FLAGS_ADAPT_EXP;
-        if ((*format == 'E')||(*format == 'G')) flags |= FLAGS_UPPERCASE;
-        idx = _etoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags);
-        format++;
-        break;
-#endif  // PRINTF_SUPPORT_EXPONENTIAL
-#endif  // PRINTF_SUPPORT_FLOAT
-      case 'c' : {
-        unsigned int l = 1U;
-        // pre padding
-        if (!(flags & FLAGS_LEFT)) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        // char output
-        out((char)va_arg(va, int), buffer, idx++, maxlen);
-        // post padding
-        if (flags & FLAGS_LEFT) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        format++;
-        break;
-      }
-
-      case 's' : {
-        const char* p = va_arg(va, char*);
-        unsigned int l = _strnlen_s(p, precision ? precision : (size_t)-1);
-        // pre padding
-        if (flags & FLAGS_PRECISION) {
-          l = (l < precision ? l : precision);
-        }
-        if (!(flags & FLAGS_LEFT)) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        // string output
-        while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) {
-          out(*(p++), buffer, idx++, maxlen);
-        }
-        // post padding
-        if (flags & FLAGS_LEFT) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        format++;
-        break;
-      }
-
-      case 'p' : {
-        width = sizeof(void*) * 2U;
-        flags |= FLAGS_ZEROPAD | FLAGS_UPPERCASE;
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-        const bool is_ll = sizeof(uintptr_t) == sizeof(long long);
-        if (is_ll) {
-          idx = _ntoa_long_long(out, buffer, idx, maxlen, (uintptr_t)va_arg(va, void*), false, 16U, precision, width, flags);
-        }
-        else {
-#endif
-          idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)((uintptr_t)va_arg(va, void*)), false, 16U, precision, width, flags);
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-        }
-#endif
-        format++;
-        break;
-      }
-
-      case '%' :
-        out('%', buffer, idx++, maxlen);
-        format++;
-        break;
-
-      default :
-        out(*format, buffer, idx++, maxlen);
-        format++;
-        break;
-    }
-  }
-
-  // termination
-  out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen);
-
-  // return written chars without terminating \0
-  return (int)idx;
-}
-
-
-///////////////////////////////////////////////////////////////////////////////
-
-int printf_(const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  char buffer[1];
-  const int ret = _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
-  va_end(va);
-  return ret;
-}
-
-
-int sprintf_(char* buffer, const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va);
-  va_end(va);
-  return ret;
-}
-
-
-int snprintf_(char* buffer, size_t count, const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  const int ret = _vsnprintf(_out_buffer, buffer, count, format, va);
-  va_end(va);
-  return ret;
-}
-
-
-int vprintf_(const char* format, va_list va)
-{
-  char buffer[1];
-  return _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
-}
-
-
-int vsnprintf_(char* buffer, size_t count, const char* format, va_list va)
-{
-  return _vsnprintf(_out_buffer, buffer, count, format, va);
-}
-
-
-int fctprintf(void (*out)(char character, void* arg), void* arg, const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  const out_fct_wrap_type out_fct_wrap = { out, arg };
-  const int ret = _vsnprintf(_out_fct, (char*)(uintptr_t)&out_fct_wrap, (size_t)-1, format, va);
-  va_end(va);
-  return ret;
-}

src/io/term/printf.h

@@ -1,117 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-// \author (c) Marco Paland (info@paland.com)
-//             2014-2019, PALANDesign Hannover, Germany
-//
-// \license The MIT License (MIT)
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-// 
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-// \brief Tiny printf, sprintf and snprintf implementation, optimized for speed on
-//        embedded systems with a very limited resources.
-//        Use this instead of bloated standard/newlib printf.
-//        These routines are thread safe and reentrant.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef _PRINTF_H_
-#define _PRINTF_H_
-
-#include <stdarg.h>
-#include <stddef.h>
-
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-
-/**
- * Output a character to a custom device like UART, used by the printf() function
- * This function is declared here only. You have to write your custom implementation somewhere
- * \param character Character to output
- */
-void _putchar(char character);
-
-
-/**
- * Tiny printf implementation
- * You have to implement _putchar if you use printf()
- * To avoid conflicts with the regular printf() API it is overridden by macro defines
- * and internal underscore-appended functions like printf_() are used
- * \param format A string that specifies the format of the output
- * \return The number of characters that are written into the array, not counting the terminating null character
- */
-#define printf printf_
-int printf_(const char* format, ...);
-
-
-/**
- * Tiny sprintf implementation
- * Due to security reasons (buffer overflow) YOU SHOULD CONSIDER USING (V)SNPRINTF INSTEAD!
- * \param buffer A pointer to the buffer where to store the formatted string. MUST be big enough to store the output!
- * \param format A string that specifies the format of the output
- * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
- */
-#define sprintf sprintf_
-int sprintf_(char* buffer, const char* format, ...);
-
-
-/**
- * Tiny snprintf/vsnprintf implementation
- * \param buffer A pointer to the buffer where to store the formatted string
- * \param count The maximum number of characters to store in the buffer, including a terminating null character
- * \param format A string that specifies the format of the output
- * \param va A value identifying a variable arguments list
- * \return The number of characters that COULD have been written into the buffer, not counting the terminating
- *         null character. A value equal or larger than count indicates truncation. Only when the returned value
- *         is non-negative and less than count, the string has been completely written.
- */
-#define snprintf  snprintf_
-#define vsnprintf vsnprintf_
-int  snprintf_(char* buffer, size_t count, const char* format, ...);
-int vsnprintf_(char* buffer, size_t count, const char* format, va_list va);
-
-
-/**
- * Tiny vprintf implementation
- * \param format A string that specifies the format of the output
- * \param va A value identifying a variable arguments list
- * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
- */
-#define vprintf vprintf_
-int vprintf_(const char* format, va_list va);
-
-
-/**
- * printf with output function
- * You may use this as dynamic alternative to printf() with its fixed _putchar() output
- * \param out An output function which takes one character and an argument pointer
- * \param arg An argument pointer for user data passed to output function
- * \param format A string that specifies the format of the output
- * \return The number of characters that are sent to the output function, not counting the terminating null character
- */
-int fctprintf(void (*out)(char character, void* arg), void* arg, const char* format, ...);
-
-
-#ifdef __cplusplus
-}
-#endif
-
-
-#endif  // _PRINTF_H_

src/io/term/term.c

@@ -11,205 +11,196 @@ because this shitty implementation will be replaced one day by Flanterm
 (once memory management is okay: paging & kernel malloc)
 */
 
-#include <limine.h>
 #include <stddef.h>
 #include <kernel.h>
-#include "term.h"
-#include "mem/misc/utils.h"
-#include "config.h"
+#include <io/term/term.h>
+#include <config.h>
+#include <io/term/flanterm.h>
+#include <io/term/flanterm_backends/fb.h>
+#include <mem/kheap.h>
+#include <limine.h>
+#include <stdarg.h>
+#include <sched/spinlock.h>
+#include <io/serial/serial.h>
 
-extern struct boot_context boot_ctx;
+#define NANOPRINTF_IMPLEMENTATION
+#include <io/term/nanoprintf.h>
 
-// Importing the PSF object file
-extern unsigned char _binary_zap_light16_psf_start[];
-extern unsigned char _binary_zap_light16_psf_end[];
+extern struct flanterm_context* ft_ctx;
+extern struct init_status init;
 
-PSF1_Header* font = (PSF1_Header*)_binary_zap_light16_psf_start;
-uint8_t* glyphs = _binary_zap_light16_psf_start + sizeof(PSF1_Header);
+struct spinlock_t term_lock = {0};
+struct spinlock_t printf_lock = {0};
 
-#define FONT_WIDTH 8
-#define FONT_HEIGHT font->characterSize
+extern int panic_count;
 
-
-
-// Character cursor
-typedef struct
+/*
+ * internal_putc - Internal putchar function
+ * @c: char to print
+ * @_: (unused, for nanoprintf)
+ *
+ * Prints a character to the terminal if it's ready,
+ * and also to the serial interface if it's ready.
+ */
+void internal_putc(int c, void *_)
 {
-	size_t x;
-	size_t y;
-} Cursor;
+    (void)_;
+    char ch = (char)c;
 
-static Cursor cursor = {0, 0};
-
-static uint8_t* fb;
-static struct limine_framebuffer* framebuffer;
-
-uint8_t lines_length[TERM_HISTORY_MAX_LINES];
-
-static inline size_t term_max_cols(void)
-{
-	return framebuffer->width / FONT_WIDTH;
-}
-
-static inline size_t term_max_lines(void)
-{
-	return framebuffer->height / FONT_HEIGHT;
-}
-
-int term_init()
-{
-	// Get framebuffer address from Limine struct
-	
-	if (!boot_ctx.fb)
-	{
-		return -ENOMEM;
+    if (init.terminal) {
+        if (panic_count == 0) {
+            spinlock_acquire(&term_lock);
+            flanterm_write(ft_ctx, &ch, 1);
+            spinlock_release(&term_lock);
+        } else {
+            flanterm_write(ft_ctx, &ch, 1);
+        }
     }
 
-	framebuffer = boot_ctx.fb;
-	fb = (uint8_t*)framebuffer->address;
-
-	memset(lines_length, 0, sizeof(lines_length));
-
-	DEBUG("terminal initialized, fb=0x%p (width=%u height=%u pitch=%u bpp=%u)", fb, framebuffer->width, framebuffer->height, framebuffer->pitch, framebuffer->bpp);
-	return 0;
-}
-
-// These are marked "static" because we don't wanna expose them all around
-// AKA they should just be seen here (kind of like private functions in cpp)
-static inline void putpixel(size_t x, size_t y, uint32_t color)
-{
-	// Guard so we don't write past fb boundaries
-	if (x >= framebuffer->width || y >= framebuffer->height) return;
-	// Depth isn't part of limine_framebuffer attributes so it will be 4
-	size_t pos = x*4 + y*framebuffer->pitch;
-	fb[pos] = color & 255; // blue channel
-	fb[pos+1] = (color >> 8) & 255; // green
-	fb[pos+2] = (color >> 16) & 255; // blue
-}
-
-static void draw_char(char c, size_t px, size_t py, uint32_t fg, uint32_t bg)
-{
-	// So we cannot write past fb
-	if (px+FONT_WIDTH > framebuffer->width || py+FONT_HEIGHT > framebuffer->height) return;
-
-	uint8_t* glyph = glyphs + ((unsigned char)c * FONT_HEIGHT);
-
-	for (size_t y=0; y<FONT_HEIGHT; y++)
-	{
-		uint8_t row = glyph[y];
-		for (size_t x=0; x<FONT_WIDTH; x++)
-		{
-			uint32_t color = (row & (0x80 >> x)) ? fg : bg;
-			putpixel(px+x, py+y, color);
+    if (init.serial) {
+        if (ch == '\n') {
+            skputc('\r');
         }
+        skputc(ch);
     }
 }
 
-static void erase_char(size_t px, size_t py)
+/*
+ * debug_putc - Internal DEBUG putchar function
+ * @c: char to print
+ * @_: (unused, for nanoprintf)
+ *
+ * Prints a character to the terminal if it's ready and if 
+ * the kernel is still initializing, and also always to the
+ * serial interface if it's ready.
+ */
+void debug_putc(int c, void *_)
 {
-	if (px+FONT_WIDTH > framebuffer->width || py+FONT_HEIGHT > framebuffer->height) return;
+    (void)_;
+    char ch = (char)c;
 
-	for (size_t y=0; y<FONT_HEIGHT; y++)
-	{
-		for (size_t x=0; x<FONT_WIDTH; x++)
-		{
-			// Black
-			putpixel(px+x, py+y, 0);
+    if (init.terminal && (!init.all || panic_count > 0)) {
+        if (panic_count == 0) {
+            spinlock_acquire(&term_lock);
+            flanterm_write(ft_ctx, &ch, 1);
+            spinlock_release(&term_lock);
+        } else {
+            flanterm_write(ft_ctx, &ch, 1);
         }
     }
+
+    if (init.serial) {
+        if (ch == '\n') {
+            skputc('\r');
+        }
+        skputc(ch);
+    }
 }
 
-void term_scroll()
+/*
+ * printf - Fromatted printing
+ * @fmt: format string
+ * @...: variadic arguments
+ *
+ * Wrapper for nanoprintf
+ *
+ * Return:
+ * <ret> - number of characters sent to the callback
+ * %-1   - error
+ */
+int printf(const char* fmt, ...)
 {
-	// Erase first text line
-	memset(fb, 255, FONT_HEIGHT*framebuffer->pitch);
-
-	// Move whole framebuffer up by one text line
-	memmove(fb, fb+(FONT_HEIGHT*framebuffer->pitch), (framebuffer->height-FONT_HEIGHT)*framebuffer->pitch);
-
-	// Clear last text line
-	size_t clear_start = (framebuffer->height - FONT_HEIGHT) * framebuffer->pitch;
-	memset(fb + clear_start, 255, FONT_HEIGHT * framebuffer->pitch);
-
-	// Shift line lengths by 1 (for backspace handling)
-	size_t max_lines = term_max_lines();
-	for (size_t i = 1; i < max_lines; i++)
-	{
-		lines_length[i - 1] = lines_length[i];
+    if (panic_count == 0) {
+        spinlock_acquire(&printf_lock);
+        va_list args;
+        va_start(args, fmt);
+        int ret = npf_vpprintf(internal_putc, NULL, fmt, args);
+        va_end(args);
+        spinlock_release(&printf_lock);
+        return ret;
+    } else {
+        va_list args;
+        va_start(args, fmt);
+        int ret = npf_vpprintf(internal_putc, NULL, fmt, args);
+        va_end(args);
+        return ret;
     }
-	lines_length[max_lines - 1] = 0;
+    return -1;
 }
 
-void putchar(char c)
+/*
+ * kprintf - Fromatted DEBUG printing 
+ * @fmt: format string
+ * @...: variadic arguments
+ *
+ * Wrapper for nanoprintf; to be used only for
+ * kernel/debug messages.
+ *
+ * Return:
+ * <ret> - number of characters sent to the callback
+ * %-1   - error
+ */
+int kprintf(const char* fmt, ...)
 {
-	const size_t max_cols = term_max_cols();
-	const size_t max_lines = term_max_lines();
-
-	if (c == '\n') {
-		lines_length[cursor.y] = cursor.x;
-		cursor.x = 0;
-
-		if (cursor.y + 1 >= max_lines)
-		{
-			term_scroll();
+    if (panic_count == 0) {
+        spinlock_acquire(&printf_lock);
+        va_list args;
+        va_start(args, fmt);
+        int ret = npf_vpprintf(debug_putc, NULL, fmt, args);
+        va_end(args);
+        spinlock_release(&printf_lock);
+        return ret;
+    } else {
+        va_list args;
+        va_start(args, fmt);
+        int ret = npf_vpprintf(debug_putc, NULL, fmt, args);
+        va_end(args);
+        return ret;
     }
-		else
-		{
-			cursor.y++;
-		}
-		return;
-	}
-
-	if (c == '\b') 
-	{
-		if (cursor.x > 0) 
-		{
-			cursor.x--;
-		}
-		else if (cursor.y > 0)
-		{
-			cursor.y--;
-			cursor.x = lines_length[cursor.y];
-		}
-		else
-		{
-			return;
-		}
-
-		erase_char(cursor.x * FONT_WIDTH, cursor.y * FONT_HEIGHT);
-		return;
-	}
-
-	if (cursor.x >= max_cols) 
-	{
-		cursor.x = 0;
-		if (cursor.y + 1 >= max_lines)
-		{
-			term_scroll();
-		}
-		else
-		{
-			cursor.y++;
-		}
-	}
-
-	draw_char(c, cursor.x * FONT_WIDTH, cursor.y * FONT_HEIGHT, WHITE, BLACK);
-	cursor.x++;
+    return -1;
 }
 
-// Overhead that could be avoided, right? (for printf)
-void _putchar(char character)
-{
-	putchar(character);
-}
-
-// Debug-printing
+/*
+ * kputs - Kernel puts
+ * @str: String to write
+ *
+ * Writes a non-formatted string to terminal
+ */
 void kputs(const char* str)
 {
 	size_t i=0;
-	while (str[i] != 0)
-	{
-		putchar(str[i]);
+	while (str[i] != 0) {
+		internal_putc(str[i], NULL);
 		i++;
 	}
 }
+
+extern struct flanterm_context* ft_ctx;
+extern struct boot_context boot_ctx;
+
+/*
+ * term_init - Video output/terminal initialization
+ *
+ * Uses Flanterm and the framebuffer given by Limine.
+ */
+void term_init()
+{
+	uint32_t bgColor = 0x252525;
+	ft_ctx = flanterm_fb_init(
+        NULL,
+        NULL,
+        boot_ctx.fb->address, boot_ctx.fb->width, boot_ctx.fb->height, boot_ctx.fb->pitch,
+        boot_ctx.fb->red_mask_size, boot_ctx.fb->red_mask_shift,
+        boot_ctx.fb->green_mask_size, boot_ctx.fb->green_mask_shift,
+        boot_ctx.fb->blue_mask_size, boot_ctx.fb->blue_mask_shift,
+        NULL,
+        NULL, NULL,
+        &bgColor, NULL,
+        NULL, NULL,
+        NULL, 0, 0, 1,
+        0, 0,
+        0,
+        0
+    );
+	init.terminal = true;
+}

src/io/term/term.h

@@ -1,32 +0,0 @@
-/*
- * @author  xamidev <xamidev@riseup.net>
- * @brief   Framebuffer-based terminal driver
- * @license GPL-3.0-only
- */
-
-#ifndef TERM_H
-#define TERM_H
-
-int term_init();
-void kputs(const char* str);
-void putchar(char c);
-
-enum TermColors
-{
-    BLACK = 0x000000,
-    WHITE = 0xffffff
-};
-
-#define PSF1_FONT_MAGIC 0x0436
-
-typedef struct
-{
-    uint16_t magic;
-    uint8_t fontMode;
-    uint8_t characterSize; // height
-} PSF1_Header;
-
-// debug 
-void term_scroll();
-
-#endif

src/kapps/kshell.c

@@ -0,0 +1,56 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PepperOS kernel shell
+ * @license GPL-3.0-only
+ */
+
+#include <io/term/term.h>
+#include <config.h>
+#include <io/kbd/ps2.h>
+#include <string/string.h>
+#include <stdint.h>
+#include <kernel.h>
+
+/*
+ * pedicel_main - Kernel shell main function
+ * @arg: argument (optional)
+ *
+ * This is the entry point for the kernel shell process.
+ * It is used to start programs and to test different things
+ * on different real hardware easily.
+ *
+ * Named after the root part of the pepper.
+ */
+void pedicel_main(void* arg)
+{
+    printf("Welcome to the kernel shell!\r\nType 'help' for a list of commands.\r\n");
+
+    for (;;) {
+        char input_buf[PEDICEL_INPUT_SIZE] = {0};
+        printf(PEDICEL_PROMPT);
+        keyboard_getline(input_buf, PEDICEL_INPUT_SIZE);
+        
+        if (strncmp(input_buf, "help", 4) == 0) {
+            printf("\r\npanic   - trigger a test panic\r\n"
+                            "syscall - trigger int 0x80\r\n"
+                            "pf      - trigger a page fault\r\n");
+            continue;
+        }
+
+        if (strncmp(input_buf, "panic", 5) == 0) {
+            panic(NULL, "test panic");
+        }
+
+        if (strncmp(input_buf, "syscall", 7) == 0) {
+            __asm__ volatile("int $0x80");
+            continue;
+        }
+
+        if (strncmp(input_buf, "pf", 2) == 0) {
+            volatile uint64_t* fault = (uint64_t*)0xdeadbeef;
+            fault[0] = 1;
+        }
+
+        printf("%s: command not found\r\n", input_buf);
+    }
+}

src/kmain.c

@@ -4,42 +4,58 @@
  * @license GPL-3.0-only
  */
 
+#include "arch/x86.h"
 #include <stdbool.h>	
 #include <stddef.h>
 #include <limine.h>
-#include "io/term/term.h"
-#include "io/term/printf.h"
-#include "io/serial/serial.h"
-#include "mem/gdt/gdt.h"
-#include "mem/misc/utils.h"
-#include "idt/idt.h"
-#include "kernel.h"
-#include "time/timer.h"
-#include "io/kbd/ps2.h"
-#include "mem/paging/pmm.h"
-#include "mem/paging/paging.h"
-#include "mem/paging/vmm.h"
-#include "mem/heap/kheap.h"
-#include "sched/process.h"
-#include "sched/scheduler.h"
-#include "config.h"
+#include <io/term/term.h>
+#include <io/serial/serial.h>
+#include <mem/gdt.h>
+#include <mem/utils.h>
+#include <kernel.h>
+#include <time/timer.h>
+#include <io/kbd/ps2.h>
+#include <mem/pmm.h>
+#include <mem/paging.h>
+#include <mem/vmm.h>
+#include <mem/kheap.h>
+#include <sched/process.h>
+#include <sched/scheduler.h>
+#include <config.h>
+#include <io/term/flanterm.h>
+#include <io/term/flanterm_backends/fb.h>
+#include <arch/x86.h>
 
 // Limine version used
 __attribute__((used, section(".limine_requests")))
 volatile LIMINE_BASE_REVISION(3);
 
-// Halt and catch fire (makes machine stall)
+int panic_count = 0;
+
+/*
+ * hcf - Halt and catch fire
+ *
+ * This function is called only in the case of an unrecoverable
+ * error. It halts interrupts, and stops execution. The machine
+ * will stay in an infinite loop state.
+ */
 void hcf()
 {
 	CLEAR_INTERRUPTS; for (;;)asm("hlt");
 }
 
-// Doing nothing (can be interrupted)
+/*
+ * idle - Make the machine idle
+ *
+ * When there is nothing else to do, this function
+ * gets called. It can be interrupted, so it allows
+ * the scheduler, timer, and keyboard to work.
+ */
 void idle() {SET_INTERRUPTS; for(;;)asm("hlt");}
 
-uint8_t kernel_stack[KERNEL_STACK_SIZE] __attribute__((aligned(16)));
-
+struct flanterm_context *ft_ctx;
 struct boot_context boot_ctx;
+struct init_status init = {0};
 
 extern volatile struct limine_framebuffer_request framebuffer_request;
 extern volatile struct limine_memmap_request memmap_request;
@@ -48,25 +64,36 @@ extern volatile struct limine_kernel_address_request kerneladdr_request;
 
 extern struct process_t* processes_list;
 extern struct process_t* current_process;
-
-void pedicel_main(void* arg)
-{
-	printf("Hello, world from a KERNEL PROCESS!");
-}
-
-void two_main(void* arg)
-{
-	printf("...process 2 speaking!!!");
-}
+struct process_t* idle_proc;
 
 void idle_main(void* arg)
 {
-	for(;;)asm("hlt");
+	for (;;) {
+		asm("hlt");
+	}
 }
 
-// This is our entry point
+void thing_main(void* arg)
+{
+	printf("What's your name, pal? ");
+	char name[10];
+	keyboard_getline(name, 10);
+	printf("\r\n{%s} is such a nice name!\r\n", name);
+}
+
+extern uintptr_t kheap_start;
+
+/*
+ * kmain - Kernel entry point
+ *
+ * This is where execution begins at handoff from Limine.
+ * The function fetches all needed information from the
+ * bootloader, initializes all kernel modules and structures,
+ * and then goes in an idle state.
+ */
 void kmain()
 {
+	CLEAR_INTERRUPTS;
 	if (!LIMINE_BASE_REVISION_SUPPORTED) hcf();
 
 	// Populate boot context
@@ -75,42 +102,27 @@ void kmain()
 	boot_ctx.hhdm = hhdm_request.response ? hhdm_request.response : NULL;
 	boot_ctx.kaddr = kerneladdr_request.response ? kerneladdr_request.response : NULL;
 
+	term_init();
 	serial_init();
-
-	memmap_display(boot_ctx.mmap);
-	hhdm_display(boot_ctx.hhdm);
-	DEBUG("kernel: phys_base=0x%p virt_base=0x%p", boot_ctx.kaddr->physical_base, boot_ctx.kaddr->virtual_base);
-
-	CLEAR_INTERRUPTS;
-	gdt_init();
-	idt_init();
 	timer_init();
 
-	pmm_init(boot_ctx.mmap, boot_ctx.hhdm);
+	x86_arch_init();
 
-	// Remap kernel , HHDM and framebuffer
-	paging_init(boot_ctx.kaddr, boot_ctx.fb);
+	boot_mem_display();
+	pmm_init(boot_ctx);
 
+	paging_init(boot_ctx);
 	kheap_init();
 
-	vmm_init();
+	keyboard_init(FR);
 	
-	struct process_t* idle_proc = process_create("idle", (void*)idle_main, 0);
-	struct process_t* pedicel = process_create("pedicel", (void*)pedicel_main, 0);
-	struct process_t* two = process_create("two", (void*)two_main, 0);
-	
-	process_display_list(processes_list);
+	process_init();
+	idle_proc = process_create("idle", (void*)idle_main, 0);
+	process_create("pedicel", (void*)pedicel_main, 0);
 
 	scheduler_init();
 
-	current_process = idle_proc; 
-    current_process->status = RUNNING;
-
-	SET_INTERRUPTS;
-
-	keyboard_init(FR);
-	term_init();
-	kputs(PEPPEROS_SPLASH);
-
+	printf(PEPPEROS_SPLASH);
+	init.all = true;
 	idle();
 }

src/mem/gdt.c

@@ -4,9 +4,9 @@
  * @license GPL-3.0-only
  */
 
-#include "gdt.h"
+#include <mem/gdt.h>
 #include <stdint.h>
-#include "io/serial/serial.h"
+#include <io/serial/serial.h>
 #include <kernel.h>
 
 // Descriptors are 8-byte wide (64bits)
@@ -14,11 +14,20 @@
 uint64_t gdt_entries[NUM_GDT_ENTRIES];
 struct GDTR gdtr;
 
+/*
+ * gdt_load - Loads Global Descriptor Table
+ */
 static void gdt_load()
 {
     asm("lgdt %0" : : "m"(gdtr));
 }
 
+/*
+ * gdt_flush - Flushes the Global Descriptor Table
+ *
+ * This function loads new Segment Selectors to make
+ * the GDT changes take effect
+ */
 static void gdt_flush()
 {
     // Here, 0x8 is the kernel code selector
@@ -42,6 +51,15 @@ static void gdt_flush()
     );
 }
 
+/*
+ * gdt_init - Global Descriptor Table initialization 
+ *
+ * This function loads a new GDT in the CPU.
+ * It contains a null descriptor, kernel code and data
+ * segments, and user code and data segments.
+ * However, we do not use segmentation to manage memory on
+ * 64-bit x86, as it's deprecated. Instead, we use paging. 
+ */
 void gdt_init()
 {
     // Null descriptor (required)

src/mem/heap/kheap.c

@@ -1,147 +0,0 @@
-/*
- * @author  xamidev <xamidev@riseup.net>
- * @brief   Kernel heap
- * @license GPL-3.0-only
- */
-
-#include "kheap.h"
-#include "mem/paging/paging.h"
-#include "mem/paging/pmm.h"
-#include <stddef.h>
-#include <kernel.h>
-#include "sched/process.h"
-#include "config.h"
-
-extern uint64_t kernel_phys_base;
-extern uint64_t kernel_virt_base;
-
-uintptr_t kheap_start;
-
-static struct heap_block_t* head = NULL;
-static uintptr_t end;
-
-// Kernel root table (level 4)
-extern uint64_t *kernel_pml4;
-
-static void kheap_grow(size_t size)
-{
-    size_t pages = ALIGN_UP(size + sizeof(struct heap_block_t), PAGE_SIZE) / PAGE_SIZE;
-    
-    if (pages == 0) pages = 1;
-    
-    for (size_t i = 0; i < pages; i++)
-    {
-        kheap_map_page();
-    }
-}
-
-void kheap_map_page()
-{
-    uintptr_t phys = pmm_alloc();
-    paging_map_page(kernel_pml4, end, phys, PTE_PRESENT | PTE_WRITABLE | PTE_NOEXEC);
-    end += PAGE_SIZE;
-    //DEBUG("Mapped first kheap page");
-}
-
-void kheap_init()
-{
-    kheap_start = ALIGN_UP(kernel_virt_base + KERNEL_SIZE, PAGE_SIZE);
-    end = kheap_start;
-
-    // At least 1 page must be mapped for it to work
-    kheap_map_page();
-
-    // Give linked list head its properties
-    head = (struct heap_block_t*)kheap_start;
-    head->size = PAGE_SIZE - sizeof(struct heap_block_t);
-    head->free = true;
-    head->next = NULL;
-    DEBUG("kheap initialized, head=0x%p, size=%u", head, head->size);
-}
-
-void* kmalloc(size_t size)
-{
-    // No size, no memory allocated!
-    if (!size) return NULL;
-    size = ALIGN(size);
-
-    struct heap_block_t* curr = head;
-
-    while (curr)
-    {
-        // Is block free and big enough for us?
-        if (curr->free && curr->size >= size)
-        {
-            // We split the block if it is big enough
-            if (curr->size >= size + BLOCK_MIN_SIZE)
-            {
-                //struct heap_block_t* new_block = (struct heap_block_t*)((uintptr_t)curr + sizeof(struct heap_block_t) + size);
-                struct heap_block_t* split = (struct heap_block_t*)((uintptr_t)curr + sizeof(*curr) + size);
-                
-                split->size = curr->size - size - sizeof(*curr);
-                split->free = true;
-                split->next = curr->next;
-
-                curr->next = split;
-                curr->size = size;
-            }
-
-            // Found a good block, we return it
-            curr->free = false;
-            return (void*)((uintptr_t)curr + sizeof(struct heap_block_t));
-        }
-        // Continue browsing the list if nothing good was found yet
-        curr = curr->next;
-    }
-
-    // If we're here it means we didn't have enough memory
-    // for the block allocation. So we will allocate more..
-    uintptr_t old_end = end;
-    kheap_grow(size + sizeof(struct heap_block_t));
-
-    struct heap_block_t* block = (struct heap_block_t*)old_end;
-    block->size = ALIGN_UP(end - old_end - sizeof(struct heap_block_t), 16);
-    block->free = true;
-    block->next = NULL;
-
-    // Put the block at the end of the list
-    curr = head;
-    while (curr->next)
-    {
-        curr = curr->next;
-    }
-    curr->next = block;
-
-    return kmalloc(size);
-}
-
-void kfree(void* ptr)
-{
-    // Nothing to free
-    if (!ptr) return;
-
-    // Set it free!
-    struct heap_block_t* block = (struct heap_block_t*)((uintptr_t)ptr - sizeof(struct heap_block_t));
-    block->free = true;
-
-    // merge adjacent free blocks (coalescing)
-    struct heap_block_t* curr = head;
-    while (curr && curr->next)
-    {
-        if (curr->free && curr->next->free)
-        {
-            curr->size += sizeof(*curr) + curr->next->size;
-            curr->next = curr->next->next;
-            continue;
-        }
-        curr = curr->next;
-    }
-}
-
-// Should alloc enough for a stack (at least 64kb) to be used for a process.
-// Should return a pointer to top of the stack (as stack grows DOWNWARDS)
-void* kalloc_stack()
-{
-    uint8_t* ptr = kmalloc(PROCESS_STACK_SIZE); // As it's out of kmalloc, stack is already mapped into kernel space
-    return ptr ? ptr+PROCESS_STACK_SIZE : NULL;
-}

src/mem/kheap.c

@@ -0,0 +1,160 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Kernel heap
+ * @license GPL-3.0-only
+ */
+
+#include <mem/kheap.h>
+#include <mem/paging.h>
+#include <mem/pmm.h>
+#include <stddef.h>
+#include <kernel.h>
+#include <sched/process.h>
+#include <config.h>
+
+extern uint64_t kernel_phys_base;
+extern uint64_t kernel_virt_base;
+
+uintptr_t kheap_start;
+
+static struct heap_block_t* head = NULL;
+static uintptr_t end;
+
+// Kernel root table (level 4)
+extern uint64_t *kernel_pml4;
+
+/*
+ * kheap_init - Kernel heap initialization
+ *
+ * This function physically allocates and maps enough pages
+ * of memory for KHEAP_SIZE, which is defined in config.h.
+ *
+ * It then creates one big heap block, which will be the
+ * base for a linked list.
+ */
+void kheap_init()
+{
+    kheap_start = ALIGN_UP(kernel_virt_base + KERNEL_SIZE, PAGE_SIZE);
+    
+    size_t heap_pages = ALIGN_UP(KHEAP_SIZE, PAGE_SIZE) / PAGE_SIZE;
+    DEBUG("Mapping %d kernel heap pages at 0x%p", heap_pages, kheap_start);
+
+    uintptr_t current_addr = kheap_start;
+
+    // Map/alloc enough pages for heap (KHEAP_SIZE)
+    for (size_t i=0; i<heap_pages; i++) {
+        uintptr_t phys = pmm_alloc();
+        if (phys == 0) {
+            panic(NULL, "Not enough memory available to initialize kernel heap.");
+        }
+
+        paging_map_page(kernel_pml4, current_addr, phys, PTE_PRESENT | PTE_WRITABLE);
+        current_addr += PAGE_SIZE;
+    }
+
+    end = current_addr;
+
+    // Give linked list head its properties
+    head = (struct heap_block_t*)kheap_start;
+    head->size = (end-kheap_start) - sizeof(struct heap_block_t);
+    head->free = true;
+    head->next = NULL;
+    DEBUG("Kernel heap initialized, head=0x%p, size=%u bytes", head, head->size);
+}
+
+/*
+ * kmalloc - Kernel memory allocation
+ * @size: number of bytes to allocate
+ *
+ * Looks for a big enough free block and marks it
+ * as taken. Each block of memory is preceded by
+ * the linked list header.
+ *
+ * Return:
+ * <ptr> - Pointer to at least <size> bytes of usable memory
+ * NULL  - No more memory, or no valid size given
+ */
+void* kmalloc(size_t size)
+{
+    // No size, no memory allocated!
+    if (!size) return NULL;
+    size = ALIGN(size);
+
+    struct heap_block_t* curr = head;
+
+    while (curr) {
+        // Is block free and big enough for us?
+        if (curr->free && curr->size >= size) {
+            // We split the block if it is big enough
+            if (curr->size >= size + sizeof(struct heap_block_t) + 16) {
+                struct heap_block_t* split = (struct heap_block_t*)((uintptr_t)curr + sizeof(struct heap_block_t) + size);
+                
+                split->size = curr->size - size - sizeof(struct heap_block_t);
+                split->free = true;
+                split->next = curr->next;
+
+                curr->next = split;
+                curr->size = size;
+            }
+
+            // Found a good block, we return it
+            curr->free = false;
+            return (void*)((uintptr_t)curr + sizeof(struct heap_block_t));
+        }
+        // Continue browsing the list if nothing good was found yet
+        curr = curr->next;
+    }
+
+    // No growing. If we're here it means the initial pool
+    // wasn't sufficient. Too bad.
+    DEBUG("Kernel heap is OUT OF MEMORY!");
+    // if we were terrorists maybe we should panic
+    // or just wait for others to free stuff?
+    return NULL;
+}
+
+/*
+ * kfree - Kernel memory freeing
+ * @ptr: pointer to memory region to free
+ *
+ * Marks the memory block beginning at <ptr>
+ * as free. Also merges adjacent free blocks
+ * to lessen fragmentation.
+ */
+void kfree(void* ptr)
+{
+    // Nothing to free
+    if (!ptr) return;
+
+    // Set it free!
+    struct heap_block_t* block = (struct heap_block_t*)((uintptr_t)ptr - sizeof(struct heap_block_t));
+    block->free = true;
+
+    // merge adjacent free blocks (coalescing)
+    struct heap_block_t* curr = head;
+    while (curr && curr->next) {
+        if (curr->free && curr->next->free) {
+            curr->size += sizeof(*curr) + curr->next->size;
+            curr->next = curr->next->next;
+            continue;
+        }
+        curr = curr->next;
+    }
+}
+
+/*
+ * kalloc_stack - Stack memory allocation
+ *
+ * Allocates a memory region of at least PROCESS_STACK_SIZE,
+ * to be used as a stack for a process. The pointer returned
+ * points to the end of the region, as the stack grows downwards.
+ *
+ * Return:
+ * <ptr> - Pointer to a region after at least PROCESS_STACK_SIZE bytes of usable memory
+ * NULL  - No more memory
+ */
+void* kalloc_stack()
+{
+    uint8_t* ptr = kmalloc(PROCESS_STACK_SIZE); // As it's out of kmalloc, stack is already mapped into kernel space
+    return ptr ? ptr+PROCESS_STACK_SIZE : NULL;
+}

src/mem/misc/utils.c

@@ -1,128 +0,0 @@
-/*
- * @author  xamidev <xamidev@riseup.net>
- * @brief   Common memory utilities
- * @license GPL-3.0-only
- */
-
-#include <stddef.h>
-#include <stdint.h>
-#include <limine.h>
-#include "kernel.h"
-#include "string/string.h"
-
-// We won't be linked to standard library, but still need the basic mem* functions
-// so everything goes allright with the compiler
-
-// We use the "restrict" keyword on pointers so that the compiler knows it can
-// do more optimization on them (and as it's a much used function, it's good to
-// be able to do that)
-void* memcpy(void* restrict dest, const void* restrict src, size_t n)
-{
-	uint8_t* restrict pdest = (uint8_t* restrict)dest;
-	const uint8_t* restrict psrc = (const uint8_t* restrict)src;
-
-	for (size_t i=0; i<n; i++)
-	{
-		pdest[i] = psrc[i];
-	}
-
-	return dest;
-}
-
-void* memset(void* s, int c, size_t n)
-{
-	uint8_t* p = (uint8_t*)s;
-
-	for (size_t i=0; i<n; i++)
-	{
-		p[i] = (uint8_t)c;
-	}
-
-	return s;
-}
-
-void* memmove(void *dest, const void* src, size_t n)
-{
-	uint8_t* pdest = (uint8_t*)dest;
-	const uint8_t* psrc = (uint8_t*)src;
-
-	if (src > dest)
-	{
-		for (size_t i=0; i<n; i++)
-		{
-			pdest[i] = psrc[i];
-		}
-	} else if (src < dest) 
-	{
-		for (size_t i=n; i>0; i--)
-		{
-			pdest[i-1] = psrc[i-1];
-		}
-	}
-	return dest;	
-}
-
-int memcmp(const void* s1, const void* s2, size_t n)
-{
-	const uint8_t* p1 = (const uint8_t*)s1;
-	const uint8_t* p2 = (const uint8_t*)s2;
-
-	for (size_t i=0; i<n; i++)
-	{
-		if (p1[i] != p2[i])
-		{
-			return p1[i] < p2[i] ? -1 : 1;
-		}
-	}
-
-	return 0;
-}
-
-// Display the memmap so we see how the memory is laid out at handoff
-void memmap_display(struct limine_memmap_response* response)
-{
-	DEBUG("Got memory map from Limine: revision %u, %u entries", response->revision, response->entry_count);
-
-	for (size_t i=0; i<response->entry_count; i++)
-	{
-		struct limine_memmap_entry* entry = response->entries[i];
-		char type[32] = {0};
-		switch(entry->type)
-		{
-			case LIMINE_MEMMAP_USABLE:
-				strcpy(type, "USABLE");
-				break;
-			case LIMINE_MEMMAP_RESERVED:
-				strcpy(type, "RESERVED");
-				break;
-			case LIMINE_MEMMAP_ACPI_RECLAIMABLE:
-				strcpy(type, "ACPI_RECLAIMABLE");
-				break;
-			case LIMINE_MEMMAP_ACPI_NVS:
-				strcpy(type, "ACPI_NVS");
-				break;
-			case LIMINE_MEMMAP_BAD_MEMORY:
-				strcpy(type, "BAD_MEMORY");
-				break;
-			case LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE:
-				strcpy(type, "BOOTLOADER_RECLAIMABLE");
-				break;
-			case LIMINE_MEMMAP_KERNEL_AND_MODULES:
-				strcpy(type, "KERNEL_AND_MODULES");
-				break;
-			case LIMINE_MEMMAP_FRAMEBUFFER:
-				strcpy(type, "FRAMEBUFFER");
-				break;
-			default:
-				strcpy(type, "UNKNOWN");
-				break;
-		}
-		DEBUG("entry %02u: [0x%016x | %016u bytes] - %s", i, entry->base, entry->length, type);
-	}
-}
-
-// Display the HHDM
-void hhdm_display(struct limine_hhdm_response* hhdm)
-{
-	DEBUG("Got HHDM revision=%u offset=0x%p", hhdm->revision, hhdm->offset);
-}

src/mem/paging.c

@@ -4,12 +4,12 @@
  * @license GPL-3.0-only
  */
 
-#include "paging.h"
-#include "pmm.h"
+#include <mem/paging.h>
+#include <mem/pmm.h>
 #include <kernel.h>
 #include <stddef.h>
 #include <limine.h>
-#include "config.h"
+#include <config.h>
 
 /*
 Paging on x86 uses four different page table levels:
@@ -24,23 +24,46 @@ If we use 1GB huge pages: PML4 -> PDPT -> 1gb pages
 4KB (regular size): PML4 -> PDPT -> PD -> PT -> 4kb pages
 */
 
+/*
+ * load_cr3 - Load a new value into the CR3 register
+ * @value: the value to load
+ *
+ * This function is used to load the physical address
+ * of the root page table (PML4), to switch the paging
+ * structures the CPU sees and uses.
+ */
 void load_cr3(uint64_t value) {
     asm volatile ("mov %0, %%cr3" :: "r"(value) : "memory");
 }
 
-// To flush TLB
+/*
+ * invlpg - Invalidates a Translation Lookaside Buffer entry
+ * @addr: page memory address
+ *
+ * This function is used to flush at least the TLB entrie(s)
+ * for the page that contains the <addr> address.
+ */
 static inline void invlpg(void *addr)
 {
     asm volatile("invlpg (%0)" :: "r"(addr) : "memory");
 }
 
-// Allocates a 512-entry 64bit page table/directory/whatever (zeroed)
+/*
+ * alloc_page_table - Page table allocation
+ *
+ * This function allocates enough memory for a 512-entry
+ * 64-bit page table, for any level (PML4/3/2).
+ *
+ * Memory allocated here is zeroed.
+ *
+ * Return:
+ * <virt> - Pointer to allocated page table
+ */
 static uint64_t* alloc_page_table()
 {
     uint64_t* virt = (uint64_t*)PHYS_TO_VIRT(pmm_alloc());
 
-    for (size_t i=0; i<512; i++)
-    {
+    for (size_t i=0; i<512; i++) {
         virt[i] = 0;
     }
     return virt;
@@ -50,10 +73,19 @@ static uint64_t* alloc_page_table()
 __attribute__((aligned(4096)))
 uint64_t *kernel_pml4;
 
-// Map a page, taking virt and phys address. This will go through the paging structures
-// beginning at the given root table, translate the virtual address in indexes in
-// page table/directories, and then mapping the correct page table entry with the
-// given physical address + flags
+/*
+ * paging_map_page - Mapping a memory page
+ * @root_table: Address of the PML4
+ * @virt:       Virtual address
+ * @phys:       Physical address
+ * @flags:      Flags to set on page
+ *
+ * This function maps the physical address <phys> to the virtual
+ * address <virt>, using the paging structures beginning at
+ * <root_table>. <flags> can be set according to the PTE_FLAGS enum.
+ *
+ * If a page table/directory entry is not present yet, it creates it.
+ */
 void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_t flags)
 {
     virt = PAGE_ALIGN_DOWN(virt);
@@ -70,32 +102,26 @@ void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_
     // PML4
     // If the entry at index is not present, allocate enough space for it
     // then populate the entry with correct addr + flags
-    if (!(root_table[pml4_i] & PTE_PRESENT))
-    {
+    if (!(root_table[pml4_i] & PTE_PRESENT)) {
         pdpt = alloc_page_table();
         root_table[pml4_i] = VIRT_TO_PHYS(pdpt) | PTE_PRESENT | PTE_WRITABLE;
-    }
-    else {
+    } else {
         pdpt = (uint64_t *)PHYS_TO_VIRT(root_table[pml4_i] & PTE_ADDR_MASK);
     }
 
     // PDPT: same here
-    if (!(pdpt[pdpt_i] & PTE_PRESENT))
-    {
+    if (!(pdpt[pdpt_i] & PTE_PRESENT)) {
         pd = alloc_page_table();
         pdpt[pdpt_i] = VIRT_TO_PHYS(pd) | PTE_PRESENT | PTE_WRITABLE;
-    } 
-    else {
+    } else {
         pd = (uint64_t *)PHYS_TO_VIRT(pdpt[pdpt_i] & PTE_ADDR_MASK);
     }
 
     // PD: and here
-    if (!(pd[pd_i] & PTE_PRESENT))
-    {
+    if (!(pd[pd_i] & PTE_PRESENT)) {
         pt = alloc_page_table();
         pd[pd_i] = VIRT_TO_PHYS(pt) | PTE_PRESENT | PTE_WRITABLE;
-    }
-    else {
+    } else {
         pt = (uint64_t *)PHYS_TO_VIRT(pd[pd_i] & PTE_ADDR_MASK);
     }
 
@@ -109,9 +135,16 @@ void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_
 uint64_t kernel_phys_base;
 uint64_t kernel_virt_base;
 
-extern struct boot_context boot_ctx;
-
-void paging_init()
+/*
+ * paging_init - Paging initialization
+ * @boot_ctx: Boot context structure
+ *
+ * This function initializes new paging structures, to replace
+ * the ones given by the bootloader.
+ *
+ * It maps the kernel, the HHDM space, and the framebuffer.
+ */
+void paging_init(struct boot_context boot_ctx)
 {
     // We should map the kernel, GDT, IDT, stack, framebuffer.
     // Optionally we could map ACPI tables (we can find them in the Limine memmap)
@@ -129,32 +162,25 @@ void paging_init()
 
     // Find max physical address from limine memmap
     uint64_t max_phys = 0;
-    for (uint64_t i=0; i<boot_ctx.mmap->entry_count; i++)
-    {
+    for (uint64_t i=0; i<boot_ctx.mmap->entry_count; i++) {
         struct limine_memmap_entry* entry = boot_ctx.mmap->entries[i];
-        if (entry->length == 0)
-        {
+        if (entry->length == 0) {
             continue;
         }
         uint64_t top = entry->base + entry->length;
-        if (top > max_phys)
-        {
+        if (top > max_phys) {
             max_phys = top;
         }
-        //DEBUG("max_phys=0x%p", max_phys);
     }
 
-    // 4GB
-    if (max_phys > 0x100000000)
-    {
-        DEBUG("WARNING: max_phys capped to 4GB (0x100000000) (from max_phys=%p)", max_phys);
-        max_phys = 0x100000000;
+    // 8GB
+    if (max_phys > PAGING_MAX_PHYS) {
+        DEBUG("WARNING: max_phys capped to PAGING_MAX_PHYS (from max_phys=%p)", max_phys);
+        max_phys = PAGING_MAX_PHYS;
     }
 
-    // HHDM map up to max_phys or 4GB, whichever is smaller, using given offset
-    for (uint64_t i=0; i<max_phys; i += PAGE_SIZE)
-    {
-        //paging_kmap_page(i+hhdm_off, i, PTE_WRITABLE);
+    // HHDM map up to max_phys or PAGING_MAX_PHYS, whichever is smaller, using given offset
+    for (uint64_t i=0; i<max_phys; i += PAGE_SIZE) {
         paging_map_page(kernel_pml4, i+hhdm_off, i, PTE_WRITABLE | PTE_PRESENT);
         page_count++;
     }
@@ -164,9 +190,7 @@ void paging_init()
     // SOME DAY when we want a safer kernel we should map .text as Read/Exec
     // .rodata as Read and .data as Read/Write
     // For now who gives a shit, let's RWX all kernel
-    for (uint64_t i = 0; i < KERNEL_SIZE; i += PAGE_SIZE)
-    {
-        //paging_kmap_page(kernel_virt_base+i, kernel_phys_base+i, PTE_WRITABLE);
+    for (uint64_t i = 0; i < KERNEL_SIZE; i += PAGE_SIZE) {
         paging_map_page(kernel_pml4, kernel_virt_base+i, kernel_phys_base+i, PTE_WRITABLE);
         page_count++;
     }
@@ -178,16 +202,14 @@ void paging_init()
     uint64_t fb_size = fb->pitch * fb->height;
     uint64_t fb_pages = (fb_size + PAGE_SIZE-1)/PAGE_SIZE;
 
-    // Map the framebuffer (with cache-disable & write-through)
-    for (uint64_t i=0; i<fb_pages; i++)
-    {
-        //paging_kmap_page(fb_virt+i*PAGE_SIZE, fb_phys+i*PAGE_SIZE, PTE_WRITABLE | PTE_PCD | PTE_PWT);
-        paging_map_page(kernel_pml4, fb_virt+i*PAGE_SIZE, fb_phys+i*PAGE_SIZE, PTE_WRITABLE | PTE_PCD | PTE_PWT);
+    // Map the framebuffer (PWT set, and no PCD means PAT1 [Write-Combining] for this region)
+    for (uint64_t i=0; i<fb_pages; i++) {
+        paging_map_page(kernel_pml4, fb_virt+i*PAGE_SIZE, fb_phys+i*PAGE_SIZE, PTE_WRITABLE | PTE_PWT);
         page_count++;
     }
     DEBUG("Mapped %u pages for framebuffer", page_count);
 
     // Finally, we load the physical address of our PML4 (root table) into cr3
     load_cr3(VIRT_TO_PHYS(kernel_pml4));
-    DEBUG("cr3 loaded, we're still alive");
+    DEBUG("Loaded kernel PML4 into CR3");
 }

src/mem/paging/pmm.c

@@ -1,110 +0,0 @@
-/*
- * @author  xamidev <xamidev@riseup.net>
- * @brief   Physical memory manager from freelist
- * @license GPL-3.0-only
- */
-
-/*
-pmm - Physical Memory Manager
-will manage 4kb pages physically
-it will probably need to get some info from Limine,
-to see which pages are used by kernel/bootloader/mmio/fb etc.
-*/
-
-#include "paging.h"
-#include <limine.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <kernel.h>
-#include "mem/misc/utils.h"
-#include "pmm.h"
-
-/*
-First we'll have to discover the physical memory layout,
-and for that we can use a Limine request.
-*/
-
-/*
-We will look for the biggest usable physical memory region
-and use this for the bitmap. The reserved memory will be ignored.
-*/
-
-struct limine_memmap_entry* biggest_entry;
-
-static void pmm_find_biggest_usable_region(struct limine_memmap_response* memmap, struct limine_hhdm_response* hhdm)
-{
-    // Max length of a usable memory region
-    uint64_t length_max = 0;
-    uint64_t offset = hhdm->offset;
-
-    DEBUG("Usable Memory:");
-    for (size_t i=0; i<memmap->entry_count; i++)
-    {
-        struct limine_memmap_entry* entry = memmap->entries[i];
-
-        if (entry->type == LIMINE_MEMMAP_USABLE)
-        {
-            DEBUG("0x%p-0x%p mapped at 0x%p-0x%p", entry->base, entry->base+entry->length,
-                        entry->base+offset, entry->base+entry->length+offset);
-            if (entry->length > length_max)
-            {
-                length_max = entry->length;
-                biggest_entry = entry;
-            }
-        }
-    }
-
-    DEBUG("Biggest usable memory region:");
-    DEBUG("0x%p-0x%p mapped at 0x%p-0x%p", biggest_entry->base, biggest_entry->base + biggest_entry->length,
-            biggest_entry->base+offset, biggest_entry->base+biggest_entry->length+offset);
-}
-
-// Offset from Higher Half Direct Map
-uint64_t hhdm_off;
-
-static uintptr_t g_freelist = 0;
-
-uintptr_t pmm_alloc()
-{
-    if (!g_freelist)
-	{
-		panic(NULL, "PMM is out of memory!");		
-	}
-    uintptr_t addr = g_freelist;
-    g_freelist = *(uintptr_t*) PHYS_TO_VIRT(g_freelist);
-    return addr;
-}
-
-void pmm_free(uintptr_t addr)
-{
-    *(uintptr_t*) PHYS_TO_VIRT(addr) = g_freelist;
-    g_freelist = addr;
-}
-
-static void pmm_init_freelist()
-{
-    // We simply call pmm_free() on each page that is marked USABLE
-    // in our big memory region.
-    uint64_t base = ALIGN_UP(biggest_entry->base, PAGE_SIZE);
-    uint64_t end = ALIGN_DOWN(biggest_entry->base + biggest_entry->length, PAGE_SIZE);
-
-    uint64_t page_count=0;
-    for (uint64_t addr = base; addr < end; addr += PAGE_SIZE)
-    {
-        pmm_free(addr);
-        //DEBUG("page %u lives at phys 0x%p (virt 0x%p)", page_count, addr, PHYS_TO_VIRT(addr));
-        page_count++;
-    }
-    DEBUG("%u frames in freelist, available for use (%u bytes)", page_count, page_count*PAGE_SIZE);
-}
-
-void pmm_init(struct limine_memmap_response* memmap, struct limine_hhdm_response* hhdm)
-{
-    hhdm_off = hhdm->offset;
-    pmm_find_biggest_usable_region(memmap, hhdm);
-    //pmm_allocate_bitmap(hhdm); too complicated for my small brain
-    
-    // Now we have biggest USABLE region,
-    // so to populate the free list we just iterate through it
-    pmm_init_freelist();
-}

src/mem/pmm.c

@@ -0,0 +1,110 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Physical memory manager from freelist
+ * @license GPL-3.0-only
+ */
+
+/*
+pmm - Physical Memory Manager
+will manage 4kb pages physically
+it will probably need to get some info from Limine,
+to see which pages are used by kernel/bootloader/mmio/fb etc.
+*/
+
+#include "config.h"
+#include <mem/paging.h>
+#include <limine.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <kernel.h>
+#include <mem/utils.h>
+#include <mem/pmm.h>
+
+/*
+First we'll have to discover the physical memory layout,
+and for that we can use a Limine request.
+*/
+
+// Offset from Higher Half Direct Map
+uint64_t hhdm_off;
+
+static uintptr_t g_freelist = 0;
+
+/*
+ * pmm_alloc - Allocate a physical page
+ *
+ * This function allocates a single physical page (frame)
+ * 
+ * Return:
+ * <addr> - Address for the allocated page
+ */
+uintptr_t pmm_alloc()
+{
+    if (!g_freelist) {
+		panic(NULL, "PMM is out of memory!");		
+	}
+    uintptr_t addr = g_freelist;
+    g_freelist = *(uintptr_t*) PHYS_TO_VIRT(g_freelist);
+    return addr;
+}
+
+/*
+ * pmm_free - Frees a memory page
+ * @addr: Address to the page
+ */
+void pmm_free(uintptr_t addr)
+{
+    *(uintptr_t*) PHYS_TO_VIRT(addr) = g_freelist;
+    g_freelist = addr;
+}
+
+/*
+ * pmm_init_freelist - PMM freelist initialization
+ *
+ * This function marks the biggest memory region as
+ * free, so we can use it in pmm_alloc.
+ */
+static void pmm_init_freelist(struct limine_memmap_response* memmap)
+{
+    uint64_t total_pages = 0;
+
+    for (size_t i=0; i<memmap->entry_count; i++) {
+        struct limine_memmap_entry* entry = memmap->entries[i];
+
+        if (entry->type == LIMINE_MEMMAP_USABLE) {
+            uint64_t base = ALIGN_UP(entry->base, PAGE_SIZE);
+            uint64_t end = ALIGN_DOWN(entry->base + entry->length, PAGE_SIZE);
+
+            if (end > PAGING_MAX_PHYS) {
+                end = PAGING_MAX_PHYS;
+            }
+
+            // Region above PAGING_MAX_PHYS
+            if (base >= end) continue;
+
+            for (uint64_t addr = base; addr < end; addr += PAGE_SIZE) {
+                pmm_free(addr);
+                total_pages++;
+            }
+        }
+    }
+
+    DEBUG("%u frames in freelist, %u bytes available (%u MB)", total_pages, total_pages*PAGE_SIZE, total_pages*PAGE_SIZE/1000000);
+}
+
+/*
+ * pmm_init - Physical memory manager initialization
+ * @boot_ctx: Boot context structure
+ *
+ * This function prepares the PMM for use.
+ * The PMM works with a freelist.
+ */
+void pmm_init(struct boot_context boot_ctx)
+{
+    hhdm_off = boot_ctx.hhdm->offset;
+    //pmm_find_biggest_usable_region(boot_ctx.mmap, boot_ctx.hhdm);
+
+    // Now we have biggest USABLE region,
+    // so to populate the free list we just iterate through it
+    pmm_init_freelist(boot_ctx.mmap);
+}

src/mem/utils.c

@@ -0,0 +1,122 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Common memory utilities
+ * @license GPL-3.0-only
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <limine.h>
+#include <kernel.h>
+#include <string/string.h>
+
+// We won't be linked to standard library, but still need the basic mem* functions
+// so everything goes allright with the compiler
+
+// We use the "restrict" keyword on pointers so that the compiler knows it can
+// do more optimization on them (and as it's a much used function, it's good to
+// be able to do that)
+
+/*
+ * memcpy - Copy memory from one place to another
+ * @dest: pointer to the destination region
+ * @src:  pointer to the source region
+ * @n:    amount of bytes to copy
+ *
+ * This function copies n bytes of memory from
+ * src to dest.
+ *
+ * Return:
+ * <dest> - Pointer to destination region
+ */
+void* memcpy(void* restrict dest, const void* restrict src, size_t n)
+{
+	uint8_t* restrict pdest = (uint8_t* restrict)dest;
+	const uint8_t* restrict psrc = (const uint8_t* restrict)src;
+
+	for (size_t i=0; i<n; i++) {
+		pdest[i] = psrc[i];
+	}
+
+	return dest;
+}
+
+/*
+ * memset - Sets a memory region to given byte
+ * @s:    pointer to memory region
+ * @c:    byte to be written
+ * @n:    amount of bytes to write
+ *
+ * This function writes n times the byte c
+ * to the memory region pointed to by s.
+ *
+ * Return:
+ * <s> - Pointer to memory region
+ */
+void* memset(void* s, int c, size_t n)
+{
+	uint8_t* p = (uint8_t*)s;
+
+	for (size_t i=0; i<n; i++) {
+		p[i] = (uint8_t)c;
+	}
+
+	return s;
+}
+
+/*
+ * memmove - Move memory from one place to another
+ * @dest: pointer to the destination region
+ * @src:  pointer to the source region
+ * @n:    amount of bytes to move
+ *
+ * This function moves n bytes of memory from
+ * src to dest.
+ *
+ * Return:
+ * <dest> - Pointer to destination region
+ */
+void* memmove(void *dest, const void* src, size_t n)
+{
+	uint8_t* pdest = (uint8_t*)dest;
+	const uint8_t* psrc = (uint8_t*)src;
+
+	if (src > dest) {
+		for (size_t i=0; i<n; i++) {
+			pdest[i] = psrc[i];
+		}
+	} else if (src < dest) {
+		for (size_t i=n; i>0; i--) {
+			pdest[i-1] = psrc[i-1];
+		}
+	}
+	return dest;	
+}
+
+/*
+ * memcmp - Compare two memory regions
+ * @s1:   pointer to the first region
+ * @s2:   pointer to the second region
+ * @n:    amount of bytes to compare
+ *
+ * This function compares n bytes of memory
+ * bewteen regions pointed to by s1 and s2.
+ *
+ * Return:
+ * %0     - if s1 and s2 are equal 
+ * %-1    - if s1 is smaller than s2
+ * %1     - if s1 is greater than s2
+ */
+int memcmp(const void* s1, const void* s2, size_t n)
+{
+	const uint8_t* p1 = (const uint8_t*)s1;
+	const uint8_t* p2 = (const uint8_t*)s2;
+
+	for (size_t i=0; i<n; i++) {
+		if (p1[i] != p2[i]) {
+			return p1[i] < p2[i] ? -1 : 1;
+		}
+	}
+
+	return 0;
+}

src/mem/vmm.c

@@ -13,10 +13,10 @@ in a specified virtual space
 compared to the PMM which allocs/frees 4kb frames ("physical pages").
 */
 
-#include "vmm.h"
-#include "paging.h"
+#include <mem/vmm.h>
+#include <mem/paging.h>
 #include <stddef.h>
-#include "pmm.h"
+#include <mem/pmm.h>
 #include <kernel.h>
 
 void* vmm_pt_root = 0;
@@ -24,6 +24,14 @@ void* vmm_pt_root = 0;
 // Linked list head for virtual memory objects
 struct vm_object* vm_objs = NULL;
 
+/*
+ * Will have to be rewritten and expanded,
+ * to prepare for userspace.
+ * The platform-agnostic flags will be removed
+ * because as long as the kernel is x86 only,
+ * we don't need over complication.
+ * Plus I don't plan to port to other architectures
+*/
 
 uint64_t convert_x86_vm_flags(size_t flags)
 {
@@ -68,5 +76,6 @@ void vmm_setup_pt_root()
 
 void vmm_init()
 {
-    vmm_setup_pt_root();
+    // NO U
+    //vmm_setup_pt_root();
 }

src/sched/process.c

@@ -5,13 +5,16 @@
  */
 
 #include <stddef.h>
-#include "process.h"
-#include "mem/heap/kheap.h"
-#include "kernel.h"
-#include "string/string.h"
-#include "mem/gdt/gdt.h"
-#include "config.h"
-#include "io/serial/serial.h"
+#include <sched/process.h>
+#include <mem/kheap.h>
+#include <kernel.h>
+#include <string/string.h>
+#include <mem/gdt.h>
+#include <config.h>
+#include <io/serial/serial.h>
+
+#include <io/term/flanterm.h>
+extern struct flanterm_context* ft_ctx;
 
 struct process_t* processes_list;
 struct process_t* current_process;
@@ -20,19 +23,27 @@ extern uint64_t *kernel_pml4;
 
 size_t next_free_pid = 0;
 
+/*
+ * process_init - Initializes process list
+ */
 void process_init()
 {
     processes_list = NULL;
     current_process = NULL;
 }
 
-// Only for debug
+/*
+ * process_display_list - Debug function to display processes
+ * @processes_list: head of the process linked list
+ *
+ * This function prints the linked list of processes
+ * to the DEBUG output.
+ */
 void process_display_list(struct process_t* processes_list)
 {
     int process_view_id = 0;
     struct process_t* tmp = processes_list;
-    while (tmp != NULL)
-    {
+    while (tmp != NULL) {
         DEBUG("{%d: %p} -> ", process_view_id, tmp);
         tmp = tmp->next;
         process_view_id++;
@@ -40,11 +51,23 @@ void process_display_list(struct process_t* processes_list)
     DEBUG("NULL");
 }
 
+/*
+ * process_create - Create a process
+ * @name:     name of the process
+ * @function: beginning of process executable code
+ * @arg:      (optional) argument provided to process
+ *
+ * This function creates a process, gives it all
+ * necessary context and a stack, and adds the
+ * process to the linked list.
+ *
+ * Return:
+ * <proc> - pointer to created process
+ */
 struct process_t* process_create(char* name, void(*function)(void*), void* arg)
 {
     CLEAR_INTERRUPTS;
     struct process_t* proc = (struct process_t*)kmalloc(sizeof(struct process_t));
-    
     struct cpu_status_t* ctx = (struct cpu_status_t*)kmalloc(sizeof(struct cpu_status_t));
 
     // No more memory?
@@ -80,34 +103,40 @@ struct process_t* process_create(char* name, void(*function)(void*), void* arg)
     return proc;
 }
 
+/*
+ * process_add - Add a process to the end of the linked list
+ * @processes_list: pointer to the head of the linked list
+ * @process:        process to add at the end of the linked list
+ */
 void process_add(struct process_t** processes_list, struct process_t* process)
 {
     if (!process) return;
     process->next = NULL;
 
-    if (*processes_list == NULL)
-    {
+    if (*processes_list == NULL) {
         // List is empty
         *processes_list = process;
         return;
     }
 
     struct process_t* tmp = *processes_list;
-    while (tmp->next != NULL)
-    {
+    while (tmp->next != NULL) {
         tmp = tmp->next;
     }
     // We're at last process before NULL
     tmp->next = process;
-    // process->next = NULL;
 }
 
+/*
+ * process_delete - Delete a process from the linked list
+ * @processes_list: pointer to head of linked list
+ * @process:        the process to delete from the list
+ */
 void process_delete(struct process_t** processes_list, struct process_t* process)
 {
     if (!processes_list || !*processes_list || !process) return;
 
-    if (*processes_list == process)
-    {
+    if (*processes_list == process) {
         // process to delete is at head
         *processes_list = process->next;
         process->next = NULL;
@@ -116,13 +145,11 @@ void process_delete(struct process_t** processes_list, struct process_t* process
     }
 
     struct process_t* tmp = *processes_list;
-    while (tmp->next && tmp->next != process)
-    {
+    while (tmp->next && tmp->next != process) {
         tmp = tmp->next;
     }
 
-    if (tmp->next == NULL)
-    {
+    if (tmp->next == NULL) {
         // Didn't find the process
         return;
     }
@@ -133,44 +160,40 @@ void process_delete(struct process_t** processes_list, struct process_t* process
     kfree(process);
 }
 
+/*
+ * process_get_next - Get the next process (unused)
+ * @process: pointer to process
+ *
+ * Return:
+ * <process->next> - process right after the one specified
+ */
 struct process_t* process_get_next(struct process_t* process)
 {
     if (!process) return NULL;
     return process->next;
 }
 
-// (from gdt) This will switch tasks ONLY in ring 0
-// KERNEL CS = 0x08
-// KERNEL SS = 0x10
-__attribute__((naked, noreturn))
-void process_switch(uint64_t stack_addr, uint64_t code_addr)
-{
-    asm volatile(" \
-        push $0x10 \n\
-        push %0 \n\
-        push $0x202 \n\
-        push $0x08 \n\
-        push %1 \n\
-        iretq \n\
-        " :: "r"(stack_addr), "r"(code_addr));
-}
-
-
-// Will be used to clean up resources (if any, when we implement it)
-// Just mark as DEAD then idle. Scheduler will delete process at next timer interrupt % quantum.
+/*
+ * process_exit - Exit from a process
+ *
+ * This function is pushed to all process stacks, as a last
+ * return address. Once the process is done executing, it 
+ * ends up here.
+ *
+ * Process is marked as DEAD, and then execution loops.
+ * Next time the scheduler sees the process, it will
+ * automatically delete it from the linked list.
+ */
 void process_exit()
 {
     DEBUG("Exiting from process '%s'", current_process->name);
     CLEAR_INTERRUPTS;
-    if (current_process)
-    {
+    if (current_process) {
         current_process->status = DEAD;
     }
     SET_INTERRUPTS;
     
-    outb(0x20, 0x20);
-    for (;;)
-    {
+    for (;;) {
         asm("hlt");
     }
 }

src/sched/scheduler.c

@@ -4,52 +4,77 @@
  * @license GPL-3.0-only
  */
 
-#include "kernel.h"
-#include "process.h"
-#include "mem/paging/paging.h"
+#include <kernel.h>
+#include <sched/process.h>
+#include <mem/paging.h>
 #include <stdint.h>
-#include "io/serial/serial.h"
+#include <io/serial/serial.h>
 
 extern struct process_t* processes_list;
 extern struct process_t* current_process;
+extern struct process_t* idle_proc;
 
+/*
+ * scheduler_init - Choose the first process
+ */
 void scheduler_init()
 {
-    // Choose first process?
     current_process = processes_list;
 }
 
+/*
+ * scheduler_schedule - Main scheduling routine
+ * @context: CPU context of previous process
+ *
+ * Chooses the next process that we should run.
+ * The routine is executed every SCHEDULER_QUANTUM ticks.
+ *
+ * Return:
+ * <context> - CPU context for next process
+ */
 struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context)
 {
+    if (context == NULL) {
+        panic(NULL, "Scheduler called with NULL context"); 
+    }
+
+    if (current_process == NULL) {
+        // If no more processes, then set IDLE as the current process, that's it.
+        current_process = idle_proc;
+    }
+
+    if (current_process == idle_proc && current_process->next == NULL)
+    {
+        return idle_proc->context;
+    }
+
     current_process->context = context;
-    current_process->status = READY;
 
     for (;;) {
         struct process_t* prev_process = current_process;
-        if (current_process->next != NULL)
-        {
+        if (current_process->next != NULL) {
             current_process = current_process->next;
-        } else
-        {
+        } else {
             current_process = processes_list;
         }
         
-        if (current_process != NULL && current_process->status == DEAD)
-        {
+        if (current_process != NULL && current_process->status == DEAD) {
             process_delete(&prev_process, current_process);
-        } else
-        {
+            current_process = NULL;
+            return idle_proc->context;
+        } else {
             current_process->status = RUNNING;
+/*             if (prev_process != current_process) {
+                DEBUG("Changed from {pid=%u, name=%s} to {pid=%u, name=%s}", prev_process->pid, prev_process->name, current_process->pid, current_process->name);
+            } */
             break;
         }
     }
 
-
-    // Current_process gets wrong context?? (iret_rip points to other stuff than process function; like putpixel() for example)
-    DEBUG("current_process={pid=%u, name='%s', root_page_table[virt]=%p}", current_process->pid, current_process->name, current_process->root_page_table);
+    //DEBUG("current_process={pid=%u, name='%s', root_page_table[virt]=%p}", current_process->pid, current_process->name, current_process->root_page_table);
 
     load_cr3(VIRT_TO_PHYS((uint64_t)current_process->root_page_table));
-    DEBUG("loaded process pml4 into cr3");
+    //DEBUG("Loaded process PML4 into CR3");
 
     return current_process->context;
 }

src/sched/spinlock.c

@@ -0,0 +1,44 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Spinlock implementation
+ * @license GPL-3.0-only
+ */
+
+#include <stdatomic.h>
+#include <stdbool.h>
+#include <kernel.h>
+#include <sched/spinlock.h>
+
+/*
+ * spinlock_acquire - Lock a lock
+ * @lock: pointer to desired spinlock
+ *
+ * Saves the RFLAGS register, then acquires a lock.
+ * Pause instruction is used to ease the CPU.
+ */
+void spinlock_acquire(struct spinlock_t* lock)
+{
+    uint64_t rflags;
+    asm volatile("pushfq ; pop %0 ; cli" : "=rm"(rflags) : : "memory");
+
+    while (__atomic_test_and_set(&lock->locked, __ATOMIC_ACQUIRE)) {
+        __builtin_ia32_pause();
+    }
+
+    lock->rflags = rflags;
+}
+
+/*
+ * spinlock_release - Unlock a lock
+ * @lock: pointer to desired spinlock
+ *
+ * Gets saved RFLAGS register from the lock and
+ * unlocks it (clears locked state).
+ * RFLAGS is then restored.
+ */
+void spinlock_release(struct spinlock_t* lock)
+{
+    uint64_t rflags = lock->rflags;
+    __atomic_clear(&lock->locked, __ATOMIC_RELEASE);
+    asm volatile("push %0 ; popfq" : : "rm"(rflags) : "memory");
+}

src/sched/task.S

@@ -1,7 +0,0 @@
-; Task (process) switching
-
-bits 64
-
-global switch_to_task
-switch_to_task:
-

src/string/string.c

@@ -6,6 +6,16 @@
 
 #include <stddef.h>
 
+/*
+ * strcpy - copy a NULL-terminated string
+ * @dest: destination buffer where the string is copied
+ * @src:  source string to copy from
+ *
+ * Copies the string pointed to by @src (including the terminating
+ * NULL byte) into the buffer pointed to by @dest.
+ *
+ * Return: pointer to the destination string (@dest)
+ */
 char* strcpy(char *dest, const char *src)
 {
     char *temp = dest;
@@ -13,20 +23,79 @@ char* strcpy(char *dest, const char *src)
     return temp;
 }
 
-// https://stackoverflow.com/questions/2488563/strcat-implementation
-char *strcat(char *dest, const char *src){
+/*
+ * strcat - append a NUL-terminated string
+ * @dest: destination buffer containing the initial string
+ * @src:  source string to append
+ *
+ * Appends the string pointed to by @src to the end of the string
+ * pointed to by @dest. The terminating NUL byte in @dest is
+ * overwritten and a new terminating NUL byte is added.
+ *
+ * The destination buffer must be large enough to hold the result.
+ *
+ * Taken from: https://stackoverflow.com/questions/2488563/strcat-implementation
+ *
+ * Return: pointer to the destination string (@dest)
+ */
+char *strcat(char *dest, const char *src)
+{
     size_t i,j;
-    for (i = 0; dest[i] != '\0'; i++)
-        ;
+    for (i = 0; dest[i] != '\0'; i++);
+
     for (j = 0; src[j] != '\0'; j++)
         dest[i+j] = src[j];
+    
     dest[i+j] = '\0';
     return dest;
 }
 
-// https://stackoverflow.com/questions/14159625/implementation-of-strncpy
+/*
+ * strncpy - copy a string with length limit
+ * @dst: destination buffer
+ * @src: source string
+ * @n:   maximum number of bytes to copy
+ *
+ * Copies up to @n bytes from @src to @dst. Copying stops early if a
+ * NULL byte is encountered in @src. If @src is shorter than @n, the
+ * remaining bytes in @dst are left unchanged in this implementation.
+ *
+ * Note: This differs slightly from the standard strncpy behavior,
+ * which pads the remaining bytes with NULL.
+ *
+ * Taken from: https://stackoverflow.com/questions/14159625/implementation-of-strncpy
+ */
 void strncpy(char* dst, const char* src, size_t n)
 {
    size_t i = 0;
    while(i++ != n && (*dst++ = *src++));
 }
+
+
+/*
+ * strncmp - compare two strings up to n characters
+ * @s1: first string
+ * @s2: second string
+ * @n:  number of bytes to compare
+ *
+ * Taken from: https://github.com/DevSolar/pdclib/blob/master/functions/string/strncmp.c
+ *
+ * Return:
+ * $0  - @s1 and @s2 are equal
+ * $<0 - @s1 is less than @s2
+ * $>0 - @s1 is greater than @s2 
+ */
+int strncmp(const char* s1, const char* s2, size_t n)
+{
+    while ( n && *s1 && ( *s1 == *s2 ) ) {
+        ++s1;
+        ++s2;
+        --n;
+    }
+    if ( n == 0 ) {
+        return 0;
+    }
+    else {
+        return ( *(unsigned char *)s1 - *(unsigned char *)s2 );
+    }
+}

src/time/timer.c

@@ -5,8 +5,9 @@
  */
 
 #include <stdint.h>
-#include "io/serial/serial.h"
+#include <io/serial/serial.h>
 #include <kernel.h>
+#include <config.h>
 
 /*
 For now, the timer module will be using the PIC.
@@ -18,6 +19,15 @@ interested in multi-core functionnality like SMP)
 
 volatile uint64_t ticks = 0;
 
+extern struct init_status init;
+
+/*
+ * pic_remap - Remap the Programmable Interrupt Controller
+ *
+ * By default, interrupts are mapped at the wrong place.
+ * This function remaps interrupt numbers so interrupts
+ * don't conflict with each other. 
+ */
 void pic_remap()
 {
     uint8_t master_mask = inb(0x21);
@@ -45,6 +55,12 @@ void pic_remap()
     outb(0xA1, slave_mask);
 }
 
+/*
+ * pic_enable - Enable the Programmable Interrupt Controller
+ *
+ * This function enables IRQ0 and IRQ1, which correspond to
+ * the timer and keyboard interrupts, respectively.
+ */
 void pic_enable()
 {
     // Enabling IRQ0 (unmasking it) but not the others
@@ -55,12 +71,15 @@ void pic_enable()
 }
 
 /*
-Base frequency = 1.193182 MHz
-1 tick per ms (divide by 1000) = roughly 1193 Hz
-*/
+ * pit_init - Initialization of the Programmable Interval Timer
+ *
+ * The PIT is the simplest timer we can get working on x86.
+ * It has a base frequency of 1.193182 MHz.
+ * A custom frequency can be set using TIMER_FREQUENCY macro.
+ */
 void pit_init()
 {
-    uint32_t frequency = 1000; // 1 kHz
+    uint32_t frequency = TIMER_FREQUENCY;
     uint32_t divisor = 1193182 / frequency;
 
     // Set PIT to mode 3, channel 0
@@ -71,17 +90,25 @@ void pit_init()
     outb(0x40, (divisor >> 8) & 0xFF);
 }
 
-// Wait n ticks
-// Given that there's a tick every 1ms, wait n milliseconds
+/*
+ * timer_wait - Wait for X ticks
+ *
+ * By default, the timer frequency is 1000Hz, meaning
+ * ticks are equal to milliseconds.
+ */
 void timer_wait(uint64_t wait_ticks)
 {
     uint64_t then = ticks + wait_ticks;
-    while (ticks < then)
-    {
+    while (ticks < then) {
         asm("hlt");
     };
 }
 
+/*
+ * timer_init - Initialization of the timer
+ *
+ * This function wakes the PIT.
+ */
 void timer_init()
 {
     // Remapping the PIC, because at startup it conflicts with
@@ -91,4 +118,5 @@ void timer_init()
     pic_enable();
     pit_init();
     DEBUG("PIT initialized");
+    init.timer = true;
 }

test.bin

@@ -1 +0,0 @@
-ｸ<EFBFBD>ｭﾞ<EFBFBD>