https://github.com/rob2309/simpleos2
SimpleOS2 is a very simple x86_64 OS I am creating for learning purposes.
https://github.com/rob2309/simpleos2
amd64 apic apic-timer asm c cpp efi efi-development kernel operating-system operating-system-learning process-management uefi uefi-boot uefi-development x86 x86-64
Last synced: 2 months ago
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SimpleOS2 is a very simple x86_64 OS I am creating for learning purposes.
- Host: GitHub
- URL: https://github.com/rob2309/simpleos2
- Owner: Rob2309
- License: other
- Created: 2019-01-15T19:36:53.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2021-04-23T12:01:46.000Z (about 4 years ago)
- Last Synced: 2025-02-28T19:52:53.828Z (3 months ago)
- Topics: amd64, apic, apic-timer, asm, c, cpp, efi, efi-development, kernel, operating-system, operating-system-learning, process-management, uefi, uefi-boot, uefi-development, x86, x86-64
- Language: C
- Homepage:
- Size: 3.51 MB
- Stars: 7
- Watchers: 1
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# SimpleOS2
This is a very simple x86_64 OS I am creating for learning purposes.
## Implemented features:
- Simple UEFI Bootloader (to be replaced by GRUB in the future?)
- Physical and Virtual memory management
- Terminal that can print 32-Bit colored text and receive keyboard input
- Interrupt handling
- APIC Timer support
- IOAPIC support
- User mode processes
- Kernel Threads
- Multitasking & Multithreading
- System calls via syscall instruction
- Linux-like virtual file system (with mount support)
- file system permissions with read, write, execute and setuid permissions
- FileSystem driver API
- Character- and BlockDevice driver API
- Multi-Core support
- Usermode SSE & FPU support
- Basic shell that can run programs with command line arguments
- Basic ACPI support using ACPICA (currently only shutdown supported)
- Basic readonly Ext2 driver (used for ramdisk)
- Usermode C++ library for basic interaction with the Kernel (Function definitions for all important syscalls)
## Planned features:
- HDD support (SATA)
- USB support (madness)
- IP Stack
- Full C library support
## Specs
This OS should basically run on any x86_64 machine that supports UEFI. If you find a machine that does not work with SimpleOS2, please contact me.
## Building SimpleOS2
### Prerequisites
- Some kind of Linux environment (or WSL)
- Standard 64-Bit Elf GCC
- Standard 64-Bit mingw GCC
- NASM
- mtools
- debugfs
- parted
### Build commands
- ``make depcheck``: check if all dependencies are installed
- ``make partition``: build a raw partition image that contains the OS
- ``make disk``: build a raw disk image that contains the OS
- ``make diskvbox``: build a virtualbox disk image (.vdi) that contains the OS
- ``make clean``: remove everything but the sources
## Emulating SimpleOS2
- ``make runkvm``: run the OS in qemu (requires qemu-system-i86_64)
- ``make runvbox``: run the OS in VirtualBox (Requires a VirtualBox machine with name 'SimpleOS2' and partition.vdi as hard disk, chipset has to be ICH9)
- ``make debug``: run the OS in qemu and debug it in GDB
## Configurations
- every command above can be followed by ``config=Release`` or ``config=ReleaseDbg`` to use/build a Release configuration of the OS
## Running on real Hardware
I have run SimpleOS2 on my own hardware several times and never encountered any damage. Nevertheless, I do not take any responsibility for any kind of damage to your system! Since SimpleOS2 has no disk writing functionality yet, data corruption is pretty much impossible.
## Modifying SimpleOS2
[DEVELOPMENT.md](DEVELOPMENT.md) contains information for developers who want to have fun with SimpleOS2
## Lessons learned
- When your Code works on Qemu but triple faults on VirtualBox, you have missed some very important minor detail in the AMD64 spec
- When your Code works on VirtualBox but triple faults on Qemu, chances are Qemu does not recognize that you've written to the KernelGSBase MSR (you have to write 0 to gs and fs)
- When your SMP Code crashes when booting more that two Processor Cores, they are probably booting on the same stack (took 2 days to find this stupid bug)
- *NEVER* *EVER* forget that stacks grow down. I spent multiple days searching seemingly random bugs, just to notice that I allocated a memory area for some stack and forgot that the stack should begin at the **end** of the allocated space