valkyrie
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Published
20 hours ago •
aesophor
aesophor
🔮 A UNIX-like toy kernel built from scratch (for AArch64) with preemptive multi-threading, VM, CoW fork(), buddy, slob, VFS, FAT32.
VALKYRIE
A UNIX-like toy operating system built from scratch in C++20
Kernel Features
- AArch64 kernel with (user & kernel) preemptive multi-threading
- Copy-on-write
fork() - Virtual memory
- Virtual filesystem (VFS)
- FAT32 filesystem (supports long filenames)
- /dev, /proc, /tmp filesystem
- Self-made C++ standard library
Build and Run
Build requirements
- GNU make
- aarch64 (cross) compiler toolchain
- qemu-system-aarch64
Installing ARMv8 (cross) compiler toolchain and QEMU
# Arch Linux (x86_64)
sudo pacman -S aarch64-linux-gnu-gcc aarch64-linux-gnu-gdb qemu-arch-extra
# macOS (x86_64)
brew tap messense/macos-cross-toolchains
brew install aarch64-unknown-linux-gnu qemu
# macOS (Apple Silicon)
brew install aarch64-elf-gcc aarch64-elf-binutils qemu
Building and running valkyrie
git clone https://github.com/aesophor/valkyrie
cd valkyrie
make && make run
Syscalls
int sys_read(int fd, void __user *buf, size_t count);
int sys_write(int fd, const void __user *buf, size_t count);
int sys_open(const char __user *pathname, int options);
int sys_close(int fd);
int sys_fork();
int sys_exec(const char __user *name, const char __user *argv[]);
[[noreturn]] void sys_exit(int error_code);
int sys_getpid();
int sys_wait(int __user *wstatus);
int sys_sched_yield();
long sys_kill(pid_t pid, int signal);
int sys_signal(int signal, void(__user *handler)());
int sys_access(const char __user *pathname, int options);
int sys_chdir(const char __user *pathname);
int sys_mkdir(const char __user *pathname);
int sys_rmdir(const char __user *pathname);
int sys_unlink(const char __user *pathname);
int sys_mount(const char __user *device_name, const char __user *mountpoint,
const char __user *fs_name);
int sys_umount(const char __user *mountpoint);
int sys_mknod(const char __user *pathname, mode_t mode, dev_t dev);
int sys_getcwd(char __user *buf);
void __user *sys_mmap(void __user *addr, size_t len, int prot, int flags, int fd,
int file_offset);
int sys_munmap(void __user *addr, size_t len);
User Programs
- init
- login
- sh
- ls
- cat
- mkdir
- touch
- fork_test
- page_fault_test
- procfs_test
- vfs_test_dev
- vfs_test_mnt
- vfs_test_orw
- mmap_illegal_read
- mmap_illegal_write
aesophor