font.psf was copied from the soso repository,
which was referenced many times when building this. Thanks to the devs on them.
:)
- Clang 11.0.0
clangis nice because it doesn't require building a full cross-compiler toolchain.
- lld 11.0.0
- NOTE: The explicit
-targetpassed to clang does not explicitly specify an OS (or vendor), so by default, clang under the hood will use a GCC toolchain, which explicitly calls gcc/g++ for the link step. This will mean any linker flags passed to clang during linking will be passed to gcc. For some versions of gcc, the flag-fuse-ld=lldwill only use an executable explictly calledlldrather than searching for programs likelld-11, potentially resulting in some errors. (I trying to figure out why I kept hittingcollect2: fatal error: cannot find ‘ld’.) If you happen toapt-getlldwith a specific version number, you can work around this by eitherapt-getinglldwithout the version number, or symlinking yourlld-{version}tolld.
- NOTE: The explicit
- ld 2.35.2
- FIXME: Turns out I've been using the system linker for flat binaries. I should get rid of this and just use lld.
- CMake 3.15.4
- tar 1.32
- Used for making the filesystem used by userboot.
- grub-file 2.04-5
- grub-mkrescue 2.04-5
$ mkdir build
$ cd build
$ cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_C_COMPILER=clang
# Just make the kernel.
$ ninja # or `ninja kernel`
# Make the ramdisk which will contain some user code.
$ ninja initrd
# Optional: Make a bootable cdrom image that also contains the initial ramdisk.
$ ninja myos.iso# RECOMMENDED: Running without displaying graphics. Logs and interaction are
# done exclusively through emulated serial ports on QEMU. Running in this mode
# does not require any graphics and text is completely done through the user
# console. This allows for kernel logs to be piped to user commands for
# automation.
$ qemu-system-i386 -cdrom myos.iso -nographic
OR
$ qemu-system-i386 -kernel kernel/kernel -initrd initrd -nographic
OR
$ qemu-system-i386 -kernel kernel/kernel -nographicExit QEMU with Alt+2, type quit, ENTER.
Note that launching QEMU with -nographic can mess up the terminal on some
shells. Use reset after exiting QEMU to fix this.
-serial file:serial.log- Writes to COM1 will be written to
serial.log. This is not needed when-nographicis used.
- Writes to COM1 will be written to
-no-reboot- Do not reboot on a kernel crash.
Kernel tests are run automatically at startup.
If userboot is provided, then once Userboot Stage 2 is launched and a shell
opens up, then you can type runtests to run userspace tests.
If an initial ramdisk is provided, the kernel will jump to the start of the ramdisk and execute instructions from there in userspace. This program is called the userboot. The initial ramdisk is formatted such that the first stage of userboot, which is a flat binary, is at the very start of the initial ramdisk. Immediately following it is a USTART-formatted filesystem that userboot parses.
TODO: Move the userboot directory into its own repo.
# Run from root directory
$ clang-format -style=file -i $(find . -name '*.h') $(find . -name '*.cpp') libcxx/include/*
$ yapf -i --style="{indent_width: 2}" userboot/make_initrd.pygrep for them.
$ objdump -b binary user_program.bin -D -m i386 |& lessEverything in each of the top-level project directories should effectively be independent of each other (the kernel should be able to be built independently of userboot, and userboot should not be hardcoded to depend on this libc).
Subprojects in each subdirectory can depend on each other, but should be easily substituable for similar tools (userboot can be substituted for any other program that the kernel can run on startup, and userboot can use any other libc that can run on this kernel).