c88170f6e0
This very large commit is mainly focused on getting the APs started and to a state where they're waiting to have work scheduled. (Actually scheduling on them is for another commit.) To do this, a bunch of major changes were needed: - Moving a lot of the CPU initialization (including for the BSP) to init_cpu(). This includes setting up IST stacks, writing MSRs, and creating the cpu_data structure. For the APs, this also creates and installs the GDT and TSS, and installs the global IDT. - Creating the AP startup code, which tries to be as position independent as possible. It's copied from its location to 0x8000 for AP startup, and some of it is fixed at that address. The AP startup code jumps from real mode to long mode with paging in one swell foop. - Adding limited IPI capability to the lapic class. This will need to improve. - Renaming cpu/cpu.* to cpu/cpu_id.* because it was just annoying in GDB and really isn't anything but cpu_id anymore. - Moved all the GDT, TSS, and IDT code into their own files and made them classes instead of a mess of free functions. - Got rid of bsp_cpu_data everywhere. Now always call the new current_cpu() to get the current CPU's cpu_data. - Device manager keeps a list of APIC ids now. This should go somewhere else eventually, device_manager needs to be refactored away. - Moved some more things (notably the g_kernel_stacks vma) to the pre-constructor setup in memory_bootstrap. That whole file is in bad need of a refactor.
jsix: A hobby operating system
jsix is the hobby operating system that I am currently building. It's far from finished, or even being usable. Instead, it's a sandbox for me to play with kernel-level code and explore architectures.
The design goals of the project are:
-
Modernity - I'm not interested in designing for legacy systems, or running on all hardware out there. My target is only 64 bit architecutres, and modern commodity hardware. Currently that means x64 systems with Nehalem or newer CPUs and UEFI firmware. (See this list for the currently required CPU features.) Eventually I'd like to work on an AArch64 port, partly to force myself to factor out the architecture-dependent pieces of the code base.
-
Modularity - I'd like to pull as much of the system out into separate processes as possible, in the microkernel fashion. A sub-goal of this is to explore where the bottlenecks of such a microkernel are now, and whether eschewing legacy hardware will let me design a system that's less bogged down by the traditional microkernel problems.
-
Exploration - I'm really mostly doing this to have fun learning and exploring modern OS development. Modular design may be tossed out (hopefully temporarily) in some places to allow me to play around with the related hardware.
A note on the name: This kernel was originally named Popcorn, but I have since
discovered that the Popcorn Linux project is also developing a kernel with that
name, started around the same time as this project. So I've renamed this kernel
jsix (Always styled jsix or j6, never capitalized) as an homage to L4, xv6,
and my wonderful wife.
Building
jsix uses the Ninja build tool, and generates the build files for it with a custom tool called Bonnibel. Bonnibel can be installed with Cargo, or downloaded as a prebuilt binary from its Github repository.
Requrirements:
- bonnibel
- ninja
- clang
- nasm
- mtools
- curl for downloading the toolchain
Setting up the cross toolchain
Running pb sync will download and unpack the toolchain into sysroot.
Compiling the toolchain yourself
If you have clang and curl installed, runing the scripts/build_sysroot.sh
script will download and build a LLVM toolchain configured for building jsix
host binaries.
Building and running jsix
Once the toolchain has been set up, running Bonnibel's pb init command will
set up the build configuration, and pb build will actually run the build. If
you have qemu-system-x86_64 installed, the qemu.sh script will to run jsix
in QEMU -nographic mode.
I personally run this either from a real debian amd64 testing/buster machine or a windows WSL debian testing/buster installation. The following should be enough to set up such a system to build the kernel:
sudo apt install qemu-system-x86 nasm clang-10 mtools curl ninja-build
sudo update-alternatives /usr/bin/clang clang /usr/bin/clang-10 1000
sudo update-alternatives /usr/bin/clang++ clang++ /usr/bin/clang++-10 1000
curl -L -o pb https://github.com/justinian/bonnibel_rs/releases/download/v2.3.0/pb-linux-amd64 && chmod a+x pb