576a7a7c82
Change the early startup code to set TCR_EL1.IPS to ID_AA64MMFR0_EL1.PARange if it has a defined value (the currently defined values have the same meanings), but use 48-bit PAs if 52-bit PAs are supported because 52-bit PAs have a different translation table format that we don't support. Stash the computed TCR_EL1 in a variable and use it in the context switch code.
The Little Kernel Embedded Operating System
The LK kernel is an SMP-aware kernel designed for small systems ported to a variety of platforms and cpu architectures.
See https://github.com/littlekernel/lk for the latest version.
High Level Features
- Fully-reentrant multi-threaded preemptive kernel
- Portable to many 32 and 64 bit architectures
- Support for wide variety of embedded and larger platforms
- Powerful modular build system
- Large number of utility components selectable at build time
Supported architectures
- ARM32
-
- Cortex-M class cores (armv6m - armv8m)
-
- ARMv7+ Cortex-A class cores
- ARM64
- RISC-V 32 and 64bit bit in machine and supervisor mode
- x86-32 and x86-64 386 up through modern cores
- microblaze
- MIPS
- OpenRISC 1000
TODO
To build and test for ARM on linux
- install or build qemu. v2.4 and above is recommended.
- install gcc for embedded arm (see note 1)
- run scripts/do-qemuarm (from the lk directory)
- you should see 'welcome to lk/MP'
This will get you a interactive prompt into LK which is running in qemu arm machine 'virt' emulation. type 'help' for commands.
Note: for ubuntu x86-64: sudo apt-get install gcc-arm-none-eabi or fetch a prebuilt toolchain from https://newos.org/toolchains/x86_64-elf-10.2.0-Linux-x86_64.tar.xz