91128ad729
- Add a percpu structure for each cpu, akin to x86-64 and riscv. Pointed to by x18, which is now reserved for this in the kernel. Tweaked exception and context switch routines to leave x18 alone. - Remove the cpu-trapping spinlock logic that is unused in mainline, probably. (Can add a new version of it back if it's necessary). - Switch fdtwalk helper to using the newer, cleaner way of initializing secondaries using the PSCI CPU_ON argument that should be pretty standard on modern implementations. (Possibly an issue with old firmware). - Remove the notion of computing the cpu ID from the Affinity levels, which doesn't really work properly on modern ARM CPUs which more or less abandoned the logical meaning of AFFn.
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.
It is used in a variety of open source and closed source projects, notably the bootloader for a lot of Android phones of various make.
See https://github.com/littlekernel/lk for the latest version.
For comprehensive documentation, see Index.
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
- ARMv8 and ARMv9 cores
- RISC-V 32 and 64bit bit in machine and supervisor mode
- x86-32 and x86-64
- Motorola 68000
- Microblaze
- MIPS
- OpenRISC 1000
- VAX (experimental)