slos

SLOS represents Simple Light OS. This repository is for the source code of SLOS running in ARM processor. It is tested in Cortex-A9 in Xilinx Zynq7000 chipset (currently tested in coraz7 board) but seems to be expanded to other products.

Implementation list

1. Process Management
   • TCB (Task Control Block)
   • task fork - forkyi()
   • GIC - interrupt handler (top half / bottom half)
   • task synchronization(spin lock)
   • task state - TASK_RUNNING, TASK_WAITING
2. Timer frame work
   • realtime timer, sched timer, oneshot timer
   • timer interrupt handler
3. Realtime scheduler for rt task
   • Earliest Deadline First scheduler
   • preemptive context switch
4. CFS scheduler for task others
   • run q and wait q
   • imitate Linux run q and CFS scheduler
   • sched entity with virtual runtime
   • shell task, worker task, cpu idle task, and dummy task
5. Memory Management
   • page frame pool
   • small page table walk
   • virtual memory manager
   • page fault handler
   • demand paging
6. SLFS (Simple Light File System)
   • based on ramdisk
   • 2 level file system : file size up to 800KB
   • ram disk and elf loader for use applications
7. syscalls through the svc instruction - libslos.a
8. Hardware-Software codesign
   • Two FPGA (modcore, odev) implementations for a custom peripheral HW in PL subsystem
   • Script base Vivado project implementation
   • a device driver with DMA interrupt handler
   • a device driver for out-stream device
9. SMP (Symmetric Multiprocessor)
   • CPU 0 and CPU 1 boots up and running with the identical kernel
   • PERCPU resource storage
   • SGI (Software Generated Interrupt) between CPU 0 and CPU 1
   • Mailbox for communication between CPU 0 and CPU 1

Build system:

• CMake build, Make build both are working
• Kconfig
• Statically linked device tree for device driver

Refer A little book on custom OS developement from scratch.pdf for more information.

Notes: To petalinux-package for cora z7, petalinux v2023.2 is used and verified