MicroEmbeddedOS

Some things, only to do their own, will feel something

基于raspi4b bcm2711 cortex-A72平台的微型嵌入式操作系统，简单的实现了内存管理、进程管理、文件管理、设备管理

同时还实现了虚拟文件系统、虚拟内存、系统调用、中断调用以及日志系统

kernel infomation

PBASE: address of peripheral

#define PBASE 0xFE000000

GIC_BASE_ADDR：address of GIC

#define GIC_BASE_ADDR (0xFF840000)

address of kernel loading

	. = 0x80000, 

kernel

make clean
make
make run

debug

make debug

bash gdb.sh

running goal

qemu-system-aarch64 -machine raspi4b1g -nographic -kernel build/ma_a.bin
Welcome MicroEmbeddedOS v0.1 (2024 10-15)

 /\_/\      /\_/\      /\_/\
( o.o )    ( o.o )    ( o.o )
 > ^ <      > ^ <      > ^ <

Image layout:
  .text.boot: 0x00080000 - 0x00080080 (   128 B)
       .text: 0x00080080 - 0x00087164 ( 28900 B)
     .rodata: 0x00087164 - 0x00087aaa (  2374 B)
       .data: 0x00087aaa - 0x0008c000 ( 17750 B)
        .bss: 0x0008c000 - 0x001444f8 (754936 B)

microembeeded os loading address: 0x00080000
memory: 522988KB available, 130747 free pages
idmap_pg_dir: 0x0008b000
mem_map address: 0x00400000
alloc_page: allocate page address: 0x00400000
alloc_page: allocate page address: 0x00401000
alloc_page: allocate page address: 0x00402000
identify mapping done
alloc_page: allocate page address: 0x00403000
enable mmu done
alloc_page: allocate page address: 0x00404000
alloc_page: allocate page address: 0x00405000
alloc_page: allocate page address: 0x00406000
test_access_map_address: [ access 0x1ffff000 done ]
Bad mode for Sync Abort handler detected, far:0x20001000 esr:0x96000046
gic_init [ cpu_base:0xff842000, dist_base:0xff841000, gic_irqs:160 ]
ssd_memory sram address: 0x000ac460
ssd_memory end sram address: 0x000cc45f


add_inode_to_directory: parent dir is root?
create root dir success:  /
home
tmp
usr
var
root
boot
sys
fs has initialized!
liuzixuan-shell /> Core0 Local Timer interrupt received
current pid: 0
pick_next_task_kernel: pick next thread (pid 1)
kernel_thread1: 10
pick_next_task_kernel: pick next thread (pid 3)
kernel_thread3: 3
pick_next_task_kernel: pick next thread (pid 2)
Core0 Local Timer interrupt received
current pid: 2
pick_next_task_kernel: pick next thread (pid 2)

process manage

directory: kernel/

description: preemptive switching with priority based scheduling policy (clock interrupt based)

virtual ssd

directory: dev/

description: the maximum capacity is 128KB, and each data block is read and written with a size of 4KB

interface

• ssd_read_block
• ssd_write_block

file system

directory: fs/

description: implement an ext2-like file system

interface:

• ext2fs_create
• fs_write
• fs_read
• fs_close

mlog subsystem

directory: mlog/

expected subsystem plan

• mlog subsystem ×
• directory tidy √
• process manage --->>>
• shell implement ×
• driver manage --->>>