Embeded linux OS Reading Notes

 

 

Linux:

 

1 Single Kernel Mode

Linux is a single kernel mode, and externalProgramIn different memory address spaces, the program can only be accessed through the: System Call interface.

In Linux, the single kernel mode is dynamic.

 

2. No user thread

Create a new thread by using clone.

 

3 Non-preemptive:

 

4 Process:

4.1 process no.: PID

4.2 status: running, uninterruptable, interruptable, stopped, zombie.

4.3 sub-process and parent process

4.4 INT: top half & bottom half

4.5 system call

4.6 atomic operation

Spinlock: For SMP. Lock or unlock, loop to occupy the CPU.

Semaphore: Up and down, if 0 wait.

4.7 comunication

Pipe

FIFO

IPC

 

 

 

5. Memory Management

Storage Management Virtual Memory Page Mode

 

 

 

6. File System:

6.1 VFS

Inode, flash,

6.2 file system type

6.3 log files

 

 

7 device management

7.1 Overview

Interrupt + DMA

7.2 Device Files

Devfs/

7.3 device Registration and Management

Mount umount

 

 

8. pilot process

8.1 initial steps

The initial steps are related to the micro-processing hardware structure, so they are not portable.

The Linux boot process includes:

After the processor is started, Execute Rom to startCode

Rom startup code initializes CPU, Ram Ctrl, SOC

Configure Memory Map

Execute booter Loader

Loader load Linux core from memory or TFTP

 

 

 

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Ref:

Arm & Linux Embedded System tutorial (2) Beihang