"ksyms" is the right command to get the symbols actually exported in
kernel. I dont know what is the corresponding commnad in FC, but I
hope there should be something.
Which distro u r using and kernel version?. Can u please tell me the package name?
How do you get "man kallsyms"?. I am geting only man proc and there i could see
/proc/kallsyms entry and i already posted the output. What about that comments?
> Can anybody please explain me :
>
> 1. What is System. map file?
its a file in which contains all the symbols (variables, function
names) defined in kernel image. It has nothing to do with exported
symbols. It contains all the symbols in kernel with their virtual
addresses. This file is created using "nm" utility on kernel image.
One of the use of this file is to make the OOPs message more readable.
Thanks for explaining..
> 2. What is /proc/kallsyms entry? what's the use of this entry?
Mentioned above
> 3. How can i know all exported sysmbol in kernel and which i can use?
by using ksyms commnad, dont know how to do in FC
>
>
> > by default in standard kernel, no system call functions are exported,
> is it? then how can you write your device driver without using any system
> call? Do you mean that if i want to write my driver , i have to compile my kernel?
Sorry ,Actually i mean to say kernel module, not device driver.And moreever i mean to say kernel system call which is started with sys_
For writting the device driver, you dont need to call the system call.
System call is the kernel function, exposed to user space through some
tricks.
Well we suppose not to do but we can ..a dirty coding can call exported kernel system call.
Basically you can say sytem calls are the kernel functions
which can be called from user space application. Device Driver code is
much below in heirarchy, which directly deals with hardware. If we see
OS as layer software, device driver falls somewhere in the lower layer
of operating system, intracting with hardware and system calls fall in
to top layer of OS.
Hope I am not confusing more :-)
regards,
Gaurav
