Re: Linking with kernel code (Makefile)

The character device is a good idea!!!
But how would the device's mmap be implemented?
I know how the read and write work, but they copy the data from one space
to another, which would be slow if there is much communication. Because
this looses the benifits of shared memory

About the kernel linking, I'm not making a module driver, 
I'm trying to recompile the kernel after adding my file (kshared.c)
I guess I should be able to access all structures and functions in the
kernel, if I succeed to link correctly with the files containing those
functions and structures, but I'm not so good at make files.

--- "Albert D. Cahalan" <acahalan@cs.uml.edu> wrote:

quoted

What I want to do:
    create a shared memory segment between user space and kernel space

Create a character device.
Have the driver allocate memory.
Let the user mmap() it.

quoted

    I can't link with the array or the function, this also happens

with

quoted

all functions that are not defined in 'ksyms'
    Even though I declared 'newseg' and 'shm_segs' as 'extern' in my

file
...

quoted

But while making bzImage, it gives the error unresolved external

'newseg'

quoted

So my question is how can I link to the kernel source code, or am I

not

quoted

allowed to?

You are not allowed to use interfaces that are not exported.
This is partly to prevent you from depending on code that is
very likely to change, and partly to prevent a Microsoft Linux
or similar abuse of the GPL.

If you really need it, make a non-module driver. Maybe after
that gets accepted into the main kernel you could convince
Linus to export the function you want for module use.

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