[rtl] mmap of kernel memory

[Jens Michaelsen <SteenbeckDigital@compuserve.com>]

As the shared memory mechanism described for RtLinuX is medium flexible
only, I woundered
if it would be possible to add the shared memory to something like rt_fifo.

I took some code from ./driver/sound/soundcard.c 

My first try:

char * mem;

init_module() /* OK */
{mem=kmalloc(1024,GFPxx); return 0; }

cleanup()       /* OK */
{kfree(mem);}

my_read()       /* OK */
{put_usr();}

my_write() /* OK */
{get_usr()}

my_mmap() /* says OK but doesNT work */
{remap_page_range();}

failed. I only get zeros in my application that does the mmap() to the
device.
Read or write works fine, also using a real file for mmap in application
works fine too.

Any mechanism knowledge around?

Jens Michaelsen
--- [rtl] ---
For more information on Real-Time Linux see:
http://rtlinux.cs.nmt.edu/