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<p class="MsoNormal">I would like to expand support for MAP_SHARED in mmap(). I would like to run a few ideas by the group to see which direction to go. I really only need to expand MAP_SHARED support for some LIBBSD drivers that I want to create. There
are two approaches I can take.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The first approach is to just add a mmap handler function in “struct _rtems_filesystem_file_handlers_r”. The mmap() restrictions on MAP_SHARED would be removed. The mmap handler for all RTEMS file systems (except SHM) would get the default
mmap handler (return EINVAL). SHM would get a handler similar to the one found in mmap.c. In RTEMS-LIBBSD, the RTEMS character device handler (devfs_devs.c) would be free to pass the mmap request on to FREEBSD drivers.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The second approach includes the first approach but adds support for RTEMS device drivers. We would need to add a mmap handler to “rtems_driver_address_table”. The “IMFS_device_handlers” would add a mmap handler to device_mmap(). We
would need a new rtems_deviceio_mmap() function to call the drivers mmap handler. I don’t think any BSPs will be affected because the mmap handler of “rtems_driver_address_table” should initialize to NULL. Any BSP would them be free to add a handler to process
mmap calls.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any opposition to the two approaches? If not, which one would you prefer?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Kevin Kirspel<o:p></o:p></p>
<p class="MsoNormal">Electrical Engineer - Sr. Staff<o:p></o:p></p>
<p class="MsoNormal">Idexx Roswell<o:p></o:p></p>
<p class="MsoNormal">235 Hembree Park Drive<o:p></o:p></p>
<p class="MsoNormal">Roswell GA 30076<o:p></o:p></p>
<p class="MsoNormal">Tel: (770)-510-4444 ext. 81642<o:p></o:p></p>
<p class="MsoNormal">Direct: (770)-688-1642<o:p></o:p></p>
<p class="MsoNormal">Fax: (770)-510-4445<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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