mmap'd physical memory not updating user virtual
I am writing a user space MAC driver in Linux 2.6.23 hosted on a Arm11 mpcore. A contiguous block of physical memory is allocated and mmap'd to userspace.
/dev/mem with O_SYNC flag is used to mmap so that the user virtual memory is uncached (with no much benefit).
kptr = kmalloc(sz, GFP_DMA|GFP_KERNEL);
pptr = __pa(kptr);
fd = open("/dev/mem", O_RDWR|O_SYNC);
uptr = mmap(0, sz, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_LOCKED,fd, pptr);
The map'd user virtual memory is carved into network buffers and used for DMA.The MAC is successfully able to DMA ethernet frames to the physical memory. From the Rx interrupt handler bh (kernel logical memory) the frames received could be viewed and the cache functions also work fine. However, the mmap'd memory in user space does not reflect the changes.
Why is the physical memory mapped to user virtual does not reflect the chages ?
Or any suggestions on what could be going wrong here ?
Deb Rupam Banerjee
P.S: Please note that all buffer alignment's are taken care of.
|Where's That Pesky Hidden Word?||Aug 28, 2015|
|A Project to Guarantee Better Security for Open-Source Projects||Aug 27, 2015|
|Concerning Containers' Connections: on Docker Networking||Aug 26, 2015|
|My Network Go-Bag||Aug 24, 2015|
|Doing Astronomy with Python||Aug 19, 2015|
|Build a “Virtual SuperComputer” with Process Virtualization||Aug 18, 2015|
- Concerning Containers' Connections: on Docker Networking
- Where's That Pesky Hidden Word?
- Problems with Ubuntu's Software Center and How Canonical Plans to Fix Them
- A Project to Guarantee Better Security for Open-Source Projects
- Firefox Security Exploit Targets Linux Users and Web Developers
- My Network Go-Bag
- Doing Astronomy with Python
- Build a “Virtual SuperComputer” with Process Virtualization
- Three More Lessons
- Calling All Linux Nerds!