On Wed, May 28, 2014 at 06:47:24PM +0530, Pranay Srivastava wrote:
Hi
I need to capture all writes on page which is memory mapped by the user program.
For what and what are you going to do with them once you "capture" them? Are you trying to capture them in the kernel or in userspace?
I've tried setting the vm_page_prot by disabling the VM_WRITE flag but even then the page fault occurs only once during the first write. VM_SHARED is set to stop COW in the __do_fault.
I was also trying to set_memory_ro(this may not be available for all archs?) however I can't do that while handling the fault since the page table entries are created later after the vm_operations_struct->fault has installed the page for the fault.
I'm not having any clues on how to do this. Any help would be really helpful on this.
I don't think this is going to be possible, sorry, please go revisit the reason you think you want to do this. greg k-h