Re: ptrace and pfn mappings

[Benjamin Herrenschmidt]

> I think the best idea is to add a new ->access method to the vm_operations
> that's called by access_process_vm() when it exists and VM_IO or VM_PFNMAP
> are set.   ->access would take the required object locks and copy out the
> data manually.  This should work both for spufs and drm.

Another option is to have access_process_vm() lookup the PTE and lock it
while copying the data from the page.

something like

	- lookup pte & lock
	- check if pte still present
	- copy data to temp kernel buffer
	- unlock pte
	- copy data to user buffer

Ben.

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