I am developing a virtual device driver such that the user can write to the driver a process' pid and a virtual address, and the module will use these two values to get the memory contents of the target process. I am wondering if there is any easy functions that can fetch user page's data at this virtual address.

I have tried get_user but this is not possible because the modules executing get_user at another process's context. I also tried to use ptrace_readdata, however, it seems that the file at /kernel/ptrace.c leaves a function access_process_vm undefined and also I don't know how to compile the source code of my module with this file (the linker seaches file in /linux/include by default). I am wondering if there are any other solutions...