On Tue, 2008-02-26 at 08:49 -0600, Maynard Johnson wrote: > 2. Compile C program as 32-bit; then run it. While the program is > waiting for input, obtain its PID and do 'cat /proc/<pid>/maps' to > get > the address of where libc is loaded. > 3. From the dir where you build the uaccess_test kernel module: > 'insmod ./uaccess_test.ko lib_addr=0x<mem_loc_libc>' > This should succeed. dmesg to verify. > 4. Unload the module. > 5. Recompile your C program with -m64; start it up and obtain the > address of libc again (now a 64-bit address). > 6. Load the uaccess_test kernel module and pass > 'lib_addr=0x<mem_loc_libc>'. Note that this time, the load fails. > dmesg to see debug printk's.
Sounds to me that your kernel module will try to copy_from_user() from the user context of ... insmod :-) You need to do your copy_from_user() from within the context of the program you try to access the memory from ! If you need to access another context than the current one, you then need to use a different mechanism, such as get_user_pages(), though beware that you can only do that for memory, not SPE local store or register mappings. Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
