Mark the kernel read-only data as write-protected in the pagetables,
in order to catch accidental (and incorrect) writes to such const
data. This option may have a slight performance impact because a
portion of the kernel code won't be covered by a TLB anymore.
If in doubt, say "N".

Enabling this option turns a certain set of sanity checks for user
copy operations into compile time failures.

The copy_from_user() etc checks are there to help test if there
are sufficient security checks on the length argument of
the copy operation, by having gcc prove that the argument is
within bounds.

If unsure, or if you run an older (pre 4.4) gcc, say N.