In support of Kernel Address Space Layout Randomization (KASLR),
this randomizes the physical address at which the kernel image
is decompressed and the virtual address where the kernel
image is mapped, as a security feature that deters exploit
attempts relying on knowledge of the location of kernel
code internals.

On 64-bit, the kernel physical and virtual addresses are
randomized separately. The physical address will be anywhere
between 16MB and the top of physical memory (up to 64TB). The
virtual address will be randomized from 16MB up to 1GB (9 bits
of entropy). Note that this also reduces the memory space
available to kernel modules from 1.5GB to 1GB.

On 32-bit, the kernel physical and virtual addresses are
randomized together. They will be randomized from 16MB up to
512MB (8 bits of entropy).

Entropy is generated using the RDRAND instruction if it is
supported. If RDTSC is supported, its value is mixed into
the entropy pool as well. If neither RDRAND nor RDTSC are
supported, then entropy is read from the i8254 timer. The
usable entropy is limited by the kernel being built using
2GB addressing, and that PHYSICAL_ALIGN must be at a
minimum of 2MB. As a result, only 10 bits of entropy are
theoretically possible, but the implementations are further
limited due to memory layouts.

If unsure, say Y.