Tests on the main 64-bit architectures prove that the ASLR is stable and does
not result in noticable performance degradation.
Position Independent Executables (PIE) are built on every platform, as this
allows enabling ASLR without rebuilding world and no problems with
stability were encountered when using PIEs with ASLR disabled.
For 64-bit executables set honor_sbrk to 0. This allows ASLR to use
bss grow region for mappings. Sbrk is currently deprecated and not
widely used, so this setting should not have any significant impact
on the OS memory footprint.
On 32-bit architectures the implementation is however still unstable
- please refer to attached analysis and https://reviews.freebsd.org/D27025.
Contrary to other test-cases the issues were encountered when trying to perform buildworld.
For the sake of safety keep ASLR is disabled for 32-bit executables on 64-bit machines, too.