The #spectre and #meltdown attacks were subject to great concerns in the last weeks.
Eben Upton made brilliant explanation of how and why they work in his blog post.
There is already project on Github which can be used to test if your ARM AArch64 processor is vulnerable to such attacks.
As Cortex-A7 and Cortex-A53 are not affected of these attacks this means all our boards with A20, A33, A64 processors are immune.
For A10, A13, AM335X (Cortex-A8), RK3188 (Cortex-A9) we need to do some further investigation.
olimex 
Jan 10, 2018 @ 04:44:08
ARM has a table of Core, Spectre, Meltdown https://developer.arm.com/support/security-update A9 is affected by V1 and V2 (Spectre), but not V3 or V3a (Meltdown). A8 is similar, but as now, V1 is marked as “Yes (under review)”.