A hacker has discovered a special debugging mechanism within
central processing units (CPUs) made by Advanced Micro Devices.
The mode potentially allows to learn more about how exactly
AMD's chips work, reverse engineer them and make further
discoveries regarding their capabilities. It should be
understood that that present all the assumptions regarding the
mode are just theories. According to a discovery made by hackes
who names himself Czerno AMD processors (Athlon XP and better)
have included firmware-based debugging features that expand
greatly over standard, architecturally defined capabilities of
x86. For some reason though, the manufacturer has been tightly
secretive about these features; hint of their existence was
gained by glancing at the list of undocumented machine specific
registers (MSRs). There are at least four new machine specific
registers (MSR) that are involved in the expanded debug
facilities. All those MSRs are "password" protected against
casual access : read/write access (RDMSR/WRMSR)