On Mon, May 17, 2021 at 02:17:05PM -0500, Rob Herring wrote: > On Mon, May 17, 2021 at 10:55 AM Sudeep Holla <sudeep.holla@xxxxxxx> wrote: > > > > The CLKSCREW attack [0] exposed security vulnerabilities in energy management > > implementations where untrusted software had direct access to clock and > > voltage hardware controls. In this attack, the malicious software was able to > > place the platform into unsafe overclocked or undervolted configurations. Such > > configurations then enabled the injection of predictable faults to reveal > > secrets. > > > > Many Arm-based systems used to or still use voltage regulator and clock > > frameworks in the kernel. These frameworks allow callers to independently > > manipulate frequency and voltage settings. Such implementations can render > > systems susceptible to this form of attack. > > > > Attacks such as CLKSCREW are now being mitigated by not having direct and > > independent control of clock and voltage in the kernel and moving that > > control to a trusted entity, such as the SCP firmware or secure world > > firmware/software which are to perform sanity checking on the requested > > performance levels, thereby preventing any attempted malicious programming. > > > > With the advent of such an abstraction, there is a need to replace the > > generic clock and regulator bindings used by such devices with a generic > > performance domains bindings. > > > > [0] https://www.usenix.org/conference/usenixsecurity17/technical-sessions/presentation/tang > > > > Link: https://lore.kernel.org/r/20201116181356.804590-1-sudeep.holla@xxxxxxx > > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > > Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx> > > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> Thanks Rob. Viresh, I noticed I haven't cc-ed linux-pm list, do you need me to post there or are you happy to pick it up from here when Hector's mediatek cpufreq drivers using this are ready to be merged ? -- Regards, Sudeep
