On Mon Nov 28, 2022 at 12:44 PM AEST, Benjamin Gray wrote: > The DEXCR Speculative Branch Hint Enable (SBHE) aspect controls whether > the hints provided by BO field of Branch instructions are obeyed during > speculative execution. > > SBHE behaviour per ISA 3.1B: > > 0: The hints provided by BO field of Branch instructions may be > ignored during speculative execution > > 1: The hints provided by BO field of Branch instructions are obeyed > during speculative execution > > Add a sysctl entry to allow changing this aspect globally in the system > at runtime: > > /proc/sys/kernel/speculative_branch_hint_enable > > Three values are supported: > > -1: Disable DEXCR SBHE sysctl override > 0: Override and set DEXCR[SBHE] aspect to 0 > 1: Override and set DEXCR[SBHE] aspect to 1 > > Internally, introduces a mechanism to apply arbitrary system wide > overrides on top of the prctl() config.
Why have an override for this, and not others? Thanks, Nick
