> + case CPU_ID_CORTEX_A15: > + case CPU_ID_CORTEX_A57: > + case CPU_ID_CORTEX_A72: > + /* > + * Vulnerable; BPIALL is "not effective" so must use > + * ICIALLU and hope the firmware set the magic bit in > + * the ACTLR that actually forces a BTB flush. > + */ > + ci->ci_flush_bp = cortex_a15_flush_bp; > + break; > + }
Unfortunately there is an A57 erratum (833069) that when "Disabling MMU Translation with CPUACTLR_EL1 "Enable Invalidates of BTB" bit set can cause Invalidate by PA or VA to fail". The only safe way to trigger BTB invalidation on A57 is to disable and enable the MMU.
