6.5.6 BTB invalidation and context switches

The BTB is tagged by all memory space information required to uniquely identify a virtual memory space, ASID, VMID, security, and Exception level. All predictions are checked at branch resolution time to ensure that a legal branch is resolved. Therefore, flushing the BTB on a context switch is not required. AArch64 state does not implement BTB flush instructions.
The processor automatically invalidates the BTB when either stage of the MMU is disabled.
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