Well, they may not have speculative execution,but some of them do have branch prediction these days; which probably leaks a certain amount of information. Eg, the cortex M7 (no mmu,mpu optional, has branch prediction)

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kragen 4 days ago | parent [-]

I think Cortex-M7 also often has split I+D caches?

	▲	ajb 4 days ago \| parent [-]
		Yes. That's what Arm supply, a SoC vendor may add a unified second level.