Post #2991567
2026-03-05 12:38 UTC
@jannic@hachyderm.io that MSPLIM thing you linked to seems to be specific to Cortex-M chips, probably for when you don't have an MMU?
When you have an MMU, I imagine explicit stack pointer limit checks probably cause unnecessary hardware overhead compared to relying on implicit bounding by guard pages?
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@jannic@hachyderm.io 2026-03-05 20:10
@jann@infosec.exchange These chips do have an MPU (memory protection unit, like an MMU but without the capability to remap memory addresses). So MSPLIM is not strictly necessary to implement some kind of stack overflow protection, but much easier to set up. Additional hardware overhead could be a reason it's not used on bigger CPUs, yes. And with many cores, each core would need a separate stack limit.