When Ldaxr Doesn't Work: Exclusive Accesses and Cacheability on AArch64
Why a load exclusive (ldaxr) raised a Data Abort on real Raspberry Pi 5 hardware but not in QEMU, and what cacheability has to do with AArch64 exclusive accesses.
Summary
A recent issue with the ldaxr instruction on Raspberry Pi 5 hardware led to a Data Abort, a problem not observed in QEMU. The article explains the relationship between cacheability and exclusive accesses in the AArch64 architecture, shedding light on important hardware nuances.
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