CVE-2026-11985 Cross-thread FPU register leak on ARM when FPU enabled without register sharing

On the Zephyr ARM port, enabling the hardware FPU CONFIGFPU forces the "Floating point ABI" choice, which defaults to CONFIGFPHARDABI. Both FPHARDABI and FPSOFTABI permit the compiler to emit hardware FP instructions in any function, even code that never uses floating-point types. However, the...