On Wed, Jan 10, 2024 at 01:59:53PM +0800, richard clark wrote: > A ported driver in linux kernel calls '__sync_val_compare_and_swap', That is a builtin function. It does not necessarily expand to an actual function call. aarch64 will typically expand it to inline code. > the cross-compiler 'aarch64-linux-gnu-gcc' doesn't complain > '__aarch64_cas1_sync' undefined reference, but the native compiler > will complain. As Mark mentioned, I double check that both cross and > native compiler should have ''-moutline-atomics' option enabled, do > you know the reason for that? Ah, so you are requesting external functions. I am no aarch64 expert, but apparently there were some problems in GCC 11, maybe that is what you saw? Or with some distros, anyway. It also matters if you have ARMv8.1-A enabled, the LSE instructions. Open a GCC bug report if you have more details? Thanks, Segher
