On Thu, Jan 11, 2024 at 09:42:40AM +0800, richard clark wrote: > On Wed, Jan 10, 2024 at 10:12 PM Segher Boessenkool > <segher@xxxxxxxxxxxxxxxxxxx> wrote: > > > > 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. > > > native gcc version: > gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0 > cross-compiler gcc version: > aarch64-linux-gnu-gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0 > > Interesting, the same '__sync_val_compare_and_swap' in the .c file > will be 'U __aarch64_cas4_sync' in the .o file compiled by native, > will be 't __cmpxchg_case_mb_32' in the .o file compiled by > aarch64-linux-gnu-gcc... don't know what the reason is The __cmpxchg_case_mb_32() function is kernel code from arch/arm64/include/asm/cmpxchg.h, so I do not believe that's being generated by the compiler from __sync_val_compare_and_swap(). Are you certain that's being built from the exact same C file? Are you able to share the code in question? Where has it come from in the first place? Thanks, Mark.
