Re: [PATCH v2 4/8] configure: Disable out-of-line atomic operations on Aarch64

[Richard Henderson <richard.henderson@linaro.org>]

On 2/16/22 04:01, Philippe Mathieu-Daudé via wrote:
> GCC 10.1 introduced the -moutline-atomics option on Aarch64.
> This options is enabled by default, and triggers a link failure:
> 
>    Undefined symbols for architecture arm64:
>      "___aarch64_cas1_acq_rel", referenced from:
>          _qmp_migrate_recover in migration_migration.c.o
>          _cpu_atomic_cmpxchgb_mmu in accel_tcg_cputlb.c.o
>          _cpu_atomic_fetch_sminb_mmu in accel_tcg_cputlb.c.o
>          _cpu_atomic_fetch_uminb_mmu in accel_tcg_cputlb.c.o
>          _cpu_atomic_fetch_smaxb_mmu in accel_tcg_cputlb.c.o
>          _cpu_atomic_fetch_umaxb_mmu in accel_tcg_cputlb.c.o
>          _cpu_atomic_smin_fetchb_mmu in accel_tcg_cputlb.c.o
>          ...
>      "___aarch64_ldadd4_acq_rel", referenced from:
>          _multifd_recv_new_channel in migration_multifd.c.o
>          _monitor_event in monitor_hmp.c.o
>          _handle_hmp_command in monitor_hmp.c.o
>          _colo_compare_finalize in net_colo-compare.c.o
>          _flatview_unref in softmmu_memory.c.o
>          _virtio_scsi_hotunplug in hw_scsi_virtio-scsi.c.o
>          _tcg_register_thread in tcg_tcg.c.o
>          ...
>      "___aarch64_swp4_acq", referenced from:
>          _qemu_spin_lock in softmmu_cpu-timers.c.o
>          _cpu_get_ticks in softmmu_cpu-timers.c.o
>          _qemu_spin_lock in softmmu_icount.c.o
>          _cpu_exec in accel_tcg_cpu-exec.c.o
>          _page_flush_tb_1.isra.0 in accel_tcg_translate-all.c.o
>          _page_entry_lock in accel_tcg_translate-all.c.o
>          _do_tb_phys_invalidate in accel_tcg_translate-all.c.o
>          ...
> 
> QEMU implements its own atomic operations using C11 builtin helpers.
> Disable the GCC out-of-line atomic ops.
> 
> Signed-off-by: Philippe Mathieu-Daudé<f4bug@amsat.org>
> ---
> Cc: Stefan Hajnoczi<stefanha@redhat.com>
> Cc: Paolo Bonzini<pbonzini@redhat.com>
> 
> Clearly out of my understanding, but at least it links and the qtests
> pass.
> ---
>   configure | 12 ++++++++++++
>   1 file changed, 12 insertions(+)

These should have been supplied by libgcc.a, which we're supposed to be linking against. 
Something is wrong with your installation.


r~