On 9/26/18 1:59 AM, Florian Weimer wrote:
> * rth:
>
>> diff --git a/libgcc/config/aarch64/lse.c b/libgcc/config/aarch64/lse.c
>> new file mode 100644
>> index 00000000000..20f4bde741f
>> --- /dev/null
>> +++ b/libgcc/config/aarch64/lse.c
>
>> +static void __attribute__((constructor))
>> +init_have_atomics(void)
>> +{
>> + unsigned long hwcap = getauxval(AT_HWCAP);
>> + __aa64_have_atomics = (hwcap & HWCAP_ATOMICS) != 0;
>> +}
>
> Is there an expectation that it is possible to use the atomics in IFUNC
> resolvers? Then this needs an explanation why it is safe to run with
> the other kind of atomics until the initialization of
> __aa64_have_atomics has happened.
Yes. The explanation is simple, in that the !have_atomics path is also atomic.
It will simply use the slower load/store-exclusive path.
Perhaps, despite the official ARMv8.1-Atomics name, LSE was in fact a better
choice for a name after all, as its lack does not imply a lack of atomicity.
And a comment, to be sure.
> (GNU style requires a space before a parenthesis, at least in a function
> call or function declarator.)
Yes, of course. It's no longer automatic for my fingers and eyes.
r~
