Re: [PATCH] aarch64: simplify the DT_AARCH64_VARIANT_PCS handling code

[Szabolcs Nagy <Szabolcs dot Nagy at arm dot com>]

On 10/07/2019 20:46, Florian Weimer wrote:
> * Szabolcs Nagy:
> 
>> On 09/07/2019 13:55, Szabolcs Nagy wrote:
>>> Remove unnecessary variant_pcs field: the dynamic tag can be checked
>>> directly.
>>>
>>> I'll commit this tomorrow unless there are comments.
>>> Then backport it with the variant pcs support to release branches
>>> https://sourceware.org/ml/libc-alpha/2019-05/msg00523.html
>>
>> i was about to back port this but i wonder if
>> glibc has policy that a release branch cannot
>> change libc internal abi between dynamic linker
>> and lib*.so to allow reliable updates?
>>
>> this patch changes the size of map->l_info array.
> 
> The usual issue involves changing the size of _rtld_global and
> _rtld_global_ro.
> 
> I don't know to what extent libc and libdl access link maps directly,
> without going through ld.so.  I don't recall seeing anything like
> that, but that doesn't mean much.

i'll try to do some analysis, but e.g. l_tls_* is after l_info
in struct link_map and i'd expect those to be accessed by
libpthreads and ld.so as well.