[PATCH 2/3] mips: Fix SIGRTMAX definition

[Adhemerval Zanella]

On 23/04/2020 17:41, Joseph Myers wrote:
> On Thu, 23 Apr 2020, Adhemerval Zanella via Libc-alpha wrote:
> 
>> MIPS support up to 96 real time signal, instead of current 95.  This
>> increases the NSIG value, however it does not incur in a compat
>> issue for older programs (which won't access the new element).
>> The sys_siglist is automatically expanded as well.
> 
> The fact that you're changing ABI test baselines for existing symbol 
> versions demonstrates that this is not a safe change (you can't change the 
> size of exported data symbols without adding a new symbol version because 
> of issues with copy relocations - this is what the "Symbol `%s' has 
> different size in shared object, consider re-linking" message from the 
> dynamic linker is about).

Indeed, I forgot about copy relocations and that it is possible to link
new applications against sys_errlist.

> 
> We have the #errlist-compat mechanism in Versions files for having 
> different symbol versions for differently-sized versions of sys_errlist.  
> It looks like sys_siglist has a simpler system involving OLD_SIGLIST_SIZE, 
> OLD2_SIGLIST_SIZE and hardcoded version conditionals in 
> sysdeps/gnu/siglist.c.  To make this change, you'll need to add some kind 
> of support for having three compat versions for these symbols (so four 
> versions for them in total), with different sizes, so that existing 
> versions keep their existing sizes.

Ack, I will update the patch.

> 
> It will also be necessary to update 
> sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist for such a new 
> version in addition to the three ABI baselines changed in this patch.
> 

Ack.