[PATCH] elf: Fix tst-gnu2-tls2 on some environments

[Adhemerval Zanella Netto]

On 19/01/26 12:18, Florian Weimer wrote:
> * Adhemerval Zanella Netto:
> 
>> On 19/01/26 11:22, Florian Weimer wrote:
>>> * Adhemerval Zanella:
>>>
>>>> On armv7a vfpv4 tst-gnu2-tls2 fails with:
>>>>
>>>>   open tst-gnu2-tls2mod0.so
>>>>   open tst-gnu2-tls2mod1.so
>>>>   open tst-gnu2-tls2mod2.so
>>>>   close tst-gnu2-tls2mod0.so
>>>>   close tst-gnu2-tls2mod1.so
>>>>   open tst-gnu2-tls2mod0.so
>>>>   open tst-gnu2-tls2mod1.so
>>>>   Didn't expect signal from child: got `Aborted'
>>>>
>>>> Because AFTER_TLSDESC_CALL might clobber caller-saved registers and
>>>> the zero array might call the memset function resolution, which itself
>>>> might clobber some vector registers.
>>>
>>> Isn't AFTER_TLSDESC_CALL a noop on 32-bit Arm
>>
>> It depends on the hardware, with HWCAP_ARM_VFP we checks if d0-d15 register
>> are correctly handled, and with HWCAP_ARM_VFPD32 with also check d16-d31.
> 
> What does the ABI say about preserving vector registers?
This is related to 64c7e344289ed085517c2227d8e3b06388242c13, where
_dl_tlsdesc_dynamic slow-path has the peculiar calling convention.