Re: [PATCH] aarch64: Remove ld.so __tls_get_addr plt usage

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 05/04/24 11:58, Szabolcs Nagy wrote:
> The 04/05/2024 09:35, Adhemerval Zanella wrote:
>> Use the hidden alias instead.
>>
>> Checked on aarch64-linux-gnu.
> 
> does this change behaviour in case __tls_get_addr is interposed?
> 
> 

Do we support symbol interposition for symbols in implementation namespace?
If so, we will need to revert x86 to use the same semantic and document it
properly.

>> ---
>>  sysdeps/aarch64/dl-tlsdesc.S                  | 3 ++-
>>  sysdeps/unix/sysv/linux/aarch64/localplt.data | 2 --
>>  2 files changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/sysdeps/aarch64/dl-tlsdesc.S b/sysdeps/aarch64/dl-tlsdesc.S
>> index 9b253b39dd..4febf2ad21 100644
>> --- a/sysdeps/aarch64/dl-tlsdesc.S
>> +++ b/sysdeps/aarch64/dl-tlsdesc.S
>> @@ -220,7 +220,7 @@ _dl_tlsdesc_dynamic:
>>  	SAVE_Q_REGISTERS
>>  
>>  	mov	x0, x1
>> -	bl	__tls_get_addr
>> +	bl	HIDDEN_JUMPTARGET(__tls_get_addr)
>>  
>>  	mrs	x1, tpidr_el0
>>  	sub	PTR_REG (0), PTR_REG (0), PTR_REG (1)
>> @@ -246,5 +246,6 @@ _dl_tlsdesc_dynamic:
>>  	b	1b
>>  	cfi_endproc
>>  	.size	_dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
>> +	.hidden HIDDEN_JUMPTARGET(__tls_get_addr)
>>  # undef NSAVEXREGPAIRS
>>  #endif
>> diff --git a/sysdeps/unix/sysv/linux/aarch64/localplt.data b/sysdeps/unix/sysv/linux/aarch64/localplt.data
>> index 5d217cc50d..5dd07472df 100644
>> --- a/sysdeps/unix/sysv/linux/aarch64/localplt.data
>> +++ b/sysdeps/unix/sysv/linux/aarch64/localplt.data
>> @@ -9,5 +9,3 @@ libm.so: matherr
>>  # If outline atomics are used, libgcc (built outside of glibc) may
>>  # call __getauxval using the PLT.
>>  libc.so: __getauxval ?
>> -# The dynamic loader needs __tls_get_addr for TLS.
>> -ld.so: __tls_get_addr
>> -- 
>> 2.34.1
>>