Re: [PATCH v5 02/16] powerpc: Override __ALIGN and __ALIGN_STR macros

[Sathvika Vasireddy <sv@linux.ibm.com>]

Hi Peter,

On 03/11/22 14:18, Peter Zijlstra wrote:
> On Wed, Nov 02, 2022 at 12:35:07PM +0000, Christophe Leroy wrote:
>>
>> Le 28/10/2022 à 16:33, Sathvika Vasireddy a écrit :
>>> In a subsequent patch, we would want to annotate powerpc assembly functions
>>> with SYM_FUNC_START_LOCAL macro. This macro depends on __ALIGN macro.
>>>
>>> The default expansion of __ALIGN macro is:
>>>           #define __ALIGN      .align 4,0x90
>>>
>>> So, override __ALIGN and __ALIGN_STR macros to use the same alignment as
>>> that of the existing _GLOBAL macro. Also, do not pad with 0x90, because
>>> repeated 0x90s are not a nop or trap on powerpc.
>> By the way, do we know what the instruction 0x90909090 is on powerpc ?
>> Is that something valid or not ?
> Please also look at the version that's in tip/x86/core (and next). This
> stuff should be gone now.
>
> include/linux/linkage.h now reads like:
>
> #ifndef __ALIGN
> #define __ALIGN                 .balign CONFIG_FUNCTION_ALIGNMENT
> #define __ALIGN_STR             __stringify(__ALIGN)
> #endif

Since the above mentioned changes are not a part of powerpc/merge branch 
yet, I am retaining this patch for this merge cycle and will post a 
cleanup patch (to move to using FUNCTION_ALIGNMENT_4B) after the next -rc1.

Thanks,
Sathvika