Re: [PATCH v2] rs6000: Rework option -mpowerpc64 handling [PR106680]

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi Segher,

on 2022/12/24 04:26, Segher Boessenkool wrote:
> Hi!
> 
> On Wed, Oct 12, 2022 at 04:12:21PM +0800, Kewen.Lin wrote:
>> PR106680 shows that -m32 -mpowerpc64 is different from
>> -mpowerpc64 -m32, this is determined by the way how we
>> handle option powerpc64 in rs6000_handle_option.
>>
>> Segher pointed out this difference should be taken as
>> a bug and we should ensure that option powerpc64 is
>> independent of -m32/-m64.  So this patch removes the
>> handlings in rs6000_handle_option and add some necessary
>> supports in rs6000_option_override_internal instead.
> 
> Sorry for the late review.
> 
>> +  /* Don't expect powerpc64 enabled on those OSes with OS_MISSING_POWERPC64,
>> +     since they don't support saving the high part of 64-bit registers on
>> +     context switch.  If the user explicitly specifies it, we won't interfere
>> +     with the user's specification.  */
> 
> It depends on the OS, and what you call "context switch".  For example
> on Linux the context switches done by the kernel are fine, only things
> done by setjmp/longjmp and getcontext/setcontext are not.  So just be a
> bit more vague here?  "Since they do not save and restore the high half
> of the GPRs correctly in all cases", something like that?
> 
> Okay for trunk like that.  Thanks!
> 

Thanks!  Adjusted as you suggested and committed in r13-4894-gacc727cf02a144.

BR,
Kewen