remove the last set_fs() in common code, and remove it for x86 and powerpc v3

[Christophe Leroy]

Le 10/09/2020 à 10:04, David Laight a écrit :
> From: Linus Torvalds
>> Sent: 09 September 2020 22:34
>> On Wed, Sep 9, 2020 at 11:42 AM Segher Boessenkool
>> <segher at kernel.crashing.org> wrote:
>>>
>>> It will not work like this in GCC, no.  The LLVM people know about that.
>>> I do not know why they insist on pushing this, being incompatible and
>>> everything.
>>
>> Umm. Since they'd be the ones supporting this, *gcc* would be the
>> incompatible one, not clang.
> 
> I had an 'interesting' idea.
> 
> Can you use a local asm register variable as an input and output to
> an 'asm volatile goto' statement?
> 
> Well you can - but is it guaranteed to work :-)
> 

With gcc at least it should work according to 
https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html

They even explicitely tell: "The only supported use for this feature is 
to specify registers for input and output operands when calling Extended 
asm "

Christophe