Re: [PATCH v2] x86: fix early boot crash on gcc-10

[Jakub Jelinek]

On Wed, Apr 22, 2020 at 03:49:24PM +0200, Borislav Petkov wrote:
> On Wed, Apr 22, 2020 at 01:40:07PM +0200, Peter Zijlstra wrote:
> > You haz a whitespace issue there.
> 
> Fixed.
> 
> > Also, can we get this in writing, signed in blood, from the various
> > compiler teams ;-)
> 
> Yah, I wouldn't want to go fix this again in gcc11 or so. That's why I
> wanted the explicit marking but let's try this first - it is too simple
> to pass over without having tested it.

If virtual blood is enough, AFAIK GCC has never tried to accept volatile
inline asm (asm ("") is such; non-volatile asm such as int x; asm ("" : "=r" (x));
could be e.g. dead code eliminated) in the statements between function call and
return when deciding about what function can be tail-called or can use
tail-recursion and there are no plans to change that.

	Jakub