Re: Build failures with gcc 4.5 and older

[Thomas Gleixner]

On Tue, 14 Aug 2018, Guenter Roeck wrote:
> On 08/14/2018 04:20 PM, Linus Torvalds wrote:
> > On Tue, Aug 14, 2018 at 4:02 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > wrote:
> > > 
> > > The m68k build still fails because 0cc3cd21657 ("cpu/hotplug: Boot HT
> > > siblings at least once") was evidently never tested on CONFIG_SMP=n.
> > > How could that come about - the patch is six weeks old??
> > 
> > Ehh, meet the joys of embargoes.
> > 
> > The code was tested (and people even found subtle arm64 problems due
> > to that testing), but because it couldn't be made public until today,
> > it didn't go through all the usual infrastructure we depend on.
> > 
> > But:
> > 
> > > kernel/cpu.c: In function 'boot_cpu_hotplug_init':
> > > kernel/cpu.c:2275:2: error: 'struct cpuhp_cpu_state' has no member named
> > > 'booted_once'
> > 
> > it should be fixed now in -git.
> > 
> > > @@ -490,6 +490,8 @@ struct mm_struct {
> > >   #endif
> > >          } __randomize_layout;
> > > 
> > > +       int wibble;
> > > +
> > 
> > Can we call this something informative? Like
> > 
> >          int __gcc_4_4_is_garbage_that_shouldnt_be_used;
> > 
> > or something?
> > 
> > That is, if we actually want to really drag out this whole pointless
> > pain of allowing ancient compilers?
> > 
> > Guys, at some point we need to switch to 4.6. The people who feel the
> > pain today *will* feel the pain at some point. Just get it over with
> > already.
> > 
> 
> For my part I am all for making gcc 4.6 mandatory.

No objections from my side.

Thanks,

	tglx