Re: Build failures with gcc 4.5 and older

[Guenter Roeck <linux@roeck-us.net>]

On 08/14/2018 04:20 PM, Linus Torvalds wrote:
> On Tue, Aug 14, 2018 at 4:02 PM Andrew Morton <akpm@linux-foundation.org> 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.

Guenter