Re: kernel miscompilation with gcc 4.8 for ARMv5

[Mike Looijmans <mike.looijmans@topic.nl>]

On 07/10/2013 02:34 PM, Enrico Scholz wrote:
> Enrico Scholz
> <enrico.scholz-wttK6gPy29v+Hn7q9Vec/7NAH6kLmebB@public.gmane.org>
> writes:
>
>> is it expected that recent gcc 4.8[1] compiles the kernel correctly?
>> Kernels for ARMv5 platforms (PXA168 -> 3.4.52, MX28 -> 3.8.13) fail here
>> 100% at early boot with
>
> Applying two upstream kernel commits
> 455bd4c430b0c0a361f38e8658a0d6cb469942b5 (ARM: 7668/1: fix
> memset-related crashes caused by recent GCC (4.7.2) optimizations) and
> 418df63adac56841ef6b0f1fcf435bc64d4ed177 (ARM: 7670/1: fix the memset
> fix) seem to fix the problem for me.
>

I encountered a compilation problem for MIPS kernels (version 3.3 and 
below) with the new GCC compiler:


  arch/mips/mm/page.c:89:6: error: 'clear_page' alias in between 
function and variable is not supported
void clear_page(void *page) __attribute__((alias("clear_page_array")));
        ^
arch/mips/mm/page.c:84:12: error: 'clear_page_array' aliased declaration 
[-Werror]
static u32 clear_page_array[0x120 / 4];
              ^
arch/mips/mm/page.c:108:6: error: 'copy_page' alias in between function 
and variable is not supported
void copy_page(void *to, void *from) 
__attribute__((alias("copy_page_array")));
       ^
arch/mips/mm/page.c:102:12: error: 'copy_page_array' aliased declaration 
[-Werror]
static u32 copy_page_array[0x540 / 4];


So I'll probably have to go and look for backports to apply here. Anyone 
happen to come across this one already?
(Looking in the git history for that file suggests applying 
c022630633624a75b3b58f43dd3c6cc896a56cff from upstream)

A 3.8 kernel is running just fine with gcc 4.8.