Re: [PATCH] compiler-intel: fix wrong compiler barrier() macro

From: Pranith Kumar
Date: Wed Apr 29 2015 - 13:18:50 EST


On Wed, Apr 29, 2015 at 12:59 PM, Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
> On 04/29/2015 06:40 PM, Pranith Kumar wrote:
>>
>> On Wed, Apr 29, 2015 at 10:59 AM, mancha security <mancha1@xxxxxxxx>
>> wrote:
>>>
>>>
>>> The problem is that ICC defines __GNUC__ so barrier() gets defined
>>> in compiler-gcc.h. Your commit removed an #undef from compiler-intel.h
>>> so compiler.h will never define barrier to __memory_barrier().
>>
>>
>> OK, I see your point. But, ICC has support for GCC inline assembly. So
>> the change does not seem to be making any difference. We are using our
>> own asm barrier rather than the inbuilt one provided by ICC.
>
>
> It does make a difference: gcc inline assembly is not supported by
> /ecc/, see that it's wrapped within the ifdef __ECC part. I believe,
> that should be for ia64 which we have under arch/, no?

Yes, looks like this breaks building the kernel with ecc compiler on
IA64. Has anyone tried building it with ECC on ia64 lately(or ever)?

Reviewed-by: Pranith Kumar <bobby.prani@xxxxxxxxx>

--
Pranith
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