mk: fix scope of disabling AVX512F support

  AVX512 was disabled for GCC because of Bugzilla issue 97 [1],
the GCC defect submitted for the issue [2] highlighted that this is
a known binutils version 2.30 issue.

Narrowed the scope of no-avx512 to the this specific binutils version.

[1]
https://bugs.dpdk.org/show_bug.cgi?id=97

[2]
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096

Fixes: 8d07c82b239f ("mk: disable gcc AVX512F support")
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
Cc: Tom Barbette <barbette@kth.se>
Cc: Thomas Monjalon <thomas@monjalon.net>
Cc: Yongseok Koh <yskoh@mellanox.com>
Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>
Cc: Bruce Richardson <bruce.richardson@intel.com>
    We need similar check for meson which is missing right now.
---
 mk/rte.cpuflags.mk                       | 2 ++
 mk/toolchain/gcc/rte.toolchain-compat.mk | 2 ++
 2 files changed, 4 insertions(+)
  

19/12/2018 20:29, Ferruh Yigit:
> AVX512 was disabled for GCC because of Bugzilla issue 97 [1],
> the GCC defect submitted for the issue [2] highlighted that this is
> a known binutils version 2.30 issue.
> 
> Narrowed the scope of no-avx512 to the this specific binutils version.
[...]
>  # disable AVX512F support of gcc as a workaround for Bug 97
>  ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
> +ifneq ($(filter 2.30%,$(LD_VERSION)),)
>  MACHINE_CFLAGS += -mno-avx512f

I think we should print a warning here.
There is a function $(warning) or $(info) for such case.
  

On 12/19/2018 7:58 PM, Thomas Monjalon wrote:
> 19/12/2018 20:29, Ferruh Yigit:
>> AVX512 was disabled for GCC because of Bugzilla issue 97 [1],
>> the GCC defect submitted for the issue [2] highlighted that this is
>> a known binutils version 2.30 issue.
>>
>> Narrowed the scope of no-avx512 to the this specific binutils version.
> [...]
>>  # disable AVX512F support of gcc as a workaround for Bug 97
>>  ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
>> +ifneq ($(filter 2.30%,$(LD_VERSION)),)
>>  MACHINE_CFLAGS += -mno-avx512f
> 
> I think we should print a warning here.
> There is a function $(warning) or $(info) for such case.

I can add but it prints warning per component, so it prints a lot.
  

19/12/2018 21:20, Ferruh Yigit:
> On 12/19/2018 7:58 PM, Thomas Monjalon wrote:
> > 19/12/2018 20:29, Ferruh Yigit:
> >> AVX512 was disabled for GCC because of Bugzilla issue 97 [1],
> >> the GCC defect submitted for the issue [2] highlighted that this is
> >> a known binutils version 2.30 issue.
> >>
> >> Narrowed the scope of no-avx512 to the this specific binutils version.
> > [...]
> >>  # disable AVX512F support of gcc as a workaround for Bug 97
> >>  ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
> >> +ifneq ($(filter 2.30%,$(LD_VERSION)),)
> >>  MACHINE_CFLAGS += -mno-avx512f
> > 
> > I think we should print a warning here.
> > There is a function $(warning) or $(info) for such case.
> 
> I can add but it prints warning per component, so it prints a lot.

I think we can choose to print only when compiling EAL
by checking $(findstring eal,$(lastword $(MAKEFILE_LIST)))

One more comment: it would be good to have this fix with meson too.
  

On 12/19/2018 8:28 PM, Thomas Monjalon wrote:
> 19/12/2018 21:20, Ferruh Yigit:
>> On 12/19/2018 7:58 PM, Thomas Monjalon wrote:
>>> 19/12/2018 20:29, Ferruh Yigit:
>>>> AVX512 was disabled for GCC because of Bugzilla issue 97 [1],
>>>> the GCC defect submitted for the issue [2] highlighted that this is
>>>> a known binutils version 2.30 issue.
>>>>
>>>> Narrowed the scope of no-avx512 to the this specific binutils version.
>>> [...]
>>>>  # disable AVX512F support of gcc as a workaround for Bug 97
>>>>  ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
>>>> +ifneq ($(filter 2.30%,$(LD_VERSION)),)
>>>>  MACHINE_CFLAGS += -mno-avx512f
>>>
>>> I think we should print a warning here.
>>> There is a function $(warning) or $(info) for such case.
>>
>> I can add but it prints warning per component, so it prints a lot.
> 
> I think we can choose to print only when compiling EAL
> by checking $(findstring eal,$(lastword $(MAKEFILE_LIST)))

Thanks for hint, I will use it.

> 
> One more comment: it would be good to have this fix with meson too.

Agreed, only I am not quite sure how to fix it in meson.
  

On Wed, Dec 19, 2018 at 08:53:34PM +0000, Ferruh Yigit wrote:
> On 12/19/2018 8:28 PM, Thomas Monjalon wrote:
> > 19/12/2018 21:20, Ferruh Yigit:
> >> On 12/19/2018 7:58 PM, Thomas Monjalon wrote:
> >>> 19/12/2018 20:29, Ferruh Yigit:
> >>>> AVX512 was disabled for GCC because of Bugzilla issue 97 [1],
> >>>> the GCC defect submitted for the issue [2] highlighted that this is
> >>>> a known binutils version 2.30 issue.
> >>>>
> >>>> Narrowed the scope of no-avx512 to the this specific binutils version.
> >>> [...]
> >>>>  # disable AVX512F support of gcc as a workaround for Bug 97
> >>>>  ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
> >>>> +ifneq ($(filter 2.30%,$(LD_VERSION)),)
> >>>>  MACHINE_CFLAGS += -mno-avx512f
> >>>
> >>> I think we should print a warning here.
> >>> There is a function $(warning) or $(info) for such case.
> >>
> >> I can add but it prints warning per component, so it prints a lot.
> > 
> > I think we can choose to print only when compiling EAL
> > by checking $(findstring eal,$(lastword $(MAKEFILE_LIST)))
> 
> Thanks for hint, I will use it.
> 
> > 
> > One more comment: it would be good to have this fix with meson too.
> 
> Agreed, only I am not quite sure how to fix it in meson.

One suggestion, but the snippet below in main meson.build file, and put the
printing of a message in one of the EAL meson.build files.

/Bruce

ldver = run_command('ld', '-v').stdout().strip()
if ldver.contains('2.30')
     # take action here
endif