[CentOS] C7 Kernel module compilation

Il 08/08/19 23:23, Akemi Yagi ha scritto:
> On Wed, Aug 7, 2019 at 11:00 PM Alessandro Baggi
> <alessandro.baggi at gmail.com> wrote:
>>
>> Il 07/08/19 20:15, Akemi Yagi ha scritto:
>>> On Wed, Aug 7, 2019 at 9:00 AM Alessandro Baggi
>>> <alessandro.baggi at gmail.com> wrote:
>>>>
>>>> Il 07/08/19 01:02, Phil Perry ha scritto:
>>>>> On 06/08/2019 14:45, Alessandro Baggi wrote:
>>>
>>>>> Please post the actual error message in dmesg or /var/log/messages.
>>>>>
>>>>> It's likely that the kernel is just grumbling that the module is not
>>>>> signed (missing key), but it's just noise unless you're using
>>>>> SecureBoot. Posting the actual message in full will help determine if
>>>>> that is the case.
>>>>>
>>>>> Thanks
>>>>>
>>>>> Phil
>>>>
>>>> Hi, thank you for your reply,
>>>> I solve adding in "General Setup" values of current kernel on
>>>> localversion option and adding Module.symver from
>>>> /boot/symver-version.gz to module directory.
>>>>
>>>> Now I get another problem compiling the third party module (i2c-nct6775):
>>>>
>>>> "CONFIG_RETPOLINE=y but not supported by the compiler. Compiler update
>>>> recomended. Stop."
>>>>
>>>> I tried using scl gcc7 and 8 but get the same issue.
>>>>
>>>> I checked that retpoline is related to Spectre but checking on centos with:
>>>>
>>>> cat /sys/devices/system/cpu/vulnerabilities/spectre_v2
>>>>
>>>> I get:
>>>>
>>>> Mitigation: IBRS (kernel), IBPB
>>>>
>>>> and RETPOLINE seems disabled (I'm wrong?).
>>>>
>>>> I ridden in a blog post that I can disable this check commenting out
>>>> some lines starting from N. 166 of arch/Makefile but I don't think this
>>>> is the best approach.
>>>>
>>>> At this point I can't understand what means the previous error and why I
>>>> get this error when compiling i2c-nct6775.
>>>>
>>>> Can someone point me in the right direction?
>>>
>>> Please post the output from:
>>>
>>> rpm -qa kernel\* | sort
>>>
>>> and
>>>
>>> uname -r
>>>
>>> Akemi
>>
>> kernel-3.10.0-957.12.1.el7.x86_64
>> kernel-3.10.0-957.12.2.el7.x86_64
>> kernel-3.10.0-957.21.3.el7.x86_64
>> kernel-3.10.0-957.27.2.el7.x86_64
>> kernel-3.10.0-957.el7.x86_64
>> kernel-devel-3.10.0-957.21.3.el7.x86_64
>> kernel-devel-3.10.0-957.27.2.el7.x86_64
>> kernel-headers-3.10.0-957.27.2.el7.x86_64
>> kernel-ml-5.1.0-1.el7.elrepo.x86_64
>> kernel-ml-devel-5.1.0-1.el7.elrepo.x86_64
>> kernel-tools-3.10.0-957.27.2.el7.x86_64
>> kernel-tools-libs-3.10.0-957.27.2.el7.x86_64
>> kernel-tools-libs-devel-3.10.0-957.27.2.el7.x86_64
>>
>>
>> 3.10.0-957.27.2.el7.x86_64
> 
> So, you tried to build the i2c-nct6775 module against
> kernel-3.10.0-957.27.2.el7 under the running kernel 3.10.0-957.27.2
> and you have a matching version of kernel-devel. Then I don't quite
> understand why you get the "not supported by the compiler" error...
> 
> Akemi
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> 

I noticed also that if I run make modules, the module is compiled but if 
I try to build it standalone I got this error.

Thank you for your time.