Re: [PATCH] genericx86: tune for i586 instead of atom

[Bruce Ashfield <bruce.ashfield@windriver.com>]

On 13-09-04 03:46 AM, Jonathan Liu wrote:
> On 4 September 2013 14:12, Jonathan Liu <net147@gmail.com> wrote:
>> On 4 September 2013 13:56, Jonathan Liu <net147@gmail.com> wrote:
>>> On 4 September 2013 13:44, Bruce Ashfield <bruce.ashfield@gmail.com> wrote:
>>>> On Tue, Sep 3, 2013 at 11:30 PM, Jonathan Liu <net147@gmail.com> wrote:
>>>>> Hi Bruce,
>>>>>
>>>>> The kernel output is the following:
>>>>> Loading /vmlinuz.........ready.
>>>>> This kernel requires the following features not present on the CPU:
>>>>> movbe
>>>>> Unable to boot - please use a kernel appropriate for your CPU.
>>>>>
>>>>> It stops at that stage and the kernel doesn't boot at all. I started
>>>>> having this issue after switching my BSP to Linux 3.10.
>>>>
>>>> I take it your BSP is based on the genericx86 BSP/configuration ? The entire
>>>> kernel build is done with:
>>>>
>>>> oe_runmake ${KERNEL_IMAGETYPE_FOR_MAKE} ${KERNEL_ALT_IMAGETYPE}
>>>> CC="${KERNEL_CC}" LD="${KERNEL_LD}" ${KERNEL_EXTRA_ARGS}
>>>>
>>>> And unless you've put something in KERNEL_EXTRA_ARGS, that means
>>>> the kernel configuration and its own Makefiles determine all compile flags and
>>>> optimizations.
>>>>
>>>> So switching that config file should have no impact on the build.
>>>>
>>>> To confirm .. you are saying after that change you can boot again ? Best to
>>>> hear from Darren/Tom or Ross on this one.
>>>>
>>>> Bruce
>>>
>>> You're right. It doesn't seem to have any impact.
>>> Please disregard this patch.
>>>
>>> I will try to look into this further to work out what is enabling the
>>> use of movbe in the kernel.
>>
>> I suspect it is CONFIG_MATOM=y in the kernel config (see
>> http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?id=2b9b6d8c715b23fa119261c32ad360681f4464a9).
>> I am rebuilding my image to test.
>
> I have confirmed it is CONFIG_MATOM=y that was causing the boot issue.

That would definitely make a difference. If you are using the genericx86
PC, the default tuning was atom+ IIRC (a line has to be drawn somewhere),
  and you can discuss that with the Intel guys.

But you can easily carry a configuration fragment in your own layer that
disables that option if you want that same BSP to work on your platform.

Cheers,

Bruce

>
> Regards,
> Jonathan
>
>>
>> Regards,
>> Jonathan
>>
>>>
>>> Regards,
>>> Jonathan
>>>
>>>>
>>>>>
>>>>> Regards,
>>>>> Jonathan
>>>>>
>>>>> On 4 September 2013 13:23, Bruce Ashfield <bruce.ashfield@gmail.com> wrote:
>>>>>> On Tue, Sep 3, 2013 at 9:43 PM, Jonathan Liu <net147@gmail.com> wrote:
>>>>>>> Tuning for Intel Atom CPU can in result instructions being used that are
>>>>>>> not compatible with older x86 CPUs such as Intel Pentium Dual-Core
>>>>>>> E2200. This can result in Linux 3.10 failing to boot with:
>>>>>>> "This kernel requires the following features not present on the CPU:
>>>>>>> movbe
>>>>>>> Unable to boot - please use a kernel appropriate for your CPU.".
>>>>>>
>>>>>> That's a bit surprising, do you have a bootlog to share ? This tune
>>>>>> file shouldn't
>>>>>> impact the kernel build options, and if it is, that's a bug.
>>>>>>
>>>>>> If the error shows up on the switch to userspace, then that's a different story.
>>>>>>
>>>>>> Bruce
>>>>>>
>>>>>>>
>>>>>>> Signed-off-by: Jonathan Liu <net147@gmail.com>
>>>>>>> ---
>>>>>>>   meta-yocto-bsp/conf/machine/genericx86.conf | 2 +-
>>>>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/meta-yocto-bsp/conf/machine/genericx86.conf b/meta-yocto-bsp/conf/machine/genericx86.conf
>>>>>>> index ff5cbc9..f5d9cd5 100644
>>>>>>> --- a/meta-yocto-bsp/conf/machine/genericx86.conf
>>>>>>> +++ b/meta-yocto-bsp/conf/machine/genericx86.conf
>>>>>>> @@ -3,7 +3,7 @@
>>>>>>>
>>>>>>>   #@DESCRIPTION: Machine configuration for generic X86 (32-bit) PCs. Supports a moderately wide range of drivers that should boot and be usable on "typical" hardware.
>>>>>>>
>>>>>>> -include conf/machine/include/tune-atom.inc
>>>>>>> +include conf/machine/include/tune-i586.inc
>>>>>>>
>>>>>>>   MACHINE_FEATURES = "screen keyboard pci usbhost ext2 ext3 x86 wifi acpi alsa"
>>>>>>>
>>>>>>> --
>>>>>>> 1.8.4
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> poky mailing list
>>>>>>> poky@yoctoproject.org
>>>>>>> https://lists.yoctoproject.org/listinfo/poky
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> "Thou shalt not follow the NULL pointer, for chaos and madness await
>>>>>> thee at its end"
>>>>
>>>>
>>>>
>>>> --
>>>> "Thou shalt not follow the NULL pointer, for chaos and madness await
>>>> thee at its end"
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