32 bit kernel on 64 bit machine

[Graeme Russ]

Hi Krishna,

Please keep ML Cc'd

On Fri, Apr 20, 2012 at 1:57 PM, er krishna <erkrishna at gmail.com> wrote:
> Graeme,
>
> Thanks for the reply.
>
> On Fri, Apr 20, 2012 at 11:49 AM, Graeme Russ <graeme.russ at gmail.com> wrote:
>>
>> Hi Krishna,
>>
>> On Fri, Apr 20, 2012 at 1:45 PM, er krishna <erkrishna at gmail.com> wrote:
>> > Hi All,
>> >
>> > Is it possible to boot the 64 bit machine through 32 bit compiled kernel
>> > ? I
>>
>> Yes
>
>
> How ? What are the exact steps ? I mean how I will compile the kernel (flags
> and all) that will boot on 64 bit processor ? My problem is I have 64 bit
> fc16 and Sandybridge 64 bit machine. I need to compile the kernel for 32 bit
> with these setup and boot it.

The steps you performed I believe will have built a 32-bit kernel

>> > tried its compilation on fedora 16 64 bit and intel sandybridge 64 bit
>> > with
>> > following option:
>> >
>> >
>> > $ make ARCH=i386 menuconfig
>> >
>> > $ make ARCH=i386 –j4
>> >
>> >
>> > but it failed to boot. Any suggestion if it can be done by any way.
>>
>> You cannot use a 32-bit kernel with 64-bit user-space
>>
>
> Sorry, I didn't get you here. Do you mean to say that 64 bit application
> won't work on 32 bit kernel. if its then its fine.

Yes, that is what I mean't - If all you userspace (libraries,
applications etc) are 64-bit then a 32-bit kernel cannot run them. You
should have at least got a kernel panic that init could not be run

By 'fine' you mean that your setup is fine and you tried to run the
32-bit kernel using 32-bit userspace? If so, there is obviously
another problem.

Regards,

Graeme