[U-Boot] [PATCH 2/2] sandbox: Convert SANDBOX_BITS_PER_LONG to Kconfig

[Simon Glass]

Hi Bin,

On 6 August 2017 at 03:13, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Simon,
>
> On Sun, Aug 6, 2017 at 1:16 PM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Bin,
>>
>> On 3 August 2017 at 18:17, Bin Meng <bmeng.cn at gmail.com> wrote:
>>> Hi Simon,
>>>
>>> On Thu, Aug 3, 2017 at 11:24 PM, Simon Glass <sjg at chromium.org> wrote:
>>>> Hi Bin,
>>>>
>>>> On 1 August 2017 at 17:33, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>> Convert SANDBOX_BITS_PER_LONG to Kconfig and assign it a correct
>>>>> number depending on which host we are going to build and run.
>>>>>
>>>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>>>> ---
>>>>>
>>>>>  arch/sandbox/Kconfig         | 5 +++++
>>>>>  board/sandbox/README.sandbox | 7 +++----
>>>>>  scripts/config_whitelist.txt | 1 -
>>>>>  3 files changed, 8 insertions(+), 5 deletions(-)
>>>>
>>>> Reviewed-by: Simon Glass <sjg at chromium.org>
>>>>
>>>> Is it OK to build 64-bit sandbox on a 32-bit machine? Does that actually work?
>>>>
>>>> If then I think we need a 3-way setting like:
>>>>
>>>> - 32-bit
>>>> - 64-bit
>>>> - native (i.e. whatever the host is)
>>>
>>> That means cross-compiling sandbox. So far this is not working. I will
>>> take a look.
>>
>> Or perhaps we just require it to use the bit size of the host? Does
>> compiling 64-bit U-Boot on a 32-bit machine actually work?
>>
>
> I have not looked into that further but I suspect there is more work
> than the bit size of the host, for example, linking 64-bit vs. 32-bit
> libraries?

But does it compile 64-bit sandbox OK on a 32-bit machine? I would
have thought it would complain.

I'm not really asking for this feature, it's just that I don't
understand how your patch works, and don't necessarily want to lose
the ability to build a 32-bit sandbox. It is to some extent a helpful
build/unit test for 32-bit boards which we still have many of.

Regards,
Simon