Re: [PATCH 01/25] asm-generic: Change time_t and clock_t to 64 bit

Ley Foon Tan
2014-05-13T10:17:43Z

On Tue, May 13, 2014 at 5:50 PM, James Hogan <james.hogan@imgtec.com> wrote:
> Hi,
>
> On 13/05/14 10:32, Ley Foon Tan wrote:
>> On Tue, May 13, 2014 at 5:15 PM, James Hogan <james.hogan@imgtec.com> wrote:
>>> On 13 May 2014 10:02, Ley Foon Tan <lftan@altera.com> wrote:
>>>> /*
>>>> + * Use 64 bit time_t and clock_t as default. 32 bit users can provide an override to
>>>> + * define these as "long" if needed.
>>>> + */
>>>> +#ifndef __kernel_time_t
>>>> +typedef long long __kernel_time_t;
>>>> +#endif
>>>> +
>>>> +#ifndef __kernel_clock_t
>>>> +typedef long long __kernel_clock_t;
>>>> +#endif
>>>
>>> I think having this as the first patch in the series will break
>>> bisection for existing 32-bit arches. This needs to be done in such a
>>> way that at no intermediate commit are __kernel_time_t or
>>> __kernel_clock_t the wrong size for existing arches, e.g. by having a
>>> first patch which makes the typedefs conditional but leaves them as
>>> __kernel_long_t, and a final patch that changes the default after all
>>> the arches have got their overrides in place.
>>
>> Your suggestion is something as below?
>
> Yeh, although I like Thomas' idea better, then each existing 32-bit arch
> can just select the Kconfig symbol to get the smaller type.
>
> IIRC Kconfig won't even complain if you select a symbol which doesn't
> exist yet.
When we export this posix_types.h file for user software, they need to
define this config, eg: CONFIG_32BIT_TIME to use 32 bit time. Is this
what we want to do?

Regards
Ley Foon