On Tuesday 13 May 2014 18:17:40 Ley Foon Tan wrote: > On Tue, May 13, 2014 at 5:50 PM, James Hogan <james.hogan@xxxxxxxxxx> 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@xxxxxxxxxx> wrote: > >>> On 13 May 2014 10:02, Ley Foon Tan <lftan@xxxxxxxxxx> 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? No, this doesn't really work: You can't use CONFIG_* symbols in user-visible header files. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
