On Fri, Sep 28, 2018 at 2:08 PM, Andy Lutomirski <[email protected]> wrote: > > >> On Sep 28, 2018, at 1:26 PM, Thomas Gleixner <[email protected]> wrote: >> >>> On Fri, 28 Sep 2018, Max Filippov wrote: >>> >>>> On Fri, Sep 28, 2018 at 11:02 AM, Andy Lutomirski <[email protected]> >>>> wrote: >>>> There may be a much nicer solution. Unless I missed something, only >>>> mips and xtensa even have the possibility of cmpxchg being missing. >>>> We could just make those arches supply a futex-detecting helper. >>> >>> In case of xtensa availability of cmpxchg is known at build time. >> >> That makes it even simpler. Could you provide a patch which selects >> CONFIG_HAVE_FUTEX_CMPXCHG for the right set of CPUs please? >> >> > > I think that’s the wrong approach, since it won’t cover mips. How about > adding this to mips and xtensa only: > > static inline void arch_have_futex_cmpxchg(void) {...}; > #define arch_have_futex_cmpxchg arch_have_futex_cmpxchg > > And getting rid of the config option.
I'd rather do that, given that defining Kconfig entries that describe parts of xtensa configuration is somewhat awkward and redundant. -- Thanks. -- Max
