On 06/18/2014 09:25 AM, Dave Hansen wrote: > On 06/18/2014 07:59 AM, H. Peter Anvin wrote: >> On 06/18/2014 07:35 AM, Dave Hansen wrote: >>> It looks like static_cpu_has() is the right thing to use instead of >>> boot_cpu_has(). But, this doesn't just obfuscate things. >>> >>> We actually _want_ the compiler to cull code out when the config option >>> is off. Things like do_bounds() will see code savings with _some_ kind >>> of #ifdef rather than using static_cpu_has(). >>> >>> So, we can either use the well worn, consistent with other features in >>> x86, cpu_has_$foo approach. Or, we can roll our own macros. >> >> We could do something like: >> >> #define MPX_ENABLED (IS_ENABLED(CONFIG_X86_MPX) && >> static_cpu_has(X86_FEATURE_MPX)) > > How about something like the attached patch? > > This lets us use static_cpu_has() for the checks, and allows us to > easily add new checks for other features that might be compile-time > disabled. >
Hmm... I would like something similar to required-features.h which reflect features which *cannot* be enabled or will always be ignored; we actually already have a handful of those. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/