Blackbird™ Linux sources for OpenPOWER https://git.raptorcs.com/git/blackbird-op-linux/atom?h=v4.2 2014-02-18T20:38:37+00:00 2014-02-18T20:38:37+00:00 Ard Biesheuvel ard.biesheuvel@linaro.org 2014-02-08T12:34:09+00:00 urn:sha1:67bad2fdb754dbef14596c0b5d28b3a12c8dfe84 This patch adds support for advertising optional CPU features over udev using the modalias, and for declaring compatibility with/dependency upon such a feature in a module. The mapping between feature numbers and actual features should be provided by the architecture in a file called <asm/cpufeature.h> which exports the following functions/macros: - cpu_feature(FEAT), a preprocessor macro that maps token FEAT to a numeric index; - bool cpu_have_feature(n), returning whether this CPU has support for feature #n; - MAX_CPU_FEATURES, an upper bound for 'n' in the previous function. The feature can then be enabled by setting CONFIG_GENERIC_CPU_AUTOPROBE for the architecture. For instance, a module that registers its module init function using module_cpu_feature_match(FEAT_X, module_init_function) will be probed automatically when the CPU's support for the 'FEAT_X' feature is advertised over udev, and will only allow the module to be loaded by hand if the 'FEAT_X' feature is supported. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>