From 804a655825369a50fc59bab624b55c7733d1529b Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 8 Feb 2014 13:34:09 +0100 Subject: cpu: add generic support for CPU feature based module autoloading 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 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 Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 67bad2fdb754dbef14596c0b5d28b3a12c8dfe84) Signed-off-by: Mark Brown --- scripts/mod/file2alias.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'scripts/mod/file2alias.c') diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 25e5cb0aaef..506146e5f4a 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -1135,6 +1135,16 @@ static int do_x86cpu_entry(const char *filename, void *symval, } ADD_TO_DEVTABLE("x86cpu", x86_cpu_id, do_x86cpu_entry); +/* LOOKS like cpu:type:*:feature:*FEAT* */ +static int do_cpu_entry(const char *filename, void *symval, char *alias) +{ + DEF_FIELD(symval, cpu_feature, feature); + + sprintf(alias, "cpu:type:*:feature:*%04X*", feature); + return 1; +} +ADD_TO_DEVTABLE("cpu", cpu_feature, do_cpu_entry); + /* Looks like: mei:S */ static int do_mei_entry(const char *filename, void *symval, char *alias) -- cgit v1.2.3