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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-02-08 13:34:09 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-18 12:38:37 -0800
commit67bad2fdb754dbef14596c0b5d28b3a12c8dfe84 (patch)
tree05c3cd5f809618319346f9642549460f95149f02 /scripts/mod
parent91219a3b20325689eb80f7598cce2dc745db171d (diff)
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 <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>
Diffstat (limited to 'scripts/mod')
-rw-r--r--scripts/mod/devicetable-offsets.c3
-rw-r--r--scripts/mod/file2alias.c10
2 files changed, 13 insertions, 0 deletions
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index bb5d115ca671..f282516acc7b 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -174,6 +174,9 @@ int main(void)
DEVID_FIELD(x86_cpu_id, model);
DEVID_FIELD(x86_cpu_id, vendor);
+ DEVID(cpu_feature);
+ DEVID_FIELD(cpu_feature, feature);
+
DEVID(mei_cl_device_id);
DEVID_FIELD(mei_cl_device_id, name);
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 25e5cb0aaef6..506146e5f4a8 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)

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