This patch implements a generic modalias 'cpu:feature:...' which
enables CPU feature flag based module loading in a generic way.
All the arch needs to do is enable CONFIG_ARCH_HAS_CPU_AUTOPROBE
and export a u32 called 'cpu_features'. (What each bit actually
means is irrelevant on this level.)
Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
drivers/base/cpu.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 49c6f4b..a661d31 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -276,6 +276,30 @@ static void cpu_device_release(struct device *dev)
}
#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
+ssize_t print_cpu_modalias(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ extern u32 __weak cpu_features;
+ ssize_t n;
+ int i;
+ u32 f;
+
+ /*
+ * With 32 features maximum (taking 3 bytes each to print), we don't
+ * need to worry about overrunning the PAGE_SIZE sized buffer.
+ */
+ n = sprintf(buf, "cpu:feature:");
+ for (f = cpu_features, i = 0; f; f >>= 1, i++)
+ if (f & 1)
+ n += sprintf(&buf[n], ",%02X", i);
+ buf[n++] = '\n';
+ return n;
+}
+
+ssize_t __attribute__((weak, alias("print_cpu_modalias")))
+arch_print_cpu_modalias(struct device *, struct device_attribute *, char *);
+
static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
{
char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
--
1.8.3.2
--
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