Add driver auto probing for x86 features v4

[linux-flexiantxendom0-3.2.10.git] / arch / x86 / kernel / cpuid.c

diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index a524353..7c89880 100644 (file)
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -40,6 +40,7 @@
 #include <linux/notifier.h>
 #include <linux/uaccess.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
 
 #include <asm/processor.h>
 #include <asm/msr.h>
@@ -138,13 +139,57 @@ static const struct file_operations cpuid_fops = {
        .open = cpuid_open,
 };
 
+static ssize_t print_cpu_modalias(struct device *dev,
+                                 struct device_attribute *attr,
+                                 char *bufptr)
+{
+       int size = PAGE_SIZE;
+       int i, n;
+       char *buf = bufptr;
+
+       n = snprintf(buf, size, "x86cpu:vendor:%04X:family:"
+                    "%04X:model:%04X:feature:",
+               boot_cpu_data.x86_vendor,
+               boot_cpu_data.x86,
+               boot_cpu_data.x86_model);
+       size -= n;
+       buf += n;
+       size -= 2;
+       for (i = 0; i < NCAPINTS*32; i++) {
+               if (boot_cpu_has(i)) {
+                       n = snprintf(buf, size, ",%04X", i);
+                       if (n < 0) {
+                               WARN(1, "x86 features overflow page\n");
+                               break;
+                       }
+                       size -= n;
+                       buf += n;
+               }
+       }
+       *buf++ = ',';
+       *buf++ = '\n';
+       return buf - bufptr;
+}
+
+static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
+
 static __cpuinit int cpuid_device_create(int cpu)
 {
        struct device *dev;
+       int err;
 
        dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL,
                            "cpu%d", cpu);
-       return IS_ERR(dev) ? PTR_ERR(dev) : 0;
+       if (IS_ERR(dev))
+               return PTR_ERR(dev);
+
+       err = device_create_file(dev, &dev_attr_modalias);
+       if (err) {
+               /* keep device around on error. attribute is optional. */
+               err = 0;
+       }
+
+       return 0;
 }
 
 static void cpuid_device_destroy(int cpu)
@@ -182,6 +227,17 @@ static char *cpuid_devnode(struct device *dev, umode_t *mode)
        return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
 }
 
+static int cpuid_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+       char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+       if (buf) {
+               print_cpu_modalias(NULL, NULL, buf);
+               add_uevent_var(env, "MODALIAS=%s", buf);
+               kfree(buf);
+       }
+       return 0;
+}
+
 static int __init cpuid_init(void)
 {
        int i, err = 0;
@@ -200,6 +256,7 @@ static int __init cpuid_init(void)
                goto out_chrdev;
        }
        cpuid_class->devnode = cpuid_devnode;
+       cpuid_class->dev_uevent = cpuid_dev_uevent;
        for_each_online_cpu(i) {
                err = cpuid_device_create(i);
                if (err != 0)