4 files changed, 120 insertions, 1 deletions

diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
new file mode 100644
index 00000000000..ff501e511d9
--- /dev/null
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -0,0 +1,13 @@
+#ifndef _CPU_DEVICE_ID
+#define _CPU_DEVICE_ID 1
+
+/*
+ * Declare drivers belonging to specific x86 CPUs
+ * Similar in spirit to pci_device_id and related PCI functions
+ */
+
+#include <linux/mod_devicetable.h>
+
+extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
+
+#endif
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 25f24dccdcf..6ab6aa2fdfd 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -16,6 +16,7 @@ obj-y			:= intel_cacheinfo.o scattered.o topology.o
 obj-y			+= proc.o capflags.o powerflags.o common.o
 obj-y			+= vmware.o hypervisor.o sched.o mshyperv.o
 obj-y			+= rdrand.o
+obj-y			+= match.o
 
 obj-$(CONFIG_X86_32)	+= bugs.o
 obj-$(CONFIG_X86_64)	+= bugs_64.o
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
new file mode 100644
index 00000000000..7acc961422e
--- /dev/null
+++ b/arch/x86/kernel/cpu/match.c
@@ -0,0 +1,48 @@
+#include <asm/cpu_device_id.h>
+#include <asm/processor.h>
+#include <linux/cpu.h>
+#include <linux/module.h>
+
+/**
+ * x86_match_cpu - match current CPU again an array of x86_cpu_ids
+ * @match: Pointer to array of x86_cpu_ids. Last entry terminated with
+ *         {}.
+ *
+ * Return the entry if the current CPU matches the entries in the
+ * passed x86_cpu_id match table. Otherwise NULL.  The match table
+ * contains vendor (X86_VENDOR_*), family, model and feature bits or
+ * respective wildcard entries.
+ *
+ * A typical table entry would be to match a specific CPU
+ * { X86_VENDOR_INTEL, 6, 0x12 }
+ * or to match a specific CPU feature
+ * { X86_FEATURE_MATCH(X86_FEATURE_FOOBAR) }
+ *
+ * Fields can be wildcarded with %X86_VENDOR_ANY, %X86_FAMILY_ANY,
+ * %X86_MODEL_ANY, %X86_FEATURE_ANY or 0 (except for vendor)
+ *
+ * Arrays used to match for this should also be declared using
+ * MODULE_DEVICE_TABLE(x86_cpu, ...)
+ *
+ * This always matches against the boot cpu, assuming models and features are
+ * consistent over all CPUs.
+ */
+const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
+{
+	const struct x86_cpu_id *m;
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	for (m = match; m->vendor | m->family | m->model | m->feature; m++) {
+		if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
+			continue;
+		if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
+			continue;
+		if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
+			continue;
+		if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
+			continue;
+		return m;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(x86_match_cpu);
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index a524353d93f..7c89880eefd 100644
--- 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)