6 files changed, 165 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 000000000000..ff501e511d91
--- /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 25f24dccdcfa..6ab6aa2fdfdd 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 000000000000..7acc961422e7
--- /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 a524353d93f2..7c89880eefd0 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)
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index b29e7f6f8fa5..cff2cc08f45a 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -571,4 +571,25 @@ struct amba_id {
 #endif
 };
 
+/*
+ * Match x86 CPUs for CPU specific drivers.
+ * See documentation of "x86_match_cpu" for details.
+ */
+
+struct x86_cpu_id {
+        __u16 vendor;
+        __u16 family;
+        __u16 model;
+        __u16 feature;  /* bit index */
+        kernel_ulong_t driver_data;
+};
+
+#define X86_FEATURE_MATCH(x) \
+        { X86_VENDOR_ANY, X86_FAMILY_ANY, X86_MODEL_ANY, x }
+
+#define X86_VENDOR_ANY 0xffff
+#define X86_FAMILY_ANY 0
+#define X86_MODEL_ANY  0
+#define X86_FEATURE_ANY 0       /* Same as FPU, you can't test for that */
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index c0e14b3f2306..026ba38759ca 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1013,6 +1013,30 @@ static int do_amba_entry(const char *filename,
 }
 ADD_TO_DEVTABLE("amba", struct amba_id, do_amba_entry);
 
+/* LOOKS like x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:*,FEAT,*
+ * All fields are numbers. It would be nicer to use strings for vendor
+ * and feature, but getting those out of the build system here is too
+ * complicated.
+ */
+
+static int do_x86cpu_entry(const char *filename, struct x86_cpu_id *id,
+                           char *alias)
+{
+        id->feature = TO_NATIVE(id->feature);
+        id->family = TO_NATIVE(id->family);
+        id->model = TO_NATIVE(id->model);
+        id->vendor = TO_NATIVE(id->vendor);
+
+        strcpy(alias, "x86cpu:");
+        ADD(alias, "vendor:",  id->vendor != X86_VENDOR_ANY, id->vendor);
+        ADD(alias, ":family:", id->family != X86_FAMILY_ANY, id->family);
+        ADD(alias, ":model:",  id->model  != X86_MODEL_ANY,  id->model);
+        ADD(alias, ":feature:*,", id->feature != X86_FEATURE_ANY, id->feature);
+        strcat(alias, ",*");
+        return 1;
+}
+ADD_TO_DEVTABLE("x86cpu", struct x86_cpu_id, do_x86cpu_entry);
+
 /* Does namelen bytes of name exactly match the symbol? */
 static bool sym_is(const char *name, unsigned namelen, const char *symbol)
 {