Initial import

1 files changed, 245 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
new file mode 100644
index 000000000..83741a715
--- /dev/null
+++ b/arch/x86/kernel/cpuid.c
@@ -0,0 +1,245 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2000-2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
+ *   USA; either version 2 of the License, or (at your option) any later
+ *   version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * x86 CPUID access device
+ *
+ * This device is accessed by lseek() to the appropriate CPUID level
+ * and then read in chunks of 16 bytes.  A larger size means multiple
+ * reads of consecutive levels.
+ *
+ * The lower 32 bits of the file position is used as the incoming %eax,
+ * and the upper 32 bits of the file position as the incoming %ecx,
+ * the latter intended for "counting" eax levels like eax=4.
+ *
+ * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on
+ * an SMP box will direct the access to CPU %d.
+ */
+
+#include <linux/module.h>
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/smp.h>
+#include <linux/major.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+#include <linux/uaccess.h>
+#include <linux/gfp.h>
+
+#include <asm/processor.h>
+#include <asm/msr.h>
+
+static struct class *cpuid_class;
+
+struct cpuid_regs {
+	u32 eax, ebx, ecx, edx;
+};
+
+static void cpuid_smp_cpuid(void *cmd_block)
+{
+	struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block;
+
+	cpuid_count(cmd->eax, cmd->ecx,
+		    &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
+}
+
+static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
+{
+	loff_t ret;
+	struct inode *inode = file->f_mapping->host;
+
+	mutex_lock(&inode->i_mutex);
+	switch (orig) {
+	case 0:
+		file->f_pos = offset;
+		ret = file->f_pos;
+		break;
+	case 1:
+		file->f_pos += offset;
+		ret = file->f_pos;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	mutex_unlock(&inode->i_mutex);
+	return ret;
+}
+
+static ssize_t cpuid_read(struct file *file, char __user *buf,
+			  size_t count, loff_t *ppos)
+{
+	char __user *tmp = buf;
+	struct cpuid_regs cmd;
+	int cpu = iminor(file_inode(file));
+	u64 pos = *ppos;
+	ssize_t bytes = 0;
+	int err = 0;
+
+	if (count % 16)
+		return -EINVAL;	/* Invalid chunk size */
+
+	for (; count; count -= 16) {
+		cmd.eax = pos;
+		cmd.ecx = pos >> 32;
+		err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1);
+		if (err)
+			break;
+		if (copy_to_user(tmp, &cmd, 16)) {
+			err = -EFAULT;
+			break;
+		}
+		tmp += 16;
+		bytes += 16;
+		*ppos = ++pos;
+	}
+
+	return bytes ? bytes : err;
+}
+
+static int cpuid_open(struct inode *inode, struct file *file)
+{
+	unsigned int cpu;
+	struct cpuinfo_x86 *c;
+
+	cpu = iminor(file_inode(file));
+	if (cpu >= nr_cpu_ids || !cpu_online(cpu))
+		return -ENXIO;	/* No such CPU */
+
+	c = &cpu_data(cpu);
+	if (c->cpuid_level < 0)
+		return -EIO;	/* CPUID not supported */
+
+	return 0;
+}
+
+/*
+ * File operations we support
+ */
+static const struct file_operations cpuid_fops = {
+	.owner = THIS_MODULE,
+	.llseek = cpuid_seek,
+	.read = cpuid_read,
+	.open = cpuid_open,
+};
+
+static int cpuid_device_create(int cpu)
+{
+	struct device *dev;
+
+	dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL,
+			    "cpu%d", cpu);
+	return PTR_ERR_OR_ZERO(dev);
+}
+
+static void cpuid_device_destroy(int cpu)
+{
+	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
+}
+
+static int cpuid_class_cpu_callback(struct notifier_block *nfb,
+				    unsigned long action, void *hcpu)
+{
+	unsigned int cpu = (unsigned long)hcpu;
+	int err = 0;
+
+	switch (action) {
+	case CPU_UP_PREPARE:
+		err = cpuid_device_create(cpu);
+		break;
+	case CPU_UP_CANCELED:
+	case CPU_UP_CANCELED_FROZEN:
+	case CPU_DEAD:
+		cpuid_device_destroy(cpu);
+		break;
+	}
+	return notifier_from_errno(err);
+}
+
+static struct notifier_block __refdata cpuid_class_cpu_notifier =
+{
+	.notifier_call = cpuid_class_cpu_callback,
+};
+
+static char *cpuid_devnode(struct device *dev, umode_t *mode)
+{
+	return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
+}
+
+static int __init cpuid_init(void)
+{
+	int i, err = 0;
+	i = 0;
+
+	if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
+			      "cpu/cpuid", &cpuid_fops)) {
+		printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
+		       CPUID_MAJOR);
+		err = -EBUSY;
+		goto out;
+	}
+	cpuid_class = class_create(THIS_MODULE, "cpuid");
+	if (IS_ERR(cpuid_class)) {
+		err = PTR_ERR(cpuid_class);
+		goto out_chrdev;
+	}
+	cpuid_class->devnode = cpuid_devnode;
+
+	cpu_notifier_register_begin();
+	for_each_online_cpu(i) {
+		err = cpuid_device_create(i);
+		if (err != 0)
+			goto out_class;
+	}
+	__register_hotcpu_notifier(&cpuid_class_cpu_notifier);
+	cpu_notifier_register_done();
+
+	err = 0;
+	goto out;
+
+out_class:
+	i = 0;
+	for_each_online_cpu(i) {
+		cpuid_device_destroy(i);
+	}
+	cpu_notifier_register_done();
+	class_destroy(cpuid_class);
+out_chrdev:
+	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
+out:
+	return err;
+}
+
+static void __exit cpuid_exit(void)
+{
+	int cpu = 0;
+
+	cpu_notifier_register_begin();
+	for_each_online_cpu(cpu)
+		cpuid_device_destroy(cpu);
+	class_destroy(cpuid_class);
+	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
+	__unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
+	cpu_notifier_register_done();
+}
+
+module_init(cpuid_init);
+module_exit(cpuid_exit);
+
+MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
+MODULE_DESCRIPTION("x86 generic CPUID driver");
+MODULE_LICENSE("GPL");