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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 11:17:01 +0200
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 11:17:01 +0200
commit9a163ed8e0552fdcffe405d2ea7134819a81456e (patch)
treeb322fd2afbb812ba7ddfd22f3734aaab007c2aa5 /arch/x86/kernel/msr.c
parentf7627e2513987bb5d4e8cb13c4e0a478352141ac (diff)
i386: move kernel
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/msr.c')
-rw-r--r--arch/x86/kernel/msr.c224
1 files changed, 224 insertions, 0 deletions
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
new file mode 100644
index 00000000000..0c1069b8d63
--- /dev/null
+++ b/arch/x86/kernel/msr.c
@@ -0,0 +1,224 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2000 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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * msr.c
+ *
+ * x86 MSR access device
+ *
+ * This device is accessed by lseek() to the appropriate register number
+ * and then read/write in chunks of 8 bytes. A larger size means multiple
+ * reads or writes of the same register.
+ *
+ * This driver uses /dev/cpu/%d/msr 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/smp_lock.h>
+#include <linux/major.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
+
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+static struct class *msr_class;
+
+static loff_t msr_seek(struct file *file, loff_t offset, int orig)
+{
+ loff_t ret = -EINVAL;
+
+ lock_kernel();
+ switch (orig) {
+ case 0:
+ file->f_pos = offset;
+ ret = file->f_pos;
+ break;
+ case 1:
+ file->f_pos += offset;
+ ret = file->f_pos;
+ }
+ unlock_kernel();
+ return ret;
+}
+
+static ssize_t msr_read(struct file *file, char __user * buf,
+ size_t count, loff_t * ppos)
+{
+ u32 __user *tmp = (u32 __user *) buf;
+ u32 data[2];
+ u32 reg = *ppos;
+ int cpu = iminor(file->f_path.dentry->d_inode);
+ int err;
+
+ if (count % 8)
+ return -EINVAL; /* Invalid chunk size */
+
+ for (; count; count -= 8) {
+ err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
+ if (err)
+ return -EIO;
+ if (copy_to_user(tmp, &data, 8))
+ return -EFAULT;
+ tmp += 2;
+ }
+
+ return ((char __user *)tmp) - buf;
+}
+
+static ssize_t msr_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ const u32 __user *tmp = (const u32 __user *)buf;
+ u32 data[2];
+ u32 reg = *ppos;
+ int cpu = iminor(file->f_path.dentry->d_inode);
+ int err;
+
+ if (count % 8)
+ return -EINVAL; /* Invalid chunk size */
+
+ for (; count; count -= 8) {
+ if (copy_from_user(&data, tmp, 8))
+ return -EFAULT;
+ err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
+ if (err)
+ return -EIO;
+ tmp += 2;
+ }
+
+ return ((char __user *)tmp) - buf;
+}
+
+static int msr_open(struct inode *inode, struct file *file)
+{
+ unsigned int cpu = iminor(file->f_path.dentry->d_inode);
+ struct cpuinfo_x86 *c = &(cpu_data)[cpu];
+
+ if (cpu >= NR_CPUS || !cpu_online(cpu))
+ return -ENXIO; /* No such CPU */
+ if (!cpu_has(c, X86_FEATURE_MSR))
+ return -EIO; /* MSR not supported */
+
+ return 0;
+}
+
+/*
+ * File operations we support
+ */
+static const struct file_operations msr_fops = {
+ .owner = THIS_MODULE,
+ .llseek = msr_seek,
+ .read = msr_read,
+ .write = msr_write,
+ .open = msr_open,
+};
+
+static int msr_device_create(int i)
+{
+ int err = 0;
+ struct device *dev;
+
+ dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, i), "msr%d",i);
+ if (IS_ERR(dev))
+ err = PTR_ERR(dev);
+ return err;
+}
+
+static int msr_class_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ msr_device_create(cpu);
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata msr_class_cpu_notifier =
+{
+ .notifier_call = msr_class_cpu_callback,
+};
+
+static int __init msr_init(void)
+{
+ int i, err = 0;
+ i = 0;
+
+ if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
+ printk(KERN_ERR "msr: unable to get major %d for msr\n",
+ MSR_MAJOR);
+ err = -EBUSY;
+ goto out;
+ }
+ msr_class = class_create(THIS_MODULE, "msr");
+ if (IS_ERR(msr_class)) {
+ err = PTR_ERR(msr_class);
+ goto out_chrdev;
+ }
+ for_each_online_cpu(i) {
+ err = msr_device_create(i);
+ if (err != 0)
+ goto out_class;
+ }
+ register_hotcpu_notifier(&msr_class_cpu_notifier);
+
+ err = 0;
+ goto out;
+
+out_class:
+ i = 0;
+ for_each_online_cpu(i)
+ device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
+ class_destroy(msr_class);
+out_chrdev:
+ unregister_chrdev(MSR_MAJOR, "cpu/msr");
+out:
+ return err;
+}
+
+static void __exit msr_exit(void)
+{
+ int cpu = 0;
+ for_each_online_cpu(cpu)
+ device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ class_destroy(msr_class);
+ unregister_chrdev(MSR_MAJOR, "cpu/msr");
+ unregister_hotcpu_notifier(&msr_class_cpu_notifier);
+}
+
+module_init(msr_init);
+module_exit(msr_exit)
+
+MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
+MODULE_DESCRIPTION("x86 generic MSR driver");
+MODULE_LICENSE("GPL");