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Diffstat (limited to 'arch/x86/kernel/msr.c')
-rw-r--r--arch/x86/kernel/msr.c179
1 files changed, 130 insertions, 49 deletions
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 0c1069b8d63..c9603ac80de 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -1,6 +1,7 @@
/* ----------------------------------------------------------------------- *
- *
- * Copyright 2000 H. Peter Anvin - All Rights Reserved
+ *
+ * Copyright 2000-2008 H. Peter Anvin - All Rights Reserved
+ * Copyright 2009 Intel Corporation; author: H. Peter Anvin
*
* 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
@@ -11,8 +12,6 @@
* ----------------------------------------------------------------------- */
/*
- * msr.c
- *
* x86 MSR access device
*
* This device is accessed by lseek() to the appropriate register number
@@ -31,25 +30,25 @@
#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 <linux/uaccess.h>
+#include <linux/gfp.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;
+ loff_t ret;
+ struct inode *inode = file_inode(file);
- lock_kernel();
+ mutex_lock(&inode->i_mutex);
switch (orig) {
case 0:
file->f_pos = offset;
@@ -58,19 +57,23 @@ static loff_t msr_seek(struct file *file, loff_t offset, int orig)
case 1:
file->f_pos += offset;
ret = file->f_pos;
+ break;
+ default:
+ ret = -EINVAL;
}
- unlock_kernel();
+ mutex_unlock(&inode->i_mutex);
return ret;
}
-static ssize_t msr_read(struct file *file, char __user * buf,
- size_t count, loff_t * ppos)
+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;
+ int cpu = iminor(file_inode(file));
+ int err = 0;
+ ssize_t bytes = 0;
if (count % 8)
return -EINVAL; /* Invalid chunk size */
@@ -78,13 +81,16 @@ static ssize_t msr_read(struct file *file, char __user * buf,
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;
+ break;
+ if (copy_to_user(tmp, &data, 8)) {
+ err = -EFAULT;
+ break;
+ }
tmp += 2;
+ bytes += 8;
}
- return ((char __user *)tmp) - buf;
+ return bytes ? bytes : err;
}
static ssize_t msr_write(struct file *file, const char __user *buf,
@@ -93,31 +99,88 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
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;
+ int cpu = iminor(file_inode(file));
+ int err = 0;
+ ssize_t bytes = 0;
if (count % 8)
return -EINVAL; /* Invalid chunk size */
for (; count; count -= 8) {
- if (copy_from_user(&data, tmp, 8))
- return -EFAULT;
+ if (copy_from_user(&data, tmp, 8)) {
+ err = -EFAULT;
+ break;
+ }
err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
if (err)
- return -EIO;
+ break;
tmp += 2;
+ bytes += 8;
+ }
+
+ return bytes ? bytes : err;
+}
+
+static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg)
+{
+ u32 __user *uregs = (u32 __user *)arg;
+ u32 regs[8];
+ int cpu = iminor(file_inode(file));
+ int err;
+
+ switch (ioc) {
+ case X86_IOC_RDMSR_REGS:
+ if (!(file->f_mode & FMODE_READ)) {
+ err = -EBADF;
+ break;
+ }
+ if (copy_from_user(&regs, uregs, sizeof regs)) {
+ err = -EFAULT;
+ break;
+ }
+ err = rdmsr_safe_regs_on_cpu(cpu, regs);
+ if (err)
+ break;
+ if (copy_to_user(uregs, &regs, sizeof regs))
+ err = -EFAULT;
+ break;
+
+ case X86_IOC_WRMSR_REGS:
+ if (!(file->f_mode & FMODE_WRITE)) {
+ err = -EBADF;
+ break;
+ }
+ if (copy_from_user(&regs, uregs, sizeof regs)) {
+ err = -EFAULT;
+ break;
+ }
+ err = wrmsr_safe_regs_on_cpu(cpu, regs);
+ if (err)
+ break;
+ if (copy_to_user(uregs, &regs, sizeof regs))
+ err = -EFAULT;
+ break;
+
+ default:
+ err = -ENOTTY;
+ break;
}
- return ((char __user *)tmp) - buf;
+ return err;
}
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];
+ unsigned int cpu = iminor(file_inode(file));
+ struct cpuinfo_x86 *c;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
- if (cpu >= NR_CPUS || !cpu_online(cpu))
+ if (cpu >= nr_cpu_ids || !cpu_online(cpu))
return -ENXIO; /* No such CPU */
+
+ c = &cpu_data(cpu);
if (!cpu_has(c, X86_FEATURE_MSR))
return -EIO; /* MSR not supported */
@@ -133,48 +196,58 @@ static const struct file_operations msr_fops = {
.read = msr_read,
.write = msr_write,
.open = msr_open,
+ .unlocked_ioctl = msr_ioctl,
+ .compat_ioctl = msr_ioctl,
};
-static int msr_device_create(int i)
+static int msr_device_create(int cpu)
{
- 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;
+ dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu), NULL,
+ "msr%d", cpu);
+ return IS_ERR(dev) ? PTR_ERR(dev) : 0;
+}
+
+static void msr_device_destroy(int cpu)
+{
+ device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
}
static int msr_class_cpu_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+ unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
+ int err = 0;
switch (action) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- msr_device_create(cpu);
+ case CPU_UP_PREPARE:
+ err = msr_device_create(cpu);
break;
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ msr_device_destroy(cpu);
break;
}
- return NOTIFY_OK;
+ return notifier_from_errno(err);
}
-static struct notifier_block __cpuinitdata msr_class_cpu_notifier =
-{
+static struct notifier_block __refdata msr_class_cpu_notifier = {
.notifier_call = msr_class_cpu_callback,
};
+static char *msr_devnode(struct device *dev, umode_t *mode)
+{
+ return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt));
+}
+
static int __init msr_init(void)
{
int i, err = 0;
i = 0;
- if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
+ if (__register_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr", &msr_fops)) {
printk(KERN_ERR "msr: unable to get major %d for msr\n",
MSR_MAJOR);
err = -EBUSY;
@@ -185,12 +258,16 @@ static int __init msr_init(void)
err = PTR_ERR(msr_class);
goto out_chrdev;
}
+ msr_class->devnode = msr_devnode;
+
+ cpu_notifier_register_begin();
for_each_online_cpu(i) {
err = msr_device_create(i);
if (err != 0)
goto out_class;
}
- register_hotcpu_notifier(&msr_class_cpu_notifier);
+ __register_hotcpu_notifier(&msr_class_cpu_notifier);
+ cpu_notifier_register_done();
err = 0;
goto out;
@@ -198,10 +275,11 @@ static int __init msr_init(void)
out_class:
i = 0;
for_each_online_cpu(i)
- device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
+ msr_device_destroy(i);
+ cpu_notifier_register_done();
class_destroy(msr_class);
out_chrdev:
- unregister_chrdev(MSR_MAJOR, "cpu/msr");
+ __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
out:
return err;
}
@@ -209,11 +287,14 @@ out:
static void __exit msr_exit(void)
{
int cpu = 0;
+
+ cpu_notifier_register_begin();
for_each_online_cpu(cpu)
- device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ msr_device_destroy(cpu);
class_destroy(msr_class);
- unregister_chrdev(MSR_MAJOR, "cpu/msr");
- unregister_hotcpu_notifier(&msr_class_cpu_notifier);
+ __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
+ __unregister_hotcpu_notifier(&msr_class_cpu_notifier);
+ cpu_notifier_register_done();
}
module_init(msr_init);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-06 19:38:24 +0000