linux-sg2042/arch/x86/kernel/msr.c

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/* ----------------------------------------------------------------------- *
*
* 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
* 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 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/major.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/uaccess.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/gfp.h>
#include <asm/processor.h>
#include <asm/msr.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;
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 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 = 0;
ssize_t bytes = 0;
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)
break;
if (copy_to_user(tmp, &data, 8)) {
err = -EFAULT;
break;
}
tmp += 2;
bytes += 8;
}
return bytes ? bytes : err;
}
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 = 0;
ssize_t bytes = 0;
if (count % 8)
return -EINVAL; /* Invalid chunk size */
for (; count; count -= 8) {
if (copy_from_user(&data, tmp, 8)) {
err = -EFAULT;
break;
}
err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
if (err)
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->f_path.dentry->d_inode);
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 err;
}
static int msr_open(struct inode *inode, struct file *file)
{
unsigned int cpu;
struct cpuinfo_x86 *c;
cpu = iminor(file->f_path.dentry->d_inode);
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 */
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,
.unlocked_ioctl = msr_ioctl,
.compat_ioctl = msr_ioctl,
};
static int __cpuinit msr_device_create(int cpu)
{
struct device *dev;
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 __cpuinit msr_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 = msr_device_create(cpu);
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
msr_device_destroy(cpu);
break;
}
return notifier_from_errno(err);
}
static struct notifier_block __refdata msr_class_cpu_notifier = {
.notifier_call = msr_class_cpu_callback,
};
static char *msr_devnode(struct device *dev, mode_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, 0, NR_CPUS, "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;
}
msr_class->devnode = msr_devnode;
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)
msr_device_destroy(i);
class_destroy(msr_class);
out_chrdev:
__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
out:
return err;
}
static void __exit msr_exit(void)
{
int cpu = 0;
for_each_online_cpu(cpu)
msr_device_destroy(cpu);
class_destroy(msr_class);
__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "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");