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x86, msr: Export the register-setting MSR functions via /dev/*/msr

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Make it possible to access the all-register-setting/getting MSR
functions via the MSR driver.  This is implemented as an ioctl() on
the standard MSR device node.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <petkovbb@gmail.com>
This commit is contained in:
H. Peter Anvin
2009-08-31 14:16:57 -07:00
parent 8b956bf1f0
commit ff55df53df
3 changed files with 60 additions and 2 deletions
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51
arch/x86/kernel/msr.c
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@@ -1,6 +1,7 @@
/* ----------------------------------------------------------------------- *
*
* 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
@@ -121,6 +122,54 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
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 = iminor(file->f_path.dentry->d_inode);
@@ -151,6 +200,8 @@ 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 __cpuinit msr_device_create(int cpu)