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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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1
Documentation/ioctl/ioctl-number.txt
View file

@ -121,6 +121,7 @@ Code Seq# Include File Comments
'c' 00-7F linux/comstats.h conflict!
'c' 00-7F linux/coda.h conflict!
'c' 80-9F arch/s390/include/asm/chsc.h
'c' A0-AF arch/x86/include/asm/msr.h
'd' 00-FF linux/char/drm/drm/h conflict!
'd' F0-FF linux/digi1.h
'e' all linux/digi1.h conflict!

10
arch/x86/include/asm/msr.h
View file

@ -3,10 +3,16 @@
#include <asm/msr-index.h>
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/ioctl.h>
#define X86_IOC_RDMSR_REGS _IOWR('c', 0xA0, __u32[8])
#define X86_IOC_WRMSR_REGS _IOWR('c', 0xA1, __u32[8])
#ifdef __KERNEL__
#include <asm/asm.h>
#include <asm/errno.h>
#include <asm/cpumask.h>
@ -286,6 +292,6 @@ static inline int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
return wrmsr_safe_regs(regs);
}
#endif /* CONFIG_SMP */
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_MSR_H */

51
arch/x86/kernel/msr.c
View file

@ -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)