linux/arch/x86/kernel/cpuid.c
Paul Gortmaker 148f9bb877 x86: delete __cpuinit usage from all x86 files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files.  x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:56 -04:00

245 lines
5.4 KiB
C

/* ----------------------------------------------------------------------- *
*
* Copyright 2000-2008 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.
*
* ----------------------------------------------------------------------- */
/*
* x86 CPUID access device
*
* This device is accessed by lseek() to the appropriate CPUID level
* and then read in chunks of 16 bytes. A larger size means multiple
* reads of consecutive levels.
*
* The lower 32 bits of the file position is used as the incoming %eax,
* and the upper 32 bits of the file position as the incoming %ecx,
* the latter intended for "counting" eax levels like eax=4.
*
* This driver uses /dev/cpu/%d/cpuid 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 <linux/gfp.h>
#include <asm/processor.h>
#include <asm/msr.h>
static struct class *cpuid_class;
struct cpuid_regs {
u32 eax, ebx, ecx, edx;
};
static void cpuid_smp_cpuid(void *cmd_block)
{
struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block;
cpuid_count(cmd->eax, cmd->ecx,
&cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
}
static loff_t cpuid_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 cpuid_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
char __user *tmp = buf;
struct cpuid_regs cmd;
int cpu = iminor(file_inode(file));
u64 pos = *ppos;
ssize_t bytes = 0;
int err = 0;
if (count % 16)
return -EINVAL; /* Invalid chunk size */
for (; count; count -= 16) {
cmd.eax = pos;
cmd.ecx = pos >> 32;
err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1);
if (err)
break;
if (copy_to_user(tmp, &cmd, 16)) {
err = -EFAULT;
break;
}
tmp += 16;
bytes += 16;
*ppos = ++pos;
}
return bytes ? bytes : err;
}
static int cpuid_open(struct inode *inode, struct file *file)
{
unsigned int cpu;
struct cpuinfo_x86 *c;
cpu = iminor(file_inode(file));
if (cpu >= nr_cpu_ids || !cpu_online(cpu))
return -ENXIO; /* No such CPU */
c = &cpu_data(cpu);
if (c->cpuid_level < 0)
return -EIO; /* CPUID not supported */
return 0;
}
/*
* File operations we support
*/
static const struct file_operations cpuid_fops = {
.owner = THIS_MODULE,
.llseek = cpuid_seek,
.read = cpuid_read,
.open = cpuid_open,
};
static int cpuid_device_create(int cpu)
{
struct device *dev;
dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL,
"cpu%d", cpu);
return IS_ERR(dev) ? PTR_ERR(dev) : 0;
}
static void cpuid_device_destroy(int cpu)
{
device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
}
static int cpuid_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 = cpuid_device_create(cpu);
break;
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
cpuid_device_destroy(cpu);
break;
}
return notifier_from_errno(err);
}
static struct notifier_block __refdata cpuid_class_cpu_notifier =
{
.notifier_call = cpuid_class_cpu_callback,
};
static char *cpuid_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
}
static int __init cpuid_init(void)
{
int i, err = 0;
i = 0;
if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
"cpu/cpuid", &cpuid_fops)) {
printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
CPUID_MAJOR);
err = -EBUSY;
goto out;
}
cpuid_class = class_create(THIS_MODULE, "cpuid");
if (IS_ERR(cpuid_class)) {
err = PTR_ERR(cpuid_class);
goto out_chrdev;
}
cpuid_class->devnode = cpuid_devnode;
get_online_cpus();
for_each_online_cpu(i) {
err = cpuid_device_create(i);
if (err != 0)
goto out_class;
}
register_hotcpu_notifier(&cpuid_class_cpu_notifier);
put_online_cpus();
err = 0;
goto out;
out_class:
i = 0;
for_each_online_cpu(i) {
cpuid_device_destroy(i);
}
put_online_cpus();
class_destroy(cpuid_class);
out_chrdev:
__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
out:
return err;
}
static void __exit cpuid_exit(void)
{
int cpu = 0;
get_online_cpus();
for_each_online_cpu(cpu)
cpuid_device_destroy(cpu);
class_destroy(cpuid_class);
__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
put_online_cpus();
}
module_init(cpuid_init);
module_exit(cpuid_exit);
MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
MODULE_DESCRIPTION("x86 generic CPUID driver");
MODULE_LICENSE("GPL");