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#ident "$Id$"
/* ----------------------------------------------------------------------- *
*
* Copyright 2000 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.
*
* ----------------------------------------------------------------------- */
/*
* cpuid.c
*
* 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.
*
* 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/config.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 <asm/processor.h>
#include <asm/msr.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#ifdef CONFIG_SMP
struct cpuid_command {
int cpu;
u32 reg;
u32 *data;
};
static void cpuid_smp_cpuid(void *cmd_block)
{
struct cpuid_command *cmd = (struct cpuid_command *) cmd_block;
if ( cmd->cpu == smp_processor_id() )
cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2], &cmd->data[3]);
}
extern inline void do_cpuid(int cpu, u32 reg, u32 *data)
{
struct cpuid_command cmd;
if ( cpu == smp_processor_id() ) {
cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
} else {
cmd->cpu = cpu;
cmd->reg = reg;
cmd->data = data;
smp_call_function(cpuid_smp_cpuid, (void *)cmd, 1, 1);
}
}
#else /* ! CONFIG_SMP */
extern inline void do_cpuid(int cpu, u32 reg, u32 *data)
{
cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
}
#endif /* ! CONFIG_SMP */
static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
{
switch (orig) {
case 0:
file->f_pos = offset;
return file->f_pos;
case 1:
file->f_pos += offset;
return file->f_pos;
default:
return -EINVAL; /* SEEK_END not supported */
}
}
static ssize_t cpuid_read(struct file * file, char * buf,
size_t count, loff_t *ppos)
{
u32 *tmp = (u32 *)buf;
u32 data[4];
size_t rv;
u32 reg = *ppos;
int cpu = MINOR(file->f_dentry->d_inode->i_rdev);
if ( count % 16 )
return -EINVAL; /* Invalid chunk size */
for ( rv = 0 ; count ; count -= 16 ) {
do_cpuid(cpu, reg, data);
if ( copy_to_user(tmp,&data,16) )
return -EFAULT;
tmp += 4;
*ppos = reg++;
}
return ((char *)tmp) - buf;
}
static int cpuid_open(struct inode *inode, struct file *file)
{
int cpu = MINOR(file->f_dentry->d_inode->i_rdev);
if ( !(cpu_online_map & (1UL << cpu)) )
return -ENXIO; /* No such CPU */
MOD_INC_USE_COUNT;
return 0;
}
static int cpuid_release(struct inode *inode, struct file *file)
{
MOD_DEC_USE_COUNT;
return 0;
}
/*
* File operations we support
*/
static struct file_operations cpuid_fops = {
llseek: cpuid_seek,
read: cpuid_read,
open: cpuid_open,
release: cpuid_release,
};
int __init cpuid_init(void)
{
if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
CPUID_MAJOR);
return -EBUSY;
}
return 0;
}
void __exit cpuid_exit(void)
{
}
module_init(cpuid_init);
module_exit(cpuid_exit)
EXPORT_NO_SYMBOLS;
MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
MODULE_DESCRIPTION("x86 generic CPUID driver");
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