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* CPU Microcode Update interface for Linux
*
* Copyright (C) 2000 Tigran Aivazian
*
* This driver allows to upgrade microcode on Intel processors
* belonging to P6 family - PentiumPro, Pentium II, Pentium III etc.
*
* Reference: Section 8.10 of Volume III, Intel Pentium III Manual,
* Order Number 243192 or download from:
*
* http://developer.intel.com/design/pentiumii/manuals/243192.htm
*
* 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; either version
* 2 of the License, or (at your option) any later version.
*
* 1.0 16 February 2000, Tigran Aivazian <tigran@sco.com>
* Initial release.
* 1.01 18 February 2000, Tigran Aivazian <tigran@sco.com>
* Added read() support + cleanups.
* 1.02 21 February 2000, Tigran Aivazian <tigran@sco.com>
* Added 'device trimming' support. open(O_WRONLY) zeroes
* and frees the saved copy of applied microcode.
* 1.03 29 February 2000, Tigran Aivazian <tigran@sco.com>
* Made to use devfs (/dev/cpu/microcode) + cleanups.
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>
#include <asm/msr.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#define MICROCODE_VERSION "1.03"
MODULE_DESCRIPTION("CPU (P6) microcode update driver");
MODULE_AUTHOR("Tigran Aivazian <tigran@ocston.org>");
EXPORT_NO_SYMBOLS;
/* VFS interface */
static int microcode_open(struct inode *, struct file *);
static int microcode_release(struct inode *, struct file *);
static ssize_t microcode_read(struct file *, char *, size_t, loff_t *);
static ssize_t microcode_write(struct file *, const char *, size_t, loff_t *);
/* internal helpers to do the work */
static int do_microcode_update(void);
static void do_update_one(void *);
/*
* Bits in microcode_status. (31 bits of room for future expansion)
*/
#define MICROCODE_IS_OPEN 0 /* set if device is in use */
static unsigned long microcode_status = 0;
/* the actual array of microcode blocks, each 2048 bytes */
static struct microcode *microcode = NULL;
static unsigned int microcode_num = 0;
static char *mc_applied = NULL; /* holds an array of applied microcode blocks */
static unsigned int mc_fsize; /* used often, so compute once at microcode_init() */
static struct file_operations microcode_fops = {
read: microcode_read,
write: microcode_write,
open: microcode_open,
release: microcode_release,
};
static devfs_handle_t devfs_handle;
static int __init microcode_init(void)
{
devfs_handle = devfs_register(NULL, "cpu/microcode", 0, DEVFS_FL_DEFAULT, 0, 0,
S_IFREG | S_IRUSR | S_IWUSR, 0, 0, µcode_fops, NULL);
if (!devfs_handle) {
printk(KERN_ERR "microcode: can't create /dev/cpu/microcode\n");
return -ENOMEM;
}
/* XXX assume no hotplug CPUs so smp_num_cpus does not change */
mc_fsize = smp_num_cpus * sizeof(struct microcode);
printk(KERN_INFO "P6 Microcode Update Driver v%s registered\n", MICROCODE_VERSION);
return 0;
}
static void __exit microcode_exit(void)
{
devfs_unregister(devfs_handle);
if (mc_applied)
kfree(mc_applied);
printk(KERN_INFO "P6 Microcode Update Driver v%s unregistered\n", MICROCODE_VERSION);
}
module_init(microcode_init);
module_exit(microcode_exit);
/*
* We enforce only one user at a time here with open/close.
*/
static int microcode_open(struct inode *inode, struct file *file)
{
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
/* one at a time, please */
if (test_and_set_bit(MICROCODE_IS_OPEN, µcode_status))
return -EBUSY;
if ((file->f_flags & O_ACCMODE) == O_WRONLY && mc_applied) {
devfs_set_file_size(devfs_handle, 0);
memset(mc_applied, 0, mc_fsize);
kfree(mc_applied);
mc_applied = NULL;
}
MOD_INC_USE_COUNT;
return 0;
}
static int microcode_release(struct inode *inode, struct file *file)
{
clear_bit(MICROCODE_IS_OPEN, µcode_status);
MOD_DEC_USE_COUNT;
return 0;
}
/* a pointer to 'struct update_req' is passed to the IPI hanlder = do_update_one()
* update_req[cpu].err is set to 1 if update failed on 'cpu', 0 otherwise
* if err==0, microcode[update_req[cpu].slot] points to applied block of microcode
*/
struct update_req {
int err;
int slot;
} update_req[NR_CPUS];
static int do_microcode_update(void)
{
int i, error = 0, err;
struct microcode *m;
if (smp_call_function(do_update_one, (void *)update_req, 1, 1) != 0)
panic("do_microcode_update(): timed out waiting for other CPUs\n");
do_update_one((void *)update_req);
for (i=0; i<smp_num_cpus; i++) {
err = update_req[i].err;
error += err;
if (!err) {
m = (struct microcode *)mc_applied + i;
memcpy(m, µcode[update_req[i].slot], sizeof(struct microcode));
}
}
return error;
}
static void do_update_one(void *arg)
{
int cpu_num = smp_processor_id();
struct cpuinfo_x86 *c = cpu_data + cpu_num;
struct update_req *req = (struct update_req *)arg + cpu_num;
unsigned int pf = 0, val[2], rev, sig;
int i;
req->err = 1; /* be pessimistic */
if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6)
return;
sig = c->x86_mask + (c->x86_model<<4) + (c->x86<<8);
if (c->x86_model >= 5) {
/* get processor flags from BBL_CR_OVRD MSR (0x17) */
rdmsr(0x17, val[0], val[1]);
pf = 1 << ((val[1] >> 18) & 7);
}
for (i=0; i<microcode_num; i++)
if (microcode[i].sig == sig && microcode[i].pf == pf &&
microcode[i].ldrver == 1 && microcode[i].hdrver == 1) {
rdmsr(0x8B, val[0], rev);
if (microcode[i].rev <= rev) {
printk(KERN_ERR
"microcode: CPU%d not 'upgrading' to earlier revision"
" %d (current=%d)\n", cpu_num, microcode[i].rev, rev);
} else {
int sum = 0;
struct microcode *m = µcode[i];
unsigned int *sump = (unsigned int *)(m+1);
while (--sump >= (unsigned int *)m)
sum += *sump;
if (sum != 0) {
printk(KERN_ERR "microcode: CPU%d aborting, "
"bad checksum\n", cpu_num);
break;
}
wrmsr(0x79, (unsigned int)(m->bits), 0);
__asm__ __volatile__ ("cpuid");
rdmsr(0x8B, val[0], val[1]);
req->err = 0;
req->slot = i;
printk(KERN_ERR "microcode: CPU%d updated from revision "
"%d to %d, date=%08x\n",
cpu_num, rev, val[1], m->date);
}
break;
}
}
static ssize_t microcode_read(struct file *file, char *buf, size_t len, loff_t *ppos)
{
if (*ppos >= mc_fsize)
return 0;
if (*ppos + len > mc_fsize)
len = mc_fsize - *ppos;
if (copy_to_user(buf, mc_applied + *ppos, len))
return -EFAULT;
*ppos += len;
return len;
}
static ssize_t microcode_write(struct file *file, const char *buf, size_t len, loff_t *ppos)
{
ssize_t ret;
if (len % sizeof(struct microcode) != 0) {
printk(KERN_ERR "microcode: can only write in N*%d bytes units\n",
sizeof(struct microcode));
return -EINVAL;
}
if (!mc_applied) {
mc_applied = kmalloc(mc_fsize, GFP_KERNEL);
if (!mc_applied) {
printk(KERN_ERR "microcode: out of memory for saved microcode\n");
return -ENOMEM;
}
memset(mc_applied, 0, mc_fsize);
}
lock_kernel();
microcode_num = len/sizeof(struct microcode);
microcode = vmalloc(len);
if (!microcode) {
ret = -ENOMEM;
goto out_unlock;
}
if (copy_from_user(microcode, buf, len)) {
ret = -EFAULT;
goto out_vfree;
}
if(do_microcode_update()) {
ret = -EIO;
goto out_vfree;
}
devfs_set_file_size(devfs_handle, mc_fsize);
ret = (ssize_t)len;
out_vfree:
vfree(microcode);
out_unlock:
unlock_kernel();
return ret;
}
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