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linux/arch/x86/kernel/cpu/mtrr/if.c
Jesse Barnes 99fc8d424b x86, 32-bit: trim memory not covered by wb mtrrs 
On some machines, buggy BIOSes don't properly setup WB MTRRs to cover all
available RAM, meaning the last few megs (or even gigs) of memory will be
marked uncached.  Since Linux tends to allocate from high memory addresses
first, this causes the machine to be unusably slow as soon as the kernel
starts really using memory (i.e.  right around init time).

This patch works around the problem by scanning the MTRRs at boot and
figuring out whether the current end_pfn value (setup by early e820 code)
goes beyond the highest WB MTRR range, and if so, trimming it to match.  A
fairly obnoxious KERN_WARNING is printed too, letting the user know that
not all of their memory is available due to a likely BIOS bug.

Something similar could be done on i386 if needed, but the boot ordering
would be slightly different, since the MTRR code on i386 depends on the
boot_cpu_data structure being setup.

This patch fixes a bug in the last patch that caused the code to run on
non-Intel machines (AMD machines apparently don't need it and it's untested
on other non-Intel machines, so best keep it off).

Further enhancements and fixes from:

  Yinghai Lu <Yinghai.Lu@Sun.COM>
  Andi Kleen <ak@suse.de>

Signed-off-by: Jesse Barnes <jesse.barnes@intel.com>
Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:18 +01:00

437 lines
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#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/capability.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#define LINE_SIZE 80
#include <asm/mtrr.h>
#include "mtrr.h"
#define FILE_FCOUNT(f) (((struct seq_file *)((f)->private_data))->private)
static const char *const mtrr_strings[MTRR_NUM_TYPES] =
{
"uncachable", /* 0 */
"write-combining", /* 1 */
"?", /* 2 */
"?", /* 3 */
"write-through", /* 4 */
"write-protect", /* 5 */
"write-back", /* 6 */
};
const char *mtrr_attrib_to_str(int x)
{
return (x <= 6) ? mtrr_strings[x] : "?";
}
#ifdef CONFIG_PROC_FS
static int
mtrr_file_add(unsigned long base, unsigned long size,
unsigned int type, bool increment, struct file *file, int page)
{
int reg, max;
unsigned int *fcount = FILE_FCOUNT(file);
max = num_var_ranges;
if (fcount == NULL) {
fcount = kzalloc(max * sizeof *fcount, GFP_KERNEL);
if (!fcount)
return -ENOMEM;
FILE_FCOUNT(file) = fcount;
}
if (!page) {
if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
return -EINVAL;
base >>= PAGE_SHIFT;
size >>= PAGE_SHIFT;
}
reg = mtrr_add_page(base, size, type, true);
if (reg >= 0)
++fcount[reg];
return reg;
}
static int
mtrr_file_del(unsigned long base, unsigned long size,
struct file *file, int page)
{
int reg;
unsigned int *fcount = FILE_FCOUNT(file);
if (!page) {
if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
return -EINVAL;
base >>= PAGE_SHIFT;
size >>= PAGE_SHIFT;
}
reg = mtrr_del_page(-1, base, size);
if (reg < 0)
return reg;
if (fcount == NULL)
return reg;
if (fcount[reg] < 1)
return -EINVAL;
--fcount[reg];
return reg;
}
/* RED-PEN: seq_file can seek now. this is ignored. */
static ssize_t
mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
/* Format of control line:
"base=%Lx size=%Lx type=%s" OR:
"disable=%d"
*/
{
int i, err;
unsigned long reg;
unsigned long long base, size;
char *ptr;
char line[LINE_SIZE];
size_t linelen;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!len)
return -EINVAL;
memset(line, 0, LINE_SIZE);
if (len > LINE_SIZE)
len = LINE_SIZE;
if (copy_from_user(line, buf, len - 1))
return -EFAULT;
linelen = strlen(line);
ptr = line + linelen - 1;
if (linelen && *ptr == '\n')
*ptr = '\0';
if (!strncmp(line, "disable=", 8)) {
reg = simple_strtoul(line + 8, &ptr, 0);
err = mtrr_del_page(reg, 0, 0);
if (err < 0)
return err;
return len;
}
if (strncmp(line, "base=", 5))
return -EINVAL;
base = simple_strtoull(line + 5, &ptr, 0);
for (; isspace(*ptr); ++ptr) ;
if (strncmp(ptr, "size=", 5))
return -EINVAL;
size = simple_strtoull(ptr + 5, &ptr, 0);
if ((base & 0xfff) || (size & 0xfff))
return -EINVAL;
for (; isspace(*ptr); ++ptr) ;
if (strncmp(ptr, "type=", 5))
return -EINVAL;
ptr += 5;
for (; isspace(*ptr); ++ptr) ;
for (i = 0; i < MTRR_NUM_TYPES; ++i) {
if (strcmp(ptr, mtrr_strings[i]))
continue;
base >>= PAGE_SHIFT;
size >>= PAGE_SHIFT;
err =
mtrr_add_page((unsigned long) base, (unsigned long) size, i,
true);
if (err < 0)
return err;
return len;
}
return -EINVAL;
}
static long
mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
{
int err = 0;
mtrr_type type;
unsigned long size;
struct mtrr_sentry sentry;
struct mtrr_gentry gentry;
void __user *arg = (void __user *) __arg;
switch (cmd) {
case MTRRIOC_ADD_ENTRY:
case MTRRIOC_SET_ENTRY:
case MTRRIOC_DEL_ENTRY:
case MTRRIOC_KILL_ENTRY:
case MTRRIOC_ADD_PAGE_ENTRY:
case MTRRIOC_SET_PAGE_ENTRY:
case MTRRIOC_DEL_PAGE_ENTRY:
case MTRRIOC_KILL_PAGE_ENTRY:
if (copy_from_user(&sentry, arg, sizeof sentry))
return -EFAULT;
break;
case MTRRIOC_GET_ENTRY:
case MTRRIOC_GET_PAGE_ENTRY:
if (copy_from_user(&gentry, arg, sizeof gentry))
return -EFAULT;
break;
#ifdef CONFIG_COMPAT
case MTRRIOC32_ADD_ENTRY:
case MTRRIOC32_SET_ENTRY:
case MTRRIOC32_DEL_ENTRY:
case MTRRIOC32_KILL_ENTRY:
case MTRRIOC32_ADD_PAGE_ENTRY:
case MTRRIOC32_SET_PAGE_ENTRY:
case MTRRIOC32_DEL_PAGE_ENTRY:
case MTRRIOC32_KILL_PAGE_ENTRY: {
struct mtrr_sentry32 __user *s32 = (struct mtrr_sentry32 __user *)__arg;
err = get_user(sentry.base, &s32->base);
err |= get_user(sentry.size, &s32->size);
err |= get_user(sentry.type, &s32->type);
if (err)
return err;
break;
}
case MTRRIOC32_GET_ENTRY:
case MTRRIOC32_GET_PAGE_ENTRY: {
struct mtrr_gentry32 __user *g32 = (struct mtrr_gentry32 __user *)__arg;
err = get_user(gentry.regnum, &g32->regnum);
err |= get_user(gentry.base, &g32->base);
err |= get_user(gentry.size, &g32->size);
err |= get_user(gentry.type, &g32->type);
if (err)
return err;
break;
}
#endif
}
switch (cmd) {
default:
return -ENOTTY;
case MTRRIOC_ADD_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_ADD_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err =
mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
file, 0);
break;
case MTRRIOC_SET_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_SET_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
break;
case MTRRIOC_DEL_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_DEL_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = mtrr_file_del(sentry.base, sentry.size, file, 0);
break;
case MTRRIOC_KILL_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_KILL_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = mtrr_del(-1, sentry.base, sentry.size);
break;
case MTRRIOC_GET_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_GET_ENTRY:
#endif
if (gentry.regnum >= num_var_ranges)
return -EINVAL;
mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
/* Hide entries that go above 4GB */
if (gentry.base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
|| size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
gentry.base = gentry.size = gentry.type = 0;
else {
gentry.base <<= PAGE_SHIFT;
gentry.size = size << PAGE_SHIFT;
gentry.type = type;
}
break;
case MTRRIOC_ADD_PAGE_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_ADD_PAGE_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err =
mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
file, 1);
break;
case MTRRIOC_SET_PAGE_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_SET_PAGE_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err =
mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
break;
case MTRRIOC_DEL_PAGE_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_DEL_PAGE_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = mtrr_file_del(sentry.base, sentry.size, file, 1);
break;
case MTRRIOC_KILL_PAGE_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_KILL_PAGE_ENTRY:
#endif
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = mtrr_del_page(-1, sentry.base, sentry.size);
break;
case MTRRIOC_GET_PAGE_ENTRY:
#ifdef CONFIG_COMPAT
case MTRRIOC32_GET_PAGE_ENTRY:
#endif
if (gentry.regnum >= num_var_ranges)
return -EINVAL;
mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
/* Hide entries that would overflow */
if (size != (__typeof__(gentry.size))size)
gentry.base = gentry.size = gentry.type = 0;
else {
gentry.size = size;
gentry.type = type;
}
break;
}
if (err)
return err;
switch(cmd) {
case MTRRIOC_GET_ENTRY:
case MTRRIOC_GET_PAGE_ENTRY:
if (copy_to_user(arg, &gentry, sizeof gentry))
err = -EFAULT;
break;
#ifdef CONFIG_COMPAT
case MTRRIOC32_GET_ENTRY:
case MTRRIOC32_GET_PAGE_ENTRY: {
struct mtrr_gentry32 __user *g32 = (struct mtrr_gentry32 __user *)__arg;
err = put_user(gentry.base, &g32->base);
err |= put_user(gentry.size, &g32->size);
err |= put_user(gentry.regnum, &g32->regnum);
err |= put_user(gentry.type, &g32->type);
break;
}
#endif
}
return err;
}
static int
mtrr_close(struct inode *ino, struct file *file)
{
int i, max;
unsigned int *fcount = FILE_FCOUNT(file);
if (fcount != NULL) {
max = num_var_ranges;
for (i = 0; i < max; ++i) {
while (fcount[i] > 0) {
mtrr_del(i, 0, 0);
--fcount[i];
}
}
kfree(fcount);
FILE_FCOUNT(file) = NULL;
}
return single_release(ino, file);
}
static int mtrr_seq_show(struct seq_file *seq, void *offset);
static int mtrr_open(struct inode *inode, struct file *file)
{
if (!mtrr_if)
return -EIO;
if (!mtrr_if->get)
return -ENXIO;
return single_open(file, mtrr_seq_show, NULL);
}
static const struct file_operations mtrr_fops = {
.owner = THIS_MODULE,
.open = mtrr_open,
.read = seq_read,
.llseek = seq_lseek,
.write = mtrr_write,
.unlocked_ioctl = mtrr_ioctl,
.compat_ioctl = mtrr_ioctl,
.release = mtrr_close,
};
static struct proc_dir_entry *proc_root_mtrr;
static int mtrr_seq_show(struct seq_file *seq, void *offset)
{
char factor;
int i, max, len;
mtrr_type type;
unsigned long base, size;
len = 0;
max = num_var_ranges;
for (i = 0; i < max; i++) {
mtrr_if->get(i, &base, &size, &type);
if (size == 0)
mtrr_usage_table[i] = 0;
else {
if (size < (0x100000 >> PAGE_SHIFT)) {
/* less than 1MB */
factor = 'K';
size <<= PAGE_SHIFT - 10;
} else {
factor = 'M';
size >>= 20 - PAGE_SHIFT;
}
/* RED-PEN: base can be > 32bit */
len += seq_printf(seq,
"reg%02i: base=0x%05lx000 (%4luMB), size=%4lu%cB: %s, count=%d\n",
i, base, base >> (20 - PAGE_SHIFT), size, factor,
mtrr_attrib_to_str(type), mtrr_usage_table[i]);
}
}
return 0;
}
static int __init mtrr_if_init(void)
{
struct cpuinfo_x86 *c = &boot_cpu_data;
if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
(!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
(!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
(!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
return -ENODEV;
proc_root_mtrr =
create_proc_entry("mtrr", S_IWUSR | S_IRUGO, &proc_root);
if (proc_root_mtrr) {
proc_root_mtrr->owner = THIS_MODULE;
proc_root_mtrr->proc_fops = &mtrr_fops;
}
return 0;
}
arch_initcall(mtrr_if_init);
#endif /* CONFIG_PROC_FS */
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