arch/x86/kernel/cpu/mtrr/if.c

   1 #include <linux/capability.h>
   2 #include <linux/seq_file.h>
   3 #include <linux/uaccess.h>
   4 #include <linux/proc_fs.h>
   5 #include <linux/module.h>
   6 #include <linux/ctype.h>
   7 #include <linux/string.h>
   8 #include <linux/slab.h>
   9 #include <linux/init.h>
  10
  11 #define LINE_SIZE 80
  12
  13 #include <asm/mtrr.h>
  14
  15 #include "mtrr.h"
  16
  17 #define FILE_FCOUNT(f) (((struct seq_file *)((f)->private_data))->private)
  18
  19 static const char *const mtrr_strings[MTRR_NUM_TYPES] =
  20 {
  21         "uncachable",           /* 0 */
  22         "write-combining",      /* 1 */
  23         "?",                    /* 2 */
  24         "?",                    /* 3 */
  25         "write-through",        /* 4 */
  26         "write-protect",        /* 5 */
  27         "write-back",           /* 6 */
  28 };
  29
  30 const char *mtrr_attrib_to_str(int x)
  31 {
  32         return (x <= 6) ? mtrr_strings[x] : "?";
  33 }
  34
  35 #ifdef CONFIG_PROC_FS
  36
  37 static int
  38 mtrr_file_add(unsigned long base, unsigned long size,
  39               unsigned int type, bool increment, struct file *file, int page)
  40 {
  41         unsigned int *fcount = FILE_FCOUNT(file);
  42         int reg, max;
  43
  44         max = num_var_ranges;
  45         if (fcount == NULL) {
  46                 fcount = kzalloc(max * sizeof *fcount, GFP_KERNEL);
  47                 if (!fcount)
  48                         return -ENOMEM;
  49                 FILE_FCOUNT(file) = fcount;
  50         }
  51         if (!page) {
  52                 if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
  53                         return -EINVAL;
  54                 base >>= PAGE_SHIFT;
  55                 size >>= PAGE_SHIFT;
  56         }
  57         reg = mtrr_add_page(base, size, type, true);
  58         if (reg >= 0)
  59                 ++fcount[reg];
  60         return reg;
  61 }
  62
  63 static int
  64 mtrr_file_del(unsigned long base, unsigned long size,
  65               struct file *file, int page)
  66 {
  67         unsigned int *fcount = FILE_FCOUNT(file);
  68         int reg;
  69
  70         if (!page) {
  71                 if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
  72                         return -EINVAL;
  73                 base >>= PAGE_SHIFT;
  74                 size >>= PAGE_SHIFT;
  75         }
  76         reg = mtrr_del_page(-1, base, size);
  77         if (reg < 0)
  78                 return reg;
  79         if (fcount == NULL)
  80                 return reg;
  81         if (fcount[reg] < 1)
  82                 return -EINVAL;
  83         --fcount[reg];
  84         return reg;
  85 }
  86
  87 /*
  88  * seq_file can seek but we ignore it.
  89  *
  90  * Format of control line:
  91  *    "base=%Lx size=%Lx type=%s" or "disable=%d"
  92  */
  93 static ssize_t
  94 mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
  95 {
  96         int i, err;
  97         unsigned long reg;
  98         unsigned long long base, size;
  99         char *ptr;
 100         char line[LINE_SIZE];
 101         int length;
 102         size_t linelen;
 103
 104         if (!capable(CAP_SYS_ADMIN))
 105                 return -EPERM;
 106
 107         memset(line, 0, LINE_SIZE);
 108
 109         length = len;
 110         length--;
 111
 112         if (length > LINE_SIZE - 1)
 113                 length = LINE_SIZE - 1;
 114
 115         if (length < 0)
 116                 return -EINVAL;
 117
 118         if (copy_from_user(line, buf, length))
 119                 return -EFAULT;
 120
 121         linelen = strlen(line);
 122         ptr = line + linelen - 1;
 123         if (linelen && *ptr == '\n')
 124                 *ptr = '\0';
 125
 126         if (!strncmp(line, "disable=", 8)) {
 127                 reg = simple_strtoul(line + 8, &ptr, 0);
 128                 err = mtrr_del_page(reg, 0, 0);
 129                 if (err < 0)
 130                         return err;
 131                 return len;
 132         }
 133
 134         if (strncmp(line, "base=", 5))
 135                 return -EINVAL;
 136
 137         base = simple_strtoull(line + 5, &ptr, 0);
 138         ptr = skip_spaces(ptr);
 139
 140         if (strncmp(ptr, "size=", 5))
 141                 return -EINVAL;
 142
 143         size = simple_strtoull(ptr + 5, &ptr, 0);
 144         if ((base & 0xfff) || (size & 0xfff))
 145                 return -EINVAL;
 146         ptr = skip_spaces(ptr);
 147
 148         if (strncmp(ptr, "type=", 5))
 149                 return -EINVAL;
 150         ptr = skip_spaces(ptr + 5);
 151
 152         for (i = 0; i < MTRR_NUM_TYPES; ++i) {
 153                 if (strcmp(ptr, mtrr_strings[i]))
 154                         continue;
 155                 base >>= PAGE_SHIFT;
 156                 size >>= PAGE_SHIFT;
 157                 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true);
 158                 if (err < 0)
 159                         return err;
 160                 return len;
 161         }
 162         return -EINVAL;
 163 }
 164
 165 static long
 166 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 167 {
 168         int err = 0;
 169         mtrr_type type;
 170         unsigned long base;
 171         unsigned long size;
 172         struct mtrr_sentry sentry;
 173         struct mtrr_gentry gentry;
 174         void __user *arg = (void __user *) __arg;
 175
 176         switch (cmd) {
 177         case MTRRIOC_ADD_ENTRY:
 178         case MTRRIOC_SET_ENTRY:
 179         case MTRRIOC_DEL_ENTRY:
 180         case MTRRIOC_KILL_ENTRY:
 181         case MTRRIOC_ADD_PAGE_ENTRY:
 182         case MTRRIOC_SET_PAGE_ENTRY:
 183         case MTRRIOC_DEL_PAGE_ENTRY:
 184         case MTRRIOC_KILL_PAGE_ENTRY:
 185                 if (copy_from_user(&sentry, arg, sizeof sentry))
 186                         return -EFAULT;
 187                 break;
 188         case MTRRIOC_GET_ENTRY:
 189         case MTRRIOC_GET_PAGE_ENTRY:
 190                 if (copy_from_user(&gentry, arg, sizeof gentry))
 191                         return -EFAULT;
 192                 break;
 193 #ifdef CONFIG_COMPAT
 194         case MTRRIOC32_ADD_ENTRY:
 195         case MTRRIOC32_SET_ENTRY:
 196         case MTRRIOC32_DEL_ENTRY:
 197         case MTRRIOC32_KILL_ENTRY:
 198         case MTRRIOC32_ADD_PAGE_ENTRY:
 199         case MTRRIOC32_SET_PAGE_ENTRY:
 200         case MTRRIOC32_DEL_PAGE_ENTRY:
 201         case MTRRIOC32_KILL_PAGE_ENTRY: {
 202                 struct mtrr_sentry32 __user *s32;
 203
 204                 s32 = (struct mtrr_sentry32 __user *)__arg;
 205                 err = get_user(sentry.base, &s32->base);
 206                 err |= get_user(sentry.size, &s32->size);
 207                 err |= get_user(sentry.type, &s32->type);
 208                 if (err)
 209                         return err;
 210                 break;
 211         }
 212         case MTRRIOC32_GET_ENTRY:
 213         case MTRRIOC32_GET_PAGE_ENTRY: {
 214                 struct mtrr_gentry32 __user *g32;
 215
 216                 g32 = (struct mtrr_gentry32 __user *)__arg;
 217                 err = get_user(gentry.regnum, &g32->regnum);
 218                 err |= get_user(gentry.base, &g32->base);
 219                 err |= get_user(gentry.size, &g32->size);
 220                 err |= get_user(gentry.type, &g32->type);
 221                 if (err)
 222                         return err;
 223                 break;
 224         }
 225 #endif
 226         }
 227
 228         switch (cmd) {
 229         default:
 230                 return -ENOTTY;
 231         case MTRRIOC_ADD_ENTRY:
 232 #ifdef CONFIG_COMPAT
 233         case MTRRIOC32_ADD_ENTRY:
 234 #endif
 235                 if (!capable(CAP_SYS_ADMIN))
 236                         return -EPERM;
 237                 err =
 238                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 239                                   file, 0);
 240                 break;
 241         case MTRRIOC_SET_ENTRY:
 242 #ifdef CONFIG_COMPAT
 243         case MTRRIOC32_SET_ENTRY:
 244 #endif
 245                 if (!capable(CAP_SYS_ADMIN))
 246                         return -EPERM;
 247                 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
 248                 break;
 249         case MTRRIOC_DEL_ENTRY:
 250 #ifdef CONFIG_COMPAT
 251         case MTRRIOC32_DEL_ENTRY:
 252 #endif
 253                 if (!capable(CAP_SYS_ADMIN))
 254                         return -EPERM;
 255                 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
 256                 break;
 257         case MTRRIOC_KILL_ENTRY:
 258 #ifdef CONFIG_COMPAT
 259         case MTRRIOC32_KILL_ENTRY:
 260 #endif
 261                 if (!capable(CAP_SYS_ADMIN))
 262                         return -EPERM;
 263                 err = mtrr_del(-1, sentry.base, sentry.size);
 264                 break;
 265         case MTRRIOC_GET_ENTRY:
 266 #ifdef CONFIG_COMPAT
 267         case MTRRIOC32_GET_ENTRY:
 268 #endif
 269                 if (gentry.regnum >= num_var_ranges)
 270                         return -EINVAL;
 271                 mtrr_if->get(gentry.regnum, &base, &size, &type);
 272
 273                 /* Hide entries that go above 4GB */
 274                 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
 275                     || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
 276                         gentry.base = gentry.size = gentry.type = 0;
 277                 else {
 278                         gentry.base = base << PAGE_SHIFT;
 279                         gentry.size = size << PAGE_SHIFT;
 280                         gentry.type = type;
 281                 }
 282
 283                 break;
 284         case MTRRIOC_ADD_PAGE_ENTRY:
 285 #ifdef CONFIG_COMPAT
 286         case MTRRIOC32_ADD_PAGE_ENTRY:
 287 #endif
 288                 if (!capable(CAP_SYS_ADMIN))
 289                         return -EPERM;
 290                 err =
 291                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 292                                   file, 1);
 293                 break;
 294         case MTRRIOC_SET_PAGE_ENTRY:
 295 #ifdef CONFIG_COMPAT
 296         case MTRRIOC32_SET_PAGE_ENTRY:
 297 #endif
 298                 if (!capable(CAP_SYS_ADMIN))
 299                         return -EPERM;
 300                 err =
 301                     mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
 302                 break;
 303         case MTRRIOC_DEL_PAGE_ENTRY:
 304 #ifdef CONFIG_COMPAT
 305         case MTRRIOC32_DEL_PAGE_ENTRY:
 306 #endif
 307                 if (!capable(CAP_SYS_ADMIN))
 308                         return -EPERM;
 309                 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
 310                 break;
 311         case MTRRIOC_KILL_PAGE_ENTRY:
 312 #ifdef CONFIG_COMPAT
 313         case MTRRIOC32_KILL_PAGE_ENTRY:
 314 #endif
 315                 if (!capable(CAP_SYS_ADMIN))
 316                         return -EPERM;
 317                 err = mtrr_del_page(-1, sentry.base, sentry.size);
 318                 break;
 319         case MTRRIOC_GET_PAGE_ENTRY:
 320 #ifdef CONFIG_COMPAT
 321         case MTRRIOC32_GET_PAGE_ENTRY:
 322 #endif
 323                 if (gentry.regnum >= num_var_ranges)
 324                         return -EINVAL;
 325                 mtrr_if->get(gentry.regnum, &base, &size, &type);
 326                 /* Hide entries that would overflow */
 327                 if (size != (__typeof__(gentry.size))size)
 328                         gentry.base = gentry.size = gentry.type = 0;
 329                 else {
 330                         gentry.base = base;
 331                         gentry.size = size;
 332                         gentry.type = type;
 333                 }
 334                 break;
 335         }
 336
 337         if (err)
 338                 return err;
 339
 340         switch (cmd) {
 341         case MTRRIOC_GET_ENTRY:
 342         case MTRRIOC_GET_PAGE_ENTRY:
 343                 if (copy_to_user(arg, &gentry, sizeof gentry))
 344                         err = -EFAULT;
 345                 break;
 346 #ifdef CONFIG_COMPAT
 347         case MTRRIOC32_GET_ENTRY:
 348         case MTRRIOC32_GET_PAGE_ENTRY: {
 349                 struct mtrr_gentry32 __user *g32;
 350
 351                 g32 = (struct mtrr_gentry32 __user *)__arg;
 352                 err = put_user(gentry.base, &g32->base);
 353                 err |= put_user(gentry.size, &g32->size);
 354                 err |= put_user(gentry.regnum, &g32->regnum);
 355                 err |= put_user(gentry.type, &g32->type);
 356                 break;
 357         }
 358 #endif
 359         }
 360         return err;
 361 }
 362
 363 static int mtrr_close(struct inode *ino, struct file *file)
 364 {
 365         unsigned int *fcount = FILE_FCOUNT(file);
 366         int i, max;
 367
 368         if (fcount != NULL) {
 369                 max = num_var_ranges;
 370                 for (i = 0; i < max; ++i) {
 371                         while (fcount[i] > 0) {
 372                                 mtrr_del(i, 0, 0);
 373                                 --fcount[i];
 374                         }
 375                 }
 376                 kfree(fcount);
 377                 FILE_FCOUNT(file) = NULL;
 378         }
 379         return single_release(ino, file);
 380 }
 381
 382 static int mtrr_seq_show(struct seq_file *seq, void *offset);
 383
 384 static int mtrr_open(struct inode *inode, struct file *file)
 385 {
 386         if (!mtrr_if)
 387                 return -EIO;
 388         if (!mtrr_if->get)
 389                 return -ENXIO;
 390         return single_open(file, mtrr_seq_show, NULL);
 391 }
 392
 393 static const struct file_operations mtrr_fops = {
 394         .owner                  = THIS_MODULE,
 395         .open                   = mtrr_open,
 396         .read                   = seq_read,
 397         .llseek                 = seq_lseek,
 398         .write                  = mtrr_write,
 399         .unlocked_ioctl         = mtrr_ioctl,
 400         .compat_ioctl           = mtrr_ioctl,
 401         .release                = mtrr_close,
 402 };
 403
 404 static int mtrr_seq_show(struct seq_file *seq, void *offset)
 405 {
 406         char factor;
 407         int i, max, len;
 408         mtrr_type type;
 409         unsigned long base, size;
 410
 411         len = 0;
 412         max = num_var_ranges;
 413         for (i = 0; i < max; i++) {
 414                 mtrr_if->get(i, &base, &size, &type);
 415                 if (size == 0) {
 416                         mtrr_usage_table[i] = 0;
 417                         continue;
 418                 }
 419                 if (size < (0x100000 >> PAGE_SHIFT)) {
 420                         /* less than 1MB */
 421                         factor = 'K';
 422                         size <<= PAGE_SHIFT - 10;
 423                 } else {
 424                         factor = 'M';
 425                         size >>= 20 - PAGE_SHIFT;
 426                 }
 427                 /* Base can be > 32bit */
 428                 len += seq_printf(seq, "reg%02i: base=0x%06lx000 "
 429                         "(%5luMB), size=%5lu%cB, count=%d: %s\n",
 430                         i, base, base >> (20 - PAGE_SHIFT), size,
 431                         factor, mtrr_usage_table[i],
 432                         mtrr_attrib_to_str(type));
 433         }
 434         return 0;
 435 }
 436
 437 static int __init mtrr_if_init(void)
 438 {
 439         struct cpuinfo_x86 *c = &boot_cpu_data;
 440
 441         if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
 442             (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
 443             (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
 444             (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
 445                 return -ENODEV;
 446
 447         proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
 448         return 0;
 449 }
 450 arch_initcall(mtrr_if_init);
 451 #endif                  /*  CONFIG_PROC_FS  */