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 size;
 171         struct mtrr_sentry sentry;
 172         struct mtrr_gentry gentry;
 173         void __user *arg = (void __user *) __arg;
 174
 175         switch (cmd) {
 176         case MTRRIOC_ADD_ENTRY:
 177         case MTRRIOC_SET_ENTRY:
 178         case MTRRIOC_DEL_ENTRY:
 179         case MTRRIOC_KILL_ENTRY:
 180         case MTRRIOC_ADD_PAGE_ENTRY:
 181         case MTRRIOC_SET_PAGE_ENTRY:
 182         case MTRRIOC_DEL_PAGE_ENTRY:
 183         case MTRRIOC_KILL_PAGE_ENTRY:
 184                 if (copy_from_user(&sentry, arg, sizeof sentry))
 185                         return -EFAULT;
 186                 break;
 187         case MTRRIOC_GET_ENTRY:
 188         case MTRRIOC_GET_PAGE_ENTRY:
 189                 if (copy_from_user(&gentry, arg, sizeof gentry))
 190                         return -EFAULT;
 191                 break;
 192 #ifdef CONFIG_COMPAT
 193         case MTRRIOC32_ADD_ENTRY:
 194         case MTRRIOC32_SET_ENTRY:
 195         case MTRRIOC32_DEL_ENTRY:
 196         case MTRRIOC32_KILL_ENTRY:
 197         case MTRRIOC32_ADD_PAGE_ENTRY:
 198         case MTRRIOC32_SET_PAGE_ENTRY:
 199         case MTRRIOC32_DEL_PAGE_ENTRY:
 200         case MTRRIOC32_KILL_PAGE_ENTRY: {
 201                 struct mtrr_sentry32 __user *s32;
 202
 203                 s32 = (struct mtrr_sentry32 __user *)__arg;
 204                 err = get_user(sentry.base, &s32->base);
 205                 err |= get_user(sentry.size, &s32->size);
 206                 err |= get_user(sentry.type, &s32->type);
 207                 if (err)
 208                         return err;
 209                 break;
 210         }
 211         case MTRRIOC32_GET_ENTRY:
 212         case MTRRIOC32_GET_PAGE_ENTRY: {
 213                 struct mtrr_gentry32 __user *g32;
 214
 215                 g32 = (struct mtrr_gentry32 __user *)__arg;
 216                 err = get_user(gentry.regnum, &g32->regnum);
 217                 err |= get_user(gentry.base, &g32->base);
 218                 err |= get_user(gentry.size, &g32->size);
 219                 err |= get_user(gentry.type, &g32->type);
 220                 if (err)
 221                         return err;
 222                 break;
 223         }
 224 #endif
 225         }
 226
 227         switch (cmd) {
 228         default:
 229                 return -ENOTTY;
 230         case MTRRIOC_ADD_ENTRY:
 231 #ifdef CONFIG_COMPAT
 232         case MTRRIOC32_ADD_ENTRY:
 233 #endif
 234                 if (!capable(CAP_SYS_ADMIN))
 235                         return -EPERM;
 236                 err =
 237                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 238                                   file, 0);
 239                 break;
 240         case MTRRIOC_SET_ENTRY:
 241 #ifdef CONFIG_COMPAT
 242         case MTRRIOC32_SET_ENTRY:
 243 #endif
 244                 if (!capable(CAP_SYS_ADMIN))
 245                         return -EPERM;
 246                 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
 247                 break;
 248         case MTRRIOC_DEL_ENTRY:
 249 #ifdef CONFIG_COMPAT
 250         case MTRRIOC32_DEL_ENTRY:
 251 #endif
 252                 if (!capable(CAP_SYS_ADMIN))
 253                         return -EPERM;
 254                 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
 255                 break;
 256         case MTRRIOC_KILL_ENTRY:
 257 #ifdef CONFIG_COMPAT
 258         case MTRRIOC32_KILL_ENTRY:
 259 #endif
 260                 if (!capable(CAP_SYS_ADMIN))
 261                         return -EPERM;
 262                 err = mtrr_del(-1, sentry.base, sentry.size);
 263                 break;
 264         case MTRRIOC_GET_ENTRY:
 265 #ifdef CONFIG_COMPAT
 266         case MTRRIOC32_GET_ENTRY:
 267 #endif
 268                 if (gentry.regnum >= num_var_ranges)
 269                         return -EINVAL;
 270                 mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
 271
 272                 /* Hide entries that go above 4GB */
 273                 if (gentry.base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
 274                     || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
 275                         gentry.base = gentry.size = gentry.type = 0;
 276                 else {
 277                         gentry.base <<= PAGE_SHIFT;
 278                         gentry.size = size << PAGE_SHIFT;
 279                         gentry.type = type;
 280                 }
 281
 282                 break;
 283         case MTRRIOC_ADD_PAGE_ENTRY:
 284 #ifdef CONFIG_COMPAT
 285         case MTRRIOC32_ADD_PAGE_ENTRY:
 286 #endif
 287                 if (!capable(CAP_SYS_ADMIN))
 288                         return -EPERM;
 289                 err =
 290                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 291                                   file, 1);
 292                 break;
 293         case MTRRIOC_SET_PAGE_ENTRY:
 294 #ifdef CONFIG_COMPAT
 295         case MTRRIOC32_SET_PAGE_ENTRY:
 296 #endif
 297                 if (!capable(CAP_SYS_ADMIN))
 298                         return -EPERM;
 299                 err =
 300                     mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
 301                 break;
 302         case MTRRIOC_DEL_PAGE_ENTRY:
 303 #ifdef CONFIG_COMPAT
 304         case MTRRIOC32_DEL_PAGE_ENTRY:
 305 #endif
 306                 if (!capable(CAP_SYS_ADMIN))
 307                         return -EPERM;
 308                 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
 309                 break;
 310         case MTRRIOC_KILL_PAGE_ENTRY:
 311 #ifdef CONFIG_COMPAT
 312         case MTRRIOC32_KILL_PAGE_ENTRY:
 313 #endif
 314                 if (!capable(CAP_SYS_ADMIN))
 315                         return -EPERM;
 316                 err = mtrr_del_page(-1, sentry.base, sentry.size);
 317                 break;
 318         case MTRRIOC_GET_PAGE_ENTRY:
 319 #ifdef CONFIG_COMPAT
 320         case MTRRIOC32_GET_PAGE_ENTRY:
 321 #endif
 322                 if (gentry.regnum >= num_var_ranges)
 323                         return -EINVAL;
 324                 mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
 325                 /* Hide entries that would overflow */
 326                 if (size != (__typeof__(gentry.size))size)
 327                         gentry.base = gentry.size = gentry.type = 0;
 328                 else {
 329                         gentry.size = size;
 330                         gentry.type = type;
 331                 }
 332                 break;
 333         }
 334
 335         if (err)
 336                 return err;
 337
 338         switch (cmd) {
 339         case MTRRIOC_GET_ENTRY:
 340         case MTRRIOC_GET_PAGE_ENTRY:
 341                 if (copy_to_user(arg, &gentry, sizeof gentry))
 342                         err = -EFAULT;
 343                 break;
 344 #ifdef CONFIG_COMPAT
 345         case MTRRIOC32_GET_ENTRY:
 346         case MTRRIOC32_GET_PAGE_ENTRY: {
 347                 struct mtrr_gentry32 __user *g32;
 348
 349                 g32 = (struct mtrr_gentry32 __user *)__arg;
 350                 err = put_user(gentry.base, &g32->base);
 351                 err |= put_user(gentry.size, &g32->size);
 352                 err |= put_user(gentry.regnum, &g32->regnum);
 353                 err |= put_user(gentry.type, &g32->type);
 354                 break;
 355         }
 356 #endif
 357         }
 358         return err;
 359 }
 360
 361 static int mtrr_close(struct inode *ino, struct file *file)
 362 {
 363         unsigned int *fcount = FILE_FCOUNT(file);
 364         int i, max;
 365
 366         if (fcount != NULL) {
 367                 max = num_var_ranges;
 368                 for (i = 0; i < max; ++i) {
 369                         while (fcount[i] > 0) {
 370                                 mtrr_del(i, 0, 0);
 371                                 --fcount[i];
 372                         }
 373                 }
 374                 kfree(fcount);
 375                 FILE_FCOUNT(file) = NULL;
 376         }
 377         return single_release(ino, file);
 378 }
 379
 380 static int mtrr_seq_show(struct seq_file *seq, void *offset);
 381
 382 static int mtrr_open(struct inode *inode, struct file *file)
 383 {
 384         if (!mtrr_if)
 385                 return -EIO;
 386         if (!mtrr_if->get)
 387                 return -ENXIO;
 388         return single_open(file, mtrr_seq_show, NULL);
 389 }
 390
 391 static const struct file_operations mtrr_fops = {
 392         .owner                  = THIS_MODULE,
 393         .open                   = mtrr_open,
 394         .read                   = seq_read,
 395         .llseek                 = seq_lseek,
 396         .write                  = mtrr_write,
 397         .unlocked_ioctl         = mtrr_ioctl,
 398         .compat_ioctl           = mtrr_ioctl,
 399         .release                = mtrr_close,
 400 };
 401
 402 static int mtrr_seq_show(struct seq_file *seq, void *offset)
 403 {
 404         char factor;
 405         int i, max, len;
 406         mtrr_type type;
 407         unsigned long base, size;
 408
 409         len = 0;
 410         max = num_var_ranges;
 411         for (i = 0; i < max; i++) {
 412                 mtrr_if->get(i, &base, &size, &type);
 413                 if (size == 0) {
 414                         mtrr_usage_table[i] = 0;
 415                         continue;
 416                 }
 417                 if (size < (0x100000 >> PAGE_SHIFT)) {
 418                         /* less than 1MB */
 419                         factor = 'K';
 420                         size <<= PAGE_SHIFT - 10;
 421                 } else {
 422                         factor = 'M';
 423                         size >>= 20 - PAGE_SHIFT;
 424                 }
 425                 /* Base can be > 32bit */
 426                 len += seq_printf(seq, "reg%02i: base=0x%06lx000 "
 427                         "(%5luMB), size=%5lu%cB, count=%d: %s\n",
 428                         i, base, base >> (20 - PAGE_SHIFT), size,
 429                         factor, mtrr_usage_table[i],
 430                         mtrr_attrib_to_str(type));
 431         }
 432         return 0;
 433 }
 434
 435 static int __init mtrr_if_init(void)
 436 {
 437         struct cpuinfo_x86 *c = &boot_cpu_data;
 438
 439         if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
 440             (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
 441             (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
 442             (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
 443                 return -ENODEV;
 444
 445         proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
 446         return 0;
 447 }
 448 arch_initcall(mtrr_if_init);
 449 #endif                  /*  CONFIG_PROC_FS  */