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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/capability.h>
   3 #include <linux/seq_file.h>
   4 #include <linux/uaccess.h>
   5 #include <linux/proc_fs.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         memset(&gentry, 0, sizeof(gentry));
 177
 178         switch (cmd) {
 179         case MTRRIOC_ADD_ENTRY:
 180         case MTRRIOC_SET_ENTRY:
 181         case MTRRIOC_DEL_ENTRY:
 182         case MTRRIOC_KILL_ENTRY:
 183         case MTRRIOC_ADD_PAGE_ENTRY:
 184         case MTRRIOC_SET_PAGE_ENTRY:
 185         case MTRRIOC_DEL_PAGE_ENTRY:
 186         case MTRRIOC_KILL_PAGE_ENTRY:
 187                 if (copy_from_user(&sentry, arg, sizeof sentry))
 188                         return -EFAULT;
 189                 break;
 190         case MTRRIOC_GET_ENTRY:
 191         case MTRRIOC_GET_PAGE_ENTRY:
 192                 if (copy_from_user(&gentry, arg, sizeof gentry))
 193                         return -EFAULT;
 194                 break;
 195 #ifdef CONFIG_COMPAT
 196         case MTRRIOC32_ADD_ENTRY:
 197         case MTRRIOC32_SET_ENTRY:
 198         case MTRRIOC32_DEL_ENTRY:
 199         case MTRRIOC32_KILL_ENTRY:
 200         case MTRRIOC32_ADD_PAGE_ENTRY:
 201         case MTRRIOC32_SET_PAGE_ENTRY:
 202         case MTRRIOC32_DEL_PAGE_ENTRY:
 203         case MTRRIOC32_KILL_PAGE_ENTRY: {
 204                 struct mtrr_sentry32 __user *s32;
 205
 206                 s32 = (struct mtrr_sentry32 __user *)__arg;
 207                 err = get_user(sentry.base, &s32->base);
 208                 err |= get_user(sentry.size, &s32->size);
 209                 err |= get_user(sentry.type, &s32->type);
 210                 if (err)
 211                         return err;
 212                 break;
 213         }
 214         case MTRRIOC32_GET_ENTRY:
 215         case MTRRIOC32_GET_PAGE_ENTRY: {
 216                 struct mtrr_gentry32 __user *g32;
 217
 218                 g32 = (struct mtrr_gentry32 __user *)__arg;
 219                 err = get_user(gentry.regnum, &g32->regnum);
 220                 err |= get_user(gentry.base, &g32->base);
 221                 err |= get_user(gentry.size, &g32->size);
 222                 err |= get_user(gentry.type, &g32->type);
 223                 if (err)
 224                         return err;
 225                 break;
 226         }
 227 #endif
 228         }
 229
 230         switch (cmd) {
 231         default:
 232                 return -ENOTTY;
 233         case MTRRIOC_ADD_ENTRY:
 234 #ifdef CONFIG_COMPAT
 235         case MTRRIOC32_ADD_ENTRY:
 236 #endif
 237                 if (!capable(CAP_SYS_ADMIN))
 238                         return -EPERM;
 239                 err =
 240                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 241                                   file, 0);
 242                 break;
 243         case MTRRIOC_SET_ENTRY:
 244 #ifdef CONFIG_COMPAT
 245         case MTRRIOC32_SET_ENTRY:
 246 #endif
 247                 if (!capable(CAP_SYS_ADMIN))
 248                         return -EPERM;
 249                 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
 250                 break;
 251         case MTRRIOC_DEL_ENTRY:
 252 #ifdef CONFIG_COMPAT
 253         case MTRRIOC32_DEL_ENTRY:
 254 #endif
 255                 if (!capable(CAP_SYS_ADMIN))
 256                         return -EPERM;
 257                 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
 258                 break;
 259         case MTRRIOC_KILL_ENTRY:
 260 #ifdef CONFIG_COMPAT
 261         case MTRRIOC32_KILL_ENTRY:
 262 #endif
 263                 if (!capable(CAP_SYS_ADMIN))
 264                         return -EPERM;
 265                 err = mtrr_del(-1, sentry.base, sentry.size);
 266                 break;
 267         case MTRRIOC_GET_ENTRY:
 268 #ifdef CONFIG_COMPAT
 269         case MTRRIOC32_GET_ENTRY:
 270 #endif
 271                 if (gentry.regnum >= num_var_ranges)
 272                         return -EINVAL;
 273                 mtrr_if->get(gentry.regnum, &base, &size, &type);
 274
 275                 /* Hide entries that go above 4GB */
 276                 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
 277                     || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
 278                         gentry.base = gentry.size = gentry.type = 0;
 279                 else {
 280                         gentry.base = base << PAGE_SHIFT;
 281                         gentry.size = size << PAGE_SHIFT;
 282                         gentry.type = type;
 283                 }
 284
 285                 break;
 286         case MTRRIOC_ADD_PAGE_ENTRY:
 287 #ifdef CONFIG_COMPAT
 288         case MTRRIOC32_ADD_PAGE_ENTRY:
 289 #endif
 290                 if (!capable(CAP_SYS_ADMIN))
 291                         return -EPERM;
 292                 err =
 293                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 294                                   file, 1);
 295                 break;
 296         case MTRRIOC_SET_PAGE_ENTRY:
 297 #ifdef CONFIG_COMPAT
 298         case MTRRIOC32_SET_PAGE_ENTRY:
 299 #endif
 300                 if (!capable(CAP_SYS_ADMIN))
 301                         return -EPERM;
 302                 err =
 303                     mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
 304                 break;
 305         case MTRRIOC_DEL_PAGE_ENTRY:
 306 #ifdef CONFIG_COMPAT
 307         case MTRRIOC32_DEL_PAGE_ENTRY:
 308 #endif
 309                 if (!capable(CAP_SYS_ADMIN))
 310                         return -EPERM;
 311                 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
 312                 break;
 313         case MTRRIOC_KILL_PAGE_ENTRY:
 314 #ifdef CONFIG_COMPAT
 315         case MTRRIOC32_KILL_PAGE_ENTRY:
 316 #endif
 317                 if (!capable(CAP_SYS_ADMIN))
 318                         return -EPERM;
 319                 err = mtrr_del_page(-1, sentry.base, sentry.size);
 320                 break;
 321         case MTRRIOC_GET_PAGE_ENTRY:
 322 #ifdef CONFIG_COMPAT
 323         case MTRRIOC32_GET_PAGE_ENTRY:
 324 #endif
 325                 if (gentry.regnum >= num_var_ranges)
 326                         return -EINVAL;
 327                 mtrr_if->get(gentry.regnum, &base, &size, &type);
 328                 /* Hide entries that would overflow */
 329                 if (size != (__typeof__(gentry.size))size)
 330                         gentry.base = gentry.size = gentry.type = 0;
 331                 else {
 332                         gentry.base = base;
 333                         gentry.size = size;
 334                         gentry.type = type;
 335                 }
 336                 break;
 337         }
 338
 339         if (err)
 340                 return err;
 341
 342         switch (cmd) {
 343         case MTRRIOC_GET_ENTRY:
 344         case MTRRIOC_GET_PAGE_ENTRY:
 345                 if (copy_to_user(arg, &gentry, sizeof gentry))
 346                         err = -EFAULT;
 347                 break;
 348 #ifdef CONFIG_COMPAT
 349         case MTRRIOC32_GET_ENTRY:
 350         case MTRRIOC32_GET_PAGE_ENTRY: {
 351                 struct mtrr_gentry32 __user *g32;
 352
 353                 g32 = (struct mtrr_gentry32 __user *)__arg;
 354                 err = put_user(gentry.base, &g32->base);
 355                 err |= put_user(gentry.size, &g32->size);
 356                 err |= put_user(gentry.regnum, &g32->regnum);
 357                 err |= put_user(gentry.type, &g32->type);
 358                 break;
 359         }
 360 #endif
 361         }
 362         return err;
 363 }
 364
 365 static int mtrr_close(struct inode *ino, struct file *file)
 366 {
 367         unsigned int *fcount = FILE_FCOUNT(file);
 368         int i, max;
 369
 370         if (fcount != NULL) {
 371                 max = num_var_ranges;
 372                 for (i = 0; i < max; ++i) {
 373                         while (fcount[i] > 0) {
 374                                 mtrr_del(i, 0, 0);
 375                                 --fcount[i];
 376                         }
 377                 }
 378                 kfree(fcount);
 379                 FILE_FCOUNT(file) = NULL;
 380         }
 381         return single_release(ino, file);
 382 }
 383
 384 static int mtrr_seq_show(struct seq_file *seq, void *offset);
 385
 386 static int mtrr_open(struct inode *inode, struct file *file)
 387 {
 388         if (!mtrr_if)
 389                 return -EIO;
 390         if (!mtrr_if->get)
 391                 return -ENXIO;
 392         return single_open(file, mtrr_seq_show, NULL);
 393 }
 394
 395 static const struct file_operations mtrr_fops = {
 396         .owner                  = THIS_MODULE,
 397         .open                   = mtrr_open,
 398         .read                   = seq_read,
 399         .llseek                 = seq_lseek,
 400         .write                  = mtrr_write,
 401         .unlocked_ioctl         = mtrr_ioctl,
 402         .compat_ioctl           = mtrr_ioctl,
 403         .release                = mtrr_close,
 404 };
 405
 406 static int mtrr_seq_show(struct seq_file *seq, void *offset)
 407 {
 408         char factor;
 409         int i, max;
 410         mtrr_type type;
 411         unsigned long base, size;
 412
 413         max = num_var_ranges;
 414         for (i = 0; i < max; i++) {
 415                 mtrr_if->get(i, &base, &size, &type);
 416                 if (size == 0) {
 417                         mtrr_usage_table[i] = 0;
 418                         continue;
 419                 }
 420                 if (size < (0x100000 >> PAGE_SHIFT)) {
 421                         /* less than 1MB */
 422                         factor = 'K';
 423                         size <<= PAGE_SHIFT - 10;
 424                 } else {
 425                         factor = 'M';
 426                         size >>= 20 - PAGE_SHIFT;
 427                 }
 428                 /* Base can be > 32bit */
 429                 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n",
 430                            i, base, base >> (20 - PAGE_SHIFT),
 431                            size, factor,
 432                            mtrr_usage_table[i], 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  */