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 = kcalloc(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         memset(line, 0, LINE_SIZE);
 105
 106         len = min_t(size_t, len, LINE_SIZE - 1);
 107         length = strncpy_from_user(line, buf, len);
 108         if (length < 0)
 109                 return length;
 110
 111         linelen = strlen(line);
 112         ptr = line + linelen - 1;
 113         if (linelen && *ptr == '\n')
 114                 *ptr = '\0';
 115
 116         if (!strncmp(line, "disable=", 8)) {
 117                 reg = simple_strtoul(line + 8, &ptr, 0);
 118                 err = mtrr_del_page(reg, 0, 0);
 119                 if (err < 0)
 120                         return err;
 121                 return len;
 122         }
 123
 124         if (strncmp(line, "base=", 5))
 125                 return -EINVAL;
 126
 127         base = simple_strtoull(line + 5, &ptr, 0);
 128         ptr = skip_spaces(ptr);
 129
 130         if (strncmp(ptr, "size=", 5))
 131                 return -EINVAL;
 132
 133         size = simple_strtoull(ptr + 5, &ptr, 0);
 134         if ((base & 0xfff) || (size & 0xfff))
 135                 return -EINVAL;
 136         ptr = skip_spaces(ptr);
 137
 138         if (strncmp(ptr, "type=", 5))
 139                 return -EINVAL;
 140         ptr = skip_spaces(ptr + 5);
 141
 142         i = match_string(mtrr_strings, MTRR_NUM_TYPES, ptr);
 143         if (i < 0)
 144                 return i;
 145
 146         base >>= PAGE_SHIFT;
 147         size >>= PAGE_SHIFT;
 148         err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true);
 149         if (err < 0)
 150                 return err;
 151         return len;
 152 }
 153
 154 static long
 155 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 156 {
 157         int err = 0;
 158         mtrr_type type;
 159         unsigned long base;
 160         unsigned long size;
 161         struct mtrr_sentry sentry;
 162         struct mtrr_gentry gentry;
 163         void __user *arg = (void __user *) __arg;
 164
 165         memset(&gentry, 0, sizeof(gentry));
 166
 167         switch (cmd) {
 168         case MTRRIOC_ADD_ENTRY:
 169         case MTRRIOC_SET_ENTRY:
 170         case MTRRIOC_DEL_ENTRY:
 171         case MTRRIOC_KILL_ENTRY:
 172         case MTRRIOC_ADD_PAGE_ENTRY:
 173         case MTRRIOC_SET_PAGE_ENTRY:
 174         case MTRRIOC_DEL_PAGE_ENTRY:
 175         case MTRRIOC_KILL_PAGE_ENTRY:
 176                 if (copy_from_user(&sentry, arg, sizeof(sentry)))
 177                         return -EFAULT;
 178                 break;
 179         case MTRRIOC_GET_ENTRY:
 180         case MTRRIOC_GET_PAGE_ENTRY:
 181                 if (copy_from_user(&gentry, arg, sizeof(gentry)))
 182                         return -EFAULT;
 183                 break;
 184 #ifdef CONFIG_COMPAT
 185         case MTRRIOC32_ADD_ENTRY:
 186         case MTRRIOC32_SET_ENTRY:
 187         case MTRRIOC32_DEL_ENTRY:
 188         case MTRRIOC32_KILL_ENTRY:
 189         case MTRRIOC32_ADD_PAGE_ENTRY:
 190         case MTRRIOC32_SET_PAGE_ENTRY:
 191         case MTRRIOC32_DEL_PAGE_ENTRY:
 192         case MTRRIOC32_KILL_PAGE_ENTRY: {
 193                 struct mtrr_sentry32 __user *s32;
 194
 195                 s32 = (struct mtrr_sentry32 __user *)__arg;
 196                 err = get_user(sentry.base, &s32->base);
 197                 err |= get_user(sentry.size, &s32->size);
 198                 err |= get_user(sentry.type, &s32->type);
 199                 if (err)
 200                         return err;
 201                 break;
 202         }
 203         case MTRRIOC32_GET_ENTRY:
 204         case MTRRIOC32_GET_PAGE_ENTRY: {
 205                 struct mtrr_gentry32 __user *g32;
 206
 207                 g32 = (struct mtrr_gentry32 __user *)__arg;
 208                 err = get_user(gentry.regnum, &g32->regnum);
 209                 err |= get_user(gentry.base, &g32->base);
 210                 err |= get_user(gentry.size, &g32->size);
 211                 err |= get_user(gentry.type, &g32->type);
 212                 if (err)
 213                         return err;
 214                 break;
 215         }
 216 #endif
 217         }
 218
 219         switch (cmd) {
 220         default:
 221                 return -ENOTTY;
 222         case MTRRIOC_ADD_ENTRY:
 223 #ifdef CONFIG_COMPAT
 224         case MTRRIOC32_ADD_ENTRY:
 225 #endif
 226                 err =
 227                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 228                                   file, 0);
 229                 break;
 230         case MTRRIOC_SET_ENTRY:
 231 #ifdef CONFIG_COMPAT
 232         case MTRRIOC32_SET_ENTRY:
 233 #endif
 234                 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
 235                 break;
 236         case MTRRIOC_DEL_ENTRY:
 237 #ifdef CONFIG_COMPAT
 238         case MTRRIOC32_DEL_ENTRY:
 239 #endif
 240                 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
 241                 break;
 242         case MTRRIOC_KILL_ENTRY:
 243 #ifdef CONFIG_COMPAT
 244         case MTRRIOC32_KILL_ENTRY:
 245 #endif
 246                 err = mtrr_del(-1, sentry.base, sentry.size);
 247                 break;
 248         case MTRRIOC_GET_ENTRY:
 249 #ifdef CONFIG_COMPAT
 250         case MTRRIOC32_GET_ENTRY:
 251 #endif
 252                 if (gentry.regnum >= num_var_ranges)
 253                         return -EINVAL;
 254                 mtrr_if->get(gentry.regnum, &base, &size, &type);
 255
 256                 /* Hide entries that go above 4GB */
 257                 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
 258                     || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
 259                         gentry.base = gentry.size = gentry.type = 0;
 260                 else {
 261                         gentry.base = base << PAGE_SHIFT;
 262                         gentry.size = size << PAGE_SHIFT;
 263                         gentry.type = type;
 264                 }
 265
 266                 break;
 267         case MTRRIOC_ADD_PAGE_ENTRY:
 268 #ifdef CONFIG_COMPAT
 269         case MTRRIOC32_ADD_PAGE_ENTRY:
 270 #endif
 271                 err =
 272                     mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
 273                                   file, 1);
 274                 break;
 275         case MTRRIOC_SET_PAGE_ENTRY:
 276 #ifdef CONFIG_COMPAT
 277         case MTRRIOC32_SET_PAGE_ENTRY:
 278 #endif
 279                 err =
 280                     mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
 281                 break;
 282         case MTRRIOC_DEL_PAGE_ENTRY:
 283 #ifdef CONFIG_COMPAT
 284         case MTRRIOC32_DEL_PAGE_ENTRY:
 285 #endif
 286                 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
 287                 break;
 288         case MTRRIOC_KILL_PAGE_ENTRY:
 289 #ifdef CONFIG_COMPAT
 290         case MTRRIOC32_KILL_PAGE_ENTRY:
 291 #endif
 292                 err = mtrr_del_page(-1, sentry.base, sentry.size);
 293                 break;
 294         case MTRRIOC_GET_PAGE_ENTRY:
 295 #ifdef CONFIG_COMPAT
 296         case MTRRIOC32_GET_PAGE_ENTRY:
 297 #endif
 298                 if (gentry.regnum >= num_var_ranges)
 299                         return -EINVAL;
 300                 mtrr_if->get(gentry.regnum, &base, &size, &type);
 301                 /* Hide entries that would overflow */
 302                 if (size != (__typeof__(gentry.size))size)
 303                         gentry.base = gentry.size = gentry.type = 0;
 304                 else {
 305                         gentry.base = base;
 306                         gentry.size = size;
 307                         gentry.type = type;
 308                 }
 309                 break;
 310         }
 311
 312         if (err)
 313                 return err;
 314
 315         switch (cmd) {
 316         case MTRRIOC_GET_ENTRY:
 317         case MTRRIOC_GET_PAGE_ENTRY:
 318                 if (copy_to_user(arg, &gentry, sizeof(gentry)))
 319                         err = -EFAULT;
 320                 break;
 321 #ifdef CONFIG_COMPAT
 322         case MTRRIOC32_GET_ENTRY:
 323         case MTRRIOC32_GET_PAGE_ENTRY: {
 324                 struct mtrr_gentry32 __user *g32;
 325
 326                 g32 = (struct mtrr_gentry32 __user *)__arg;
 327                 err = put_user(gentry.base, &g32->base);
 328                 err |= put_user(gentry.size, &g32->size);
 329                 err |= put_user(gentry.regnum, &g32->regnum);
 330                 err |= put_user(gentry.type, &g32->type);
 331                 break;
 332         }
 333 #endif
 334         }
 335         return err;
 336 }
 337
 338 static int mtrr_close(struct inode *ino, struct file *file)
 339 {
 340         unsigned int *fcount = FILE_FCOUNT(file);
 341         int i, max;
 342
 343         if (fcount != NULL) {
 344                 max = num_var_ranges;
 345                 for (i = 0; i < max; ++i) {
 346                         while (fcount[i] > 0) {
 347                                 mtrr_del(i, 0, 0);
 348                                 --fcount[i];
 349                         }
 350                 }
 351                 kfree(fcount);
 352                 FILE_FCOUNT(file) = NULL;
 353         }
 354         return single_release(ino, file);
 355 }
 356
 357 static int mtrr_seq_show(struct seq_file *seq, void *offset)
 358 {
 359         char factor;
 360         int i, max;
 361         mtrr_type type;
 362         unsigned long base, size;
 363
 364         max = num_var_ranges;
 365         for (i = 0; i < max; i++) {
 366                 mtrr_if->get(i, &base, &size, &type);
 367                 if (size == 0) {
 368                         mtrr_usage_table[i] = 0;
 369                         continue;
 370                 }
 371                 if (size < (0x100000 >> PAGE_SHIFT)) {
 372                         /* less than 1MB */
 373                         factor = 'K';
 374                         size <<= PAGE_SHIFT - 10;
 375                 } else {
 376                         factor = 'M';
 377                         size >>= 20 - PAGE_SHIFT;
 378                 }
 379                 /* Base can be > 32bit */
 380                 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n",
 381                            i, base, base >> (20 - PAGE_SHIFT),
 382                            size, factor,
 383                            mtrr_usage_table[i], mtrr_attrib_to_str(type));
 384         }
 385         return 0;
 386 }
 387
 388 static int mtrr_open(struct inode *inode, struct file *file)
 389 {
 390         if (!mtrr_if)
 391                 return -EIO;
 392         if (!mtrr_if->get)
 393                 return -ENXIO;
 394         if (!capable(CAP_SYS_ADMIN))
 395                 return -EPERM;
 396         return single_open(file, mtrr_seq_show, NULL);
 397 }
 398
 399 static const struct proc_ops mtrr_proc_ops = {
 400         .proc_open              = mtrr_open,
 401         .proc_read              = seq_read,
 402         .proc_lseek             = seq_lseek,
 403         .proc_write             = mtrr_write,
 404         .proc_ioctl             = mtrr_ioctl,
 405 #ifdef CONFIG_COMPAT
 406         .proc_compat_ioctl      = mtrr_ioctl,
 407 #endif
 408         .proc_release           = mtrr_close,
 409 };
 410
 411 static int __init mtrr_if_init(void)
 412 {
 413         struct cpuinfo_x86 *c = &boot_cpu_data;
 414
 415         if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
 416             (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
 417             (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
 418             (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
 419                 return -ENODEV;
 420
 421         proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_proc_ops);
 422         return 0;
 423 }
 424 arch_initcall(mtrr_if_init);
 425 #endif                  /*  CONFIG_PROC_FS  */