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 if (!capable(CAP_SYS_ADMIN)) 105 return -EPERM; 106 107 memset(line, 0, LINE_SIZE); 108 109 length = strncpy_from_user(line, buf, LINE_SIZE - 1); 110 if (length < 0) 111 return length; 112 113 linelen = strlen(line); 114 ptr = line + linelen - 1; 115 if (linelen && *ptr == '\n') 116 *ptr = '\0'; 117 118 if (!strncmp(line, "disable=", 8)) { 119 reg = simple_strtoul(line + 8, &ptr, 0); 120 err = mtrr_del_page(reg, 0, 0); 121 if (err < 0) 122 return err; 123 return len; 124 } 125 126 if (strncmp(line, "base=", 5)) 127 return -EINVAL; 128 129 base = simple_strtoull(line + 5, &ptr, 0); 130 ptr = skip_spaces(ptr); 131 132 if (strncmp(ptr, "size=", 5)) 133 return -EINVAL; 134 135 size = simple_strtoull(ptr + 5, &ptr, 0); 136 if ((base & 0xfff) || (size & 0xfff)) 137 return -EINVAL; 138 ptr = skip_spaces(ptr); 139 140 if (strncmp(ptr, "type=", 5)) 141 return -EINVAL; 142 ptr = skip_spaces(ptr + 5); 143 144 i = match_string(mtrr_strings, MTRR_NUM_TYPES, ptr); 145 if (i < 0) 146 return i; 147 148 base >>= PAGE_SHIFT; 149 size >>= PAGE_SHIFT; 150 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true); 151 if (err < 0) 152 return err; 153 return len; 154 } 155 156 static long 157 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg) 158 { 159 int err = 0; 160 mtrr_type type; 161 unsigned long base; 162 unsigned long size; 163 struct mtrr_sentry sentry; 164 struct mtrr_gentry gentry; 165 void __user *arg = (void __user *) __arg; 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 if (!capable(CAP_SYS_ADMIN)) 227 return -EPERM; 228 err = 229 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 230 file, 0); 231 break; 232 case MTRRIOC_SET_ENTRY: 233 #ifdef CONFIG_COMPAT 234 case MTRRIOC32_SET_ENTRY: 235 #endif 236 if (!capable(CAP_SYS_ADMIN)) 237 return -EPERM; 238 err = mtrr_add(sentry.base, sentry.size, sentry.type, false); 239 break; 240 case MTRRIOC_DEL_ENTRY: 241 #ifdef CONFIG_COMPAT 242 case MTRRIOC32_DEL_ENTRY: 243 #endif 244 if (!capable(CAP_SYS_ADMIN)) 245 return -EPERM; 246 err = mtrr_file_del(sentry.base, sentry.size, file, 0); 247 break; 248 case MTRRIOC_KILL_ENTRY: 249 #ifdef CONFIG_COMPAT 250 case MTRRIOC32_KILL_ENTRY: 251 #endif 252 if (!capable(CAP_SYS_ADMIN)) 253 return -EPERM; 254 err = mtrr_del(-1, sentry.base, sentry.size); 255 break; 256 case MTRRIOC_GET_ENTRY: 257 #ifdef CONFIG_COMPAT 258 case MTRRIOC32_GET_ENTRY: 259 #endif 260 if (gentry.regnum >= num_var_ranges) 261 return -EINVAL; 262 mtrr_if->get(gentry.regnum, &base, &size, &type); 263 264 /* Hide entries that go above 4GB */ 265 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)) 266 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))) 267 gentry.base = gentry.size = gentry.type = 0; 268 else { 269 gentry.base = base << PAGE_SHIFT; 270 gentry.size = size << PAGE_SHIFT; 271 gentry.type = type; 272 } 273 274 break; 275 case MTRRIOC_ADD_PAGE_ENTRY: 276 #ifdef CONFIG_COMPAT 277 case MTRRIOC32_ADD_PAGE_ENTRY: 278 #endif 279 if (!capable(CAP_SYS_ADMIN)) 280 return -EPERM; 281 err = 282 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 283 file, 1); 284 break; 285 case MTRRIOC_SET_PAGE_ENTRY: 286 #ifdef CONFIG_COMPAT 287 case MTRRIOC32_SET_PAGE_ENTRY: 288 #endif 289 if (!capable(CAP_SYS_ADMIN)) 290 return -EPERM; 291 err = 292 mtrr_add_page(sentry.base, sentry.size, sentry.type, false); 293 break; 294 case MTRRIOC_DEL_PAGE_ENTRY: 295 #ifdef CONFIG_COMPAT 296 case MTRRIOC32_DEL_PAGE_ENTRY: 297 #endif 298 if (!capable(CAP_SYS_ADMIN)) 299 return -EPERM; 300 err = mtrr_file_del(sentry.base, sentry.size, file, 1); 301 break; 302 case MTRRIOC_KILL_PAGE_ENTRY: 303 #ifdef CONFIG_COMPAT 304 case MTRRIOC32_KILL_PAGE_ENTRY: 305 #endif 306 if (!capable(CAP_SYS_ADMIN)) 307 return -EPERM; 308 err = mtrr_del_page(-1, sentry.base, sentry.size); 309 break; 310 case MTRRIOC_GET_PAGE_ENTRY: 311 #ifdef CONFIG_COMPAT 312 case MTRRIOC32_GET_PAGE_ENTRY: 313 #endif 314 if (gentry.regnum >= num_var_ranges) 315 return -EINVAL; 316 mtrr_if->get(gentry.regnum, &base, &size, &type); 317 /* Hide entries that would overflow */ 318 if (size != (__typeof__(gentry.size))size) 319 gentry.base = gentry.size = gentry.type = 0; 320 else { 321 gentry.base = base; 322 gentry.size = size; 323 gentry.type = type; 324 } 325 break; 326 } 327 328 if (err) 329 return err; 330 331 switch (cmd) { 332 case MTRRIOC_GET_ENTRY: 333 case MTRRIOC_GET_PAGE_ENTRY: 334 if (copy_to_user(arg, &gentry, sizeof gentry)) 335 err = -EFAULT; 336 break; 337 #ifdef CONFIG_COMPAT 338 case MTRRIOC32_GET_ENTRY: 339 case MTRRIOC32_GET_PAGE_ENTRY: { 340 struct mtrr_gentry32 __user *g32; 341 342 g32 = (struct mtrr_gentry32 __user *)__arg; 343 err = put_user(gentry.base, &g32->base); 344 err |= put_user(gentry.size, &g32->size); 345 err |= put_user(gentry.regnum, &g32->regnum); 346 err |= put_user(gentry.type, &g32->type); 347 break; 348 } 349 #endif 350 } 351 return err; 352 } 353 354 static int mtrr_close(struct inode *ino, struct file *file) 355 { 356 unsigned int *fcount = FILE_FCOUNT(file); 357 int i, max; 358 359 if (fcount != NULL) { 360 max = num_var_ranges; 361 for (i = 0; i < max; ++i) { 362 while (fcount[i] > 0) { 363 mtrr_del(i, 0, 0); 364 --fcount[i]; 365 } 366 } 367 kfree(fcount); 368 FILE_FCOUNT(file) = NULL; 369 } 370 return single_release(ino, file); 371 } 372 373 static int mtrr_seq_show(struct seq_file *seq, void *offset); 374 375 static int mtrr_open(struct inode *inode, struct file *file) 376 { 377 if (!mtrr_if) 378 return -EIO; 379 if (!mtrr_if->get) 380 return -ENXIO; 381 return single_open(file, mtrr_seq_show, NULL); 382 } 383 384 static const struct file_operations mtrr_fops = { 385 .owner = THIS_MODULE, 386 .open = mtrr_open, 387 .read = seq_read, 388 .llseek = seq_lseek, 389 .write = mtrr_write, 390 .unlocked_ioctl = mtrr_ioctl, 391 .compat_ioctl = mtrr_ioctl, 392 .release = mtrr_close, 393 }; 394 395 static int mtrr_seq_show(struct seq_file *seq, void *offset) 396 { 397 char factor; 398 int i, max; 399 mtrr_type type; 400 unsigned long base, size; 401 402 max = num_var_ranges; 403 for (i = 0; i < max; i++) { 404 mtrr_if->get(i, &base, &size, &type); 405 if (size == 0) { 406 mtrr_usage_table[i] = 0; 407 continue; 408 } 409 if (size < (0x100000 >> PAGE_SHIFT)) { 410 /* less than 1MB */ 411 factor = 'K'; 412 size <<= PAGE_SHIFT - 10; 413 } else { 414 factor = 'M'; 415 size >>= 20 - PAGE_SHIFT; 416 } 417 /* Base can be > 32bit */ 418 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n", 419 i, base, base >> (20 - PAGE_SHIFT), 420 size, factor, 421 mtrr_usage_table[i], mtrr_attrib_to_str(type)); 422 } 423 return 0; 424 } 425 426 static int __init mtrr_if_init(void) 427 { 428 struct cpuinfo_x86 *c = &boot_cpu_data; 429 430 if ((!cpu_has(c, X86_FEATURE_MTRR)) && 431 (!cpu_has(c, X86_FEATURE_K6_MTRR)) && 432 (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) && 433 (!cpu_has(c, X86_FEATURE_CENTAUR_MCR))) 434 return -ENODEV; 435 436 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops); 437 return 0; 438 } 439 arch_initcall(mtrr_if_init); 440 #endif /* CONFIG_PROC_FS */ 441