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 len = min_t(size_t, len, LINE_SIZE - 1); 110 length = strncpy_from_user(line, buf, len); 111 if (length < 0) 112 return length; 113 114 linelen = strlen(line); 115 ptr = line + linelen - 1; 116 if (linelen && *ptr == '\n') 117 *ptr = '\0'; 118 119 if (!strncmp(line, "disable=", 8)) { 120 reg = simple_strtoul(line + 8, &ptr, 0); 121 err = mtrr_del_page(reg, 0, 0); 122 if (err < 0) 123 return err; 124 return len; 125 } 126 127 if (strncmp(line, "base=", 5)) 128 return -EINVAL; 129 130 base = simple_strtoull(line + 5, &ptr, 0); 131 ptr = skip_spaces(ptr); 132 133 if (strncmp(ptr, "size=", 5)) 134 return -EINVAL; 135 136 size = simple_strtoull(ptr + 5, &ptr, 0); 137 if ((base & 0xfff) || (size & 0xfff)) 138 return -EINVAL; 139 ptr = skip_spaces(ptr); 140 141 if (strncmp(ptr, "type=", 5)) 142 return -EINVAL; 143 ptr = skip_spaces(ptr + 5); 144 145 i = match_string(mtrr_strings, MTRR_NUM_TYPES, ptr); 146 if (i < 0) 147 return i; 148 149 base >>= PAGE_SHIFT; 150 size >>= PAGE_SHIFT; 151 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true); 152 if (err < 0) 153 return err; 154 return len; 155 } 156 157 static long 158 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg) 159 { 160 int err = 0; 161 mtrr_type type; 162 unsigned long base; 163 unsigned long size; 164 struct mtrr_sentry sentry; 165 struct mtrr_gentry gentry; 166 void __user *arg = (void __user *) __arg; 167 168 switch (cmd) { 169 case MTRRIOC_ADD_ENTRY: 170 case MTRRIOC_SET_ENTRY: 171 case MTRRIOC_DEL_ENTRY: 172 case MTRRIOC_KILL_ENTRY: 173 case MTRRIOC_ADD_PAGE_ENTRY: 174 case MTRRIOC_SET_PAGE_ENTRY: 175 case MTRRIOC_DEL_PAGE_ENTRY: 176 case MTRRIOC_KILL_PAGE_ENTRY: 177 if (copy_from_user(&sentry, arg, sizeof(sentry))) 178 return -EFAULT; 179 break; 180 case MTRRIOC_GET_ENTRY: 181 case MTRRIOC_GET_PAGE_ENTRY: 182 if (copy_from_user(&gentry, arg, sizeof(gentry))) 183 return -EFAULT; 184 break; 185 #ifdef CONFIG_COMPAT 186 case MTRRIOC32_ADD_ENTRY: 187 case MTRRIOC32_SET_ENTRY: 188 case MTRRIOC32_DEL_ENTRY: 189 case MTRRIOC32_KILL_ENTRY: 190 case MTRRIOC32_ADD_PAGE_ENTRY: 191 case MTRRIOC32_SET_PAGE_ENTRY: 192 case MTRRIOC32_DEL_PAGE_ENTRY: 193 case MTRRIOC32_KILL_PAGE_ENTRY: { 194 struct mtrr_sentry32 __user *s32; 195 196 s32 = (struct mtrr_sentry32 __user *)__arg; 197 err = get_user(sentry.base, &s32->base); 198 err |= get_user(sentry.size, &s32->size); 199 err |= get_user(sentry.type, &s32->type); 200 if (err) 201 return err; 202 break; 203 } 204 case MTRRIOC32_GET_ENTRY: 205 case MTRRIOC32_GET_PAGE_ENTRY: { 206 struct mtrr_gentry32 __user *g32; 207 208 g32 = (struct mtrr_gentry32 __user *)__arg; 209 err = get_user(gentry.regnum, &g32->regnum); 210 err |= get_user(gentry.base, &g32->base); 211 err |= get_user(gentry.size, &g32->size); 212 err |= get_user(gentry.type, &g32->type); 213 if (err) 214 return err; 215 break; 216 } 217 #endif 218 } 219 220 switch (cmd) { 221 default: 222 return -ENOTTY; 223 case MTRRIOC_ADD_ENTRY: 224 #ifdef CONFIG_COMPAT 225 case MTRRIOC32_ADD_ENTRY: 226 #endif 227 if (!capable(CAP_SYS_ADMIN)) 228 return -EPERM; 229 err = 230 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 231 file, 0); 232 break; 233 case MTRRIOC_SET_ENTRY: 234 #ifdef CONFIG_COMPAT 235 case MTRRIOC32_SET_ENTRY: 236 #endif 237 if (!capable(CAP_SYS_ADMIN)) 238 return -EPERM; 239 err = mtrr_add(sentry.base, sentry.size, sentry.type, false); 240 break; 241 case MTRRIOC_DEL_ENTRY: 242 #ifdef CONFIG_COMPAT 243 case MTRRIOC32_DEL_ENTRY: 244 #endif 245 if (!capable(CAP_SYS_ADMIN)) 246 return -EPERM; 247 err = mtrr_file_del(sentry.base, sentry.size, file, 0); 248 break; 249 case MTRRIOC_KILL_ENTRY: 250 #ifdef CONFIG_COMPAT 251 case MTRRIOC32_KILL_ENTRY: 252 #endif 253 if (!capable(CAP_SYS_ADMIN)) 254 return -EPERM; 255 err = mtrr_del(-1, sentry.base, sentry.size); 256 break; 257 case MTRRIOC_GET_ENTRY: 258 #ifdef CONFIG_COMPAT 259 case MTRRIOC32_GET_ENTRY: 260 #endif 261 if (gentry.regnum >= num_var_ranges) 262 return -EINVAL; 263 mtrr_if->get(gentry.regnum, &base, &size, &type); 264 265 /* Hide entries that go above 4GB */ 266 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)) 267 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))) 268 gentry.base = gentry.size = gentry.type = 0; 269 else { 270 gentry.base = base << PAGE_SHIFT; 271 gentry.size = size << PAGE_SHIFT; 272 gentry.type = type; 273 } 274 275 break; 276 case MTRRIOC_ADD_PAGE_ENTRY: 277 #ifdef CONFIG_COMPAT 278 case MTRRIOC32_ADD_PAGE_ENTRY: 279 #endif 280 if (!capable(CAP_SYS_ADMIN)) 281 return -EPERM; 282 err = 283 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 284 file, 1); 285 break; 286 case MTRRIOC_SET_PAGE_ENTRY: 287 #ifdef CONFIG_COMPAT 288 case MTRRIOC32_SET_PAGE_ENTRY: 289 #endif 290 if (!capable(CAP_SYS_ADMIN)) 291 return -EPERM; 292 err = 293 mtrr_add_page(sentry.base, sentry.size, sentry.type, false); 294 break; 295 case MTRRIOC_DEL_PAGE_ENTRY: 296 #ifdef CONFIG_COMPAT 297 case MTRRIOC32_DEL_PAGE_ENTRY: 298 #endif 299 if (!capable(CAP_SYS_ADMIN)) 300 return -EPERM; 301 err = mtrr_file_del(sentry.base, sentry.size, file, 1); 302 break; 303 case MTRRIOC_KILL_PAGE_ENTRY: 304 #ifdef CONFIG_COMPAT 305 case MTRRIOC32_KILL_PAGE_ENTRY: 306 #endif 307 if (!capable(CAP_SYS_ADMIN)) 308 return -EPERM; 309 err = mtrr_del_page(-1, sentry.base, sentry.size); 310 break; 311 case MTRRIOC_GET_PAGE_ENTRY: 312 #ifdef CONFIG_COMPAT 313 case MTRRIOC32_GET_PAGE_ENTRY: 314 #endif 315 if (gentry.regnum >= num_var_ranges) 316 return -EINVAL; 317 mtrr_if->get(gentry.regnum, &base, &size, &type); 318 /* Hide entries that would overflow */ 319 if (size != (__typeof__(gentry.size))size) 320 gentry.base = gentry.size = gentry.type = 0; 321 else { 322 gentry.base = base; 323 gentry.size = size; 324 gentry.type = type; 325 } 326 break; 327 } 328 329 if (err) 330 return err; 331 332 switch (cmd) { 333 case MTRRIOC_GET_ENTRY: 334 case MTRRIOC_GET_PAGE_ENTRY: 335 if (copy_to_user(arg, &gentry, sizeof(gentry))) 336 err = -EFAULT; 337 break; 338 #ifdef CONFIG_COMPAT 339 case MTRRIOC32_GET_ENTRY: 340 case MTRRIOC32_GET_PAGE_ENTRY: { 341 struct mtrr_gentry32 __user *g32; 342 343 g32 = (struct mtrr_gentry32 __user *)__arg; 344 err = put_user(gentry.base, &g32->base); 345 err |= put_user(gentry.size, &g32->size); 346 err |= put_user(gentry.regnum, &g32->regnum); 347 err |= put_user(gentry.type, &g32->type); 348 break; 349 } 350 #endif 351 } 352 return err; 353 } 354 355 static int mtrr_close(struct inode *ino, struct file *file) 356 { 357 unsigned int *fcount = FILE_FCOUNT(file); 358 int i, max; 359 360 if (fcount != NULL) { 361 max = num_var_ranges; 362 for (i = 0; i < max; ++i) { 363 while (fcount[i] > 0) { 364 mtrr_del(i, 0, 0); 365 --fcount[i]; 366 } 367 } 368 kfree(fcount); 369 FILE_FCOUNT(file) = NULL; 370 } 371 return single_release(ino, file); 372 } 373 374 static int mtrr_seq_show(struct seq_file *seq, void *offset); 375 376 static int mtrr_open(struct inode *inode, struct file *file) 377 { 378 if (!mtrr_if) 379 return -EIO; 380 if (!mtrr_if->get) 381 return -ENXIO; 382 return single_open(file, mtrr_seq_show, NULL); 383 } 384 385 static const struct file_operations mtrr_fops = { 386 .owner = THIS_MODULE, 387 .open = mtrr_open, 388 .read = seq_read, 389 .llseek = seq_lseek, 390 .write = mtrr_write, 391 .unlocked_ioctl = mtrr_ioctl, 392 .compat_ioctl = mtrr_ioctl, 393 .release = mtrr_close, 394 }; 395 396 static int mtrr_seq_show(struct seq_file *seq, void *offset) 397 { 398 char factor; 399 int i, max; 400 mtrr_type type; 401 unsigned long base, size; 402 403 max = num_var_ranges; 404 for (i = 0; i < max; i++) { 405 mtrr_if->get(i, &base, &size, &type); 406 if (size == 0) { 407 mtrr_usage_table[i] = 0; 408 continue; 409 } 410 if (size < (0x100000 >> PAGE_SHIFT)) { 411 /* less than 1MB */ 412 factor = 'K'; 413 size <<= PAGE_SHIFT - 10; 414 } else { 415 factor = 'M'; 416 size >>= 20 - PAGE_SHIFT; 417 } 418 /* Base can be > 32bit */ 419 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n", 420 i, base, base >> (20 - PAGE_SHIFT), 421 size, factor, 422 mtrr_usage_table[i], mtrr_attrib_to_str(type)); 423 } 424 return 0; 425 } 426 427 static int __init mtrr_if_init(void) 428 { 429 struct cpuinfo_x86 *c = &boot_cpu_data; 430 431 if ((!cpu_has(c, X86_FEATURE_MTRR)) && 432 (!cpu_has(c, X86_FEATURE_K6_MTRR)) && 433 (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) && 434 (!cpu_has(c, X86_FEATURE_CENTAUR_MCR))) 435 return -ENODEV; 436 437 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops); 438 return 0; 439 } 440 arch_initcall(mtrr_if_init); 441 #endif /* CONFIG_PROC_FS */ 442