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 memset(&gentry, 0, sizeof(gentry)); 169 170 switch (cmd) { 171 case MTRRIOC_ADD_ENTRY: 172 case MTRRIOC_SET_ENTRY: 173 case MTRRIOC_DEL_ENTRY: 174 case MTRRIOC_KILL_ENTRY: 175 case MTRRIOC_ADD_PAGE_ENTRY: 176 case MTRRIOC_SET_PAGE_ENTRY: 177 case MTRRIOC_DEL_PAGE_ENTRY: 178 case MTRRIOC_KILL_PAGE_ENTRY: 179 if (copy_from_user(&sentry, arg, sizeof(sentry))) 180 return -EFAULT; 181 break; 182 case MTRRIOC_GET_ENTRY: 183 case MTRRIOC_GET_PAGE_ENTRY: 184 if (copy_from_user(&gentry, arg, sizeof(gentry))) 185 return -EFAULT; 186 break; 187 #ifdef CONFIG_COMPAT 188 case MTRRIOC32_ADD_ENTRY: 189 case MTRRIOC32_SET_ENTRY: 190 case MTRRIOC32_DEL_ENTRY: 191 case MTRRIOC32_KILL_ENTRY: 192 case MTRRIOC32_ADD_PAGE_ENTRY: 193 case MTRRIOC32_SET_PAGE_ENTRY: 194 case MTRRIOC32_DEL_PAGE_ENTRY: 195 case MTRRIOC32_KILL_PAGE_ENTRY: { 196 struct mtrr_sentry32 __user *s32; 197 198 s32 = (struct mtrr_sentry32 __user *)__arg; 199 err = get_user(sentry.base, &s32->base); 200 err |= get_user(sentry.size, &s32->size); 201 err |= get_user(sentry.type, &s32->type); 202 if (err) 203 return err; 204 break; 205 } 206 case MTRRIOC32_GET_ENTRY: 207 case MTRRIOC32_GET_PAGE_ENTRY: { 208 struct mtrr_gentry32 __user *g32; 209 210 g32 = (struct mtrr_gentry32 __user *)__arg; 211 err = get_user(gentry.regnum, &g32->regnum); 212 err |= get_user(gentry.base, &g32->base); 213 err |= get_user(gentry.size, &g32->size); 214 err |= get_user(gentry.type, &g32->type); 215 if (err) 216 return err; 217 break; 218 } 219 #endif 220 } 221 222 switch (cmd) { 223 default: 224 return -ENOTTY; 225 case MTRRIOC_ADD_ENTRY: 226 #ifdef CONFIG_COMPAT 227 case MTRRIOC32_ADD_ENTRY: 228 #endif 229 if (!capable(CAP_SYS_ADMIN)) 230 return -EPERM; 231 err = 232 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 233 file, 0); 234 break; 235 case MTRRIOC_SET_ENTRY: 236 #ifdef CONFIG_COMPAT 237 case MTRRIOC32_SET_ENTRY: 238 #endif 239 if (!capable(CAP_SYS_ADMIN)) 240 return -EPERM; 241 err = mtrr_add(sentry.base, sentry.size, sentry.type, false); 242 break; 243 case MTRRIOC_DEL_ENTRY: 244 #ifdef CONFIG_COMPAT 245 case MTRRIOC32_DEL_ENTRY: 246 #endif 247 if (!capable(CAP_SYS_ADMIN)) 248 return -EPERM; 249 err = mtrr_file_del(sentry.base, sentry.size, file, 0); 250 break; 251 case MTRRIOC_KILL_ENTRY: 252 #ifdef CONFIG_COMPAT 253 case MTRRIOC32_KILL_ENTRY: 254 #endif 255 if (!capable(CAP_SYS_ADMIN)) 256 return -EPERM; 257 err = mtrr_del(-1, sentry.base, sentry.size); 258 break; 259 case MTRRIOC_GET_ENTRY: 260 #ifdef CONFIG_COMPAT 261 case MTRRIOC32_GET_ENTRY: 262 #endif 263 if (gentry.regnum >= num_var_ranges) 264 return -EINVAL; 265 mtrr_if->get(gentry.regnum, &base, &size, &type); 266 267 /* Hide entries that go above 4GB */ 268 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)) 269 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))) 270 gentry.base = gentry.size = gentry.type = 0; 271 else { 272 gentry.base = base << PAGE_SHIFT; 273 gentry.size = size << PAGE_SHIFT; 274 gentry.type = type; 275 } 276 277 break; 278 case MTRRIOC_ADD_PAGE_ENTRY: 279 #ifdef CONFIG_COMPAT 280 case MTRRIOC32_ADD_PAGE_ENTRY: 281 #endif 282 if (!capable(CAP_SYS_ADMIN)) 283 return -EPERM; 284 err = 285 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 286 file, 1); 287 break; 288 case MTRRIOC_SET_PAGE_ENTRY: 289 #ifdef CONFIG_COMPAT 290 case MTRRIOC32_SET_PAGE_ENTRY: 291 #endif 292 if (!capable(CAP_SYS_ADMIN)) 293 return -EPERM; 294 err = 295 mtrr_add_page(sentry.base, sentry.size, sentry.type, false); 296 break; 297 case MTRRIOC_DEL_PAGE_ENTRY: 298 #ifdef CONFIG_COMPAT 299 case MTRRIOC32_DEL_PAGE_ENTRY: 300 #endif 301 if (!capable(CAP_SYS_ADMIN)) 302 return -EPERM; 303 err = mtrr_file_del(sentry.base, sentry.size, file, 1); 304 break; 305 case MTRRIOC_KILL_PAGE_ENTRY: 306 #ifdef CONFIG_COMPAT 307 case MTRRIOC32_KILL_PAGE_ENTRY: 308 #endif 309 if (!capable(CAP_SYS_ADMIN)) 310 return -EPERM; 311 err = mtrr_del_page(-1, sentry.base, sentry.size); 312 break; 313 case MTRRIOC_GET_PAGE_ENTRY: 314 #ifdef CONFIG_COMPAT 315 case MTRRIOC32_GET_PAGE_ENTRY: 316 #endif 317 if (gentry.regnum >= num_var_ranges) 318 return -EINVAL; 319 mtrr_if->get(gentry.regnum, &base, &size, &type); 320 /* Hide entries that would overflow */ 321 if (size != (__typeof__(gentry.size))size) 322 gentry.base = gentry.size = gentry.type = 0; 323 else { 324 gentry.base = base; 325 gentry.size = size; 326 gentry.type = type; 327 } 328 break; 329 } 330 331 if (err) 332 return err; 333 334 switch (cmd) { 335 case MTRRIOC_GET_ENTRY: 336 case MTRRIOC_GET_PAGE_ENTRY: 337 if (copy_to_user(arg, &gentry, sizeof(gentry))) 338 err = -EFAULT; 339 break; 340 #ifdef CONFIG_COMPAT 341 case MTRRIOC32_GET_ENTRY: 342 case MTRRIOC32_GET_PAGE_ENTRY: { 343 struct mtrr_gentry32 __user *g32; 344 345 g32 = (struct mtrr_gentry32 __user *)__arg; 346 err = put_user(gentry.base, &g32->base); 347 err |= put_user(gentry.size, &g32->size); 348 err |= put_user(gentry.regnum, &g32->regnum); 349 err |= put_user(gentry.type, &g32->type); 350 break; 351 } 352 #endif 353 } 354 return err; 355 } 356 357 static int mtrr_close(struct inode *ino, struct file *file) 358 { 359 unsigned int *fcount = FILE_FCOUNT(file); 360 int i, max; 361 362 if (fcount != NULL) { 363 max = num_var_ranges; 364 for (i = 0; i < max; ++i) { 365 while (fcount[i] > 0) { 366 mtrr_del(i, 0, 0); 367 --fcount[i]; 368 } 369 } 370 kfree(fcount); 371 FILE_FCOUNT(file) = NULL; 372 } 373 return single_release(ino, file); 374 } 375 376 static int mtrr_seq_show(struct seq_file *seq, void *offset); 377 378 static int mtrr_open(struct inode *inode, struct file *file) 379 { 380 if (!mtrr_if) 381 return -EIO; 382 if (!mtrr_if->get) 383 return -ENXIO; 384 return single_open(file, mtrr_seq_show, NULL); 385 } 386 387 static const struct file_operations mtrr_fops = { 388 .owner = THIS_MODULE, 389 .open = mtrr_open, 390 .read = seq_read, 391 .llseek = seq_lseek, 392 .write = mtrr_write, 393 .unlocked_ioctl = mtrr_ioctl, 394 .compat_ioctl = mtrr_ioctl, 395 .release = mtrr_close, 396 }; 397 398 static int mtrr_seq_show(struct seq_file *seq, void *offset) 399 { 400 char factor; 401 int i, max; 402 mtrr_type type; 403 unsigned long base, size; 404 405 max = num_var_ranges; 406 for (i = 0; i < max; i++) { 407 mtrr_if->get(i, &base, &size, &type); 408 if (size == 0) { 409 mtrr_usage_table[i] = 0; 410 continue; 411 } 412 if (size < (0x100000 >> PAGE_SHIFT)) { 413 /* less than 1MB */ 414 factor = 'K'; 415 size <<= PAGE_SHIFT - 10; 416 } else { 417 factor = 'M'; 418 size >>= 20 - PAGE_SHIFT; 419 } 420 /* Base can be > 32bit */ 421 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n", 422 i, base, base >> (20 - PAGE_SHIFT), 423 size, factor, 424 mtrr_usage_table[i], mtrr_attrib_to_str(type)); 425 } 426 return 0; 427 } 428 429 static int __init mtrr_if_init(void) 430 { 431 struct cpuinfo_x86 *c = &boot_cpu_data; 432 433 if ((!cpu_has(c, X86_FEATURE_MTRR)) && 434 (!cpu_has(c, X86_FEATURE_K6_MTRR)) && 435 (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) && 436 (!cpu_has(c, X86_FEATURE_CENTAUR_MCR))) 437 return -ENODEV; 438 439 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops); 440 return 0; 441 } 442 arch_initcall(mtrr_if_init); 443 #endif /* CONFIG_PROC_FS */ 444