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; 102 103 memset(line, 0, LINE_SIZE); 104 105 len = min_t(size_t, len, LINE_SIZE - 1); 106 length = strncpy_from_user(line, buf, len); 107 if (length < 0) 108 return length; 109 110 ptr = line + length - 1; 111 if (length && *ptr == '\n') 112 *ptr = '\0'; 113 114 if (!strncmp(line, "disable=", 8)) { 115 reg = simple_strtoul(line + 8, &ptr, 0); 116 err = mtrr_del_page(reg, 0, 0); 117 if (err < 0) 118 return err; 119 return len; 120 } 121 122 if (strncmp(line, "base=", 5)) 123 return -EINVAL; 124 125 base = simple_strtoull(line + 5, &ptr, 0); 126 ptr = skip_spaces(ptr); 127 128 if (strncmp(ptr, "size=", 5)) 129 return -EINVAL; 130 131 size = simple_strtoull(ptr + 5, &ptr, 0); 132 if ((base & 0xfff) || (size & 0xfff)) 133 return -EINVAL; 134 ptr = skip_spaces(ptr); 135 136 if (strncmp(ptr, "type=", 5)) 137 return -EINVAL; 138 ptr = skip_spaces(ptr + 5); 139 140 i = match_string(mtrr_strings, MTRR_NUM_TYPES, ptr); 141 if (i < 0) 142 return i; 143 144 base >>= PAGE_SHIFT; 145 size >>= PAGE_SHIFT; 146 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true); 147 if (err < 0) 148 return err; 149 return len; 150 } 151 152 static long 153 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg) 154 { 155 int err = 0; 156 mtrr_type type; 157 unsigned long base; 158 unsigned long size; 159 struct mtrr_sentry sentry; 160 struct mtrr_gentry gentry; 161 void __user *arg = (void __user *) __arg; 162 163 memset(&gentry, 0, sizeof(gentry)); 164 165 switch (cmd) { 166 case MTRRIOC_ADD_ENTRY: 167 case MTRRIOC_SET_ENTRY: 168 case MTRRIOC_DEL_ENTRY: 169 case MTRRIOC_KILL_ENTRY: 170 case MTRRIOC_ADD_PAGE_ENTRY: 171 case MTRRIOC_SET_PAGE_ENTRY: 172 case MTRRIOC_DEL_PAGE_ENTRY: 173 case MTRRIOC_KILL_PAGE_ENTRY: 174 if (copy_from_user(&sentry, arg, sizeof(sentry))) 175 return -EFAULT; 176 break; 177 case MTRRIOC_GET_ENTRY: 178 case MTRRIOC_GET_PAGE_ENTRY: 179 if (copy_from_user(&gentry, arg, sizeof(gentry))) 180 return -EFAULT; 181 break; 182 #ifdef CONFIG_COMPAT 183 case MTRRIOC32_ADD_ENTRY: 184 case MTRRIOC32_SET_ENTRY: 185 case MTRRIOC32_DEL_ENTRY: 186 case MTRRIOC32_KILL_ENTRY: 187 case MTRRIOC32_ADD_PAGE_ENTRY: 188 case MTRRIOC32_SET_PAGE_ENTRY: 189 case MTRRIOC32_DEL_PAGE_ENTRY: 190 case MTRRIOC32_KILL_PAGE_ENTRY: { 191 struct mtrr_sentry32 __user *s32; 192 193 s32 = (struct mtrr_sentry32 __user *)__arg; 194 err = get_user(sentry.base, &s32->base); 195 err |= get_user(sentry.size, &s32->size); 196 err |= get_user(sentry.type, &s32->type); 197 if (err) 198 return err; 199 break; 200 } 201 case MTRRIOC32_GET_ENTRY: 202 case MTRRIOC32_GET_PAGE_ENTRY: { 203 struct mtrr_gentry32 __user *g32; 204 205 g32 = (struct mtrr_gentry32 __user *)__arg; 206 err = get_user(gentry.regnum, &g32->regnum); 207 err |= get_user(gentry.base, &g32->base); 208 err |= get_user(gentry.size, &g32->size); 209 err |= get_user(gentry.type, &g32->type); 210 if (err) 211 return err; 212 break; 213 } 214 #endif 215 } 216 217 switch (cmd) { 218 default: 219 return -ENOTTY; 220 case MTRRIOC_ADD_ENTRY: 221 #ifdef CONFIG_COMPAT 222 case MTRRIOC32_ADD_ENTRY: 223 #endif 224 err = 225 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 226 file, 0); 227 break; 228 case MTRRIOC_SET_ENTRY: 229 #ifdef CONFIG_COMPAT 230 case MTRRIOC32_SET_ENTRY: 231 #endif 232 err = mtrr_add(sentry.base, sentry.size, sentry.type, false); 233 break; 234 case MTRRIOC_DEL_ENTRY: 235 #ifdef CONFIG_COMPAT 236 case MTRRIOC32_DEL_ENTRY: 237 #endif 238 err = mtrr_file_del(sentry.base, sentry.size, file, 0); 239 break; 240 case MTRRIOC_KILL_ENTRY: 241 #ifdef CONFIG_COMPAT 242 case MTRRIOC32_KILL_ENTRY: 243 #endif 244 err = mtrr_del(-1, sentry.base, sentry.size); 245 break; 246 case MTRRIOC_GET_ENTRY: 247 #ifdef CONFIG_COMPAT 248 case MTRRIOC32_GET_ENTRY: 249 #endif 250 if (gentry.regnum >= num_var_ranges) 251 return -EINVAL; 252 mtrr_if->get(gentry.regnum, &base, &size, &type); 253 254 /* Hide entries that go above 4GB */ 255 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)) 256 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))) 257 gentry.base = gentry.size = gentry.type = 0; 258 else { 259 gentry.base = base << PAGE_SHIFT; 260 gentry.size = size << PAGE_SHIFT; 261 gentry.type = type; 262 } 263 264 break; 265 case MTRRIOC_ADD_PAGE_ENTRY: 266 #ifdef CONFIG_COMPAT 267 case MTRRIOC32_ADD_PAGE_ENTRY: 268 #endif 269 err = 270 mtrr_file_add(sentry.base, sentry.size, sentry.type, true, 271 file, 1); 272 break; 273 case MTRRIOC_SET_PAGE_ENTRY: 274 #ifdef CONFIG_COMPAT 275 case MTRRIOC32_SET_PAGE_ENTRY: 276 #endif 277 err = 278 mtrr_add_page(sentry.base, sentry.size, sentry.type, false); 279 break; 280 case MTRRIOC_DEL_PAGE_ENTRY: 281 #ifdef CONFIG_COMPAT 282 case MTRRIOC32_DEL_PAGE_ENTRY: 283 #endif 284 err = mtrr_file_del(sentry.base, sentry.size, file, 1); 285 break; 286 case MTRRIOC_KILL_PAGE_ENTRY: 287 #ifdef CONFIG_COMPAT 288 case MTRRIOC32_KILL_PAGE_ENTRY: 289 #endif 290 err = mtrr_del_page(-1, sentry.base, sentry.size); 291 break; 292 case MTRRIOC_GET_PAGE_ENTRY: 293 #ifdef CONFIG_COMPAT 294 case MTRRIOC32_GET_PAGE_ENTRY: 295 #endif 296 if (gentry.regnum >= num_var_ranges) 297 return -EINVAL; 298 mtrr_if->get(gentry.regnum, &base, &size, &type); 299 /* Hide entries that would overflow */ 300 if (size != (__typeof__(gentry.size))size) 301 gentry.base = gentry.size = gentry.type = 0; 302 else { 303 gentry.base = base; 304 gentry.size = size; 305 gentry.type = type; 306 } 307 break; 308 } 309 310 if (err) 311 return err; 312 313 switch (cmd) { 314 case MTRRIOC_GET_ENTRY: 315 case MTRRIOC_GET_PAGE_ENTRY: 316 if (copy_to_user(arg, &gentry, sizeof(gentry))) 317 err = -EFAULT; 318 break; 319 #ifdef CONFIG_COMPAT 320 case MTRRIOC32_GET_ENTRY: 321 case MTRRIOC32_GET_PAGE_ENTRY: { 322 struct mtrr_gentry32 __user *g32; 323 324 g32 = (struct mtrr_gentry32 __user *)__arg; 325 err = put_user(gentry.base, &g32->base); 326 err |= put_user(gentry.size, &g32->size); 327 err |= put_user(gentry.regnum, &g32->regnum); 328 err |= put_user(gentry.type, &g32->type); 329 break; 330 } 331 #endif 332 } 333 return err; 334 } 335 336 static int mtrr_close(struct inode *ino, struct file *file) 337 { 338 unsigned int *fcount = FILE_FCOUNT(file); 339 int i, max; 340 341 if (fcount != NULL) { 342 max = num_var_ranges; 343 for (i = 0; i < max; ++i) { 344 while (fcount[i] > 0) { 345 mtrr_del(i, 0, 0); 346 --fcount[i]; 347 } 348 } 349 kfree(fcount); 350 FILE_FCOUNT(file) = NULL; 351 } 352 return single_release(ino, file); 353 } 354 355 static int mtrr_seq_show(struct seq_file *seq, void *offset) 356 { 357 char factor; 358 int i, max; 359 mtrr_type type; 360 unsigned long base, size; 361 362 max = num_var_ranges; 363 for (i = 0; i < max; i++) { 364 mtrr_if->get(i, &base, &size, &type); 365 if (size == 0) { 366 mtrr_usage_table[i] = 0; 367 continue; 368 } 369 if (size < (0x100000 >> PAGE_SHIFT)) { 370 /* less than 1MB */ 371 factor = 'K'; 372 size <<= PAGE_SHIFT - 10; 373 } else { 374 factor = 'M'; 375 size >>= 20 - PAGE_SHIFT; 376 } 377 /* Base can be > 32bit */ 378 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n", 379 i, base, base >> (20 - PAGE_SHIFT), 380 size, factor, 381 mtrr_usage_table[i], mtrr_attrib_to_str(type)); 382 } 383 return 0; 384 } 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 if (!capable(CAP_SYS_ADMIN)) 393 return -EPERM; 394 return single_open(file, mtrr_seq_show, NULL); 395 } 396 397 static const struct proc_ops mtrr_proc_ops = { 398 .proc_open = mtrr_open, 399 .proc_read = seq_read, 400 .proc_lseek = seq_lseek, 401 .proc_write = mtrr_write, 402 .proc_ioctl = mtrr_ioctl, 403 #ifdef CONFIG_COMPAT 404 .proc_compat_ioctl = mtrr_ioctl, 405 #endif 406 .proc_release = mtrr_close, 407 }; 408 409 static int __init mtrr_if_init(void) 410 { 411 struct cpuinfo_x86 *c = &boot_cpu_data; 412 413 if ((!cpu_has(c, X86_FEATURE_MTRR)) && 414 (!cpu_has(c, X86_FEATURE_K6_MTRR)) && 415 (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) && 416 (!cpu_has(c, X86_FEATURE_CENTAUR_MCR))) 417 return -ENODEV; 418 419 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_proc_ops); 420 return 0; 421 } 422 arch_initcall(mtrr_if_init); 423 #endif /* CONFIG_PROC_FS */ 424