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>
17 #define FILE_FCOUNT(f) (((struct seq_file *)((f)->private_data))->private)
19 static const char *const mtrr_strings[MTRR_NUM_TYPES] =
22 "write-combining", /* 1 */
25 "write-through", /* 4 */
26 "write-protect", /* 5 */
30 const char *mtrr_attrib_to_str(int x)
32 return (x <= 6) ? mtrr_strings[x] : "?";
38 mtrr_file_add(unsigned long base, unsigned long size,
39 unsigned int type, bool increment, struct file *file, int page)
41 unsigned int *fcount = FILE_FCOUNT(file);
46 fcount = kzalloc(max * sizeof *fcount, GFP_KERNEL);
49 FILE_FCOUNT(file) = fcount;
52 if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
57 reg = mtrr_add_page(base, size, type, true);
64 mtrr_file_del(unsigned long base, unsigned long size,
65 struct file *file, int page)
67 unsigned int *fcount = FILE_FCOUNT(file);
71 if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1)))
76 reg = mtrr_del_page(-1, base, size);
88 * seq_file can seek but we ignore it.
90 * Format of control line:
91 * "base=%Lx size=%Lx type=%s" or "disable=%d"
94 mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
98 unsigned long long base, size;
100 char line[LINE_SIZE];
104 if (!capable(CAP_SYS_ADMIN))
107 memset(line, 0, LINE_SIZE);
112 if (length > LINE_SIZE - 1)
113 length = LINE_SIZE - 1;
118 if (copy_from_user(line, buf, length))
121 linelen = strlen(line);
122 ptr = line + linelen - 1;
123 if (linelen && *ptr == '\n')
126 if (!strncmp(line, "disable=", 8)) {
127 reg = simple_strtoul(line + 8, &ptr, 0);
128 err = mtrr_del_page(reg, 0, 0);
134 if (strncmp(line, "base=", 5))
137 base = simple_strtoull(line + 5, &ptr, 0);
138 ptr = skip_spaces(ptr);
140 if (strncmp(ptr, "size=", 5))
143 size = simple_strtoull(ptr + 5, &ptr, 0);
144 if ((base & 0xfff) || (size & 0xfff))
146 ptr = skip_spaces(ptr);
148 if (strncmp(ptr, "type=", 5))
150 ptr = skip_spaces(ptr + 5);
152 for (i = 0; i < MTRR_NUM_TYPES; ++i) {
153 if (strcmp(ptr, mtrr_strings[i]))
157 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true);
166 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
172 struct mtrr_sentry sentry;
173 struct mtrr_gentry gentry;
174 void __user *arg = (void __user *) __arg;
176 memset(&gentry, 0, sizeof(gentry));
179 case MTRRIOC_ADD_ENTRY:
180 case MTRRIOC_SET_ENTRY:
181 case MTRRIOC_DEL_ENTRY:
182 case MTRRIOC_KILL_ENTRY:
183 case MTRRIOC_ADD_PAGE_ENTRY:
184 case MTRRIOC_SET_PAGE_ENTRY:
185 case MTRRIOC_DEL_PAGE_ENTRY:
186 case MTRRIOC_KILL_PAGE_ENTRY:
187 if (copy_from_user(&sentry, arg, sizeof sentry))
190 case MTRRIOC_GET_ENTRY:
191 case MTRRIOC_GET_PAGE_ENTRY:
192 if (copy_from_user(&gentry, arg, sizeof gentry))
196 case MTRRIOC32_ADD_ENTRY:
197 case MTRRIOC32_SET_ENTRY:
198 case MTRRIOC32_DEL_ENTRY:
199 case MTRRIOC32_KILL_ENTRY:
200 case MTRRIOC32_ADD_PAGE_ENTRY:
201 case MTRRIOC32_SET_PAGE_ENTRY:
202 case MTRRIOC32_DEL_PAGE_ENTRY:
203 case MTRRIOC32_KILL_PAGE_ENTRY: {
204 struct mtrr_sentry32 __user *s32;
206 s32 = (struct mtrr_sentry32 __user *)__arg;
207 err = get_user(sentry.base, &s32->base);
208 err |= get_user(sentry.size, &s32->size);
209 err |= get_user(sentry.type, &s32->type);
214 case MTRRIOC32_GET_ENTRY:
215 case MTRRIOC32_GET_PAGE_ENTRY: {
216 struct mtrr_gentry32 __user *g32;
218 g32 = (struct mtrr_gentry32 __user *)__arg;
219 err = get_user(gentry.regnum, &g32->regnum);
220 err |= get_user(gentry.base, &g32->base);
221 err |= get_user(gentry.size, &g32->size);
222 err |= get_user(gentry.type, &g32->type);
233 case MTRRIOC_ADD_ENTRY:
235 case MTRRIOC32_ADD_ENTRY:
237 if (!capable(CAP_SYS_ADMIN))
240 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
243 case MTRRIOC_SET_ENTRY:
245 case MTRRIOC32_SET_ENTRY:
247 if (!capable(CAP_SYS_ADMIN))
249 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
251 case MTRRIOC_DEL_ENTRY:
253 case MTRRIOC32_DEL_ENTRY:
255 if (!capable(CAP_SYS_ADMIN))
257 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
259 case MTRRIOC_KILL_ENTRY:
261 case MTRRIOC32_KILL_ENTRY:
263 if (!capable(CAP_SYS_ADMIN))
265 err = mtrr_del(-1, sentry.base, sentry.size);
267 case MTRRIOC_GET_ENTRY:
269 case MTRRIOC32_GET_ENTRY:
271 if (gentry.regnum >= num_var_ranges)
273 mtrr_if->get(gentry.regnum, &base, &size, &type);
275 /* Hide entries that go above 4GB */
276 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
277 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
278 gentry.base = gentry.size = gentry.type = 0;
280 gentry.base = base << PAGE_SHIFT;
281 gentry.size = size << PAGE_SHIFT;
286 case MTRRIOC_ADD_PAGE_ENTRY:
288 case MTRRIOC32_ADD_PAGE_ENTRY:
290 if (!capable(CAP_SYS_ADMIN))
293 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
296 case MTRRIOC_SET_PAGE_ENTRY:
298 case MTRRIOC32_SET_PAGE_ENTRY:
300 if (!capable(CAP_SYS_ADMIN))
303 mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
305 case MTRRIOC_DEL_PAGE_ENTRY:
307 case MTRRIOC32_DEL_PAGE_ENTRY:
309 if (!capable(CAP_SYS_ADMIN))
311 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
313 case MTRRIOC_KILL_PAGE_ENTRY:
315 case MTRRIOC32_KILL_PAGE_ENTRY:
317 if (!capable(CAP_SYS_ADMIN))
319 err = mtrr_del_page(-1, sentry.base, sentry.size);
321 case MTRRIOC_GET_PAGE_ENTRY:
323 case MTRRIOC32_GET_PAGE_ENTRY:
325 if (gentry.regnum >= num_var_ranges)
327 mtrr_if->get(gentry.regnum, &base, &size, &type);
328 /* Hide entries that would overflow */
329 if (size != (__typeof__(gentry.size))size)
330 gentry.base = gentry.size = gentry.type = 0;
343 case MTRRIOC_GET_ENTRY:
344 case MTRRIOC_GET_PAGE_ENTRY:
345 if (copy_to_user(arg, &gentry, sizeof gentry))
349 case MTRRIOC32_GET_ENTRY:
350 case MTRRIOC32_GET_PAGE_ENTRY: {
351 struct mtrr_gentry32 __user *g32;
353 g32 = (struct mtrr_gentry32 __user *)__arg;
354 err = put_user(gentry.base, &g32->base);
355 err |= put_user(gentry.size, &g32->size);
356 err |= put_user(gentry.regnum, &g32->regnum);
357 err |= put_user(gentry.type, &g32->type);
365 static int mtrr_close(struct inode *ino, struct file *file)
367 unsigned int *fcount = FILE_FCOUNT(file);
370 if (fcount != NULL) {
371 max = num_var_ranges;
372 for (i = 0; i < max; ++i) {
373 while (fcount[i] > 0) {
379 FILE_FCOUNT(file) = NULL;
381 return single_release(ino, file);
384 static int mtrr_seq_show(struct seq_file *seq, void *offset);
386 static int mtrr_open(struct inode *inode, struct file *file)
392 return single_open(file, mtrr_seq_show, NULL);
395 static const struct file_operations mtrr_fops = {
396 .owner = THIS_MODULE,
401 .unlocked_ioctl = mtrr_ioctl,
402 .compat_ioctl = mtrr_ioctl,
403 .release = mtrr_close,
406 static int mtrr_seq_show(struct seq_file *seq, void *offset)
411 unsigned long base, size;
413 max = num_var_ranges;
414 for (i = 0; i < max; i++) {
415 mtrr_if->get(i, &base, &size, &type);
417 mtrr_usage_table[i] = 0;
420 if (size < (0x100000 >> PAGE_SHIFT)) {
423 size <<= PAGE_SHIFT - 10;
426 size >>= 20 - PAGE_SHIFT;
428 /* Base can be > 32bit */
429 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n",
430 i, base, base >> (20 - PAGE_SHIFT),
432 mtrr_usage_table[i], mtrr_attrib_to_str(type));
437 static int __init mtrr_if_init(void)
439 struct cpuinfo_x86 *c = &boot_cpu_data;
441 if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
442 (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
443 (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
444 (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
447 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
450 arch_initcall(mtrr_if_init);
451 #endif /* CONFIG_PROC_FS */