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 = kcalloc(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);
109 length = strncpy_from_user(line, buf, LINE_SIZE - 1);
113 linelen = strlen(line);
114 ptr = line + linelen - 1;
115 if (linelen && *ptr == '\n')
118 if (!strncmp(line, "disable=", 8)) {
119 reg = simple_strtoul(line + 8, &ptr, 0);
120 err = mtrr_del_page(reg, 0, 0);
126 if (strncmp(line, "base=", 5))
129 base = simple_strtoull(line + 5, &ptr, 0);
130 ptr = skip_spaces(ptr);
132 if (strncmp(ptr, "size=", 5))
135 size = simple_strtoull(ptr + 5, &ptr, 0);
136 if ((base & 0xfff) || (size & 0xfff))
138 ptr = skip_spaces(ptr);
140 if (strncmp(ptr, "type=", 5))
142 ptr = skip_spaces(ptr + 5);
144 i = match_string(mtrr_strings, MTRR_NUM_TYPES, ptr);
150 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true);
157 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
163 struct mtrr_sentry sentry;
164 struct mtrr_gentry gentry;
165 void __user *arg = (void __user *) __arg;
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))
179 case MTRRIOC_GET_ENTRY:
180 case MTRRIOC_GET_PAGE_ENTRY:
181 if (copy_from_user(&gentry, arg, sizeof gentry))
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;
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);
203 case MTRRIOC32_GET_ENTRY:
204 case MTRRIOC32_GET_PAGE_ENTRY: {
205 struct mtrr_gentry32 __user *g32;
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);
222 case MTRRIOC_ADD_ENTRY:
224 case MTRRIOC32_ADD_ENTRY:
226 if (!capable(CAP_SYS_ADMIN))
229 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
232 case MTRRIOC_SET_ENTRY:
234 case MTRRIOC32_SET_ENTRY:
236 if (!capable(CAP_SYS_ADMIN))
238 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
240 case MTRRIOC_DEL_ENTRY:
242 case MTRRIOC32_DEL_ENTRY:
244 if (!capable(CAP_SYS_ADMIN))
246 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
248 case MTRRIOC_KILL_ENTRY:
250 case MTRRIOC32_KILL_ENTRY:
252 if (!capable(CAP_SYS_ADMIN))
254 err = mtrr_del(-1, sentry.base, sentry.size);
256 case MTRRIOC_GET_ENTRY:
258 case MTRRIOC32_GET_ENTRY:
260 if (gentry.regnum >= num_var_ranges)
262 mtrr_if->get(gentry.regnum, &base, &size, &type);
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;
269 gentry.base = base << PAGE_SHIFT;
270 gentry.size = size << PAGE_SHIFT;
275 case MTRRIOC_ADD_PAGE_ENTRY:
277 case MTRRIOC32_ADD_PAGE_ENTRY:
279 if (!capable(CAP_SYS_ADMIN))
282 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
285 case MTRRIOC_SET_PAGE_ENTRY:
287 case MTRRIOC32_SET_PAGE_ENTRY:
289 if (!capable(CAP_SYS_ADMIN))
292 mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
294 case MTRRIOC_DEL_PAGE_ENTRY:
296 case MTRRIOC32_DEL_PAGE_ENTRY:
298 if (!capable(CAP_SYS_ADMIN))
300 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
302 case MTRRIOC_KILL_PAGE_ENTRY:
304 case MTRRIOC32_KILL_PAGE_ENTRY:
306 if (!capable(CAP_SYS_ADMIN))
308 err = mtrr_del_page(-1, sentry.base, sentry.size);
310 case MTRRIOC_GET_PAGE_ENTRY:
312 case MTRRIOC32_GET_PAGE_ENTRY:
314 if (gentry.regnum >= num_var_ranges)
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;
332 case MTRRIOC_GET_ENTRY:
333 case MTRRIOC_GET_PAGE_ENTRY:
334 if (copy_to_user(arg, &gentry, sizeof gentry))
338 case MTRRIOC32_GET_ENTRY:
339 case MTRRIOC32_GET_PAGE_ENTRY: {
340 struct mtrr_gentry32 __user *g32;
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);
354 static int mtrr_close(struct inode *ino, struct file *file)
356 unsigned int *fcount = FILE_FCOUNT(file);
359 if (fcount != NULL) {
360 max = num_var_ranges;
361 for (i = 0; i < max; ++i) {
362 while (fcount[i] > 0) {
368 FILE_FCOUNT(file) = NULL;
370 return single_release(ino, file);
373 static int mtrr_seq_show(struct seq_file *seq, void *offset);
375 static int mtrr_open(struct inode *inode, struct file *file)
381 return single_open(file, mtrr_seq_show, NULL);
384 static const struct file_operations mtrr_fops = {
385 .owner = THIS_MODULE,
390 .unlocked_ioctl = mtrr_ioctl,
391 .compat_ioctl = mtrr_ioctl,
392 .release = mtrr_close,
395 static int mtrr_seq_show(struct seq_file *seq, void *offset)
400 unsigned long base, size;
402 max = num_var_ranges;
403 for (i = 0; i < max; i++) {
404 mtrr_if->get(i, &base, &size, &type);
406 mtrr_usage_table[i] = 0;
409 if (size < (0x100000 >> PAGE_SHIFT)) {
412 size <<= PAGE_SHIFT - 10;
415 size >>= 20 - PAGE_SHIFT;
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),
421 mtrr_usage_table[i], mtrr_attrib_to_str(type));
426 static int __init mtrr_if_init(void)
428 struct cpuinfo_x86 *c = &boot_cpu_data;
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)))
436 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
439 arch_initcall(mtrr_if_init);
440 #endif /* CONFIG_PROC_FS */