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 memset(line, 0, LINE_SIZE);
105
106 len = min_t(size_t, len, LINE_SIZE - 1);
107 length = strncpy_from_user(line, buf, len);
108 if (length < 0)
109 return length;
110
111 linelen = strlen(line);
112 ptr = line + linelen - 1;
113 if (linelen && *ptr == '\n')
114 *ptr = '\0';
115
116 if (!strncmp(line, "disable=", 8)) {
117 reg = simple_strtoul(line + 8, &ptr, 0);
118 err = mtrr_del_page(reg, 0, 0);
119 if (err < 0)
120 return err;
121 return len;
122 }
123
124 if (strncmp(line, "base=", 5))
125 return -EINVAL;
126
127 base = simple_strtoull(line + 5, &ptr, 0);
128 ptr = skip_spaces(ptr);
129
130 if (strncmp(ptr, "size=", 5))
131 return -EINVAL;
132
133 size = simple_strtoull(ptr + 5, &ptr, 0);
134 if ((base & 0xfff) || (size & 0xfff))
135 return -EINVAL;
136 ptr = skip_spaces(ptr);
137
138 if (strncmp(ptr, "type=", 5))
139 return -EINVAL;
140 ptr = skip_spaces(ptr + 5);
141
142 i = match_string(mtrr_strings, MTRR_NUM_TYPES, ptr);
143 if (i < 0)
144 return i;
145
146 base >>= PAGE_SHIFT;
147 size >>= PAGE_SHIFT;
148 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true);
149 if (err < 0)
150 return err;
151 return len;
152 }
153
154 static long
155 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
156 {
157 int err = 0;
158 mtrr_type type;
159 unsigned long base;
160 unsigned long size;
161 struct mtrr_sentry sentry;
162 struct mtrr_gentry gentry;
163 void __user *arg = (void __user *) __arg;
164
165 memset(&gentry, 0, sizeof(gentry));
166
167 switch (cmd) {
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)))
177 return -EFAULT;
178 break;
179 case MTRRIOC_GET_ENTRY:
180 case MTRRIOC_GET_PAGE_ENTRY:
181 if (copy_from_user(&gentry, arg, sizeof(gentry)))
182 return -EFAULT;
183 break;
184 #ifdef CONFIG_COMPAT
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;
194
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);
199 if (err)
200 return err;
201 break;
202 }
203 case MTRRIOC32_GET_ENTRY:
204 case MTRRIOC32_GET_PAGE_ENTRY: {
205 struct mtrr_gentry32 __user *g32;
206
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);
212 if (err)
213 return err;
214 break;
215 }
216 #endif
217 }
218
219 switch (cmd) {
220 default:
221 return -ENOTTY;
222 case MTRRIOC_ADD_ENTRY:
223 #ifdef CONFIG_COMPAT
224 case MTRRIOC32_ADD_ENTRY:
225 #endif
226 err =
227 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
228 file, 0);
229 break;
230 case MTRRIOC_SET_ENTRY:
231 #ifdef CONFIG_COMPAT
232 case MTRRIOC32_SET_ENTRY:
233 #endif
234 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
235 break;
236 case MTRRIOC_DEL_ENTRY:
237 #ifdef CONFIG_COMPAT
238 case MTRRIOC32_DEL_ENTRY:
239 #endif
240 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
241 break;
242 case MTRRIOC_KILL_ENTRY:
243 #ifdef CONFIG_COMPAT
244 case MTRRIOC32_KILL_ENTRY:
245 #endif
246 err = mtrr_del(-1, sentry.base, sentry.size);
247 break;
248 case MTRRIOC_GET_ENTRY:
249 #ifdef CONFIG_COMPAT
250 case MTRRIOC32_GET_ENTRY:
251 #endif
252 if (gentry.regnum >= num_var_ranges)
253 return -EINVAL;
254 mtrr_if->get(gentry.regnum, &base, &size, &type);
255
256 /* Hide entries that go above 4GB */
257 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
258 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
259 gentry.base = gentry.size = gentry.type = 0;
260 else {
261 gentry.base = base << PAGE_SHIFT;
262 gentry.size = size << PAGE_SHIFT;
263 gentry.type = type;
264 }
265
266 break;
267 case MTRRIOC_ADD_PAGE_ENTRY:
268 #ifdef CONFIG_COMPAT
269 case MTRRIOC32_ADD_PAGE_ENTRY:
270 #endif
271 err =
272 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
273 file, 1);
274 break;
275 case MTRRIOC_SET_PAGE_ENTRY:
276 #ifdef CONFIG_COMPAT
277 case MTRRIOC32_SET_PAGE_ENTRY:
278 #endif
279 err =
280 mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
281 break;
282 case MTRRIOC_DEL_PAGE_ENTRY:
283 #ifdef CONFIG_COMPAT
284 case MTRRIOC32_DEL_PAGE_ENTRY:
285 #endif
286 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
287 break;
288 case MTRRIOC_KILL_PAGE_ENTRY:
289 #ifdef CONFIG_COMPAT
290 case MTRRIOC32_KILL_PAGE_ENTRY:
291 #endif
292 err = mtrr_del_page(-1, sentry.base, sentry.size);
293 break;
294 case MTRRIOC_GET_PAGE_ENTRY:
295 #ifdef CONFIG_COMPAT
296 case MTRRIOC32_GET_PAGE_ENTRY:
297 #endif
298 if (gentry.regnum >= num_var_ranges)
299 return -EINVAL;
300 mtrr_if->get(gentry.regnum, &base, &size, &type);
301 /* Hide entries that would overflow */
302 if (size != (__typeof__(gentry.size))size)
303 gentry.base = gentry.size = gentry.type = 0;
304 else {
305 gentry.base = base;
306 gentry.size = size;
307 gentry.type = type;
308 }
309 break;
310 }
311
312 if (err)
313 return err;
314
315 switch (cmd) {
316 case MTRRIOC_GET_ENTRY:
317 case MTRRIOC_GET_PAGE_ENTRY:
318 if (copy_to_user(arg, &gentry, sizeof(gentry)))
319 err = -EFAULT;
320 break;
321 #ifdef CONFIG_COMPAT
322 case MTRRIOC32_GET_ENTRY:
323 case MTRRIOC32_GET_PAGE_ENTRY: {
324 struct mtrr_gentry32 __user *g32;
325
326 g32 = (struct mtrr_gentry32 __user *)__arg;
327 err = put_user(gentry.base, &g32->base);
328 err |= put_user(gentry.size, &g32->size);
329 err |= put_user(gentry.regnum, &g32->regnum);
330 err |= put_user(gentry.type, &g32->type);
331 break;
332 }
333 #endif
334 }
335 return err;
336 }
337
338 static int mtrr_close(struct inode *ino, struct file *file)
339 {
340 unsigned int *fcount = FILE_FCOUNT(file);
341 int i, max;
342
343 if (fcount != NULL) {
344 max = num_var_ranges;
345 for (i = 0; i < max; ++i) {
346 while (fcount[i] > 0) {
347 mtrr_del(i, 0, 0);
348 --fcount[i];
349 }
350 }
351 kfree(fcount);
352 FILE_FCOUNT(file) = NULL;
353 }
354 return single_release(ino, file);
355 }
356
357 static int mtrr_seq_show(struct seq_file *seq, void *offset)
358 {
359 char factor;
360 int i, max;
361 mtrr_type type;
362 unsigned long base, size;
363
364 max = num_var_ranges;
365 for (i = 0; i < max; i++) {
366 mtrr_if->get(i, &base, &size, &type);
367 if (size == 0) {
368 mtrr_usage_table[i] = 0;
369 continue;
370 }
371 if (size < (0x100000 >> PAGE_SHIFT)) {
372 /* less than 1MB */
373 factor = 'K';
374 size <<= PAGE_SHIFT - 10;
375 } else {
376 factor = 'M';
377 size >>= 20 - PAGE_SHIFT;
378 }
379 /* Base can be > 32bit */
380 seq_printf(seq, "reg%02i: base=0x%06lx000 (%5luMB), size=%5lu%cB, count=%d: %s\n",
381 i, base, base >> (20 - PAGE_SHIFT),
382 size, factor,
383 mtrr_usage_table[i], mtrr_attrib_to_str(type));
384 }
385 return 0;
386 }
387
388 static int mtrr_open(struct inode *inode, struct file *file)
389 {
390 if (!mtrr_if)
391 return -EIO;
392 if (!mtrr_if->get)
393 return -ENXIO;
394 if (!capable(CAP_SYS_ADMIN))
395 return -EPERM;
396 return single_open(file, mtrr_seq_show, NULL);
397 }
398
399 static const struct proc_ops mtrr_proc_ops = {
400 .proc_open = mtrr_open,
401 .proc_read = seq_read,
402 .proc_lseek = seq_lseek,
403 .proc_write = mtrr_write,
404 .proc_ioctl = mtrr_ioctl,
405 #ifdef CONFIG_COMPAT
406 .proc_compat_ioctl = mtrr_ioctl,
407 #endif
408 .proc_release = mtrr_close,
409 };
410
411 static int __init mtrr_if_init(void)
412 {
413 struct cpuinfo_x86 *c = &boot_cpu_data;
414
415 if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
416 (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
417 (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
418 (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
419 return -ENODEV;
420
421 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_proc_ops);
422 return 0;
423 }
424 arch_initcall(mtrr_if_init);
425 #endif /* CONFIG_PROC_FS */
426
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.