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
mtrr_attrib_to_str(int x)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
mtrr_file_add(unsigned long base,unsigned long size,unsigned int type,bool increment,struct file * file,int page)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
mtrr_file_del(unsigned long base,unsigned long size,struct file * file,int page)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
mtrr_write(struct file * file,const char __user * buf,size_t len,loff_t * ppos)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
mtrr_ioctl(struct file * file,unsigned int cmd,unsigned long __arg)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
mtrr_close(struct inode * ino,struct file * file)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
mtrr_seq_show(struct seq_file * seq,void * offset)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
mtrr_open(struct inode * inode,struct file * file)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
mtrr_if_init(void)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