1 #include <linux/capability.h>
2 #include <linux/seq_file.h>
3 #include <linux/uaccess.h>
4 #include <linux/proc_fs.h>
5 #include <linux/module.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 = kzalloc(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 size_t linelen;
103
104 if (!capable(CAP_SYS_ADMIN))
105 return -EPERM;
106
107 memset(line, 0, LINE_SIZE);
108
109 length = len;
110 length--;
111
112 if (length > LINE_SIZE - 1)
113 length = LINE_SIZE - 1;
114
115 if (length < 0)
116 return -EINVAL;
117
118 if (copy_from_user(line, buf, length))
119 return -EFAULT;
120
121 linelen = strlen(line);
122 ptr = line + linelen - 1;
123 if (linelen && *ptr == '\n')
124 *ptr = '\0';
125
126 if (!strncmp(line, "disable=", 8)) {
127 reg = simple_strtoul(line + 8, &ptr, 0);
128 err = mtrr_del_page(reg, 0, 0);
129 if (err < 0)
130 return err;
131 return len;
132 }
133
134 if (strncmp(line, "base=", 5))
135 return -EINVAL;
136
137 base = simple_strtoull(line + 5, &ptr, 0);
138 ptr = skip_spaces(ptr);
139
140 if (strncmp(ptr, "size=", 5))
141 return -EINVAL;
142
143 size = simple_strtoull(ptr + 5, &ptr, 0);
144 if ((base & 0xfff) || (size & 0xfff))
145 return -EINVAL;
146 ptr = skip_spaces(ptr);
147
148 if (strncmp(ptr, "type=", 5))
149 return -EINVAL;
150 ptr = skip_spaces(ptr + 5);
151
152 for (i = 0; i < MTRR_NUM_TYPES; ++i) {
153 if (strcmp(ptr, mtrr_strings[i]))
154 continue;
155 base >>= PAGE_SHIFT;
156 size >>= PAGE_SHIFT;
157 err = mtrr_add_page((unsigned long)base, (unsigned long)size, i, true);
158 if (err < 0)
159 return err;
160 return len;
161 }
162 return -EINVAL;
163 }
164
165 static long
mtrr_ioctl(struct file * file,unsigned int cmd,unsigned long __arg)166 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
167 {
168 int err = 0;
169 mtrr_type type;
170 unsigned long base;
171 unsigned long size;
172 struct mtrr_sentry sentry;
173 struct mtrr_gentry gentry;
174 void __user *arg = (void __user *) __arg;
175
176 switch (cmd) {
177 case MTRRIOC_ADD_ENTRY:
178 case MTRRIOC_SET_ENTRY:
179 case MTRRIOC_DEL_ENTRY:
180 case MTRRIOC_KILL_ENTRY:
181 case MTRRIOC_ADD_PAGE_ENTRY:
182 case MTRRIOC_SET_PAGE_ENTRY:
183 case MTRRIOC_DEL_PAGE_ENTRY:
184 case MTRRIOC_KILL_PAGE_ENTRY:
185 if (copy_from_user(&sentry, arg, sizeof sentry))
186 return -EFAULT;
187 break;
188 case MTRRIOC_GET_ENTRY:
189 case MTRRIOC_GET_PAGE_ENTRY:
190 if (copy_from_user(&gentry, arg, sizeof gentry))
191 return -EFAULT;
192 break;
193 #ifdef CONFIG_COMPAT
194 case MTRRIOC32_ADD_ENTRY:
195 case MTRRIOC32_SET_ENTRY:
196 case MTRRIOC32_DEL_ENTRY:
197 case MTRRIOC32_KILL_ENTRY:
198 case MTRRIOC32_ADD_PAGE_ENTRY:
199 case MTRRIOC32_SET_PAGE_ENTRY:
200 case MTRRIOC32_DEL_PAGE_ENTRY:
201 case MTRRIOC32_KILL_PAGE_ENTRY: {
202 struct mtrr_sentry32 __user *s32;
203
204 s32 = (struct mtrr_sentry32 __user *)__arg;
205 err = get_user(sentry.base, &s32->base);
206 err |= get_user(sentry.size, &s32->size);
207 err |= get_user(sentry.type, &s32->type);
208 if (err)
209 return err;
210 break;
211 }
212 case MTRRIOC32_GET_ENTRY:
213 case MTRRIOC32_GET_PAGE_ENTRY: {
214 struct mtrr_gentry32 __user *g32;
215
216 g32 = (struct mtrr_gentry32 __user *)__arg;
217 err = get_user(gentry.regnum, &g32->regnum);
218 err |= get_user(gentry.base, &g32->base);
219 err |= get_user(gentry.size, &g32->size);
220 err |= get_user(gentry.type, &g32->type);
221 if (err)
222 return err;
223 break;
224 }
225 #endif
226 }
227
228 switch (cmd) {
229 default:
230 return -ENOTTY;
231 case MTRRIOC_ADD_ENTRY:
232 #ifdef CONFIG_COMPAT
233 case MTRRIOC32_ADD_ENTRY:
234 #endif
235 if (!capable(CAP_SYS_ADMIN))
236 return -EPERM;
237 err =
238 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
239 file, 0);
240 break;
241 case MTRRIOC_SET_ENTRY:
242 #ifdef CONFIG_COMPAT
243 case MTRRIOC32_SET_ENTRY:
244 #endif
245 if (!capable(CAP_SYS_ADMIN))
246 return -EPERM;
247 err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
248 break;
249 case MTRRIOC_DEL_ENTRY:
250 #ifdef CONFIG_COMPAT
251 case MTRRIOC32_DEL_ENTRY:
252 #endif
253 if (!capable(CAP_SYS_ADMIN))
254 return -EPERM;
255 err = mtrr_file_del(sentry.base, sentry.size, file, 0);
256 break;
257 case MTRRIOC_KILL_ENTRY:
258 #ifdef CONFIG_COMPAT
259 case MTRRIOC32_KILL_ENTRY:
260 #endif
261 if (!capable(CAP_SYS_ADMIN))
262 return -EPERM;
263 err = mtrr_del(-1, sentry.base, sentry.size);
264 break;
265 case MTRRIOC_GET_ENTRY:
266 #ifdef CONFIG_COMPAT
267 case MTRRIOC32_GET_ENTRY:
268 #endif
269 if (gentry.regnum >= num_var_ranges)
270 return -EINVAL;
271 mtrr_if->get(gentry.regnum, &base, &size, &type);
272
273 /* Hide entries that go above 4GB */
274 if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
275 || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
276 gentry.base = gentry.size = gentry.type = 0;
277 else {
278 gentry.base = base << PAGE_SHIFT;
279 gentry.size = size << PAGE_SHIFT;
280 gentry.type = type;
281 }
282
283 break;
284 case MTRRIOC_ADD_PAGE_ENTRY:
285 #ifdef CONFIG_COMPAT
286 case MTRRIOC32_ADD_PAGE_ENTRY:
287 #endif
288 if (!capable(CAP_SYS_ADMIN))
289 return -EPERM;
290 err =
291 mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
292 file, 1);
293 break;
294 case MTRRIOC_SET_PAGE_ENTRY:
295 #ifdef CONFIG_COMPAT
296 case MTRRIOC32_SET_PAGE_ENTRY:
297 #endif
298 if (!capable(CAP_SYS_ADMIN))
299 return -EPERM;
300 err =
301 mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
302 break;
303 case MTRRIOC_DEL_PAGE_ENTRY:
304 #ifdef CONFIG_COMPAT
305 case MTRRIOC32_DEL_PAGE_ENTRY:
306 #endif
307 if (!capable(CAP_SYS_ADMIN))
308 return -EPERM;
309 err = mtrr_file_del(sentry.base, sentry.size, file, 1);
310 break;
311 case MTRRIOC_KILL_PAGE_ENTRY:
312 #ifdef CONFIG_COMPAT
313 case MTRRIOC32_KILL_PAGE_ENTRY:
314 #endif
315 if (!capable(CAP_SYS_ADMIN))
316 return -EPERM;
317 err = mtrr_del_page(-1, sentry.base, sentry.size);
318 break;
319 case MTRRIOC_GET_PAGE_ENTRY:
320 #ifdef CONFIG_COMPAT
321 case MTRRIOC32_GET_PAGE_ENTRY:
322 #endif
323 if (gentry.regnum >= num_var_ranges)
324 return -EINVAL;
325 mtrr_if->get(gentry.regnum, &base, &size, &type);
326 /* Hide entries that would overflow */
327 if (size != (__typeof__(gentry.size))size)
328 gentry.base = gentry.size = gentry.type = 0;
329 else {
330 gentry.base = base;
331 gentry.size = size;
332 gentry.type = type;
333 }
334 break;
335 }
336
337 if (err)
338 return err;
339
340 switch (cmd) {
341 case MTRRIOC_GET_ENTRY:
342 case MTRRIOC_GET_PAGE_ENTRY:
343 if (copy_to_user(arg, &gentry, sizeof gentry))
344 err = -EFAULT;
345 break;
346 #ifdef CONFIG_COMPAT
347 case MTRRIOC32_GET_ENTRY:
348 case MTRRIOC32_GET_PAGE_ENTRY: {
349 struct mtrr_gentry32 __user *g32;
350
351 g32 = (struct mtrr_gentry32 __user *)__arg;
352 err = put_user(gentry.base, &g32->base);
353 err |= put_user(gentry.size, &g32->size);
354 err |= put_user(gentry.regnum, &g32->regnum);
355 err |= put_user(gentry.type, &g32->type);
356 break;
357 }
358 #endif
359 }
360 return err;
361 }
362
mtrr_close(struct inode * ino,struct file * file)363 static int mtrr_close(struct inode *ino, struct file *file)
364 {
365 unsigned int *fcount = FILE_FCOUNT(file);
366 int i, max;
367
368 if (fcount != NULL) {
369 max = num_var_ranges;
370 for (i = 0; i < max; ++i) {
371 while (fcount[i] > 0) {
372 mtrr_del(i, 0, 0);
373 --fcount[i];
374 }
375 }
376 kfree(fcount);
377 FILE_FCOUNT(file) = NULL;
378 }
379 return single_release(ino, file);
380 }
381
382 static int mtrr_seq_show(struct seq_file *seq, void *offset);
383
mtrr_open(struct inode * inode,struct file * file)384 static int mtrr_open(struct inode *inode, struct file *file)
385 {
386 if (!mtrr_if)
387 return -EIO;
388 if (!mtrr_if->get)
389 return -ENXIO;
390 return single_open(file, mtrr_seq_show, NULL);
391 }
392
393 static const struct file_operations mtrr_fops = {
394 .owner = THIS_MODULE,
395 .open = mtrr_open,
396 .read = seq_read,
397 .llseek = seq_lseek,
398 .write = mtrr_write,
399 .unlocked_ioctl = mtrr_ioctl,
400 .compat_ioctl = mtrr_ioctl,
401 .release = mtrr_close,
402 };
403
mtrr_seq_show(struct seq_file * seq,void * offset)404 static int mtrr_seq_show(struct seq_file *seq, void *offset)
405 {
406 char factor;
407 int i, max, len;
408 mtrr_type type;
409 unsigned long base, size;
410
411 len = 0;
412 max = num_var_ranges;
413 for (i = 0; i < max; i++) {
414 mtrr_if->get(i, &base, &size, &type);
415 if (size == 0) {
416 mtrr_usage_table[i] = 0;
417 continue;
418 }
419 if (size < (0x100000 >> PAGE_SHIFT)) {
420 /* less than 1MB */
421 factor = 'K';
422 size <<= PAGE_SHIFT - 10;
423 } else {
424 factor = 'M';
425 size >>= 20 - PAGE_SHIFT;
426 }
427 /* Base can be > 32bit */
428 len += seq_printf(seq, "reg%02i: base=0x%06lx000 "
429 "(%5luMB), size=%5lu%cB, count=%d: %s\n",
430 i, base, base >> (20 - PAGE_SHIFT), size,
431 factor, mtrr_usage_table[i],
432 mtrr_attrib_to_str(type));
433 }
434 return 0;
435 }
436
mtrr_if_init(void)437 static int __init mtrr_if_init(void)
438 {
439 struct cpuinfo_x86 *c = &boot_cpu_data;
440
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)))
445 return -ENODEV;
446
447 proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
448 return 0;
449 }
450 arch_initcall(mtrr_if_init);
451 #endif /* CONFIG_PROC_FS */
452