xref: /openbmc/linux/arch/x86/kernel/cpu/mtrr/if.c (revision 4800cd83)
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 
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 = 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
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 	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
166 mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
167 {
168 	int err = 0;
169 	mtrr_type type;
170 	unsigned long size;
171 	struct mtrr_sentry sentry;
172 	struct mtrr_gentry gentry;
173 	void __user *arg = (void __user *) __arg;
174 
175 	switch (cmd) {
176 	case MTRRIOC_ADD_ENTRY:
177 	case MTRRIOC_SET_ENTRY:
178 	case MTRRIOC_DEL_ENTRY:
179 	case MTRRIOC_KILL_ENTRY:
180 	case MTRRIOC_ADD_PAGE_ENTRY:
181 	case MTRRIOC_SET_PAGE_ENTRY:
182 	case MTRRIOC_DEL_PAGE_ENTRY:
183 	case MTRRIOC_KILL_PAGE_ENTRY:
184 		if (copy_from_user(&sentry, arg, sizeof sentry))
185 			return -EFAULT;
186 		break;
187 	case MTRRIOC_GET_ENTRY:
188 	case MTRRIOC_GET_PAGE_ENTRY:
189 		if (copy_from_user(&gentry, arg, sizeof gentry))
190 			return -EFAULT;
191 		break;
192 #ifdef CONFIG_COMPAT
193 	case MTRRIOC32_ADD_ENTRY:
194 	case MTRRIOC32_SET_ENTRY:
195 	case MTRRIOC32_DEL_ENTRY:
196 	case MTRRIOC32_KILL_ENTRY:
197 	case MTRRIOC32_ADD_PAGE_ENTRY:
198 	case MTRRIOC32_SET_PAGE_ENTRY:
199 	case MTRRIOC32_DEL_PAGE_ENTRY:
200 	case MTRRIOC32_KILL_PAGE_ENTRY: {
201 		struct mtrr_sentry32 __user *s32;
202 
203 		s32 = (struct mtrr_sentry32 __user *)__arg;
204 		err = get_user(sentry.base, &s32->base);
205 		err |= get_user(sentry.size, &s32->size);
206 		err |= get_user(sentry.type, &s32->type);
207 		if (err)
208 			return err;
209 		break;
210 	}
211 	case MTRRIOC32_GET_ENTRY:
212 	case MTRRIOC32_GET_PAGE_ENTRY: {
213 		struct mtrr_gentry32 __user *g32;
214 
215 		g32 = (struct mtrr_gentry32 __user *)__arg;
216 		err = get_user(gentry.regnum, &g32->regnum);
217 		err |= get_user(gentry.base, &g32->base);
218 		err |= get_user(gentry.size, &g32->size);
219 		err |= get_user(gentry.type, &g32->type);
220 		if (err)
221 			return err;
222 		break;
223 	}
224 #endif
225 	}
226 
227 	switch (cmd) {
228 	default:
229 		return -ENOTTY;
230 	case MTRRIOC_ADD_ENTRY:
231 #ifdef CONFIG_COMPAT
232 	case MTRRIOC32_ADD_ENTRY:
233 #endif
234 		if (!capable(CAP_SYS_ADMIN))
235 			return -EPERM;
236 		err =
237 		    mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
238 				  file, 0);
239 		break;
240 	case MTRRIOC_SET_ENTRY:
241 #ifdef CONFIG_COMPAT
242 	case MTRRIOC32_SET_ENTRY:
243 #endif
244 		if (!capable(CAP_SYS_ADMIN))
245 			return -EPERM;
246 		err = mtrr_add(sentry.base, sentry.size, sentry.type, false);
247 		break;
248 	case MTRRIOC_DEL_ENTRY:
249 #ifdef CONFIG_COMPAT
250 	case MTRRIOC32_DEL_ENTRY:
251 #endif
252 		if (!capable(CAP_SYS_ADMIN))
253 			return -EPERM;
254 		err = mtrr_file_del(sentry.base, sentry.size, file, 0);
255 		break;
256 	case MTRRIOC_KILL_ENTRY:
257 #ifdef CONFIG_COMPAT
258 	case MTRRIOC32_KILL_ENTRY:
259 #endif
260 		if (!capable(CAP_SYS_ADMIN))
261 			return -EPERM;
262 		err = mtrr_del(-1, sentry.base, sentry.size);
263 		break;
264 	case MTRRIOC_GET_ENTRY:
265 #ifdef CONFIG_COMPAT
266 	case MTRRIOC32_GET_ENTRY:
267 #endif
268 		if (gentry.regnum >= num_var_ranges)
269 			return -EINVAL;
270 		mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
271 
272 		/* Hide entries that go above 4GB */
273 		if (gentry.base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
274 		    || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
275 			gentry.base = gentry.size = gentry.type = 0;
276 		else {
277 			gentry.base <<= PAGE_SHIFT;
278 			gentry.size = size << PAGE_SHIFT;
279 			gentry.type = type;
280 		}
281 
282 		break;
283 	case MTRRIOC_ADD_PAGE_ENTRY:
284 #ifdef CONFIG_COMPAT
285 	case MTRRIOC32_ADD_PAGE_ENTRY:
286 #endif
287 		if (!capable(CAP_SYS_ADMIN))
288 			return -EPERM;
289 		err =
290 		    mtrr_file_add(sentry.base, sentry.size, sentry.type, true,
291 				  file, 1);
292 		break;
293 	case MTRRIOC_SET_PAGE_ENTRY:
294 #ifdef CONFIG_COMPAT
295 	case MTRRIOC32_SET_PAGE_ENTRY:
296 #endif
297 		if (!capable(CAP_SYS_ADMIN))
298 			return -EPERM;
299 		err =
300 		    mtrr_add_page(sentry.base, sentry.size, sentry.type, false);
301 		break;
302 	case MTRRIOC_DEL_PAGE_ENTRY:
303 #ifdef CONFIG_COMPAT
304 	case MTRRIOC32_DEL_PAGE_ENTRY:
305 #endif
306 		if (!capable(CAP_SYS_ADMIN))
307 			return -EPERM;
308 		err = mtrr_file_del(sentry.base, sentry.size, file, 1);
309 		break;
310 	case MTRRIOC_KILL_PAGE_ENTRY:
311 #ifdef CONFIG_COMPAT
312 	case MTRRIOC32_KILL_PAGE_ENTRY:
313 #endif
314 		if (!capable(CAP_SYS_ADMIN))
315 			return -EPERM;
316 		err = mtrr_del_page(-1, sentry.base, sentry.size);
317 		break;
318 	case MTRRIOC_GET_PAGE_ENTRY:
319 #ifdef CONFIG_COMPAT
320 	case MTRRIOC32_GET_PAGE_ENTRY:
321 #endif
322 		if (gentry.regnum >= num_var_ranges)
323 			return -EINVAL;
324 		mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
325 		/* Hide entries that would overflow */
326 		if (size != (__typeof__(gentry.size))size)
327 			gentry.base = gentry.size = gentry.type = 0;
328 		else {
329 			gentry.size = size;
330 			gentry.type = type;
331 		}
332 		break;
333 	}
334 
335 	if (err)
336 		return err;
337 
338 	switch (cmd) {
339 	case MTRRIOC_GET_ENTRY:
340 	case MTRRIOC_GET_PAGE_ENTRY:
341 		if (copy_to_user(arg, &gentry, sizeof gentry))
342 			err = -EFAULT;
343 		break;
344 #ifdef CONFIG_COMPAT
345 	case MTRRIOC32_GET_ENTRY:
346 	case MTRRIOC32_GET_PAGE_ENTRY: {
347 		struct mtrr_gentry32 __user *g32;
348 
349 		g32 = (struct mtrr_gentry32 __user *)__arg;
350 		err = put_user(gentry.base, &g32->base);
351 		err |= put_user(gentry.size, &g32->size);
352 		err |= put_user(gentry.regnum, &g32->regnum);
353 		err |= put_user(gentry.type, &g32->type);
354 		break;
355 	}
356 #endif
357 	}
358 	return err;
359 }
360 
361 static int mtrr_close(struct inode *ino, struct file *file)
362 {
363 	unsigned int *fcount = FILE_FCOUNT(file);
364 	int i, max;
365 
366 	if (fcount != NULL) {
367 		max = num_var_ranges;
368 		for (i = 0; i < max; ++i) {
369 			while (fcount[i] > 0) {
370 				mtrr_del(i, 0, 0);
371 				--fcount[i];
372 			}
373 		}
374 		kfree(fcount);
375 		FILE_FCOUNT(file) = NULL;
376 	}
377 	return single_release(ino, file);
378 }
379 
380 static int mtrr_seq_show(struct seq_file *seq, void *offset);
381 
382 static int mtrr_open(struct inode *inode, struct file *file)
383 {
384 	if (!mtrr_if)
385 		return -EIO;
386 	if (!mtrr_if->get)
387 		return -ENXIO;
388 	return single_open(file, mtrr_seq_show, NULL);
389 }
390 
391 static const struct file_operations mtrr_fops = {
392 	.owner			= THIS_MODULE,
393 	.open			= mtrr_open,
394 	.read			= seq_read,
395 	.llseek			= seq_lseek,
396 	.write			= mtrr_write,
397 	.unlocked_ioctl		= mtrr_ioctl,
398 	.compat_ioctl		= mtrr_ioctl,
399 	.release		= mtrr_close,
400 };
401 
402 static int mtrr_seq_show(struct seq_file *seq, void *offset)
403 {
404 	char factor;
405 	int i, max, len;
406 	mtrr_type type;
407 	unsigned long base, size;
408 
409 	len = 0;
410 	max = num_var_ranges;
411 	for (i = 0; i < max; i++) {
412 		mtrr_if->get(i, &base, &size, &type);
413 		if (size == 0) {
414 			mtrr_usage_table[i] = 0;
415 			continue;
416 		}
417 		if (size < (0x100000 >> PAGE_SHIFT)) {
418 			/* less than 1MB */
419 			factor = 'K';
420 			size <<= PAGE_SHIFT - 10;
421 		} else {
422 			factor = 'M';
423 			size >>= 20 - PAGE_SHIFT;
424 		}
425 		/* Base can be > 32bit */
426 		len += seq_printf(seq, "reg%02i: base=0x%06lx000 "
427 			"(%5luMB), size=%5lu%cB, count=%d: %s\n",
428 			i, base, base >> (20 - PAGE_SHIFT), size,
429 			factor, mtrr_usage_table[i],
430 			mtrr_attrib_to_str(type));
431 	}
432 	return 0;
433 }
434 
435 static int __init mtrr_if_init(void)
436 {
437 	struct cpuinfo_x86 *c = &boot_cpu_data;
438 
439 	if ((!cpu_has(c, X86_FEATURE_MTRR)) &&
440 	    (!cpu_has(c, X86_FEATURE_K6_MTRR)) &&
441 	    (!cpu_has(c, X86_FEATURE_CYRIX_ARR)) &&
442 	    (!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
443 		return -ENODEV;
444 
445 	proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
446 	return 0;
447 }
448 arch_initcall(mtrr_if_init);
449 #endif			/*  CONFIG_PROC_FS  */
450