xref: /openbmc/linux/arch/x86/kernel/ksysfs.c (revision ca55b2fe) 
1 /*
2  * Architecture specific sysfs attributes in /sys/kernel
3  *
4  * Copyright (C) 2007, Intel Corp.
5  *      Huang Ying <ying.huang@intel.com>
6  * Copyright (C) 2013, 2013 Red Hat, Inc.
7  *      Dave Young <dyoung@redhat.com>
8  *
9  * This file is released under the GPLv2
10  */
11 
12 #include <linux/kobject.h>
13 #include <linux/string.h>
14 #include <linux/sysfs.h>
15 #include <linux/init.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
18 #include <linux/mm.h>
19 
20 #include <asm/io.h>
21 #include <asm/setup.h>
22 
23 static ssize_t version_show(struct kobject *kobj,
24 			    struct kobj_attribute *attr, char *buf)
25 {
26 	return sprintf(buf, "0x%04x\n", boot_params.hdr.version);
27 }
28 
29 static struct kobj_attribute boot_params_version_attr = __ATTR_RO(version);
30 
31 static ssize_t boot_params_data_read(struct file *fp, struct kobject *kobj,
32 				     struct bin_attribute *bin_attr,
33 				     char *buf, loff_t off, size_t count)
34 {
35 	memcpy(buf, (void *)&boot_params + off, count);
36 	return count;
37 }
38 
39 static struct bin_attribute boot_params_data_attr = {
40 	.attr = {
41 		.name = "data",
42 		.mode = S_IRUGO,
43 	},
44 	.read = boot_params_data_read,
45 	.size = sizeof(boot_params),
46 };
47 
48 static struct attribute *boot_params_version_attrs[] = {
49 	&boot_params_version_attr.attr,
50 	NULL,
51 };
52 
53 static struct bin_attribute *boot_params_data_attrs[] = {
54 	&boot_params_data_attr,
55 	NULL,
56 };
57 
58 static struct attribute_group boot_params_attr_group = {
59 	.attrs = boot_params_version_attrs,
60 	.bin_attrs = boot_params_data_attrs,
61 };
62 
63 static int kobj_to_setup_data_nr(struct kobject *kobj, int *nr)
64 {
65 	const char *name;
66 
67 	name = kobject_name(kobj);
68 	return kstrtoint(name, 10, nr);
69 }
70 
71 static int get_setup_data_paddr(int nr, u64 *paddr)
72 {
73 	int i = 0;
74 	struct setup_data *data;
75 	u64 pa_data = boot_params.hdr.setup_data;
76 
77 	while (pa_data) {
78 		if (nr == i) {
79 			*paddr = pa_data;
80 			return 0;
81 		}
82 		data = ioremap_cache(pa_data, sizeof(*data));
83 		if (!data)
84 			return -ENOMEM;
85 
86 		pa_data = data->next;
87 		iounmap(data);
88 		i++;
89 	}
90 	return -EINVAL;
91 }
92 
93 static int __init get_setup_data_size(int nr, size_t *size)
94 {
95 	int i = 0;
96 	struct setup_data *data;
97 	u64 pa_data = boot_params.hdr.setup_data;
98 
99 	while (pa_data) {
100 		data = ioremap_cache(pa_data, sizeof(*data));
101 		if (!data)
102 			return -ENOMEM;
103 		if (nr == i) {
104 			*size = data->len;
105 			iounmap(data);
106 			return 0;
107 		}
108 
109 		pa_data = data->next;
110 		iounmap(data);
111 		i++;
112 	}
113 	return -EINVAL;
114 }
115 
116 static ssize_t type_show(struct kobject *kobj,
117 			 struct kobj_attribute *attr, char *buf)
118 {
119 	int nr, ret;
120 	u64 paddr;
121 	struct setup_data *data;
122 
123 	ret = kobj_to_setup_data_nr(kobj, &nr);
124 	if (ret)
125 		return ret;
126 
127 	ret = get_setup_data_paddr(nr, &paddr);
128 	if (ret)
129 		return ret;
130 	data = ioremap_cache(paddr, sizeof(*data));
131 	if (!data)
132 		return -ENOMEM;
133 
134 	ret = sprintf(buf, "0x%x\n", data->type);
135 	iounmap(data);
136 	return ret;
137 }
138 
139 static ssize_t setup_data_data_read(struct file *fp,
140 				    struct kobject *kobj,
141 				    struct bin_attribute *bin_attr,
142 				    char *buf,
143 				    loff_t off, size_t count)
144 {
145 	int nr, ret = 0;
146 	u64 paddr;
147 	struct setup_data *data;
148 	void *p;
149 
150 	ret = kobj_to_setup_data_nr(kobj, &nr);
151 	if (ret)
152 		return ret;
153 
154 	ret = get_setup_data_paddr(nr, &paddr);
155 	if (ret)
156 		return ret;
157 	data = ioremap_cache(paddr, sizeof(*data));
158 	if (!data)
159 		return -ENOMEM;
160 
161 	if (off > data->len) {
162 		ret = -EINVAL;
163 		goto out;
164 	}
165 
166 	if (count > data->len - off)
167 		count = data->len - off;
168 
169 	if (!count)
170 		goto out;
171 
172 	ret = count;
173 	p = ioremap_cache(paddr + sizeof(*data), data->len);
174 	if (!p) {
175 		ret = -ENOMEM;
176 		goto out;
177 	}
178 	memcpy(buf, p + off, count);
179 	iounmap(p);
180 out:
181 	iounmap(data);
182 	return ret;
183 }
184 
185 static struct kobj_attribute type_attr = __ATTR_RO(type);
186 
187 static struct bin_attribute data_attr = {
188 	.attr = {
189 		.name = "data",
190 		.mode = S_IRUGO,
191 	},
192 	.read = setup_data_data_read,
193 };
194 
195 static struct attribute *setup_data_type_attrs[] = {
196 	&type_attr.attr,
197 	NULL,
198 };
199 
200 static struct bin_attribute *setup_data_data_attrs[] = {
201 	&data_attr,
202 	NULL,
203 };
204 
205 static struct attribute_group setup_data_attr_group = {
206 	.attrs = setup_data_type_attrs,
207 	.bin_attrs = setup_data_data_attrs,
208 };
209 
210 static int __init create_setup_data_node(struct kobject *parent,
211 					 struct kobject **kobjp, int nr)
212 {
213 	int ret = 0;
214 	size_t size;
215 	struct kobject *kobj;
216 	char name[16]; /* should be enough for setup_data nodes numbers */
217 	snprintf(name, 16, "%d", nr);
218 
219 	kobj = kobject_create_and_add(name, parent);
220 	if (!kobj)
221 		return -ENOMEM;
222 
223 	ret = get_setup_data_size(nr, &size);
224 	if (ret)
225 		goto out_kobj;
226 
227 	data_attr.size = size;
228 	ret = sysfs_create_group(kobj, &setup_data_attr_group);
229 	if (ret)
230 		goto out_kobj;
231 	*kobjp = kobj;
232 
233 	return 0;
234 out_kobj:
235 	kobject_put(kobj);
236 	return ret;
237 }
238 
239 static void __init cleanup_setup_data_node(struct kobject *kobj)
240 {
241 	sysfs_remove_group(kobj, &setup_data_attr_group);
242 	kobject_put(kobj);
243 }
244 
245 static int __init get_setup_data_total_num(u64 pa_data, int *nr)
246 {
247 	int ret = 0;
248 	struct setup_data *data;
249 
250 	*nr = 0;
251 	while (pa_data) {
252 		*nr += 1;
253 		data = ioremap_cache(pa_data, sizeof(*data));
254 		if (!data) {
255 			ret = -ENOMEM;
256 			goto out;
257 		}
258 		pa_data = data->next;
259 		iounmap(data);
260 	}
261 
262 out:
263 	return ret;
264 }
265 
266 static int __init create_setup_data_nodes(struct kobject *parent)
267 {
268 	struct kobject *setup_data_kobj, **kobjp;
269 	u64 pa_data;
270 	int i, j, nr, ret = 0;
271 
272 	pa_data = boot_params.hdr.setup_data;
273 	if (!pa_data)
274 		return 0;
275 
276 	setup_data_kobj = kobject_create_and_add("setup_data", parent);
277 	if (!setup_data_kobj) {
278 		ret = -ENOMEM;
279 		goto out;
280 	}
281 
282 	ret = get_setup_data_total_num(pa_data, &nr);
283 	if (ret)
284 		goto out_setup_data_kobj;
285 
286 	kobjp = kmalloc(sizeof(*kobjp) * nr, GFP_KERNEL);
287 	if (!kobjp) {
288 		ret = -ENOMEM;
289 		goto out_setup_data_kobj;
290 	}
291 
292 	for (i = 0; i < nr; i++) {
293 		ret = create_setup_data_node(setup_data_kobj, kobjp + i, i);
294 		if (ret)
295 			goto out_clean_nodes;
296 	}
297 
298 	kfree(kobjp);
299 	return 0;
300 
301 out_clean_nodes:
302 	for (j = i - 1; j > 0; j--)
303 		cleanup_setup_data_node(*(kobjp + j));
304 	kfree(kobjp);
305 out_setup_data_kobj:
306 	kobject_put(setup_data_kobj);
307 out:
308 	return ret;
309 }
310 
311 static int __init boot_params_ksysfs_init(void)
312 {
313 	int ret;
314 	struct kobject *boot_params_kobj;
315 
316 	boot_params_kobj = kobject_create_and_add("boot_params",
317 						  kernel_kobj);
318 	if (!boot_params_kobj) {
319 		ret = -ENOMEM;
320 		goto out;
321 	}
322 
323 	ret = sysfs_create_group(boot_params_kobj, &boot_params_attr_group);
324 	if (ret)
325 		goto out_boot_params_kobj;
326 
327 	ret = create_setup_data_nodes(boot_params_kobj);
328 	if (ret)
329 		goto out_create_group;
330 
331 	return 0;
332 out_create_group:
333 	sysfs_remove_group(boot_params_kobj, &boot_params_attr_group);
334 out_boot_params_kobj:
335 	kobject_put(boot_params_kobj);
336 out:
337 	return ret;
338 }
339 
340 arch_initcall(boot_params_ksysfs_init);
341