1 /*
2  * Error log support on PowerNV.
3  *
4  * Copyright 2013,2014 IBM Corp.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/of.h>
14 #include <linux/slab.h>
15 #include <linux/sysfs.h>
16 #include <linux/fs.h>
17 #include <linux/vmalloc.h>
18 #include <linux/fcntl.h>
19 #include <linux/kobject.h>
20 #include <asm/uaccess.h>
21 #include <asm/opal.h>
22 
23 struct elog_obj {
24 	struct kobject kobj;
25 	struct bin_attribute raw_attr;
26 	uint64_t id;
27 	uint64_t type;
28 	size_t size;
29 	char *buffer;
30 };
31 #define to_elog_obj(x) container_of(x, struct elog_obj, kobj)
32 
33 struct elog_attribute {
34 	struct attribute attr;
35 	ssize_t (*show)(struct elog_obj *elog, struct elog_attribute *attr,
36 			char *buf);
37 	ssize_t (*store)(struct elog_obj *elog, struct elog_attribute *attr,
38 			 const char *buf, size_t count);
39 };
40 #define to_elog_attr(x) container_of(x, struct elog_attribute, attr)
41 
42 static ssize_t elog_id_show(struct elog_obj *elog_obj,
43 			    struct elog_attribute *attr,
44 			    char *buf)
45 {
46 	return sprintf(buf, "0x%llx\n", elog_obj->id);
47 }
48 
49 static const char *elog_type_to_string(uint64_t type)
50 {
51 	switch (type) {
52 	case 0: return "PEL";
53 	default: return "unknown";
54 	}
55 }
56 
57 static ssize_t elog_type_show(struct elog_obj *elog_obj,
58 			      struct elog_attribute *attr,
59 			      char *buf)
60 {
61 	return sprintf(buf, "0x%llx %s\n",
62 		       elog_obj->type,
63 		       elog_type_to_string(elog_obj->type));
64 }
65 
66 static ssize_t elog_ack_show(struct elog_obj *elog_obj,
67 			     struct elog_attribute *attr,
68 			     char *buf)
69 {
70 	return sprintf(buf, "ack - acknowledge log message\n");
71 }
72 
73 static ssize_t elog_ack_store(struct elog_obj *elog_obj,
74 			      struct elog_attribute *attr,
75 			      const char *buf,
76 			      size_t count)
77 {
78 	opal_send_ack_elog(elog_obj->id);
79 	sysfs_remove_file_self(&elog_obj->kobj, &attr->attr);
80 	kobject_put(&elog_obj->kobj);
81 	return count;
82 }
83 
84 static struct elog_attribute id_attribute =
85 	__ATTR(id, 0666, elog_id_show, NULL);
86 static struct elog_attribute type_attribute =
87 	__ATTR(type, 0666, elog_type_show, NULL);
88 static struct elog_attribute ack_attribute =
89 	__ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store);
90 
91 static struct kset *elog_kset;
92 
93 static ssize_t elog_attr_show(struct kobject *kobj,
94 			      struct attribute *attr,
95 			      char *buf)
96 {
97 	struct elog_attribute *attribute;
98 	struct elog_obj *elog;
99 
100 	attribute = to_elog_attr(attr);
101 	elog = to_elog_obj(kobj);
102 
103 	if (!attribute->show)
104 		return -EIO;
105 
106 	return attribute->show(elog, attribute, buf);
107 }
108 
109 static ssize_t elog_attr_store(struct kobject *kobj,
110 			       struct attribute *attr,
111 			       const char *buf, size_t len)
112 {
113 	struct elog_attribute *attribute;
114 	struct elog_obj *elog;
115 
116 	attribute = to_elog_attr(attr);
117 	elog = to_elog_obj(kobj);
118 
119 	if (!attribute->store)
120 		return -EIO;
121 
122 	return attribute->store(elog, attribute, buf, len);
123 }
124 
125 static const struct sysfs_ops elog_sysfs_ops = {
126 	.show = elog_attr_show,
127 	.store = elog_attr_store,
128 };
129 
130 static void elog_release(struct kobject *kobj)
131 {
132 	struct elog_obj *elog;
133 
134 	elog = to_elog_obj(kobj);
135 	kfree(elog->buffer);
136 	kfree(elog);
137 }
138 
139 static struct attribute *elog_default_attrs[] = {
140 	&id_attribute.attr,
141 	&type_attribute.attr,
142 	&ack_attribute.attr,
143 	NULL,
144 };
145 
146 static struct kobj_type elog_ktype = {
147 	.sysfs_ops = &elog_sysfs_ops,
148 	.release = &elog_release,
149 	.default_attrs = elog_default_attrs,
150 };
151 
152 /* Maximum size of a single log on FSP is 16KB */
153 #define OPAL_MAX_ERRLOG_SIZE	16384
154 
155 static ssize_t raw_attr_read(struct file *filep, struct kobject *kobj,
156 			     struct bin_attribute *bin_attr,
157 			     char *buffer, loff_t pos, size_t count)
158 {
159 	int opal_rc;
160 
161 	struct elog_obj *elog = to_elog_obj(kobj);
162 
163 	/* We may have had an error reading before, so let's retry */
164 	if (!elog->buffer) {
165 		elog->buffer = kzalloc(elog->size, GFP_KERNEL);
166 		if (!elog->buffer)
167 			return -EIO;
168 
169 		opal_rc = opal_read_elog(__pa(elog->buffer),
170 					 elog->size, elog->id);
171 		if (opal_rc != OPAL_SUCCESS) {
172 			pr_err("ELOG: log read failed for log-id=%llx\n",
173 			       elog->id);
174 			kfree(elog->buffer);
175 			elog->buffer = NULL;
176 			return -EIO;
177 		}
178 	}
179 
180 	memcpy(buffer, elog->buffer + pos, count);
181 
182 	return count;
183 }
184 
185 static struct elog_obj *create_elog_obj(uint64_t id, size_t size, uint64_t type)
186 {
187 	struct elog_obj *elog;
188 	int rc;
189 
190 	elog = kzalloc(sizeof(*elog), GFP_KERNEL);
191 	if (!elog)
192 		return NULL;
193 
194 	elog->kobj.kset = elog_kset;
195 
196 	kobject_init(&elog->kobj, &elog_ktype);
197 
198 	sysfs_bin_attr_init(&elog->raw_attr);
199 
200 	elog->raw_attr.attr.name = "raw";
201 	elog->raw_attr.attr.mode = 0400;
202 	elog->raw_attr.size = size;
203 	elog->raw_attr.read = raw_attr_read;
204 
205 	elog->id = id;
206 	elog->size = size;
207 	elog->type = type;
208 
209 	elog->buffer = kzalloc(elog->size, GFP_KERNEL);
210 
211 	if (elog->buffer) {
212 		rc = opal_read_elog(__pa(elog->buffer),
213 					 elog->size, elog->id);
214 		if (rc != OPAL_SUCCESS) {
215 			pr_err("ELOG: log read failed for log-id=%llx\n",
216 			       elog->id);
217 			kfree(elog->buffer);
218 			elog->buffer = NULL;
219 		}
220 	}
221 
222 	rc = kobject_add(&elog->kobj, NULL, "0x%llx", id);
223 	if (rc) {
224 		kobject_put(&elog->kobj);
225 		return NULL;
226 	}
227 
228 	rc = sysfs_create_bin_file(&elog->kobj, &elog->raw_attr);
229 	if (rc) {
230 		kobject_put(&elog->kobj);
231 		return NULL;
232 	}
233 
234 	kobject_uevent(&elog->kobj, KOBJ_ADD);
235 
236 	return elog;
237 }
238 
239 static void elog_work_fn(struct work_struct *work)
240 {
241 	__be64 size;
242 	__be64 id;
243 	__be64 type;
244 	uint64_t elog_size;
245 	uint64_t log_id;
246 	uint64_t elog_type;
247 	int rc;
248 	char name[2+16+1];
249 
250 	rc = opal_get_elog_size(&id, &size, &type);
251 	if (rc != OPAL_SUCCESS) {
252 		pr_err("ELOG: Opal log read failed\n");
253 		return;
254 	}
255 
256 	elog_size = be64_to_cpu(size);
257 	log_id = be64_to_cpu(id);
258 	elog_type = be64_to_cpu(type);
259 
260 	BUG_ON(elog_size > OPAL_MAX_ERRLOG_SIZE);
261 
262 	if (elog_size >= OPAL_MAX_ERRLOG_SIZE)
263 		elog_size  =  OPAL_MAX_ERRLOG_SIZE;
264 
265 	sprintf(name, "0x%llx", log_id);
266 
267 	/* we may get notified twice, let's handle
268 	 * that gracefully and not create two conflicting
269 	 * entries.
270 	 */
271 	if (kset_find_obj(elog_kset, name))
272 		return;
273 
274 	create_elog_obj(log_id, elog_size, elog_type);
275 }
276 
277 static DECLARE_WORK(elog_work, elog_work_fn);
278 
279 static int elog_event(struct notifier_block *nb,
280 				unsigned long events, void *change)
281 {
282 	/* check for error log event */
283 	if (events & OPAL_EVENT_ERROR_LOG_AVAIL)
284 		schedule_work(&elog_work);
285 	return 0;
286 }
287 
288 static struct notifier_block elog_nb = {
289 	.notifier_call  = elog_event,
290 	.next           = NULL,
291 	.priority       = 0
292 };
293 
294 int __init opal_elog_init(void)
295 {
296 	int rc = 0;
297 
298 	elog_kset = kset_create_and_add("elog", NULL, opal_kobj);
299 	if (!elog_kset) {
300 		pr_warn("%s: failed to create elog kset\n", __func__);
301 		return -1;
302 	}
303 
304 	rc = opal_notifier_register(&elog_nb);
305 	if (rc) {
306 		pr_err("%s: Can't register OPAL event notifier (%d)\n",
307 		__func__, rc);
308 		return rc;
309 	}
310 
311 	/* We are now ready to pull error logs from opal. */
312 	opal_resend_pending_logs();
313 
314 	return 0;
315 }
316