1 /*
2  * PowerNV OPAL Dump Interface
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 
12 #include <linux/kobject.h>
13 #include <linux/mm.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <linux/pagemap.h>
17 #include <linux/delay.h>
18 
19 #include <asm/opal.h>
20 
21 #define DUMP_TYPE_FSP	0x01
22 
23 struct dump_obj {
24 	struct kobject  kobj;
25 	struct bin_attribute dump_attr;
26 	uint32_t	id;  /* becomes object name */
27 	uint32_t	type;
28 	uint32_t	size;
29 	char		*buffer;
30 };
31 #define to_dump_obj(x) container_of(x, struct dump_obj, kobj)
32 
33 struct dump_attribute {
34 	struct attribute attr;
35 	ssize_t (*show)(struct dump_obj *dump, struct dump_attribute *attr,
36 			char *buf);
37 	ssize_t (*store)(struct dump_obj *dump, struct dump_attribute *attr,
38 			 const char *buf, size_t count);
39 };
40 #define to_dump_attr(x) container_of(x, struct dump_attribute, attr)
41 
42 static ssize_t dump_id_show(struct dump_obj *dump_obj,
43 			    struct dump_attribute *attr,
44 			    char *buf)
45 {
46 	return sprintf(buf, "0x%x\n", dump_obj->id);
47 }
48 
49 static const char* dump_type_to_string(uint32_t type)
50 {
51 	switch (type) {
52 	case 0x01: return "SP Dump";
53 	case 0x02: return "System/Platform Dump";
54 	case 0x03: return "SMA Dump";
55 	default: return "unknown";
56 	}
57 }
58 
59 static ssize_t dump_type_show(struct dump_obj *dump_obj,
60 			      struct dump_attribute *attr,
61 			      char *buf)
62 {
63 
64 	return sprintf(buf, "0x%x %s\n", dump_obj->type,
65 		       dump_type_to_string(dump_obj->type));
66 }
67 
68 static ssize_t dump_ack_show(struct dump_obj *dump_obj,
69 			     struct dump_attribute *attr,
70 			     char *buf)
71 {
72 	return sprintf(buf, "ack - acknowledge dump\n");
73 }
74 
75 /*
76  * Send acknowledgement to OPAL
77  */
78 static int64_t dump_send_ack(uint32_t dump_id)
79 {
80 	int rc;
81 
82 	rc = opal_dump_ack(dump_id);
83 	if (rc)
84 		pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
85 			__func__, dump_id, rc);
86 	return rc;
87 }
88 
89 static ssize_t dump_ack_store(struct dump_obj *dump_obj,
90 			      struct dump_attribute *attr,
91 			      const char *buf,
92 			      size_t count)
93 {
94 	dump_send_ack(dump_obj->id);
95 	sysfs_remove_file_self(&dump_obj->kobj, &attr->attr);
96 	kobject_put(&dump_obj->kobj);
97 	return count;
98 }
99 
100 /* Attributes of a dump
101  * The binary attribute of the dump itself is dynamic
102  * due to the dynamic size of the dump
103  */
104 static struct dump_attribute id_attribute =
105 	__ATTR(id, 0666, dump_id_show, NULL);
106 static struct dump_attribute type_attribute =
107 	__ATTR(type, 0666, dump_type_show, NULL);
108 static struct dump_attribute ack_attribute =
109 	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);
110 
111 static ssize_t init_dump_show(struct dump_obj *dump_obj,
112 			      struct dump_attribute *attr,
113 			      char *buf)
114 {
115 	return sprintf(buf, "1 - initiate dump\n");
116 }
117 
118 static int64_t dump_fips_init(uint8_t type)
119 {
120 	int rc;
121 
122 	rc = opal_dump_init(type);
123 	if (rc)
124 		pr_warn("%s: Failed to initiate FipS dump (%d)\n",
125 			__func__, rc);
126 	return rc;
127 }
128 
129 static ssize_t init_dump_store(struct dump_obj *dump_obj,
130 			       struct dump_attribute *attr,
131 			       const char *buf,
132 			       size_t count)
133 {
134 	dump_fips_init(DUMP_TYPE_FSP);
135 	pr_info("%s: Initiated FSP dump\n", __func__);
136 	return count;
137 }
138 
139 static struct dump_attribute initiate_attribute =
140 	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);
141 
142 static struct attribute *initiate_attrs[] = {
143 	&initiate_attribute.attr,
144 	NULL,
145 };
146 
147 static struct attribute_group initiate_attr_group = {
148 	.attrs = initiate_attrs,
149 };
150 
151 static struct kset *dump_kset;
152 
153 static ssize_t dump_attr_show(struct kobject *kobj,
154 			      struct attribute *attr,
155 			      char *buf)
156 {
157 	struct dump_attribute *attribute;
158 	struct dump_obj *dump;
159 
160 	attribute = to_dump_attr(attr);
161 	dump = to_dump_obj(kobj);
162 
163 	if (!attribute->show)
164 		return -EIO;
165 
166 	return attribute->show(dump, attribute, buf);
167 }
168 
169 static ssize_t dump_attr_store(struct kobject *kobj,
170 			       struct attribute *attr,
171 			       const char *buf, size_t len)
172 {
173 	struct dump_attribute *attribute;
174 	struct dump_obj *dump;
175 
176 	attribute = to_dump_attr(attr);
177 	dump = to_dump_obj(kobj);
178 
179 	if (!attribute->store)
180 		return -EIO;
181 
182 	return attribute->store(dump, attribute, buf, len);
183 }
184 
185 static const struct sysfs_ops dump_sysfs_ops = {
186 	.show = dump_attr_show,
187 	.store = dump_attr_store,
188 };
189 
190 static void dump_release(struct kobject *kobj)
191 {
192 	struct dump_obj *dump;
193 
194 	dump = to_dump_obj(kobj);
195 	vfree(dump->buffer);
196 	kfree(dump);
197 }
198 
199 static struct attribute *dump_default_attrs[] = {
200 	&id_attribute.attr,
201 	&type_attribute.attr,
202 	&ack_attribute.attr,
203 	NULL,
204 };
205 
206 static struct kobj_type dump_ktype = {
207 	.sysfs_ops = &dump_sysfs_ops,
208 	.release = &dump_release,
209 	.default_attrs = dump_default_attrs,
210 };
211 
212 static int64_t dump_read_info(uint32_t *dump_id, uint32_t *dump_size, uint32_t *dump_type)
213 {
214 	__be32 id, size, type;
215 	int rc;
216 
217 	type = cpu_to_be32(0xffffffff);
218 
219 	rc = opal_dump_info2(&id, &size, &type);
220 	if (rc == OPAL_PARAMETER)
221 		rc = opal_dump_info(&id, &size);
222 
223 	*dump_id = be32_to_cpu(id);
224 	*dump_size = be32_to_cpu(size);
225 	*dump_type = be32_to_cpu(type);
226 
227 	if (rc)
228 		pr_warn("%s: Failed to get dump info (%d)\n",
229 			__func__, rc);
230 	return rc;
231 }
232 
233 static int64_t dump_read_data(struct dump_obj *dump)
234 {
235 	struct opal_sg_list *list;
236 	uint64_t addr;
237 	int64_t rc;
238 
239 	/* Allocate memory */
240 	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
241 	if (!dump->buffer) {
242 		pr_err("%s : Failed to allocate memory\n", __func__);
243 		rc = -ENOMEM;
244 		goto out;
245 	}
246 
247 	/* Generate SG list */
248 	list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
249 	if (!list) {
250 		rc = -ENOMEM;
251 		goto out;
252 	}
253 
254 	/* First entry address */
255 	addr = __pa(list);
256 
257 	/* Fetch data */
258 	rc = OPAL_BUSY_EVENT;
259 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
260 		rc = opal_dump_read(dump->id, addr);
261 		if (rc == OPAL_BUSY_EVENT) {
262 			opal_poll_events(NULL);
263 			msleep(20);
264 		}
265 	}
266 
267 	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
268 		pr_warn("%s: Extract dump failed for ID 0x%x\n",
269 			__func__, dump->id);
270 
271 	/* Free SG list */
272 	opal_free_sg_list(list);
273 
274 out:
275 	return rc;
276 }
277 
278 static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
279 			      struct bin_attribute *bin_attr,
280 			      char *buffer, loff_t pos, size_t count)
281 {
282 	ssize_t rc;
283 
284 	struct dump_obj *dump = to_dump_obj(kobj);
285 
286 	if (!dump->buffer) {
287 		rc = dump_read_data(dump);
288 
289 		if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
290 			vfree(dump->buffer);
291 			dump->buffer = NULL;
292 
293 			return -EIO;
294 		}
295 		if (rc == OPAL_PARTIAL) {
296 			/* On a partial read, we just return EIO
297 			 * and rely on userspace to ask us to try
298 			 * again.
299 			 */
300 			pr_info("%s: Platform dump partially read.ID = 0x%x\n",
301 				__func__, dump->id);
302 			return -EIO;
303 		}
304 	}
305 
306 	memcpy(buffer, dump->buffer + pos, count);
307 
308 	/* You may think we could free the dump buffer now and retrieve
309 	 * it again later if needed, but due to current firmware limitation,
310 	 * that's not the case. So, once read into userspace once,
311 	 * we keep the dump around until it's acknowledged by userspace.
312 	 */
313 
314 	return count;
315 }
316 
317 static struct dump_obj *create_dump_obj(uint32_t id, size_t size,
318 					uint32_t type)
319 {
320 	struct dump_obj *dump;
321 	int rc;
322 
323 	dump = kzalloc(sizeof(*dump), GFP_KERNEL);
324 	if (!dump)
325 		return NULL;
326 
327 	dump->kobj.kset = dump_kset;
328 
329 	kobject_init(&dump->kobj, &dump_ktype);
330 
331 	sysfs_bin_attr_init(&dump->dump_attr);
332 
333 	dump->dump_attr.attr.name = "dump";
334 	dump->dump_attr.attr.mode = 0400;
335 	dump->dump_attr.size = size;
336 	dump->dump_attr.read = dump_attr_read;
337 
338 	dump->id = id;
339 	dump->size = size;
340 	dump->type = type;
341 
342 	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
343 	if (rc) {
344 		kobject_put(&dump->kobj);
345 		return NULL;
346 	}
347 
348 	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
349 	if (rc) {
350 		kobject_put(&dump->kobj);
351 		return NULL;
352 	}
353 
354 	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
355 		__func__, dump->id, dump->size);
356 
357 	kobject_uevent(&dump->kobj, KOBJ_ADD);
358 
359 	return dump;
360 }
361 
362 static int process_dump(void)
363 {
364 	int rc;
365 	uint32_t dump_id, dump_size, dump_type;
366 	struct dump_obj *dump;
367 	char name[22];
368 
369 	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
370 	if (rc != OPAL_SUCCESS)
371 		return rc;
372 
373 	sprintf(name, "0x%x-0x%x", dump_type, dump_id);
374 
375 	/* we may get notified twice, let's handle
376 	 * that gracefully and not create two conflicting
377 	 * entries.
378 	 */
379 	if (kset_find_obj(dump_kset, name))
380 		return 0;
381 
382 	dump = create_dump_obj(dump_id, dump_size, dump_type);
383 	if (!dump)
384 		return -1;
385 
386 	return 0;
387 }
388 
389 static void dump_work_fn(struct work_struct *work)
390 {
391 	process_dump();
392 }
393 
394 static DECLARE_WORK(dump_work, dump_work_fn);
395 
396 static void schedule_process_dump(void)
397 {
398 	schedule_work(&dump_work);
399 }
400 
401 /*
402  * New dump available notification
403  *
404  * Once we get notification, we add sysfs entries for it.
405  * We only fetch the dump on demand, and create sysfs asynchronously.
406  */
407 static int dump_event(struct notifier_block *nb,
408 		      unsigned long events, void *change)
409 {
410 	if (events & OPAL_EVENT_DUMP_AVAIL)
411 		schedule_process_dump();
412 
413 	return 0;
414 }
415 
416 static struct notifier_block dump_nb = {
417 	.notifier_call  = dump_event,
418 	.next           = NULL,
419 	.priority       = 0
420 };
421 
422 void __init opal_platform_dump_init(void)
423 {
424 	int rc;
425 
426 	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
427 	if (!dump_kset) {
428 		pr_warn("%s: Failed to create dump kset\n", __func__);
429 		return;
430 	}
431 
432 	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
433 	if (rc) {
434 		pr_warn("%s: Failed to create initiate dump attr group\n",
435 			__func__);
436 		kobject_put(&dump_kset->kobj);
437 		return;
438 	}
439 
440 	rc = opal_notifier_register(&dump_nb);
441 	if (rc) {
442 		pr_warn("%s: Can't register OPAL event notifier (%d)\n",
443 			__func__, rc);
444 		return;
445 	}
446 
447 	opal_dump_resend_notification();
448 }
449