12874c5fdSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
2774fea1aSStewart Smith /*
3774fea1aSStewart Smith * Error log support on PowerNV.
4774fea1aSStewart Smith *
5774fea1aSStewart Smith * Copyright 2013,2014 IBM Corp.
6774fea1aSStewart Smith */
7774fea1aSStewart Smith #include <linux/kernel.h>
8774fea1aSStewart Smith #include <linux/init.h>
974159a70SAlistair Popple #include <linux/interrupt.h>
10774fea1aSStewart Smith #include <linux/of.h>
11774fea1aSStewart Smith #include <linux/slab.h>
12774fea1aSStewart Smith #include <linux/sysfs.h>
13774fea1aSStewart Smith #include <linux/fs.h>
14774fea1aSStewart Smith #include <linux/vmalloc.h>
15774fea1aSStewart Smith #include <linux/fcntl.h>
16774fea1aSStewart Smith #include <linux/kobject.h>
177c0f6ba6SLinus Torvalds #include <linux/uaccess.h>
18774fea1aSStewart Smith #include <asm/opal.h>
19774fea1aSStewart Smith
20774fea1aSStewart Smith struct elog_obj {
21774fea1aSStewart Smith struct kobject kobj;
22774fea1aSStewart Smith struct bin_attribute raw_attr;
23774fea1aSStewart Smith uint64_t id;
24774fea1aSStewart Smith uint64_t type;
25774fea1aSStewart Smith size_t size;
26774fea1aSStewart Smith char *buffer;
27774fea1aSStewart Smith };
28774fea1aSStewart Smith #define to_elog_obj(x) container_of(x, struct elog_obj, kobj)
29774fea1aSStewart Smith
30774fea1aSStewart Smith struct elog_attribute {
31774fea1aSStewart Smith struct attribute attr;
32774fea1aSStewart Smith ssize_t (*show)(struct elog_obj *elog, struct elog_attribute *attr,
33774fea1aSStewart Smith char *buf);
34774fea1aSStewart Smith ssize_t (*store)(struct elog_obj *elog, struct elog_attribute *attr,
35774fea1aSStewart Smith const char *buf, size_t count);
36774fea1aSStewart Smith };
37774fea1aSStewart Smith #define to_elog_attr(x) container_of(x, struct elog_attribute, attr)
38774fea1aSStewart Smith
elog_id_show(struct elog_obj * elog_obj,struct elog_attribute * attr,char * buf)39774fea1aSStewart Smith static ssize_t elog_id_show(struct elog_obj *elog_obj,
40774fea1aSStewart Smith struct elog_attribute *attr,
41774fea1aSStewart Smith char *buf)
42774fea1aSStewart Smith {
43774fea1aSStewart Smith return sprintf(buf, "0x%llx\n", elog_obj->id);
44774fea1aSStewart Smith }
45774fea1aSStewart Smith
elog_type_to_string(uint64_t type)46774fea1aSStewart Smith static const char *elog_type_to_string(uint64_t type)
47774fea1aSStewart Smith {
48774fea1aSStewart Smith switch (type) {
49774fea1aSStewart Smith case 0: return "PEL";
50774fea1aSStewart Smith default: return "unknown";
51774fea1aSStewart Smith }
52774fea1aSStewart Smith }
53774fea1aSStewart Smith
elog_type_show(struct elog_obj * elog_obj,struct elog_attribute * attr,char * buf)54774fea1aSStewart Smith static ssize_t elog_type_show(struct elog_obj *elog_obj,
55774fea1aSStewart Smith struct elog_attribute *attr,
56774fea1aSStewart Smith char *buf)
57774fea1aSStewart Smith {
58774fea1aSStewart Smith return sprintf(buf, "0x%llx %s\n",
59774fea1aSStewart Smith elog_obj->type,
60774fea1aSStewart Smith elog_type_to_string(elog_obj->type));
61774fea1aSStewart Smith }
62774fea1aSStewart Smith
elog_ack_show(struct elog_obj * elog_obj,struct elog_attribute * attr,char * buf)63774fea1aSStewart Smith static ssize_t elog_ack_show(struct elog_obj *elog_obj,
64774fea1aSStewart Smith struct elog_attribute *attr,
65774fea1aSStewart Smith char *buf)
66774fea1aSStewart Smith {
67774fea1aSStewart Smith return sprintf(buf, "ack - acknowledge log message\n");
68774fea1aSStewart Smith }
69774fea1aSStewart Smith
elog_ack_store(struct elog_obj * elog_obj,struct elog_attribute * attr,const char * buf,size_t count)70774fea1aSStewart Smith static ssize_t elog_ack_store(struct elog_obj *elog_obj,
71774fea1aSStewart Smith struct elog_attribute *attr,
72774fea1aSStewart Smith const char *buf,
73774fea1aSStewart Smith size_t count)
74774fea1aSStewart Smith {
75d4263b12SAneesh Kumar K.V /*
76d4263b12SAneesh Kumar K.V * Try to self remove this attribute. If we are successful,
77d4263b12SAneesh Kumar K.V * delete the kobject itself.
78d4263b12SAneesh Kumar K.V */
79d4263b12SAneesh Kumar K.V if (sysfs_remove_file_self(&elog_obj->kobj, &attr->attr)) {
80774fea1aSStewart Smith opal_send_ack_elog(elog_obj->id);
81cc4f265aSStewart Smith kobject_put(&elog_obj->kobj);
82d4263b12SAneesh Kumar K.V }
83774fea1aSStewart Smith return count;
84774fea1aSStewart Smith }
85774fea1aSStewart Smith
86774fea1aSStewart Smith static struct elog_attribute id_attribute =
8757ad583fSRussell Currey __ATTR(id, 0444, elog_id_show, NULL);
88774fea1aSStewart Smith static struct elog_attribute type_attribute =
8957ad583fSRussell Currey __ATTR(type, 0444, elog_type_show, NULL);
90774fea1aSStewart Smith static struct elog_attribute ack_attribute =
91774fea1aSStewart Smith __ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store);
92774fea1aSStewart Smith
93774fea1aSStewart Smith static struct kset *elog_kset;
94774fea1aSStewart Smith
elog_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)95774fea1aSStewart Smith static ssize_t elog_attr_show(struct kobject *kobj,
96774fea1aSStewart Smith struct attribute *attr,
97774fea1aSStewart Smith char *buf)
98774fea1aSStewart Smith {
99774fea1aSStewart Smith struct elog_attribute *attribute;
100774fea1aSStewart Smith struct elog_obj *elog;
101774fea1aSStewart Smith
102774fea1aSStewart Smith attribute = to_elog_attr(attr);
103774fea1aSStewart Smith elog = to_elog_obj(kobj);
104774fea1aSStewart Smith
105774fea1aSStewart Smith if (!attribute->show)
106774fea1aSStewart Smith return -EIO;
107774fea1aSStewart Smith
108774fea1aSStewart Smith return attribute->show(elog, attribute, buf);
109774fea1aSStewart Smith }
110774fea1aSStewart Smith
elog_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t len)111774fea1aSStewart Smith static ssize_t elog_attr_store(struct kobject *kobj,
112774fea1aSStewart Smith struct attribute *attr,
113774fea1aSStewart Smith const char *buf, size_t len)
114774fea1aSStewart Smith {
115774fea1aSStewart Smith struct elog_attribute *attribute;
116774fea1aSStewart Smith struct elog_obj *elog;
117774fea1aSStewart Smith
118774fea1aSStewart Smith attribute = to_elog_attr(attr);
119774fea1aSStewart Smith elog = to_elog_obj(kobj);
120774fea1aSStewart Smith
121774fea1aSStewart Smith if (!attribute->store)
122774fea1aSStewart Smith return -EIO;
123774fea1aSStewart Smith
124774fea1aSStewart Smith return attribute->store(elog, attribute, buf, len);
125774fea1aSStewart Smith }
126774fea1aSStewart Smith
127774fea1aSStewart Smith static const struct sysfs_ops elog_sysfs_ops = {
128774fea1aSStewart Smith .show = elog_attr_show,
129774fea1aSStewart Smith .store = elog_attr_store,
130774fea1aSStewart Smith };
131774fea1aSStewart Smith
elog_release(struct kobject * kobj)132774fea1aSStewart Smith static void elog_release(struct kobject *kobj)
133774fea1aSStewart Smith {
134774fea1aSStewart Smith struct elog_obj *elog;
135774fea1aSStewart Smith
136774fea1aSStewart Smith elog = to_elog_obj(kobj);
137774fea1aSStewart Smith kfree(elog->buffer);
138774fea1aSStewart Smith kfree(elog);
139774fea1aSStewart Smith }
140774fea1aSStewart Smith
141774fea1aSStewart Smith static struct attribute *elog_default_attrs[] = {
142774fea1aSStewart Smith &id_attribute.attr,
143774fea1aSStewart Smith &type_attribute.attr,
144774fea1aSStewart Smith &ack_attribute.attr,
145774fea1aSStewart Smith NULL,
146774fea1aSStewart Smith };
147*32a1bda4SGreg Kroah-Hartman ATTRIBUTE_GROUPS(elog_default);
148774fea1aSStewart Smith
149774fea1aSStewart Smith static struct kobj_type elog_ktype = {
150774fea1aSStewart Smith .sysfs_ops = &elog_sysfs_ops,
151774fea1aSStewart Smith .release = &elog_release,
152*32a1bda4SGreg Kroah-Hartman .default_groups = elog_default_groups,
153774fea1aSStewart Smith };
154774fea1aSStewart Smith
155774fea1aSStewart Smith /* Maximum size of a single log on FSP is 16KB */
156774fea1aSStewart Smith #define OPAL_MAX_ERRLOG_SIZE 16384
157774fea1aSStewart Smith
raw_attr_read(struct file * filep,struct kobject * kobj,struct bin_attribute * bin_attr,char * buffer,loff_t pos,size_t count)158774fea1aSStewart Smith static ssize_t raw_attr_read(struct file *filep, struct kobject *kobj,
159774fea1aSStewart Smith struct bin_attribute *bin_attr,
160774fea1aSStewart Smith char *buffer, loff_t pos, size_t count)
161774fea1aSStewart Smith {
162774fea1aSStewart Smith int opal_rc;
163774fea1aSStewart Smith
164774fea1aSStewart Smith struct elog_obj *elog = to_elog_obj(kobj);
165774fea1aSStewart Smith
166774fea1aSStewart Smith /* We may have had an error reading before, so let's retry */
167774fea1aSStewart Smith if (!elog->buffer) {
168774fea1aSStewart Smith elog->buffer = kzalloc(elog->size, GFP_KERNEL);
169774fea1aSStewart Smith if (!elog->buffer)
170774fea1aSStewart Smith return -EIO;
171774fea1aSStewart Smith
172774fea1aSStewart Smith opal_rc = opal_read_elog(__pa(elog->buffer),
173774fea1aSStewart Smith elog->size, elog->id);
174774fea1aSStewart Smith if (opal_rc != OPAL_SUCCESS) {
175c88017cfSAndrew Donnellan pr_err_ratelimited("ELOG: log read failed for log-id=%llx\n",
176774fea1aSStewart Smith elog->id);
177774fea1aSStewart Smith kfree(elog->buffer);
178774fea1aSStewart Smith elog->buffer = NULL;
179774fea1aSStewart Smith return -EIO;
180774fea1aSStewart Smith }
181774fea1aSStewart Smith }
182774fea1aSStewart Smith
183774fea1aSStewart Smith memcpy(buffer, elog->buffer + pos, count);
184774fea1aSStewart Smith
185774fea1aSStewart Smith return count;
186774fea1aSStewart Smith }
187774fea1aSStewart Smith
create_elog_obj(uint64_t id,size_t size,uint64_t type)188aea948bbSMahesh Salgaonkar static void create_elog_obj(uint64_t id, size_t size, uint64_t type)
189774fea1aSStewart Smith {
190774fea1aSStewart Smith struct elog_obj *elog;
191774fea1aSStewart Smith int rc;
192774fea1aSStewart Smith
193774fea1aSStewart Smith elog = kzalloc(sizeof(*elog), GFP_KERNEL);
194774fea1aSStewart Smith if (!elog)
195aea948bbSMahesh Salgaonkar return;
196774fea1aSStewart Smith
197774fea1aSStewart Smith elog->kobj.kset = elog_kset;
198774fea1aSStewart Smith
199774fea1aSStewart Smith kobject_init(&elog->kobj, &elog_ktype);
200774fea1aSStewart Smith
201774fea1aSStewart Smith sysfs_bin_attr_init(&elog->raw_attr);
202774fea1aSStewart Smith
203774fea1aSStewart Smith elog->raw_attr.attr.name = "raw";
204774fea1aSStewart Smith elog->raw_attr.attr.mode = 0400;
205774fea1aSStewart Smith elog->raw_attr.size = size;
206774fea1aSStewart Smith elog->raw_attr.read = raw_attr_read;
207774fea1aSStewart Smith
208774fea1aSStewart Smith elog->id = id;
209774fea1aSStewart Smith elog->size = size;
210774fea1aSStewart Smith elog->type = type;
211774fea1aSStewart Smith
212774fea1aSStewart Smith elog->buffer = kzalloc(elog->size, GFP_KERNEL);
213774fea1aSStewart Smith
214774fea1aSStewart Smith if (elog->buffer) {
215774fea1aSStewart Smith rc = opal_read_elog(__pa(elog->buffer),
216774fea1aSStewart Smith elog->size, elog->id);
217774fea1aSStewart Smith if (rc != OPAL_SUCCESS) {
218774fea1aSStewart Smith pr_err("ELOG: log read failed for log-id=%llx\n",
219774fea1aSStewart Smith elog->id);
220774fea1aSStewart Smith kfree(elog->buffer);
221774fea1aSStewart Smith elog->buffer = NULL;
222774fea1aSStewart Smith }
223774fea1aSStewart Smith }
224774fea1aSStewart Smith
225774fea1aSStewart Smith rc = kobject_add(&elog->kobj, NULL, "0x%llx", id);
226774fea1aSStewart Smith if (rc) {
227774fea1aSStewart Smith kobject_put(&elog->kobj);
228aea948bbSMahesh Salgaonkar return;
229774fea1aSStewart Smith }
230774fea1aSStewart Smith
231aea948bbSMahesh Salgaonkar /*
232aea948bbSMahesh Salgaonkar * As soon as the sysfs file for this elog is created/activated there is
233aea948bbSMahesh Salgaonkar * a chance the opal_errd daemon (or any userspace) might read and
234aea948bbSMahesh Salgaonkar * acknowledge the elog before kobject_uevent() is called. If that
235aea948bbSMahesh Salgaonkar * happens then there is a potential race between
236aea948bbSMahesh Salgaonkar * elog_ack_store->kobject_put() and kobject_uevent() which leads to a
237aea948bbSMahesh Salgaonkar * use-after-free of a kernfs object resulting in a kernel crash.
238aea948bbSMahesh Salgaonkar *
239aea948bbSMahesh Salgaonkar * To avoid that, we need to take a reference on behalf of the bin file,
240aea948bbSMahesh Salgaonkar * so that our reference remains valid while we call kobject_uevent().
241aea948bbSMahesh Salgaonkar * We then drop our reference before exiting the function, leaving the
242aea948bbSMahesh Salgaonkar * bin file to drop the last reference (if it hasn't already).
243aea948bbSMahesh Salgaonkar */
244aea948bbSMahesh Salgaonkar
245aea948bbSMahesh Salgaonkar /* Take a reference for the bin file */
246aea948bbSMahesh Salgaonkar kobject_get(&elog->kobj);
247774fea1aSStewart Smith rc = sysfs_create_bin_file(&elog->kobj, &elog->raw_attr);
248aea948bbSMahesh Salgaonkar if (rc == 0) {
249aea948bbSMahesh Salgaonkar kobject_uevent(&elog->kobj, KOBJ_ADD);
250aea948bbSMahesh Salgaonkar } else {
251aea948bbSMahesh Salgaonkar /* Drop the reference taken for the bin file */
252774fea1aSStewart Smith kobject_put(&elog->kobj);
253774fea1aSStewart Smith }
254774fea1aSStewart Smith
255aea948bbSMahesh Salgaonkar /* Drop our reference */
256aea948bbSMahesh Salgaonkar kobject_put(&elog->kobj);
257774fea1aSStewart Smith
258aea948bbSMahesh Salgaonkar return;
259774fea1aSStewart Smith }
260774fea1aSStewart Smith
elog_event(int irq,void * data)261a8956a7bSAlistair Popple static irqreturn_t elog_event(int irq, void *data)
262774fea1aSStewart Smith {
26314ad0c58SAnton Blanchard __be64 size;
26414ad0c58SAnton Blanchard __be64 id;
26514ad0c58SAnton Blanchard __be64 type;
2662bad7423SAnton Blanchard uint64_t elog_size;
267774fea1aSStewart Smith uint64_t log_id;
268774fea1aSStewart Smith uint64_t elog_type;
269774fea1aSStewart Smith int rc;
270774fea1aSStewart Smith char name[2+16+1];
271a9cbf0b2SMukesh Ojha struct kobject *kobj;
272774fea1aSStewart Smith
27314ad0c58SAnton Blanchard rc = opal_get_elog_size(&id, &size, &type);
274774fea1aSStewart Smith if (rc != OPAL_SUCCESS) {
275fa952c54SVasant Hegde pr_err("ELOG: OPAL log info read failed\n");
276a8956a7bSAlistair Popple return IRQ_HANDLED;
277774fea1aSStewart Smith }
278774fea1aSStewart Smith
27914ad0c58SAnton Blanchard elog_size = be64_to_cpu(size);
28014ad0c58SAnton Blanchard log_id = be64_to_cpu(id);
28114ad0c58SAnton Blanchard elog_type = be64_to_cpu(type);
28214ad0c58SAnton Blanchard
283fa952c54SVasant Hegde WARN_ON(elog_size > OPAL_MAX_ERRLOG_SIZE);
284774fea1aSStewart Smith
285774fea1aSStewart Smith if (elog_size >= OPAL_MAX_ERRLOG_SIZE)
286774fea1aSStewart Smith elog_size = OPAL_MAX_ERRLOG_SIZE;
287774fea1aSStewart Smith
288774fea1aSStewart Smith sprintf(name, "0x%llx", log_id);
289774fea1aSStewart Smith
290774fea1aSStewart Smith /* we may get notified twice, let's handle
291774fea1aSStewart Smith * that gracefully and not create two conflicting
292774fea1aSStewart Smith * entries.
293774fea1aSStewart Smith */
294a9cbf0b2SMukesh Ojha kobj = kset_find_obj(elog_kset, name);
295a9cbf0b2SMukesh Ojha if (kobj) {
296a9cbf0b2SMukesh Ojha /* Drop reference added by kset_find_obj() */
297a9cbf0b2SMukesh Ojha kobject_put(kobj);
298a8956a7bSAlistair Popple return IRQ_HANDLED;
299a9cbf0b2SMukesh Ojha }
300774fea1aSStewart Smith
301774fea1aSStewart Smith create_elog_obj(log_id, elog_size, elog_type);
302774fea1aSStewart Smith
30374159a70SAlistair Popple return IRQ_HANDLED;
304774fea1aSStewart Smith }
305774fea1aSStewart Smith
opal_elog_init(void)306774fea1aSStewart Smith int __init opal_elog_init(void)
307774fea1aSStewart Smith {
30874159a70SAlistair Popple int rc = 0, irq;
309774fea1aSStewart Smith
3107dc992ecSMichael Neuling /* ELOG not supported by firmware */
3117dc992ecSMichael Neuling if (!opal_check_token(OPAL_ELOG_READ))
3127dc992ecSMichael Neuling return -1;
3137dc992ecSMichael Neuling
314774fea1aSStewart Smith elog_kset = kset_create_and_add("elog", NULL, opal_kobj);
315774fea1aSStewart Smith if (!elog_kset) {
316774fea1aSStewart Smith pr_warn("%s: failed to create elog kset\n", __func__);
317774fea1aSStewart Smith return -1;
318774fea1aSStewart Smith }
319774fea1aSStewart Smith
32074159a70SAlistair Popple irq = opal_event_request(ilog2(OPAL_EVENT_ERROR_LOG_AVAIL));
32174159a70SAlistair Popple if (!irq) {
32274159a70SAlistair Popple pr_err("%s: Can't register OPAL event irq (%d)\n",
32374159a70SAlistair Popple __func__, irq);
32474159a70SAlistair Popple return irq;
32574159a70SAlistair Popple }
32674159a70SAlistair Popple
327a8956a7bSAlistair Popple rc = request_threaded_irq(irq, NULL, elog_event,
328a8956a7bSAlistair Popple IRQF_TRIGGER_HIGH | IRQF_ONESHOT, "opal-elog", NULL);
329774fea1aSStewart Smith if (rc) {
33074159a70SAlistair Popple pr_err("%s: Can't request OPAL event irq (%d)\n",
331774fea1aSStewart Smith __func__, rc);
332774fea1aSStewart Smith return rc;
333774fea1aSStewart Smith }
334774fea1aSStewart Smith
335774fea1aSStewart Smith /* We are now ready to pull error logs from opal. */
336fc81de63SStewart Smith if (opal_check_token(OPAL_ELOG_RESEND))
337774fea1aSStewart Smith opal_resend_pending_logs();
338774fea1aSStewart Smith
339774fea1aSStewart Smith return 0;
340774fea1aSStewart Smith }
341