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 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 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 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 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 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 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 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 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 }; 147774fea1aSStewart Smith 148774fea1aSStewart Smith static struct kobj_type elog_ktype = { 149774fea1aSStewart Smith .sysfs_ops = &elog_sysfs_ops, 150774fea1aSStewart Smith .release = &elog_release, 151774fea1aSStewart Smith .default_attrs = elog_default_attrs, 152774fea1aSStewart Smith }; 153774fea1aSStewart Smith 154774fea1aSStewart Smith /* Maximum size of a single log on FSP is 16KB */ 155774fea1aSStewart Smith #define OPAL_MAX_ERRLOG_SIZE 16384 156774fea1aSStewart Smith 157774fea1aSStewart Smith static ssize_t raw_attr_read(struct file *filep, struct kobject *kobj, 158774fea1aSStewart Smith struct bin_attribute *bin_attr, 159774fea1aSStewart Smith char *buffer, loff_t pos, size_t count) 160774fea1aSStewart Smith { 161774fea1aSStewart Smith int opal_rc; 162774fea1aSStewart Smith 163774fea1aSStewart Smith struct elog_obj *elog = to_elog_obj(kobj); 164774fea1aSStewart Smith 165774fea1aSStewart Smith /* We may have had an error reading before, so let's retry */ 166774fea1aSStewart Smith if (!elog->buffer) { 167774fea1aSStewart Smith elog->buffer = kzalloc(elog->size, GFP_KERNEL); 168774fea1aSStewart Smith if (!elog->buffer) 169774fea1aSStewart Smith return -EIO; 170774fea1aSStewart Smith 171774fea1aSStewart Smith opal_rc = opal_read_elog(__pa(elog->buffer), 172774fea1aSStewart Smith elog->size, elog->id); 173774fea1aSStewart Smith if (opal_rc != OPAL_SUCCESS) { 174774fea1aSStewart Smith pr_err("ELOG: log read failed for log-id=%llx\n", 175774fea1aSStewart Smith elog->id); 176774fea1aSStewart Smith kfree(elog->buffer); 177774fea1aSStewart Smith elog->buffer = NULL; 178774fea1aSStewart Smith return -EIO; 179774fea1aSStewart Smith } 180774fea1aSStewart Smith } 181774fea1aSStewart Smith 182774fea1aSStewart Smith memcpy(buffer, elog->buffer + pos, count); 183774fea1aSStewart Smith 184774fea1aSStewart Smith return count; 185774fea1aSStewart Smith } 186774fea1aSStewart Smith 187aea948bbSMahesh Salgaonkar static void create_elog_obj(uint64_t id, size_t size, uint64_t type) 188774fea1aSStewart Smith { 189774fea1aSStewart Smith struct elog_obj *elog; 190774fea1aSStewart Smith int rc; 191774fea1aSStewart Smith 192774fea1aSStewart Smith elog = kzalloc(sizeof(*elog), GFP_KERNEL); 193774fea1aSStewart Smith if (!elog) 194aea948bbSMahesh Salgaonkar return; 195774fea1aSStewart Smith 196774fea1aSStewart Smith elog->kobj.kset = elog_kset; 197774fea1aSStewart Smith 198774fea1aSStewart Smith kobject_init(&elog->kobj, &elog_ktype); 199774fea1aSStewart Smith 200774fea1aSStewart Smith sysfs_bin_attr_init(&elog->raw_attr); 201774fea1aSStewart Smith 202774fea1aSStewart Smith elog->raw_attr.attr.name = "raw"; 203774fea1aSStewart Smith elog->raw_attr.attr.mode = 0400; 204774fea1aSStewart Smith elog->raw_attr.size = size; 205774fea1aSStewart Smith elog->raw_attr.read = raw_attr_read; 206774fea1aSStewart Smith 207774fea1aSStewart Smith elog->id = id; 208774fea1aSStewart Smith elog->size = size; 209774fea1aSStewart Smith elog->type = type; 210774fea1aSStewart Smith 211774fea1aSStewart Smith elog->buffer = kzalloc(elog->size, GFP_KERNEL); 212774fea1aSStewart Smith 213774fea1aSStewart Smith if (elog->buffer) { 214774fea1aSStewart Smith rc = opal_read_elog(__pa(elog->buffer), 215774fea1aSStewart Smith elog->size, elog->id); 216774fea1aSStewart Smith if (rc != OPAL_SUCCESS) { 217774fea1aSStewart Smith pr_err("ELOG: log read failed for log-id=%llx\n", 218774fea1aSStewart Smith elog->id); 219774fea1aSStewart Smith kfree(elog->buffer); 220774fea1aSStewart Smith elog->buffer = NULL; 221774fea1aSStewart Smith } 222774fea1aSStewart Smith } 223774fea1aSStewart Smith 224774fea1aSStewart Smith rc = kobject_add(&elog->kobj, NULL, "0x%llx", id); 225774fea1aSStewart Smith if (rc) { 226774fea1aSStewart Smith kobject_put(&elog->kobj); 227aea948bbSMahesh Salgaonkar return; 228774fea1aSStewart Smith } 229774fea1aSStewart Smith 230aea948bbSMahesh Salgaonkar /* 231aea948bbSMahesh Salgaonkar * As soon as the sysfs file for this elog is created/activated there is 232aea948bbSMahesh Salgaonkar * a chance the opal_errd daemon (or any userspace) might read and 233aea948bbSMahesh Salgaonkar * acknowledge the elog before kobject_uevent() is called. If that 234aea948bbSMahesh Salgaonkar * happens then there is a potential race between 235aea948bbSMahesh Salgaonkar * elog_ack_store->kobject_put() and kobject_uevent() which leads to a 236aea948bbSMahesh Salgaonkar * use-after-free of a kernfs object resulting in a kernel crash. 237aea948bbSMahesh Salgaonkar * 238aea948bbSMahesh Salgaonkar * To avoid that, we need to take a reference on behalf of the bin file, 239aea948bbSMahesh Salgaonkar * so that our reference remains valid while we call kobject_uevent(). 240aea948bbSMahesh Salgaonkar * We then drop our reference before exiting the function, leaving the 241aea948bbSMahesh Salgaonkar * bin file to drop the last reference (if it hasn't already). 242aea948bbSMahesh Salgaonkar */ 243aea948bbSMahesh Salgaonkar 244aea948bbSMahesh Salgaonkar /* Take a reference for the bin file */ 245aea948bbSMahesh Salgaonkar kobject_get(&elog->kobj); 246774fea1aSStewart Smith rc = sysfs_create_bin_file(&elog->kobj, &elog->raw_attr); 247aea948bbSMahesh Salgaonkar if (rc == 0) { 248aea948bbSMahesh Salgaonkar kobject_uevent(&elog->kobj, KOBJ_ADD); 249aea948bbSMahesh Salgaonkar } else { 250aea948bbSMahesh Salgaonkar /* Drop the reference taken for the bin file */ 251774fea1aSStewart Smith kobject_put(&elog->kobj); 252774fea1aSStewart Smith } 253774fea1aSStewart Smith 254aea948bbSMahesh Salgaonkar /* Drop our reference */ 255aea948bbSMahesh Salgaonkar kobject_put(&elog->kobj); 256774fea1aSStewart Smith 257aea948bbSMahesh Salgaonkar return; 258774fea1aSStewart Smith } 259774fea1aSStewart Smith 260a8956a7bSAlistair Popple static irqreturn_t elog_event(int irq, void *data) 261774fea1aSStewart Smith { 26214ad0c58SAnton Blanchard __be64 size; 26314ad0c58SAnton Blanchard __be64 id; 26414ad0c58SAnton Blanchard __be64 type; 2652bad7423SAnton Blanchard uint64_t elog_size; 266774fea1aSStewart Smith uint64_t log_id; 267774fea1aSStewart Smith uint64_t elog_type; 268774fea1aSStewart Smith int rc; 269774fea1aSStewart Smith char name[2+16+1]; 270a9cbf0b2SMukesh Ojha struct kobject *kobj; 271774fea1aSStewart Smith 27214ad0c58SAnton Blanchard rc = opal_get_elog_size(&id, &size, &type); 273774fea1aSStewart Smith if (rc != OPAL_SUCCESS) { 274fa952c54SVasant Hegde pr_err("ELOG: OPAL log info read failed\n"); 275a8956a7bSAlistair Popple return IRQ_HANDLED; 276774fea1aSStewart Smith } 277774fea1aSStewart Smith 27814ad0c58SAnton Blanchard elog_size = be64_to_cpu(size); 27914ad0c58SAnton Blanchard log_id = be64_to_cpu(id); 28014ad0c58SAnton Blanchard elog_type = be64_to_cpu(type); 28114ad0c58SAnton Blanchard 282fa952c54SVasant Hegde WARN_ON(elog_size > OPAL_MAX_ERRLOG_SIZE); 283774fea1aSStewart Smith 284774fea1aSStewart Smith if (elog_size >= OPAL_MAX_ERRLOG_SIZE) 285774fea1aSStewart Smith elog_size = OPAL_MAX_ERRLOG_SIZE; 286774fea1aSStewart Smith 287774fea1aSStewart Smith sprintf(name, "0x%llx", log_id); 288774fea1aSStewart Smith 289774fea1aSStewart Smith /* we may get notified twice, let's handle 290774fea1aSStewart Smith * that gracefully and not create two conflicting 291774fea1aSStewart Smith * entries. 292774fea1aSStewart Smith */ 293a9cbf0b2SMukesh Ojha kobj = kset_find_obj(elog_kset, name); 294a9cbf0b2SMukesh Ojha if (kobj) { 295a9cbf0b2SMukesh Ojha /* Drop reference added by kset_find_obj() */ 296a9cbf0b2SMukesh Ojha kobject_put(kobj); 297a8956a7bSAlistair Popple return IRQ_HANDLED; 298a9cbf0b2SMukesh Ojha } 299774fea1aSStewart Smith 300774fea1aSStewart Smith create_elog_obj(log_id, elog_size, elog_type); 301774fea1aSStewart Smith 30274159a70SAlistair Popple return IRQ_HANDLED; 303774fea1aSStewart Smith } 304774fea1aSStewart Smith 305774fea1aSStewart Smith int __init opal_elog_init(void) 306774fea1aSStewart Smith { 30774159a70SAlistair Popple int rc = 0, irq; 308774fea1aSStewart Smith 3097dc992ecSMichael Neuling /* ELOG not supported by firmware */ 3107dc992ecSMichael Neuling if (!opal_check_token(OPAL_ELOG_READ)) 3117dc992ecSMichael Neuling return -1; 3127dc992ecSMichael Neuling 313774fea1aSStewart Smith elog_kset = kset_create_and_add("elog", NULL, opal_kobj); 314774fea1aSStewart Smith if (!elog_kset) { 315774fea1aSStewart Smith pr_warn("%s: failed to create elog kset\n", __func__); 316774fea1aSStewart Smith return -1; 317774fea1aSStewart Smith } 318774fea1aSStewart Smith 31974159a70SAlistair Popple irq = opal_event_request(ilog2(OPAL_EVENT_ERROR_LOG_AVAIL)); 32074159a70SAlistair Popple if (!irq) { 32174159a70SAlistair Popple pr_err("%s: Can't register OPAL event irq (%d)\n", 32274159a70SAlistair Popple __func__, irq); 32374159a70SAlistair Popple return irq; 32474159a70SAlistair Popple } 32574159a70SAlistair Popple 326a8956a7bSAlistair Popple rc = request_threaded_irq(irq, NULL, elog_event, 327a8956a7bSAlistair Popple IRQF_TRIGGER_HIGH | IRQF_ONESHOT, "opal-elog", NULL); 328774fea1aSStewart Smith if (rc) { 32974159a70SAlistair Popple pr_err("%s: Can't request OPAL event irq (%d)\n", 330774fea1aSStewart Smith __func__, rc); 331774fea1aSStewart Smith return rc; 332774fea1aSStewart Smith } 333774fea1aSStewart Smith 334774fea1aSStewart Smith /* We are now ready to pull error logs from opal. */ 335fc81de63SStewart Smith if (opal_check_token(OPAL_ELOG_RESEND)) 336774fea1aSStewart Smith opal_resend_pending_logs(); 337774fea1aSStewart Smith 338774fea1aSStewart Smith return 0; 339774fea1aSStewart Smith } 340