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 { 75774fea1aSStewart Smith opal_send_ack_elog(elog_obj->id); 76cc4f265aSStewart Smith sysfs_remove_file_self(&elog_obj->kobj, &attr->attr); 77cc4f265aSStewart Smith kobject_put(&elog_obj->kobj); 78774fea1aSStewart Smith return count; 79774fea1aSStewart Smith } 80774fea1aSStewart Smith 81774fea1aSStewart Smith static struct elog_attribute id_attribute = 8257ad583fSRussell Currey __ATTR(id, 0444, elog_id_show, NULL); 83774fea1aSStewart Smith static struct elog_attribute type_attribute = 8457ad583fSRussell Currey __ATTR(type, 0444, elog_type_show, NULL); 85774fea1aSStewart Smith static struct elog_attribute ack_attribute = 86774fea1aSStewart Smith __ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store); 87774fea1aSStewart Smith 88774fea1aSStewart Smith static struct kset *elog_kset; 89774fea1aSStewart Smith 90774fea1aSStewart Smith static ssize_t elog_attr_show(struct kobject *kobj, 91774fea1aSStewart Smith struct attribute *attr, 92774fea1aSStewart Smith char *buf) 93774fea1aSStewart Smith { 94774fea1aSStewart Smith struct elog_attribute *attribute; 95774fea1aSStewart Smith struct elog_obj *elog; 96774fea1aSStewart Smith 97774fea1aSStewart Smith attribute = to_elog_attr(attr); 98774fea1aSStewart Smith elog = to_elog_obj(kobj); 99774fea1aSStewart Smith 100774fea1aSStewart Smith if (!attribute->show) 101774fea1aSStewart Smith return -EIO; 102774fea1aSStewart Smith 103774fea1aSStewart Smith return attribute->show(elog, attribute, buf); 104774fea1aSStewart Smith } 105774fea1aSStewart Smith 106774fea1aSStewart Smith static ssize_t elog_attr_store(struct kobject *kobj, 107774fea1aSStewart Smith struct attribute *attr, 108774fea1aSStewart Smith const char *buf, size_t len) 109774fea1aSStewart Smith { 110774fea1aSStewart Smith struct elog_attribute *attribute; 111774fea1aSStewart Smith struct elog_obj *elog; 112774fea1aSStewart Smith 113774fea1aSStewart Smith attribute = to_elog_attr(attr); 114774fea1aSStewart Smith elog = to_elog_obj(kobj); 115774fea1aSStewart Smith 116774fea1aSStewart Smith if (!attribute->store) 117774fea1aSStewart Smith return -EIO; 118774fea1aSStewart Smith 119774fea1aSStewart Smith return attribute->store(elog, attribute, buf, len); 120774fea1aSStewart Smith } 121774fea1aSStewart Smith 122774fea1aSStewart Smith static const struct sysfs_ops elog_sysfs_ops = { 123774fea1aSStewart Smith .show = elog_attr_show, 124774fea1aSStewart Smith .store = elog_attr_store, 125774fea1aSStewart Smith }; 126774fea1aSStewart Smith 127774fea1aSStewart Smith static void elog_release(struct kobject *kobj) 128774fea1aSStewart Smith { 129774fea1aSStewart Smith struct elog_obj *elog; 130774fea1aSStewart Smith 131774fea1aSStewart Smith elog = to_elog_obj(kobj); 132774fea1aSStewart Smith kfree(elog->buffer); 133774fea1aSStewart Smith kfree(elog); 134774fea1aSStewart Smith } 135774fea1aSStewart Smith 136774fea1aSStewart Smith static struct attribute *elog_default_attrs[] = { 137774fea1aSStewart Smith &id_attribute.attr, 138774fea1aSStewart Smith &type_attribute.attr, 139774fea1aSStewart Smith &ack_attribute.attr, 140774fea1aSStewart Smith NULL, 141774fea1aSStewart Smith }; 142774fea1aSStewart Smith 143774fea1aSStewart Smith static struct kobj_type elog_ktype = { 144774fea1aSStewart Smith .sysfs_ops = &elog_sysfs_ops, 145774fea1aSStewart Smith .release = &elog_release, 146774fea1aSStewart Smith .default_attrs = elog_default_attrs, 147774fea1aSStewart Smith }; 148774fea1aSStewart Smith 149774fea1aSStewart Smith /* Maximum size of a single log on FSP is 16KB */ 150774fea1aSStewart Smith #define OPAL_MAX_ERRLOG_SIZE 16384 151774fea1aSStewart Smith 152774fea1aSStewart Smith static ssize_t raw_attr_read(struct file *filep, struct kobject *kobj, 153774fea1aSStewart Smith struct bin_attribute *bin_attr, 154774fea1aSStewart Smith char *buffer, loff_t pos, size_t count) 155774fea1aSStewart Smith { 156774fea1aSStewart Smith int opal_rc; 157774fea1aSStewart Smith 158774fea1aSStewart Smith struct elog_obj *elog = to_elog_obj(kobj); 159774fea1aSStewart Smith 160774fea1aSStewart Smith /* We may have had an error reading before, so let's retry */ 161774fea1aSStewart Smith if (!elog->buffer) { 162774fea1aSStewart Smith elog->buffer = kzalloc(elog->size, GFP_KERNEL); 163774fea1aSStewart Smith if (!elog->buffer) 164774fea1aSStewart Smith return -EIO; 165774fea1aSStewart Smith 166774fea1aSStewart Smith opal_rc = opal_read_elog(__pa(elog->buffer), 167774fea1aSStewart Smith elog->size, elog->id); 168774fea1aSStewart Smith if (opal_rc != OPAL_SUCCESS) { 169774fea1aSStewart Smith pr_err("ELOG: log read failed for log-id=%llx\n", 170774fea1aSStewart Smith elog->id); 171774fea1aSStewart Smith kfree(elog->buffer); 172774fea1aSStewart Smith elog->buffer = NULL; 173774fea1aSStewart Smith return -EIO; 174774fea1aSStewart Smith } 175774fea1aSStewart Smith } 176774fea1aSStewart Smith 177774fea1aSStewart Smith memcpy(buffer, elog->buffer + pos, count); 178774fea1aSStewart Smith 179774fea1aSStewart Smith return count; 180774fea1aSStewart Smith } 181774fea1aSStewart Smith 182aea948bbSMahesh Salgaonkar static void create_elog_obj(uint64_t id, size_t size, uint64_t type) 183774fea1aSStewart Smith { 184774fea1aSStewart Smith struct elog_obj *elog; 185774fea1aSStewart Smith int rc; 186774fea1aSStewart Smith 187774fea1aSStewart Smith elog = kzalloc(sizeof(*elog), GFP_KERNEL); 188774fea1aSStewart Smith if (!elog) 189aea948bbSMahesh Salgaonkar return; 190774fea1aSStewart Smith 191774fea1aSStewart Smith elog->kobj.kset = elog_kset; 192774fea1aSStewart Smith 193774fea1aSStewart Smith kobject_init(&elog->kobj, &elog_ktype); 194774fea1aSStewart Smith 195774fea1aSStewart Smith sysfs_bin_attr_init(&elog->raw_attr); 196774fea1aSStewart Smith 197774fea1aSStewart Smith elog->raw_attr.attr.name = "raw"; 198774fea1aSStewart Smith elog->raw_attr.attr.mode = 0400; 199774fea1aSStewart Smith elog->raw_attr.size = size; 200774fea1aSStewart Smith elog->raw_attr.read = raw_attr_read; 201774fea1aSStewart Smith 202774fea1aSStewart Smith elog->id = id; 203774fea1aSStewart Smith elog->size = size; 204774fea1aSStewart Smith elog->type = type; 205774fea1aSStewart Smith 206774fea1aSStewart Smith elog->buffer = kzalloc(elog->size, GFP_KERNEL); 207774fea1aSStewart Smith 208774fea1aSStewart Smith if (elog->buffer) { 209774fea1aSStewart Smith rc = opal_read_elog(__pa(elog->buffer), 210774fea1aSStewart Smith elog->size, elog->id); 211774fea1aSStewart Smith if (rc != OPAL_SUCCESS) { 212774fea1aSStewart Smith pr_err("ELOG: log read failed for log-id=%llx\n", 213774fea1aSStewart Smith elog->id); 214774fea1aSStewart Smith kfree(elog->buffer); 215774fea1aSStewart Smith elog->buffer = NULL; 216774fea1aSStewart Smith } 217774fea1aSStewart Smith } 218774fea1aSStewart Smith 219774fea1aSStewart Smith rc = kobject_add(&elog->kobj, NULL, "0x%llx", id); 220774fea1aSStewart Smith if (rc) { 221774fea1aSStewart Smith kobject_put(&elog->kobj); 222aea948bbSMahesh Salgaonkar return; 223774fea1aSStewart Smith } 224774fea1aSStewart Smith 225aea948bbSMahesh Salgaonkar /* 226aea948bbSMahesh Salgaonkar * As soon as the sysfs file for this elog is created/activated there is 227aea948bbSMahesh Salgaonkar * a chance the opal_errd daemon (or any userspace) might read and 228aea948bbSMahesh Salgaonkar * acknowledge the elog before kobject_uevent() is called. If that 229aea948bbSMahesh Salgaonkar * happens then there is a potential race between 230aea948bbSMahesh Salgaonkar * elog_ack_store->kobject_put() and kobject_uevent() which leads to a 231aea948bbSMahesh Salgaonkar * use-after-free of a kernfs object resulting in a kernel crash. 232aea948bbSMahesh Salgaonkar * 233aea948bbSMahesh Salgaonkar * To avoid that, we need to take a reference on behalf of the bin file, 234aea948bbSMahesh Salgaonkar * so that our reference remains valid while we call kobject_uevent(). 235aea948bbSMahesh Salgaonkar * We then drop our reference before exiting the function, leaving the 236aea948bbSMahesh Salgaonkar * bin file to drop the last reference (if it hasn't already). 237aea948bbSMahesh Salgaonkar */ 238aea948bbSMahesh Salgaonkar 239aea948bbSMahesh Salgaonkar /* Take a reference for the bin file */ 240aea948bbSMahesh Salgaonkar kobject_get(&elog->kobj); 241774fea1aSStewart Smith rc = sysfs_create_bin_file(&elog->kobj, &elog->raw_attr); 242aea948bbSMahesh Salgaonkar if (rc == 0) { 243aea948bbSMahesh Salgaonkar kobject_uevent(&elog->kobj, KOBJ_ADD); 244aea948bbSMahesh Salgaonkar } else { 245aea948bbSMahesh Salgaonkar /* Drop the reference taken for the bin file */ 246774fea1aSStewart Smith kobject_put(&elog->kobj); 247774fea1aSStewart Smith } 248774fea1aSStewart Smith 249aea948bbSMahesh Salgaonkar /* Drop our reference */ 250aea948bbSMahesh Salgaonkar kobject_put(&elog->kobj); 251774fea1aSStewart Smith 252aea948bbSMahesh Salgaonkar return; 253774fea1aSStewart Smith } 254774fea1aSStewart Smith 255a8956a7bSAlistair Popple static irqreturn_t elog_event(int irq, void *data) 256774fea1aSStewart Smith { 25714ad0c58SAnton Blanchard __be64 size; 25814ad0c58SAnton Blanchard __be64 id; 25914ad0c58SAnton Blanchard __be64 type; 2602bad7423SAnton Blanchard uint64_t elog_size; 261774fea1aSStewart Smith uint64_t log_id; 262774fea1aSStewart Smith uint64_t elog_type; 263774fea1aSStewart Smith int rc; 264774fea1aSStewart Smith char name[2+16+1]; 265a9cbf0b2SMukesh Ojha struct kobject *kobj; 266774fea1aSStewart Smith 26714ad0c58SAnton Blanchard rc = opal_get_elog_size(&id, &size, &type); 268774fea1aSStewart Smith if (rc != OPAL_SUCCESS) { 269fa952c54SVasant Hegde pr_err("ELOG: OPAL log info read failed\n"); 270a8956a7bSAlistair Popple return IRQ_HANDLED; 271774fea1aSStewart Smith } 272774fea1aSStewart Smith 27314ad0c58SAnton Blanchard elog_size = be64_to_cpu(size); 27414ad0c58SAnton Blanchard log_id = be64_to_cpu(id); 27514ad0c58SAnton Blanchard elog_type = be64_to_cpu(type); 27614ad0c58SAnton Blanchard 277fa952c54SVasant Hegde WARN_ON(elog_size > OPAL_MAX_ERRLOG_SIZE); 278774fea1aSStewart Smith 279774fea1aSStewart Smith if (elog_size >= OPAL_MAX_ERRLOG_SIZE) 280774fea1aSStewart Smith elog_size = OPAL_MAX_ERRLOG_SIZE; 281774fea1aSStewart Smith 282774fea1aSStewart Smith sprintf(name, "0x%llx", log_id); 283774fea1aSStewart Smith 284774fea1aSStewart Smith /* we may get notified twice, let's handle 285774fea1aSStewart Smith * that gracefully and not create two conflicting 286774fea1aSStewart Smith * entries. 287774fea1aSStewart Smith */ 288a9cbf0b2SMukesh Ojha kobj = kset_find_obj(elog_kset, name); 289a9cbf0b2SMukesh Ojha if (kobj) { 290a9cbf0b2SMukesh Ojha /* Drop reference added by kset_find_obj() */ 291a9cbf0b2SMukesh Ojha kobject_put(kobj); 292a8956a7bSAlistair Popple return IRQ_HANDLED; 293a9cbf0b2SMukesh Ojha } 294774fea1aSStewart Smith 295774fea1aSStewart Smith create_elog_obj(log_id, elog_size, elog_type); 296774fea1aSStewart Smith 29774159a70SAlistair Popple return IRQ_HANDLED; 298774fea1aSStewart Smith } 299774fea1aSStewart Smith 300774fea1aSStewart Smith int __init opal_elog_init(void) 301774fea1aSStewart Smith { 30274159a70SAlistair Popple int rc = 0, irq; 303774fea1aSStewart Smith 3047dc992ecSMichael Neuling /* ELOG not supported by firmware */ 3057dc992ecSMichael Neuling if (!opal_check_token(OPAL_ELOG_READ)) 3067dc992ecSMichael Neuling return -1; 3077dc992ecSMichael Neuling 308774fea1aSStewart Smith elog_kset = kset_create_and_add("elog", NULL, opal_kobj); 309774fea1aSStewart Smith if (!elog_kset) { 310774fea1aSStewart Smith pr_warn("%s: failed to create elog kset\n", __func__); 311774fea1aSStewart Smith return -1; 312774fea1aSStewart Smith } 313774fea1aSStewart Smith 31474159a70SAlistair Popple irq = opal_event_request(ilog2(OPAL_EVENT_ERROR_LOG_AVAIL)); 31574159a70SAlistair Popple if (!irq) { 31674159a70SAlistair Popple pr_err("%s: Can't register OPAL event irq (%d)\n", 31774159a70SAlistair Popple __func__, irq); 31874159a70SAlistair Popple return irq; 31974159a70SAlistair Popple } 32074159a70SAlistair Popple 321a8956a7bSAlistair Popple rc = request_threaded_irq(irq, NULL, elog_event, 322a8956a7bSAlistair Popple IRQF_TRIGGER_HIGH | IRQF_ONESHOT, "opal-elog", NULL); 323774fea1aSStewart Smith if (rc) { 32474159a70SAlistair Popple pr_err("%s: Can't request OPAL event irq (%d)\n", 325774fea1aSStewart Smith __func__, rc); 326774fea1aSStewart Smith return rc; 327774fea1aSStewart Smith } 328774fea1aSStewart Smith 329774fea1aSStewart Smith /* We are now ready to pull error logs from opal. */ 330fc81de63SStewart Smith if (opal_check_token(OPAL_ELOG_RESEND)) 331774fea1aSStewart Smith opal_resend_pending_logs(); 332774fea1aSStewart Smith 333774fea1aSStewart Smith return 0; 334774fea1aSStewart Smith } 335