arch/powerpc/platforms/powernv/opal-elog.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Error log support on PowerNV.
   4  *
   5  * Copyright 2013,2014 IBM Corp.
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/init.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/of.h>
  11 #include <linux/slab.h>
  12 #include <linux/sysfs.h>
  13 #include <linux/fs.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/fcntl.h>
  16 #include <linux/kobject.h>
  17 #include <linux/uaccess.h>
  18 #include <asm/opal.h>
  19
  20 struct elog_obj {
  21         struct kobject kobj;
  22         struct bin_attribute raw_attr;
  23         uint64_t id;
  24         uint64_t type;
  25         size_t size;
  26         char *buffer;
  27 };
  28 #define to_elog_obj(x) container_of(x, struct elog_obj, kobj)
  29
  30 struct elog_attribute {
  31         struct attribute attr;
  32         ssize_t (*show)(struct elog_obj *elog, struct elog_attribute *attr,
  33                         char *buf);
  34         ssize_t (*store)(struct elog_obj *elog, struct elog_attribute *attr,
  35                          const char *buf, size_t count);
  36 };
  37 #define to_elog_attr(x) container_of(x, struct elog_attribute, attr)
  38
  39 static ssize_t elog_id_show(struct elog_obj *elog_obj,
  40                             struct elog_attribute *attr,
  41                             char *buf)
  42 {
  43         return sprintf(buf, "0x%llx\n", elog_obj->id);
  44 }
  45
  46 static const char *elog_type_to_string(uint64_t type)
  47 {
  48         switch (type) {
  49         case 0: return "PEL";
  50         default: return "unknown";
  51         }
  52 }
  53
  54 static ssize_t elog_type_show(struct elog_obj *elog_obj,
  55                               struct elog_attribute *attr,
  56                               char *buf)
  57 {
  58         return sprintf(buf, "0x%llx %s\n",
  59                        elog_obj->type,
  60                        elog_type_to_string(elog_obj->type));
  61 }
  62
  63 static ssize_t elog_ack_show(struct elog_obj *elog_obj,
  64                              struct elog_attribute *attr,
  65                              char *buf)
  66 {
  67         return sprintf(buf, "ack - acknowledge log message\n");
  68 }
  69
  70 static ssize_t elog_ack_store(struct elog_obj *elog_obj,
  71                               struct elog_attribute *attr,
  72                               const char *buf,
  73                               size_t count)
  74 {
  75         opal_send_ack_elog(elog_obj->id);
  76         sysfs_remove_file_self(&elog_obj->kobj, &attr->attr);
  77         kobject_put(&elog_obj->kobj);
  78         return count;
  79 }
  80
  81 static struct elog_attribute id_attribute =
  82         __ATTR(id, 0444, elog_id_show, NULL);
  83 static struct elog_attribute type_attribute =
  84         __ATTR(type, 0444, elog_type_show, NULL);
  85 static struct elog_attribute ack_attribute =
  86         __ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store);
  87
  88 static struct kset *elog_kset;
  89
  90 static ssize_t elog_attr_show(struct kobject *kobj,
  91                               struct attribute *attr,
  92                               char *buf)
  93 {
  94         struct elog_attribute *attribute;
  95         struct elog_obj *elog;
  96
  97         attribute = to_elog_attr(attr);
  98         elog = to_elog_obj(kobj);
  99
 100         if (!attribute->show)
 101                 return -EIO;
 102
 103         return attribute->show(elog, attribute, buf);
 104 }
 105
 106 static ssize_t elog_attr_store(struct kobject *kobj,
 107                                struct attribute *attr,
 108                                const char *buf, size_t len)
 109 {
 110         struct elog_attribute *attribute;
 111         struct elog_obj *elog;
 112
 113         attribute = to_elog_attr(attr);
 114         elog = to_elog_obj(kobj);
 115
 116         if (!attribute->store)
 117                 return -EIO;
 118
 119         return attribute->store(elog, attribute, buf, len);
 120 }
 121
 122 static const struct sysfs_ops elog_sysfs_ops = {
 123         .show = elog_attr_show,
 124         .store = elog_attr_store,
 125 };
 126
 127 static void elog_release(struct kobject *kobj)
 128 {
 129         struct elog_obj *elog;
 130
 131         elog = to_elog_obj(kobj);
 132         kfree(elog->buffer);
 133         kfree(elog);
 134 }
 135
 136 static struct attribute *elog_default_attrs[] = {
 137         &id_attribute.attr,
 138         &type_attribute.attr,
 139         &ack_attribute.attr,
 140         NULL,
 141 };
 142
 143 static struct kobj_type elog_ktype = {
 144         .sysfs_ops = &elog_sysfs_ops,
 145         .release = &elog_release,
 146         .default_attrs = elog_default_attrs,
 147 };
 148
 149 /* Maximum size of a single log on FSP is 16KB */
 150 #define OPAL_MAX_ERRLOG_SIZE    16384
 151
 152 static ssize_t raw_attr_read(struct file *filep, struct kobject *kobj,
 153                              struct bin_attribute *bin_attr,
 154                              char *buffer, loff_t pos, size_t count)
 155 {
 156         int opal_rc;
 157
 158         struct elog_obj *elog = to_elog_obj(kobj);
 159
 160         /* We may have had an error reading before, so let's retry */
 161         if (!elog->buffer) {
 162                 elog->buffer = kzalloc(elog->size, GFP_KERNEL);
 163                 if (!elog->buffer)
 164                         return -EIO;
 165
 166                 opal_rc = opal_read_elog(__pa(elog->buffer),
 167                                          elog->size, elog->id);
 168                 if (opal_rc != OPAL_SUCCESS) {
 169                         pr_err("ELOG: log read failed for log-id=%llx\n",
 170                                elog->id);
 171                         kfree(elog->buffer);
 172                         elog->buffer = NULL;
 173                         return -EIO;
 174                 }
 175         }
 176
 177         memcpy(buffer, elog->buffer + pos, count);
 178
 179         return count;
 180 }
 181
 182 static struct elog_obj *create_elog_obj(uint64_t id, size_t size, uint64_t type)
 183 {
 184         struct elog_obj *elog;
 185         int rc;
 186
 187         elog = kzalloc(sizeof(*elog), GFP_KERNEL);
 188         if (!elog)
 189                 return NULL;
 190
 191         elog->kobj.kset = elog_kset;
 192
 193         kobject_init(&elog->kobj, &elog_ktype);
 194
 195         sysfs_bin_attr_init(&elog->raw_attr);
 196
 197         elog->raw_attr.attr.name = "raw";
 198         elog->raw_attr.attr.mode = 0400;
 199         elog->raw_attr.size = size;
 200         elog->raw_attr.read = raw_attr_read;
 201
 202         elog->id = id;
 203         elog->size = size;
 204         elog->type = type;
 205
 206         elog->buffer = kzalloc(elog->size, GFP_KERNEL);
 207
 208         if (elog->buffer) {
 209                 rc = opal_read_elog(__pa(elog->buffer),
 210                                          elog->size, elog->id);
 211                 if (rc != OPAL_SUCCESS) {
 212                         pr_err("ELOG: log read failed for log-id=%llx\n",
 213                                elog->id);
 214                         kfree(elog->buffer);
 215                         elog->buffer = NULL;
 216                 }
 217         }
 218
 219         rc = kobject_add(&elog->kobj, NULL, "0x%llx", id);
 220         if (rc) {
 221                 kobject_put(&elog->kobj);
 222                 return NULL;
 223         }
 224
 225         rc = sysfs_create_bin_file(&elog->kobj, &elog->raw_attr);
 226         if (rc) {
 227                 kobject_put(&elog->kobj);
 228                 return NULL;
 229         }
 230
 231         kobject_uevent(&elog->kobj, KOBJ_ADD);
 232
 233         return elog;
 234 }
 235
 236 static irqreturn_t elog_event(int irq, void *data)
 237 {
 238         __be64 size;
 239         __be64 id;
 240         __be64 type;
 241         uint64_t elog_size;
 242         uint64_t log_id;
 243         uint64_t elog_type;
 244         int rc;
 245         char name[2+16+1];
 246         struct kobject *kobj;
 247
 248         rc = opal_get_elog_size(&id, &size, &type);
 249         if (rc != OPAL_SUCCESS) {
 250                 pr_err("ELOG: OPAL log info read failed\n");
 251                 return IRQ_HANDLED;
 252         }
 253
 254         elog_size = be64_to_cpu(size);
 255         log_id = be64_to_cpu(id);
 256         elog_type = be64_to_cpu(type);
 257
 258         WARN_ON(elog_size > OPAL_MAX_ERRLOG_SIZE);
 259
 260         if (elog_size >= OPAL_MAX_ERRLOG_SIZE)
 261                 elog_size  =  OPAL_MAX_ERRLOG_SIZE;
 262
 263         sprintf(name, "0x%llx", log_id);
 264
 265         /* we may get notified twice, let's handle
 266          * that gracefully and not create two conflicting
 267          * entries.
 268          */
 269         kobj = kset_find_obj(elog_kset, name);
 270         if (kobj) {
 271                 /* Drop reference added by kset_find_obj() */
 272                 kobject_put(kobj);
 273                 return IRQ_HANDLED;
 274         }
 275
 276         create_elog_obj(log_id, elog_size, elog_type);
 277
 278         return IRQ_HANDLED;
 279 }
 280
 281 int __init opal_elog_init(void)
 282 {
 283         int rc = 0, irq;
 284
 285         /* ELOG not supported by firmware */
 286         if (!opal_check_token(OPAL_ELOG_READ))
 287                 return -1;
 288
 289         elog_kset = kset_create_and_add("elog", NULL, opal_kobj);
 290         if (!elog_kset) {
 291                 pr_warn("%s: failed to create elog kset\n", __func__);
 292                 return -1;
 293         }
 294
 295         irq = opal_event_request(ilog2(OPAL_EVENT_ERROR_LOG_AVAIL));
 296         if (!irq) {
 297                 pr_err("%s: Can't register OPAL event irq (%d)\n",
 298                        __func__, irq);
 299                 return irq;
 300         }
 301
 302         rc = request_threaded_irq(irq, NULL, elog_event,
 303                         IRQF_TRIGGER_HIGH | IRQF_ONESHOT, "opal-elog", NULL);
 304         if (rc) {
 305                 pr_err("%s: Can't request OPAL event irq (%d)\n",
 306                        __func__, rc);
 307                 return rc;
 308         }
 309
 310         /* We are now ready to pull error logs from opal. */
 311         if (opal_check_token(OPAL_ELOG_RESEND))
 312                 opal_resend_pending_logs();
 313
 314         return 0;
 315 }