drivers/s390/char/monwriter.c

   1 /*
   2  * Character device driver for writing z/VM *MONITOR service records.
   3  *
   4  * Copyright IBM Corp. 2006, 2009
   5  *
   6  * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com>
   7  */
   8
   9 #define KMSG_COMPONENT "monwriter"
  10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  11
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/init.h>
  15 #include <linux/errno.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/ctype.h>
  20 #include <linux/poll.h>
  21 #include <linux/mutex.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/slab.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/ebcdic.h>
  26 #include <asm/io.h>
  27 #include <asm/appldata.h>
  28 #include <asm/monwriter.h>
  29
  30 #define MONWRITE_MAX_DATALEN    4010
  31
  32 static int mon_max_bufs = 255;
  33 static int mon_buf_count;
  34
  35 struct mon_buf {
  36         struct list_head list;
  37         struct monwrite_hdr hdr;
  38         int diag_done;
  39         char *data;
  40 };
  41
  42 static LIST_HEAD(mon_priv_list);
  43
  44 struct mon_private {
  45         struct list_head priv_list;
  46         struct list_head list;
  47         struct monwrite_hdr hdr;
  48         size_t hdr_to_read;
  49         size_t data_to_read;
  50         struct mon_buf *current_buf;
  51         struct mutex thread_mutex;
  52 };
  53
  54 /*
  55  * helper functions
  56  */
  57
  58 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
  59 {
  60         struct appldata_product_id id;
  61         int rc;
  62
  63         strncpy(id.prod_nr, "LNXAPPL", 7);
  64         id.prod_fn = myhdr->applid;
  65         id.record_nr = myhdr->record_num;
  66         id.version_nr = myhdr->version;
  67         id.release_nr = myhdr->release;
  68         id.mod_lvl = myhdr->mod_level;
  69         rc = appldata_asm(&id, fcn, (void *) buffer, myhdr->datalen);
  70         if (rc <= 0)
  71                 return rc;
  72         pr_err("Writing monitor data failed with rc=%i\n", rc);
  73         if (rc == 5)
  74                 return -EPERM;
  75         return -EINVAL;
  76 }
  77
  78 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
  79                                          struct monwrite_hdr *monhdr)
  80 {
  81         struct mon_buf *entry, *next;
  82
  83         list_for_each_entry_safe(entry, next, &monpriv->list, list)
  84                 if ((entry->hdr.mon_function == monhdr->mon_function ||
  85                      monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
  86                     entry->hdr.applid == monhdr->applid &&
  87                     entry->hdr.record_num == monhdr->record_num &&
  88                     entry->hdr.version == monhdr->version &&
  89                     entry->hdr.release == monhdr->release &&
  90                     entry->hdr.mod_level == monhdr->mod_level)
  91                         return entry;
  92
  93         return NULL;
  94 }
  95
  96 static int monwrite_new_hdr(struct mon_private *monpriv)
  97 {
  98         struct monwrite_hdr *monhdr = &monpriv->hdr;
  99         struct mon_buf *monbuf;
 100         int rc = 0;
 101
 102         if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
 103             monhdr->mon_function > MONWRITE_START_CONFIG ||
 104             monhdr->hdrlen != sizeof(struct monwrite_hdr))
 105                 return -EINVAL;
 106         monbuf = NULL;
 107         if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 108                 monbuf = monwrite_find_hdr(monpriv, monhdr);
 109         if (monbuf) {
 110                 if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
 111                         monhdr->datalen = monbuf->hdr.datalen;
 112                         rc = monwrite_diag(monhdr, monbuf->data,
 113                                            APPLDATA_STOP_REC);
 114                         list_del(&monbuf->list);
 115                         mon_buf_count--;
 116                         kfree(monbuf->data);
 117                         kfree(monbuf);
 118                         monbuf = NULL;
 119                 }
 120         } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
 121                 if (mon_buf_count >= mon_max_bufs)
 122                         return -ENOSPC;
 123                 monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
 124                 if (!monbuf)
 125                         return -ENOMEM;
 126                 monbuf->data = kzalloc(monhdr->datalen,
 127                                        GFP_KERNEL | GFP_DMA);
 128                 if (!monbuf->data) {
 129                         kfree(monbuf);
 130                         return -ENOMEM;
 131                 }
 132                 monbuf->hdr = *monhdr;
 133                 list_add_tail(&monbuf->list, &monpriv->list);
 134                 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 135                         mon_buf_count++;
 136         }
 137         monpriv->current_buf = monbuf;
 138         return rc;
 139 }
 140
 141 static int monwrite_new_data(struct mon_private *monpriv)
 142 {
 143         struct monwrite_hdr *monhdr = &monpriv->hdr;
 144         struct mon_buf *monbuf = monpriv->current_buf;
 145         int rc = 0;
 146
 147         switch (monhdr->mon_function) {
 148         case MONWRITE_START_INTERVAL:
 149                 if (!monbuf->diag_done) {
 150                         rc = monwrite_diag(monhdr, monbuf->data,
 151                                            APPLDATA_START_INTERVAL_REC);
 152                         monbuf->diag_done = 1;
 153                 }
 154                 break;
 155         case MONWRITE_START_CONFIG:
 156                 if (!monbuf->diag_done) {
 157                         rc = monwrite_diag(monhdr, monbuf->data,
 158                                            APPLDATA_START_CONFIG_REC);
 159                         monbuf->diag_done = 1;
 160                 }
 161                 break;
 162         case MONWRITE_GEN_EVENT:
 163                 rc = monwrite_diag(monhdr, monbuf->data,
 164                                    APPLDATA_GEN_EVENT_REC);
 165                 list_del(&monpriv->current_buf->list);
 166                 kfree(monpriv->current_buf->data);
 167                 kfree(monpriv->current_buf);
 168                 monpriv->current_buf = NULL;
 169                 break;
 170         default:
 171                 /* monhdr->mon_function is checked in monwrite_new_hdr */
 172                 BUG();
 173         }
 174         return rc;
 175 }
 176
 177 /*
 178  * file operations
 179  */
 180
 181 static int monwrite_open(struct inode *inode, struct file *filp)
 182 {
 183         struct mon_private *monpriv;
 184
 185         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
 186         if (!monpriv)
 187                 return -ENOMEM;
 188         INIT_LIST_HEAD(&monpriv->list);
 189         monpriv->hdr_to_read = sizeof(monpriv->hdr);
 190         mutex_init(&monpriv->thread_mutex);
 191         filp->private_data = monpriv;
 192         list_add_tail(&monpriv->priv_list, &mon_priv_list);
 193         return nonseekable_open(inode, filp);
 194 }
 195
 196 static int monwrite_close(struct inode *inode, struct file *filp)
 197 {
 198         struct mon_private *monpriv = filp->private_data;
 199         struct mon_buf *entry, *next;
 200
 201         list_for_each_entry_safe(entry, next, &monpriv->list, list) {
 202                 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
 203                         monwrite_diag(&entry->hdr, entry->data,
 204                                       APPLDATA_STOP_REC);
 205                 mon_buf_count--;
 206                 list_del(&entry->list);
 207                 kfree(entry->data);
 208                 kfree(entry);
 209         }
 210         list_del(&monpriv->priv_list);
 211         kfree(monpriv);
 212         return 0;
 213 }
 214
 215 static ssize_t monwrite_write(struct file *filp, const char __user *data,
 216                               size_t count, loff_t *ppos)
 217 {
 218         struct mon_private *monpriv = filp->private_data;
 219         size_t len, written;
 220         void *to;
 221         int rc;
 222
 223         mutex_lock(&monpriv->thread_mutex);
 224         for (written = 0; written < count; ) {
 225                 if (monpriv->hdr_to_read) {
 226                         len = min(count - written, monpriv->hdr_to_read);
 227                         to = (char *) &monpriv->hdr +
 228                                 sizeof(monpriv->hdr) - monpriv->hdr_to_read;
 229                         if (copy_from_user(to, data + written, len)) {
 230                                 rc = -EFAULT;
 231                                 goto out_error;
 232                         }
 233                         monpriv->hdr_to_read -= len;
 234                         written += len;
 235                         if (monpriv->hdr_to_read > 0)
 236                                 continue;
 237                         rc = monwrite_new_hdr(monpriv);
 238                         if (rc)
 239                                 goto out_error;
 240                         monpriv->data_to_read = monpriv->current_buf ?
 241                                 monpriv->current_buf->hdr.datalen : 0;
 242                 }
 243
 244                 if (monpriv->data_to_read) {
 245                         len = min(count - written, monpriv->data_to_read);
 246                         to = monpriv->current_buf->data +
 247                                 monpriv->hdr.datalen - monpriv->data_to_read;
 248                         if (copy_from_user(to, data + written, len)) {
 249                                 rc = -EFAULT;
 250                                 goto out_error;
 251                         }
 252                         monpriv->data_to_read -= len;
 253                         written += len;
 254                         if (monpriv->data_to_read > 0)
 255                                 continue;
 256                         rc = monwrite_new_data(monpriv);
 257                         if (rc)
 258                                 goto out_error;
 259                 }
 260                 monpriv->hdr_to_read = sizeof(monpriv->hdr);
 261         }
 262         mutex_unlock(&monpriv->thread_mutex);
 263         return written;
 264
 265 out_error:
 266         monpriv->data_to_read = 0;
 267         monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
 268         mutex_unlock(&monpriv->thread_mutex);
 269         return rc;
 270 }
 271
 272 static const struct file_operations monwrite_fops = {
 273         .owner   = THIS_MODULE,
 274         .open    = &monwrite_open,
 275         .release = &monwrite_close,
 276         .write   = &monwrite_write,
 277         .llseek  = noop_llseek,
 278 };
 279
 280 static struct miscdevice mon_dev = {
 281         .name   = "monwriter",
 282         .fops   = &monwrite_fops,
 283         .minor  = MISC_DYNAMIC_MINOR,
 284 };
 285
 286 /*
 287  * suspend/resume
 288  */
 289
 290 static int monwriter_freeze(struct device *dev)
 291 {
 292         struct mon_private *monpriv;
 293         struct mon_buf *monbuf;
 294
 295         list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
 296                 list_for_each_entry(monbuf, &monpriv->list, list) {
 297                         if (monbuf->hdr.mon_function != MONWRITE_GEN_EVENT)
 298                                 monwrite_diag(&monbuf->hdr, monbuf->data,
 299                                               APPLDATA_STOP_REC);
 300                 }
 301         }
 302         return 0;
 303 }
 304
 305 static int monwriter_restore(struct device *dev)
 306 {
 307         struct mon_private *monpriv;
 308         struct mon_buf *monbuf;
 309
 310         list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
 311                 list_for_each_entry(monbuf, &monpriv->list, list) {
 312                         if (monbuf->hdr.mon_function == MONWRITE_START_INTERVAL)
 313                                 monwrite_diag(&monbuf->hdr, monbuf->data,
 314                                               APPLDATA_START_INTERVAL_REC);
 315                         if (monbuf->hdr.mon_function == MONWRITE_START_CONFIG)
 316                                 monwrite_diag(&monbuf->hdr, monbuf->data,
 317                                               APPLDATA_START_CONFIG_REC);
 318                 }
 319         }
 320         return 0;
 321 }
 322
 323 static int monwriter_thaw(struct device *dev)
 324 {
 325         return monwriter_restore(dev);
 326 }
 327
 328 static const struct dev_pm_ops monwriter_pm_ops = {
 329         .freeze         = monwriter_freeze,
 330         .thaw           = monwriter_thaw,
 331         .restore        = monwriter_restore,
 332 };
 333
 334 static struct platform_driver monwriter_pdrv = {
 335         .driver = {
 336                 .name   = "monwriter",
 337                 .pm     = &monwriter_pm_ops,
 338         },
 339 };
 340
 341 static struct platform_device *monwriter_pdev;
 342
 343 /*
 344  * module init/exit
 345  */
 346
 347 static int __init mon_init(void)
 348 {
 349         int rc;
 350
 351         if (!MACHINE_IS_VM)
 352                 return -ENODEV;
 353
 354         rc = platform_driver_register(&monwriter_pdrv);
 355         if (rc)
 356                 return rc;
 357
 358         monwriter_pdev = platform_device_register_simple("monwriter", -1, NULL,
 359                                                         0);
 360         if (IS_ERR(monwriter_pdev)) {
 361                 rc = PTR_ERR(monwriter_pdev);
 362                 goto out_driver;
 363         }
 364
 365         /*
 366          * misc_register() has to be the last action in module_init(), because
 367          * file operations will be available right after this.
 368          */
 369         rc = misc_register(&mon_dev);
 370         if (rc)
 371                 goto out_device;
 372         return 0;
 373
 374 out_device:
 375         platform_device_unregister(monwriter_pdev);
 376 out_driver:
 377         platform_driver_unregister(&monwriter_pdrv);
 378         return rc;
 379 }
 380
 381 static void __exit mon_exit(void)
 382 {
 383         misc_deregister(&mon_dev);
 384         platform_device_unregister(monwriter_pdev);
 385         platform_driver_unregister(&monwriter_pdrv);
 386 }
 387
 388 module_init(mon_init);
 389 module_exit(mon_exit);
 390
 391 module_param_named(max_bufs, mon_max_bufs, int, 0644);
 392 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
 393                  "that can be active at one time");
 394
 395 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
 396 MODULE_DESCRIPTION("Character device driver for writing z/VM "
 397                    "APPLDATA monitor records.");
 398 MODULE_LICENSE("GPL");