drivers/s390/char/monwriter.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Character device driver for writing z/VM *MONITOR service records.
   4  *
   5  * Copyright IBM Corp. 2006, 2009
   6  *
   7  * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com>
   8  */
   9
  10 #define KMSG_COMPONENT "monwriter"
  11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/init.h>
  16 #include <linux/errno.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/miscdevice.h>
  20 #include <linux/ctype.h>
  21 #include <linux/poll.h>
  22 #include <linux/mutex.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/slab.h>
  25 #include <linux/uaccess.h>
  26 #include <asm/ebcdic.h>
  27 #include <asm/io.h>
  28 #include <asm/appldata.h>
  29 #include <asm/monwriter.h>
  30
  31 #define MONWRITE_MAX_DATALEN    4010
  32
  33 static int mon_max_bufs = 255;
  34 static int mon_buf_count;
  35
  36 struct mon_buf {
  37         struct list_head list;
  38         struct monwrite_hdr hdr;
  39         int diag_done;
  40         char *data;
  41 };
  42
  43 static LIST_HEAD(mon_priv_list);
  44
  45 struct mon_private {
  46         struct list_head priv_list;
  47         struct list_head list;
  48         struct monwrite_hdr hdr;
  49         size_t hdr_to_read;
  50         size_t data_to_read;
  51         struct mon_buf *current_buf;
  52         struct mutex thread_mutex;
  53 };
  54
  55 /*
  56  * helper functions
  57  */
  58
  59 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
  60 {
  61         struct appldata_product_id id;
  62         int rc;
  63
  64         strncpy(id.prod_nr, "LNXAPPL", 7);
  65         id.prod_fn = myhdr->applid;
  66         id.record_nr = myhdr->record_num;
  67         id.version_nr = myhdr->version;
  68         id.release_nr = myhdr->release;
  69         id.mod_lvl = myhdr->mod_level;
  70         rc = appldata_asm(&id, fcn, (void *) buffer, myhdr->datalen);
  71         if (rc <= 0)
  72                 return rc;
  73         pr_err("Writing monitor data failed with rc=%i\n", rc);
  74         if (rc == 5)
  75                 return -EPERM;
  76         return -EINVAL;
  77 }
  78
  79 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
  80                                          struct monwrite_hdr *monhdr)
  81 {
  82         struct mon_buf *entry, *next;
  83
  84         list_for_each_entry_safe(entry, next, &monpriv->list, list)
  85                 if ((entry->hdr.mon_function == monhdr->mon_function ||
  86                      monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
  87                     entry->hdr.applid == monhdr->applid &&
  88                     entry->hdr.record_num == monhdr->record_num &&
  89                     entry->hdr.version == monhdr->version &&
  90                     entry->hdr.release == monhdr->release &&
  91                     entry->hdr.mod_level == monhdr->mod_level)
  92                         return entry;
  93
  94         return NULL;
  95 }
  96
  97 static int monwrite_new_hdr(struct mon_private *monpriv)
  98 {
  99         struct monwrite_hdr *monhdr = &monpriv->hdr;
 100         struct mon_buf *monbuf;
 101         int rc = 0;
 102
 103         if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
 104             monhdr->mon_function > MONWRITE_START_CONFIG ||
 105             monhdr->hdrlen != sizeof(struct monwrite_hdr))
 106                 return -EINVAL;
 107         monbuf = NULL;
 108         if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 109                 monbuf = monwrite_find_hdr(monpriv, monhdr);
 110         if (monbuf) {
 111                 if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
 112                         monhdr->datalen = monbuf->hdr.datalen;
 113                         rc = monwrite_diag(monhdr, monbuf->data,
 114                                            APPLDATA_STOP_REC);
 115                         list_del(&monbuf->list);
 116                         mon_buf_count--;
 117                         kfree(monbuf->data);
 118                         kfree(monbuf);
 119                         monbuf = NULL;
 120                 }
 121         } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
 122                 if (mon_buf_count >= mon_max_bufs)
 123                         return -ENOSPC;
 124                 monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
 125                 if (!monbuf)
 126                         return -ENOMEM;
 127                 monbuf->data = kzalloc(monhdr->datalen,
 128                                        GFP_KERNEL | GFP_DMA);
 129                 if (!monbuf->data) {
 130                         kfree(monbuf);
 131                         return -ENOMEM;
 132                 }
 133                 monbuf->hdr = *monhdr;
 134                 list_add_tail(&monbuf->list, &monpriv->list);
 135                 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 136                         mon_buf_count++;
 137         }
 138         monpriv->current_buf = monbuf;
 139         return rc;
 140 }
 141
 142 static int monwrite_new_data(struct mon_private *monpriv)
 143 {
 144         struct monwrite_hdr *monhdr = &monpriv->hdr;
 145         struct mon_buf *monbuf = monpriv->current_buf;
 146         int rc = 0;
 147
 148         switch (monhdr->mon_function) {
 149         case MONWRITE_START_INTERVAL:
 150                 if (!monbuf->diag_done) {
 151                         rc = monwrite_diag(monhdr, monbuf->data,
 152                                            APPLDATA_START_INTERVAL_REC);
 153                         monbuf->diag_done = 1;
 154                 }
 155                 break;
 156         case MONWRITE_START_CONFIG:
 157                 if (!monbuf->diag_done) {
 158                         rc = monwrite_diag(monhdr, monbuf->data,
 159                                            APPLDATA_START_CONFIG_REC);
 160                         monbuf->diag_done = 1;
 161                 }
 162                 break;
 163         case MONWRITE_GEN_EVENT:
 164                 rc = monwrite_diag(monhdr, monbuf->data,
 165                                    APPLDATA_GEN_EVENT_REC);
 166                 list_del(&monpriv->current_buf->list);
 167                 kfree(monpriv->current_buf->data);
 168                 kfree(monpriv->current_buf);
 169                 monpriv->current_buf = NULL;
 170                 break;
 171         default:
 172                 /* monhdr->mon_function is checked in monwrite_new_hdr */
 173                 BUG();
 174         }
 175         return rc;
 176 }
 177
 178 /*
 179  * file operations
 180  */
 181
 182 static int monwrite_open(struct inode *inode, struct file *filp)
 183 {
 184         struct mon_private *monpriv;
 185
 186         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
 187         if (!monpriv)
 188                 return -ENOMEM;
 189         INIT_LIST_HEAD(&monpriv->list);
 190         monpriv->hdr_to_read = sizeof(monpriv->hdr);
 191         mutex_init(&monpriv->thread_mutex);
 192         filp->private_data = monpriv;
 193         list_add_tail(&monpriv->priv_list, &mon_priv_list);
 194         return nonseekable_open(inode, filp);
 195 }
 196
 197 static int monwrite_close(struct inode *inode, struct file *filp)
 198 {
 199         struct mon_private *monpriv = filp->private_data;
 200         struct mon_buf *entry, *next;
 201
 202         list_for_each_entry_safe(entry, next, &monpriv->list, list) {
 203                 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
 204                         monwrite_diag(&entry->hdr, entry->data,
 205                                       APPLDATA_STOP_REC);
 206                 mon_buf_count--;
 207                 list_del(&entry->list);
 208                 kfree(entry->data);
 209                 kfree(entry);
 210         }
 211         list_del(&monpriv->priv_list);
 212         kfree(monpriv);
 213         return 0;
 214 }
 215
 216 static ssize_t monwrite_write(struct file *filp, const char __user *data,
 217                               size_t count, loff_t *ppos)
 218 {
 219         struct mon_private *monpriv = filp->private_data;
 220         size_t len, written;
 221         void *to;
 222         int rc;
 223
 224         mutex_lock(&monpriv->thread_mutex);
 225         for (written = 0; written < count; ) {
 226                 if (monpriv->hdr_to_read) {
 227                         len = min(count - written, monpriv->hdr_to_read);
 228                         to = (char *) &monpriv->hdr +
 229                                 sizeof(monpriv->hdr) - monpriv->hdr_to_read;
 230                         if (copy_from_user(to, data + written, len)) {
 231                                 rc = -EFAULT;
 232                                 goto out_error;
 233                         }
 234                         monpriv->hdr_to_read -= len;
 235                         written += len;
 236                         if (monpriv->hdr_to_read > 0)
 237                                 continue;
 238                         rc = monwrite_new_hdr(monpriv);
 239                         if (rc)
 240                                 goto out_error;
 241                         monpriv->data_to_read = monpriv->current_buf ?
 242                                 monpriv->current_buf->hdr.datalen : 0;
 243                 }
 244
 245                 if (monpriv->data_to_read) {
 246                         len = min(count - written, monpriv->data_to_read);
 247                         to = monpriv->current_buf->data +
 248                                 monpriv->hdr.datalen - monpriv->data_to_read;
 249                         if (copy_from_user(to, data + written, len)) {
 250                                 rc = -EFAULT;
 251                                 goto out_error;
 252                         }
 253                         monpriv->data_to_read -= len;
 254                         written += len;
 255                         if (monpriv->data_to_read > 0)
 256                                 continue;
 257                         rc = monwrite_new_data(monpriv);
 258                         if (rc)
 259                                 goto out_error;
 260                 }
 261                 monpriv->hdr_to_read = sizeof(monpriv->hdr);
 262         }
 263         mutex_unlock(&monpriv->thread_mutex);
 264         return written;
 265
 266 out_error:
 267         monpriv->data_to_read = 0;
 268         monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
 269         mutex_unlock(&monpriv->thread_mutex);
 270         return rc;
 271 }
 272
 273 static const struct file_operations monwrite_fops = {
 274         .owner   = THIS_MODULE,
 275         .open    = &monwrite_open,
 276         .release = &monwrite_close,
 277         .write   = &monwrite_write,
 278         .llseek  = noop_llseek,
 279 };
 280
 281 static struct miscdevice mon_dev = {
 282         .name   = "monwriter",
 283         .fops   = &monwrite_fops,
 284         .minor  = MISC_DYNAMIC_MINOR,
 285 };
 286
 287 /*
 288  * suspend/resume
 289  */
 290
 291 static int monwriter_freeze(struct device *dev)
 292 {
 293         struct mon_private *monpriv;
 294         struct mon_buf *monbuf;
 295
 296         list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
 297                 list_for_each_entry(monbuf, &monpriv->list, list) {
 298                         if (monbuf->hdr.mon_function != MONWRITE_GEN_EVENT)
 299                                 monwrite_diag(&monbuf->hdr, monbuf->data,
 300                                               APPLDATA_STOP_REC);
 301                 }
 302         }
 303         return 0;
 304 }
 305
 306 static int monwriter_restore(struct device *dev)
 307 {
 308         struct mon_private *monpriv;
 309         struct mon_buf *monbuf;
 310
 311         list_for_each_entry(monpriv, &mon_priv_list, priv_list) {
 312                 list_for_each_entry(monbuf, &monpriv->list, list) {
 313                         if (monbuf->hdr.mon_function == MONWRITE_START_INTERVAL)
 314                                 monwrite_diag(&monbuf->hdr, monbuf->data,
 315                                               APPLDATA_START_INTERVAL_REC);
 316                         if (monbuf->hdr.mon_function == MONWRITE_START_CONFIG)
 317                                 monwrite_diag(&monbuf->hdr, monbuf->data,
 318                                               APPLDATA_START_CONFIG_REC);
 319                 }
 320         }
 321         return 0;
 322 }
 323
 324 static int monwriter_thaw(struct device *dev)
 325 {
 326         return monwriter_restore(dev);
 327 }
 328
 329 static const struct dev_pm_ops monwriter_pm_ops = {
 330         .freeze         = monwriter_freeze,
 331         .thaw           = monwriter_thaw,
 332         .restore        = monwriter_restore,
 333 };
 334
 335 static struct platform_driver monwriter_pdrv = {
 336         .driver = {
 337                 .name   = "monwriter",
 338                 .pm     = &monwriter_pm_ops,
 339         },
 340 };
 341
 342 static struct platform_device *monwriter_pdev;
 343
 344 /*
 345  * module init/exit
 346  */
 347
 348 static int __init mon_init(void)
 349 {
 350         int rc;
 351
 352         if (!MACHINE_IS_VM)
 353                 return -ENODEV;
 354
 355         rc = platform_driver_register(&monwriter_pdrv);
 356         if (rc)
 357                 return rc;
 358
 359         monwriter_pdev = platform_device_register_simple("monwriter", -1, NULL,
 360                                                         0);
 361         if (IS_ERR(monwriter_pdev)) {
 362                 rc = PTR_ERR(monwriter_pdev);
 363                 goto out_driver;
 364         }
 365
 366         /*
 367          * misc_register() has to be the last action in module_init(), because
 368          * file operations will be available right after this.
 369          */
 370         rc = misc_register(&mon_dev);
 371         if (rc)
 372                 goto out_device;
 373         return 0;
 374
 375 out_device:
 376         platform_device_unregister(monwriter_pdev);
 377 out_driver:
 378         platform_driver_unregister(&monwriter_pdrv);
 379         return rc;
 380 }
 381
 382 static void __exit mon_exit(void)
 383 {
 384         misc_deregister(&mon_dev);
 385         platform_device_unregister(monwriter_pdev);
 386         platform_driver_unregister(&monwriter_pdrv);
 387 }
 388
 389 module_init(mon_init);
 390 module_exit(mon_exit);
 391
 392 module_param_named(max_bufs, mon_max_bufs, int, 0644);
 393 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
 394                  "that can be active at one time");
 395
 396 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
 397 MODULE_DESCRIPTION("Character device driver for writing z/VM "
 398                    "APPLDATA monitor records.");
 399 MODULE_LICENSE("GPL");