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/slab.h>
  24 #include <linux/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 struct mon_private {
  43         struct list_head list;
  44         struct monwrite_hdr hdr;
  45         size_t hdr_to_read;
  46         size_t data_to_read;
  47         struct mon_buf *current_buf;
  48         struct mutex thread_mutex;
  49 };
  50
  51 /*
  52  * helper functions
  53  */
  54
  55 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
  56 {
  57         struct appldata_parameter_list *parm_list;
  58         struct appldata_product_id *id;
  59         int rc;
  60
  61         id = kmalloc(sizeof(*id), GFP_KERNEL);
  62         parm_list = kmalloc(sizeof(*parm_list), GFP_KERNEL);
  63         rc = -ENOMEM;
  64         if (!id || !parm_list)
  65                 goto out;
  66         memcpy(id->prod_nr, "LNXAPPL", 7);
  67         id->prod_fn = myhdr->applid;
  68         id->record_nr = myhdr->record_num;
  69         id->version_nr = myhdr->version;
  70         id->release_nr = myhdr->release;
  71         id->mod_lvl = myhdr->mod_level;
  72         rc = appldata_asm(parm_list, id, fcn,
  73                           (void *) buffer, myhdr->datalen);
  74         if (rc <= 0)
  75                 goto out;
  76         pr_err("Writing monitor data failed with rc=%i\n", rc);
  77         rc = (rc == 5) ? -EPERM : -EINVAL;
  78 out:
  79         kfree(id);
  80         kfree(parm_list);
  81         return rc;
  82 }
  83
  84 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
  85                                          struct monwrite_hdr *monhdr)
  86 {
  87         struct mon_buf *entry, *next;
  88
  89         list_for_each_entry_safe(entry, next, &monpriv->list, list)
  90                 if ((entry->hdr.mon_function == monhdr->mon_function ||
  91                      monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
  92                     entry->hdr.applid == monhdr->applid &&
  93                     entry->hdr.record_num == monhdr->record_num &&
  94                     entry->hdr.version == monhdr->version &&
  95                     entry->hdr.release == monhdr->release &&
  96                     entry->hdr.mod_level == monhdr->mod_level)
  97                         return entry;
  98
  99         return NULL;
 100 }
 101
 102 static int monwrite_new_hdr(struct mon_private *monpriv)
 103 {
 104         struct monwrite_hdr *monhdr = &monpriv->hdr;
 105         struct mon_buf *monbuf;
 106         int rc = 0;
 107
 108         if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
 109             monhdr->mon_function > MONWRITE_START_CONFIG ||
 110             monhdr->hdrlen != sizeof(struct monwrite_hdr))
 111                 return -EINVAL;
 112         monbuf = NULL;
 113         if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 114                 monbuf = monwrite_find_hdr(monpriv, monhdr);
 115         if (monbuf) {
 116                 if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
 117                         monhdr->datalen = monbuf->hdr.datalen;
 118                         rc = monwrite_diag(monhdr, monbuf->data,
 119                                            APPLDATA_STOP_REC);
 120                         list_del(&monbuf->list);
 121                         mon_buf_count--;
 122                         kfree(monbuf->data);
 123                         kfree(monbuf);
 124                         monbuf = NULL;
 125                 }
 126         } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
 127                 if (mon_buf_count >= mon_max_bufs)
 128                         return -ENOSPC;
 129                 monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
 130                 if (!monbuf)
 131                         return -ENOMEM;
 132                 monbuf->data = kzalloc(monhdr->datalen,
 133                                        GFP_KERNEL | GFP_DMA);
 134                 if (!monbuf->data) {
 135                         kfree(monbuf);
 136                         return -ENOMEM;
 137                 }
 138                 monbuf->hdr = *monhdr;
 139                 list_add_tail(&monbuf->list, &monpriv->list);
 140                 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 141                         mon_buf_count++;
 142         }
 143         monpriv->current_buf = monbuf;
 144         return rc;
 145 }
 146
 147 static int monwrite_new_data(struct mon_private *monpriv)
 148 {
 149         struct monwrite_hdr *monhdr = &monpriv->hdr;
 150         struct mon_buf *monbuf = monpriv->current_buf;
 151         int rc = 0;
 152
 153         switch (monhdr->mon_function) {
 154         case MONWRITE_START_INTERVAL:
 155                 if (!monbuf->diag_done) {
 156                         rc = monwrite_diag(monhdr, monbuf->data,
 157                                            APPLDATA_START_INTERVAL_REC);
 158                         monbuf->diag_done = 1;
 159                 }
 160                 break;
 161         case MONWRITE_START_CONFIG:
 162                 if (!monbuf->diag_done) {
 163                         rc = monwrite_diag(monhdr, monbuf->data,
 164                                            APPLDATA_START_CONFIG_REC);
 165                         monbuf->diag_done = 1;
 166                 }
 167                 break;
 168         case MONWRITE_GEN_EVENT:
 169                 rc = monwrite_diag(monhdr, monbuf->data,
 170                                    APPLDATA_GEN_EVENT_REC);
 171                 list_del(&monpriv->current_buf->list);
 172                 kfree(monpriv->current_buf->data);
 173                 kfree(monpriv->current_buf);
 174                 monpriv->current_buf = NULL;
 175                 break;
 176         default:
 177                 /* monhdr->mon_function is checked in monwrite_new_hdr */
 178                 BUG();
 179         }
 180         return rc;
 181 }
 182
 183 /*
 184  * file operations
 185  */
 186
 187 static int monwrite_open(struct inode *inode, struct file *filp)
 188 {
 189         struct mon_private *monpriv;
 190
 191         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
 192         if (!monpriv)
 193                 return -ENOMEM;
 194         INIT_LIST_HEAD(&monpriv->list);
 195         monpriv->hdr_to_read = sizeof(monpriv->hdr);
 196         mutex_init(&monpriv->thread_mutex);
 197         filp->private_data = monpriv;
 198         return nonseekable_open(inode, filp);
 199 }
 200
 201 static int monwrite_close(struct inode *inode, struct file *filp)
 202 {
 203         struct mon_private *monpriv = filp->private_data;
 204         struct mon_buf *entry, *next;
 205
 206         list_for_each_entry_safe(entry, next, &monpriv->list, list) {
 207                 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
 208                         monwrite_diag(&entry->hdr, entry->data,
 209                                       APPLDATA_STOP_REC);
 210                 mon_buf_count--;
 211                 list_del(&entry->list);
 212                 kfree(entry->data);
 213                 kfree(entry);
 214         }
 215         kfree(monpriv);
 216         return 0;
 217 }
 218
 219 static ssize_t monwrite_write(struct file *filp, const char __user *data,
 220                               size_t count, loff_t *ppos)
 221 {
 222         struct mon_private *monpriv = filp->private_data;
 223         size_t len, written;
 224         void *to;
 225         int rc;
 226
 227         mutex_lock(&monpriv->thread_mutex);
 228         for (written = 0; written < count; ) {
 229                 if (monpriv->hdr_to_read) {
 230                         len = min(count - written, monpriv->hdr_to_read);
 231                         to = (char *) &monpriv->hdr +
 232                                 sizeof(monpriv->hdr) - monpriv->hdr_to_read;
 233                         if (copy_from_user(to, data + written, len)) {
 234                                 rc = -EFAULT;
 235                                 goto out_error;
 236                         }
 237                         monpriv->hdr_to_read -= len;
 238                         written += len;
 239                         if (monpriv->hdr_to_read > 0)
 240                                 continue;
 241                         rc = monwrite_new_hdr(monpriv);
 242                         if (rc)
 243                                 goto out_error;
 244                         monpriv->data_to_read = monpriv->current_buf ?
 245                                 monpriv->current_buf->hdr.datalen : 0;
 246                 }
 247
 248                 if (monpriv->data_to_read) {
 249                         len = min(count - written, monpriv->data_to_read);
 250                         to = monpriv->current_buf->data +
 251                                 monpriv->hdr.datalen - monpriv->data_to_read;
 252                         if (copy_from_user(to, data + written, len)) {
 253                                 rc = -EFAULT;
 254                                 goto out_error;
 255                         }
 256                         monpriv->data_to_read -= len;
 257                         written += len;
 258                         if (monpriv->data_to_read > 0)
 259                                 continue;
 260                         rc = monwrite_new_data(monpriv);
 261                         if (rc)
 262                                 goto out_error;
 263                 }
 264                 monpriv->hdr_to_read = sizeof(monpriv->hdr);
 265         }
 266         mutex_unlock(&monpriv->thread_mutex);
 267         return written;
 268
 269 out_error:
 270         monpriv->data_to_read = 0;
 271         monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
 272         mutex_unlock(&monpriv->thread_mutex);
 273         return rc;
 274 }
 275
 276 static const struct file_operations monwrite_fops = {
 277         .owner   = THIS_MODULE,
 278         .open    = &monwrite_open,
 279         .release = &monwrite_close,
 280         .write   = &monwrite_write,
 281         .llseek  = noop_llseek,
 282 };
 283
 284 static struct miscdevice mon_dev = {
 285         .name   = "monwriter",
 286         .fops   = &monwrite_fops,
 287         .minor  = MISC_DYNAMIC_MINOR,
 288 };
 289
 290 /*
 291  * module init/exit
 292  */
 293
 294 static int __init mon_init(void)
 295 {
 296         if (!MACHINE_IS_VM)
 297                 return -ENODEV;
 298         /*
 299          * misc_register() has to be the last action in module_init(), because
 300          * file operations will be available right after this.
 301          */
 302         return misc_register(&mon_dev);
 303 }
 304
 305 static void __exit mon_exit(void)
 306 {
 307         misc_deregister(&mon_dev);
 308 }
 309
 310 module_init(mon_init);
 311 module_exit(mon_exit);
 312
 313 module_param_named(max_bufs, mon_max_bufs, int, 0644);
 314 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
 315                  "that can be active at one time");
 316
 317 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
 318 MODULE_DESCRIPTION("Character device driver for writing z/VM "
 319                    "APPLDATA monitor records.");
 320 MODULE_LICENSE("GPL");