drivers/s390/char/monwriter.c

   1 /*
   2  * drivers/s390/char/monwriter.c
   3  *
   4  * Character device driver for writing z/VM *MONITOR service records.
   5  *
   6  * Copyright (C) IBM Corp. 2006
   7  *
   8  * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/moduleparam.h>
  13 #include <linux/init.h>
  14 #include <linux/errno.h>
  15 #include <linux/smp_lock.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 <asm/uaccess.h>
  23 #include <asm/ebcdic.h>
  24 #include <asm/io.h>
  25 #include <asm/appldata.h>
  26 #include <asm/monwriter.h>
  27
  28 #define MONWRITE_MAX_DATALEN    4010
  29
  30 static int mon_max_bufs = 255;
  31 static int mon_buf_count;
  32
  33 struct mon_buf {
  34         struct list_head list;
  35         struct monwrite_hdr hdr;
  36         int diag_done;
  37         char *data;
  38 };
  39
  40 struct mon_private {
  41         struct list_head list;
  42         struct monwrite_hdr hdr;
  43         size_t hdr_to_read;
  44         size_t data_to_read;
  45         struct mon_buf *current_buf;
  46         struct mutex thread_mutex;
  47 };
  48
  49 /*
  50  * helper functions
  51  */
  52
  53 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
  54 {
  55         struct appldata_product_id id;
  56         int rc;
  57
  58         strcpy(id.prod_nr, "LNXAPPL");
  59         id.prod_fn = myhdr->applid;
  60         id.record_nr = myhdr->record_num;
  61         id.version_nr = myhdr->version;
  62         id.release_nr = myhdr->release;
  63         id.mod_lvl = myhdr->mod_level;
  64         rc = appldata_asm(&id, fcn, (void *) buffer, myhdr->datalen);
  65         if (rc <= 0)
  66                 return rc;
  67         if (rc == 5)
  68                 return -EPERM;
  69         printk("DIAG X'DC' error with return code: %i\n", rc);
  70         return -EINVAL;
  71 }
  72
  73 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
  74                                          struct monwrite_hdr *monhdr)
  75 {
  76         struct mon_buf *entry, *next;
  77
  78         list_for_each_entry_safe(entry, next, &monpriv->list, list)
  79                 if ((entry->hdr.mon_function == monhdr->mon_function ||
  80                      monhdr->mon_function == MONWRITE_STOP_INTERVAL) &&
  81                     entry->hdr.applid == monhdr->applid &&
  82                     entry->hdr.record_num == monhdr->record_num &&
  83                     entry->hdr.version == monhdr->version &&
  84                     entry->hdr.release == monhdr->release &&
  85                     entry->hdr.mod_level == monhdr->mod_level)
  86                         return entry;
  87
  88         return NULL;
  89 }
  90
  91 static int monwrite_new_hdr(struct mon_private *monpriv)
  92 {
  93         struct monwrite_hdr *monhdr = &monpriv->hdr;
  94         struct mon_buf *monbuf;
  95         int rc;
  96
  97         if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
  98             monhdr->mon_function > MONWRITE_START_CONFIG ||
  99             monhdr->hdrlen != sizeof(struct monwrite_hdr))
 100                 return -EINVAL;
 101         monbuf = NULL;
 102         if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 103                 monbuf = monwrite_find_hdr(monpriv, monhdr);
 104         if (monbuf) {
 105                 if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
 106                         monhdr->datalen = monbuf->hdr.datalen;
 107                         rc = monwrite_diag(monhdr, monbuf->data,
 108                                            APPLDATA_STOP_REC);
 109                         list_del(&monbuf->list);
 110                         mon_buf_count--;
 111                         kfree(monbuf->data);
 112                         kfree(monbuf);
 113                         monbuf = NULL;
 114                 }
 115         } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) {
 116                 if (mon_buf_count >= mon_max_bufs)
 117                         return -ENOSPC;
 118                 monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
 119                 if (!monbuf)
 120                         return -ENOMEM;
 121                 monbuf->data = kzalloc(monhdr->datalen,
 122                                        GFP_KERNEL | GFP_DMA);
 123                 if (!monbuf->data) {
 124                         kfree(monbuf);
 125                         return -ENOMEM;
 126                 }
 127                 monbuf->hdr = *monhdr;
 128                 list_add_tail(&monbuf->list, &monpriv->list);
 129                 if (monhdr->mon_function != MONWRITE_GEN_EVENT)
 130                         mon_buf_count++;
 131         }
 132         monpriv->current_buf = monbuf;
 133         return 0;
 134 }
 135
 136 static int monwrite_new_data(struct mon_private *monpriv)
 137 {
 138         struct monwrite_hdr *monhdr = &monpriv->hdr;
 139         struct mon_buf *monbuf = monpriv->current_buf;
 140         int rc = 0;
 141
 142         switch (monhdr->mon_function) {
 143         case MONWRITE_START_INTERVAL:
 144                 if (!monbuf->diag_done) {
 145                         rc = monwrite_diag(monhdr, monbuf->data,
 146                                            APPLDATA_START_INTERVAL_REC);
 147                         monbuf->diag_done = 1;
 148                 }
 149                 break;
 150         case MONWRITE_START_CONFIG:
 151                 if (!monbuf->diag_done) {
 152                         rc = monwrite_diag(monhdr, monbuf->data,
 153                                            APPLDATA_START_CONFIG_REC);
 154                         monbuf->diag_done = 1;
 155                 }
 156                 break;
 157         case MONWRITE_GEN_EVENT:
 158                 rc = monwrite_diag(monhdr, monbuf->data,
 159                                    APPLDATA_GEN_EVENT_REC);
 160                 list_del(&monpriv->current_buf->list);
 161                 kfree(monpriv->current_buf->data);
 162                 kfree(monpriv->current_buf);
 163                 monpriv->current_buf = NULL;
 164                 break;
 165         default:
 166                 /* monhdr->mon_function is checked in monwrite_new_hdr */
 167                 BUG();
 168         }
 169         return rc;
 170 }
 171
 172 /*
 173  * file operations
 174  */
 175
 176 static int monwrite_open(struct inode *inode, struct file *filp)
 177 {
 178         struct mon_private *monpriv;
 179
 180         monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
 181         if (!monpriv)
 182                 return -ENOMEM;
 183         lock_kernel();
 184         INIT_LIST_HEAD(&monpriv->list);
 185         monpriv->hdr_to_read = sizeof(monpriv->hdr);
 186         mutex_init(&monpriv->thread_mutex);
 187         filp->private_data = monpriv;
 188         unlock_kernel();
 189         return nonseekable_open(inode, filp);
 190 }
 191
 192 static int monwrite_close(struct inode *inode, struct file *filp)
 193 {
 194         struct mon_private *monpriv = filp->private_data;
 195         struct mon_buf *entry, *next;
 196
 197         list_for_each_entry_safe(entry, next, &monpriv->list, list) {
 198                 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
 199                         monwrite_diag(&entry->hdr, entry->data,
 200                                       APPLDATA_STOP_REC);
 201                 mon_buf_count--;
 202                 list_del(&entry->list);
 203                 kfree(entry->data);
 204                 kfree(entry);
 205         }
 206         kfree(monpriv);
 207         return 0;
 208 }
 209
 210 static ssize_t monwrite_write(struct file *filp, const char __user *data,
 211                               size_t count, loff_t *ppos)
 212 {
 213         struct mon_private *monpriv = filp->private_data;
 214         size_t len, written;
 215         void *to;
 216         int rc;
 217
 218         mutex_lock(&monpriv->thread_mutex);
 219         for (written = 0; written < count; ) {
 220                 if (monpriv->hdr_to_read) {
 221                         len = min(count - written, monpriv->hdr_to_read);
 222                         to = (char *) &monpriv->hdr +
 223                                 sizeof(monpriv->hdr) - monpriv->hdr_to_read;
 224                         if (copy_from_user(to, data + written, len)) {
 225                                 rc = -EFAULT;
 226                                 goto out_error;
 227                         }
 228                         monpriv->hdr_to_read -= len;
 229                         written += len;
 230                         if (monpriv->hdr_to_read > 0)
 231                                 continue;
 232                         rc = monwrite_new_hdr(monpriv);
 233                         if (rc)
 234                                 goto out_error;
 235                         monpriv->data_to_read = monpriv->current_buf ?
 236                                 monpriv->current_buf->hdr.datalen : 0;
 237                 }
 238
 239                 if (monpriv->data_to_read) {
 240                         len = min(count - written, monpriv->data_to_read);
 241                         to = monpriv->current_buf->data +
 242                                 monpriv->hdr.datalen - monpriv->data_to_read;
 243                         if (copy_from_user(to, data + written, len)) {
 244                                 rc = -EFAULT;
 245                                 goto out_error;
 246                         }
 247                         monpriv->data_to_read -= len;
 248                         written += len;
 249                         if (monpriv->data_to_read > 0)
 250                                 continue;
 251                         rc = monwrite_new_data(monpriv);
 252                         if (rc)
 253                                 goto out_error;
 254                 }
 255                 monpriv->hdr_to_read = sizeof(monpriv->hdr);
 256         }
 257         mutex_unlock(&monpriv->thread_mutex);
 258         return written;
 259
 260 out_error:
 261         monpriv->data_to_read = 0;
 262         monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
 263         mutex_unlock(&monpriv->thread_mutex);
 264         return rc;
 265 }
 266
 267 static const struct file_operations monwrite_fops = {
 268         .owner   = THIS_MODULE,
 269         .open    = &monwrite_open,
 270         .release = &monwrite_close,
 271         .write   = &monwrite_write,
 272 };
 273
 274 static struct miscdevice mon_dev = {
 275         .name   = "monwriter",
 276         .fops   = &monwrite_fops,
 277         .minor  = MISC_DYNAMIC_MINOR,
 278 };
 279
 280 /*
 281  * module init/exit
 282  */
 283
 284 static int __init mon_init(void)
 285 {
 286         if (MACHINE_IS_VM)
 287                 return misc_register(&mon_dev);
 288         else
 289                 return -ENODEV;
 290 }
 291
 292 static void __exit mon_exit(void)
 293 {
 294         WARN_ON(misc_deregister(&mon_dev) != 0);
 295 }
 296
 297 module_init(mon_init);
 298 module_exit(mon_exit);
 299
 300 module_param_named(max_bufs, mon_max_bufs, int, 0644);
 301 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers "
 302                  "that can be active at one time");
 303
 304 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
 305 MODULE_DESCRIPTION("Character device driver for writing z/VM "
 306                    "APPLDATA monitor records.");
 307 MODULE_LICENSE("GPL");