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