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