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