kernel/drivers/s390/char/sclp_async.c

   1 /*
   2  * Enable Asynchronous Notification via SCLP.
   3  *
   4  * Copyright IBM Corp. 2009
   5  * Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
   6  *
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/device.h>
  12 #include <linux/stat.h>
  13 #include <linux/string.h>
  14 #include <linux/slab.h>
  15 #include <linux/ctype.h>
  16 #include <linux/kmod.h>
  17 #include <linux/err.h>
  18 #include <linux/errno.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/sysctl.h>
  21 #include <linux/utsname.h>
  22 #include "sclp.h"
  23
  24 static int callhome_enabled;
  25 static struct sclp_req *request;
  26 static struct sclp_async_sccb *sccb;
  27 static int sclp_async_send_wait(char *message);
  28 static struct ctl_table_header *callhome_sysctl_header;
  29 static DEFINE_SPINLOCK(sclp_async_lock);
  30 #define SCLP_NORMAL_WRITE       0x00
  31
  32 struct async_evbuf {
  33         struct evbuf_header header;
  34         u64 reserved;
  35         u8 rflags;
  36         u8 empty;
  37         u8 rtype;
  38         u8 otype;
  39         char comp_id[12];
  40         char data[3000]; /* there is still some space left */
  41 } __attribute__((packed));
  42
  43 struct sclp_async_sccb {
  44         struct sccb_header header;
  45         struct async_evbuf evbuf;
  46 } __attribute__((packed));
  47
  48 static struct sclp_register sclp_async_register = {
  49         .send_mask = EVTYP_ASYNC_MASK,
  50 };
  51
  52 static int call_home_on_panic(struct notifier_block *self,
  53                               unsigned long event, void *data)
  54 {
  55         strncat(data, init_utsname()->nodename,
  56                 sizeof(init_utsname()->nodename));
  57         sclp_async_send_wait(data);
  58         return NOTIFY_DONE;
  59 }
  60
  61 static struct notifier_block call_home_panic_nb = {
  62         .notifier_call = call_home_on_panic,
  63         .priority = INT_MAX,
  64 };
  65
  66 static int proc_handler_callhome(struct ctl_table *ctl, int write,
  67                                  void __user *buffer, size_t *count,
  68                                  loff_t *ppos)
  69 {
  70         unsigned long val;
  71         int len, rc;
  72         char buf[3];
  73
  74         if (!*count || (*ppos && !write)) {
  75                 *count = 0;
  76                 return 0;
  77         }
  78         if (!write) {
  79                 len = snprintf(buf, sizeof(buf), "%d\n", callhome_enabled);
  80                 rc = copy_to_user(buffer, buf, sizeof(buf));
  81                 if (rc != 0)
  82                         return -EFAULT;
  83         } else {
  84                 len = *count;
  85                 rc = kstrtoul_from_user(buffer, len, 0, &val);
  86                 if (rc)
  87                         return rc;
  88                 if (val != 0 && val != 1)
  89                         return -EINVAL;
  90                 callhome_enabled = val;
  91         }
  92         *count = len;
  93         *ppos += len;
  94         return 0;
  95 }
  96
  97 static struct ctl_table callhome_table[] = {
  98         {
  99                 .procname       = "callhome",
 100                 .mode           = 0644,
 101                 .proc_handler   = proc_handler_callhome,
 102         },
 103         {}
 104 };
 105
 106 static struct ctl_table kern_dir_table[] = {
 107         {
 108                 .procname       = "kernel",
 109                 .maxlen         = 0,
 110                 .mode           = 0555,
 111                 .child          = callhome_table,
 112         },
 113         {}
 114 };
 115
 116 /*
 117  * Function used to transfer asynchronous notification
 118  * records which waits for send completion
 119  */
 120 static int sclp_async_send_wait(char *message)
 121 {
 122         struct async_evbuf *evb;
 123         int rc;
 124         unsigned long flags;
 125
 126         if (!callhome_enabled)
 127                 return 0;
 128         sccb->evbuf.header.type = EVTYP_ASYNC;
 129         sccb->evbuf.rtype = 0xA5;
 130         sccb->evbuf.otype = 0x00;
 131         evb = &sccb->evbuf;
 132         request->command = SCLP_CMDW_WRITE_EVENT_DATA;
 133         request->sccb = sccb;
 134         request->status = SCLP_REQ_FILLED;
 135         strncpy(sccb->evbuf.data, message, sizeof(sccb->evbuf.data));
 136         /*
 137          * Retain Queue
 138          * e.g. 5639CC140 500 Red Hat RHEL5 Linux for zSeries (RHEL AS)
 139          */
 140         strncpy(sccb->evbuf.comp_id, CONFIG_SCLP_ASYNC_ID,
 141                 sizeof(sccb->evbuf.comp_id));
 142         sccb->evbuf.header.length = sizeof(sccb->evbuf);
 143         sccb->header.length = sizeof(sccb->evbuf) + sizeof(sccb->header);
 144         sccb->header.function_code = SCLP_NORMAL_WRITE;
 145         rc = sclp_add_request(request);
 146         if (rc)
 147                 return rc;
 148         spin_lock_irqsave(&sclp_async_lock, flags);
 149         while (request->status != SCLP_REQ_DONE &&
 150                 request->status != SCLP_REQ_FAILED) {
 151                  sclp_sync_wait();
 152         }
 153         spin_unlock_irqrestore(&sclp_async_lock, flags);
 154         if (request->status != SCLP_REQ_DONE)
 155                 return -EIO;
 156         rc = ((struct sclp_async_sccb *)
 157                request->sccb)->header.response_code;
 158         if (rc != 0x0020)
 159                 return -EIO;
 160         if (evb->header.flags != 0x80)
 161                 return -EIO;
 162         return rc;
 163 }
 164
 165 static int __init sclp_async_init(void)
 166 {
 167         int rc;
 168
 169         rc = sclp_register(&sclp_async_register);
 170         if (rc)
 171                 return rc;
 172         rc = -EOPNOTSUPP;
 173         if (!(sclp_async_register.sclp_receive_mask & EVTYP_ASYNC_MASK))
 174                 goto out_sclp;
 175         rc = -ENOMEM;
 176         callhome_sysctl_header = register_sysctl_table(kern_dir_table);
 177         if (!callhome_sysctl_header)
 178                 goto out_sclp;
 179         request = kzalloc(sizeof(struct sclp_req), GFP_KERNEL);
 180         sccb = (struct sclp_async_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 181         if (!request || !sccb)
 182                 goto out_mem;
 183         rc = atomic_notifier_chain_register(&panic_notifier_list,
 184                                             &call_home_panic_nb);
 185         if (!rc)
 186                 goto out;
 187 out_mem:
 188         kfree(request);
 189         free_page((unsigned long) sccb);
 190         unregister_sysctl_table(callhome_sysctl_header);
 191 out_sclp:
 192         sclp_unregister(&sclp_async_register);
 193 out:
 194         return rc;
 195 }
 196 module_init(sclp_async_init);
 197
 198 static void __exit sclp_async_exit(void)
 199 {
 200         atomic_notifier_chain_unregister(&panic_notifier_list,
 201                                          &call_home_panic_nb);
 202         unregister_sysctl_table(callhome_sysctl_header);
 203         sclp_unregister(&sclp_async_register);
 204         free_page((unsigned long) sccb);
 205         kfree(request);
 206 }
 207 module_exit(sclp_async_exit);
 208
 209 MODULE_AUTHOR("Copyright IBM Corp. 2009");
 210 MODULE_AUTHOR("Hans-Joachim Picht <hans@linux.vnet.ibm.com>");
 211 MODULE_LICENSE("GPL");
 212 MODULE_DESCRIPTION("SCLP Asynchronous Notification Records");