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 = copy_from_user(buf, buffer, sizeof(buf));
  86                 if (rc != 0)
  87                         return -EFAULT;
  88                 buf[sizeof(buf) - 1] = '\0';
  89                 if (strict_strtoul(buf, 0, &val) != 0)
  90                         return -EINVAL;
  91                 if (val != 0 && val != 1)
  92                         return -EINVAL;
  93                 callhome_enabled = val;
  94         }
  95         *count = len;
  96         *ppos += len;
  97         return 0;
  98 }
  99
 100 static struct ctl_table callhome_table[] = {
 101         {
 102                 .procname       = "callhome",
 103                 .mode           = 0644,
 104                 .proc_handler   = proc_handler_callhome,
 105         },
 106         {}
 107 };
 108
 109 static struct ctl_table kern_dir_table[] = {
 110         {
 111                 .procname       = "kernel",
 112                 .maxlen         = 0,
 113                 .mode           = 0555,
 114                 .child          = callhome_table,
 115         },
 116         {}
 117 };
 118
 119 /*
 120  * Function used to transfer asynchronous notification
 121  * records which waits for send completion
 122  */
 123 static int sclp_async_send_wait(char *message)
 124 {
 125         struct async_evbuf *evb;
 126         int rc;
 127         unsigned long flags;
 128
 129         if (!callhome_enabled)
 130                 return 0;
 131         sccb->evbuf.header.type = EVTYP_ASYNC;
 132         sccb->evbuf.rtype = 0xA5;
 133         sccb->evbuf.otype = 0x00;
 134         evb = &sccb->evbuf;
 135         request->command = SCLP_CMDW_WRITE_EVENT_DATA;
 136         request->sccb = sccb;
 137         request->status = SCLP_REQ_FILLED;
 138         strncpy(sccb->evbuf.data, message, sizeof(sccb->evbuf.data));
 139         /*
 140          * Retain Queue
 141          * e.g. 5639CC140 500 Red Hat RHEL5 Linux for zSeries (RHEL AS)
 142          */
 143         strncpy(sccb->evbuf.comp_id, "000000000", sizeof(sccb->evbuf.comp_id));
 144         sccb->evbuf.header.length = sizeof(sccb->evbuf);
 145         sccb->header.length = sizeof(sccb->evbuf) + sizeof(sccb->header);
 146         sccb->header.function_code = SCLP_NORMAL_WRITE;
 147         rc = sclp_add_request(request);
 148         if (rc)
 149                 return rc;
 150         spin_lock_irqsave(&sclp_async_lock, flags);
 151         while (request->status != SCLP_REQ_DONE &&
 152                 request->status != SCLP_REQ_FAILED) {
 153                  sclp_sync_wait();
 154         }
 155         spin_unlock_irqrestore(&sclp_async_lock, flags);
 156         if (request->status != SCLP_REQ_DONE)
 157                 return -EIO;
 158         rc = ((struct sclp_async_sccb *)
 159                request->sccb)->header.response_code;
 160         if (rc != 0x0020)
 161                 return -EIO;
 162         if (evb->header.flags != 0x80)
 163                 return -EIO;
 164         return rc;
 165 }
 166
 167 static int __init sclp_async_init(void)
 168 {
 169         int rc;
 170
 171         rc = sclp_register(&sclp_async_register);
 172         if (rc)
 173                 return rc;
 174         rc = -EOPNOTSUPP;
 175         if (!(sclp_async_register.sclp_receive_mask & EVTYP_ASYNC_MASK))
 176                 goto out_sclp;
 177         rc = -ENOMEM;
 178         callhome_sysctl_header = register_sysctl_table(kern_dir_table);
 179         if (!callhome_sysctl_header)
 180                 goto out_sclp;
 181         request = kzalloc(sizeof(struct sclp_req), GFP_KERNEL);
 182         sccb = (struct sclp_async_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 183         if (!request || !sccb)
 184                 goto out_mem;
 185         rc = atomic_notifier_chain_register(&panic_notifier_list,
 186                                             &call_home_panic_nb);
 187         if (!rc)
 188                 goto out;
 189 out_mem:
 190         kfree(request);
 191         free_page((unsigned long) sccb);
 192         unregister_sysctl_table(callhome_sysctl_header);
 193 out_sclp:
 194         sclp_unregister(&sclp_async_register);
 195 out:
 196         return rc;
 197 }
 198 module_init(sclp_async_init);
 199
 200 static void __exit sclp_async_exit(void)
 201 {
 202         atomic_notifier_chain_unregister(&panic_notifier_list,
 203                                          &call_home_panic_nb);
 204         unregister_sysctl_table(callhome_sysctl_header);
 205         sclp_unregister(&sclp_async_register);
 206         free_page((unsigned long) sccb);
 207         kfree(request);
 208 }
 209 module_exit(sclp_async_exit);
 210
 211 MODULE_AUTHOR("Copyright IBM Corp. 2009");
 212 MODULE_AUTHOR("Hans-Joachim Picht <hans@linux.vnet.ibm.com>");
 213 MODULE_LICENSE("GPL");
 214 MODULE_DESCRIPTION("SCLP Asynchronous Notification Records");