drivers/s390/char/sclp_async.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Enable Asynchronous Notification via SCLP.
   4  *
   5  * Copyright IBM Corp. 2009
   6  * Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
   7  *
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/device.h>
  13 #include <linux/stat.h>
  14 #include <linux/string.h>
  15 #include <linux/slab.h>
  16 #include <linux/ctype.h>
  17 #include <linux/kmod.h>
  18 #include <linux/err.h>
  19 #include <linux/errno.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/sysctl.h>
  22 #include <linux/utsname.h>
  23 #include "sclp.h"
  24
  25 static int callhome_enabled;
  26 static struct sclp_req *request;
  27 static struct sclp_async_sccb *sccb;
  28 static int sclp_async_send_wait(char *message);
  29 static struct ctl_table_header *callhome_sysctl_header;
  30 static DEFINE_SPINLOCK(sclp_async_lock);
  31 #define SCLP_NORMAL_WRITE       0x00
  32
  33 struct async_evbuf {
  34         struct evbuf_header header;
  35         u64 reserved;
  36         u8 rflags;
  37         u8 empty;
  38         u8 rtype;
  39         u8 otype;
  40         char comp_id[12];
  41         char data[3000]; /* there is still some space left */
  42 } __attribute__((packed));
  43
  44 struct sclp_async_sccb {
  45         struct sccb_header header;
  46         struct async_evbuf evbuf;
  47 } __attribute__((packed));
  48
  49 static struct sclp_register sclp_async_register = {
  50         .send_mask = EVTYP_ASYNC_MASK,
  51 };
  52
  53 static int call_home_on_panic(struct notifier_block *self,
  54                               unsigned long event, void *data)
  55 {
  56         strncat(data, init_utsname()->nodename,
  57                 sizeof(init_utsname()->nodename));
  58         sclp_async_send_wait(data);
  59         return NOTIFY_DONE;
  60 }
  61
  62 static struct notifier_block call_home_panic_nb = {
  63         .notifier_call = call_home_on_panic,
  64         .priority = INT_MAX,
  65 };
  66
  67 static int zero;
  68 static int one = 1;
  69
  70 static struct ctl_table callhome_table[] = {
  71         {
  72                 .procname       = "callhome",
  73                 .data           = &callhome_enabled,
  74                 .maxlen         = sizeof(int),
  75                 .mode           = 0644,
  76                 .proc_handler   = proc_dointvec_minmax,
  77                 .extra1         = &zero,
  78                 .extra2         = &one,
  79         },
  80         {}
  81 };
  82
  83 static struct ctl_table kern_dir_table[] = {
  84         {
  85                 .procname       = "kernel",
  86                 .maxlen         = 0,
  87                 .mode           = 0555,
  88                 .child          = callhome_table,
  89         },
  90         {}
  91 };
  92
  93 /*
  94  * Function used to transfer asynchronous notification
  95  * records which waits for send completion
  96  */
  97 static int sclp_async_send_wait(char *message)
  98 {
  99         struct async_evbuf *evb;
 100         int rc;
 101         unsigned long flags;
 102
 103         if (!callhome_enabled)
 104                 return 0;
 105         sccb->evbuf.header.type = EVTYP_ASYNC;
 106         sccb->evbuf.rtype = 0xA5;
 107         sccb->evbuf.otype = 0x00;
 108         evb = &sccb->evbuf;
 109         request->command = SCLP_CMDW_WRITE_EVENT_DATA;
 110         request->sccb = sccb;
 111         request->status = SCLP_REQ_FILLED;
 112         strncpy(sccb->evbuf.data, message, sizeof(sccb->evbuf.data));
 113         /*
 114          * Retain Queue
 115          * e.g. 5639CC140 500 Red Hat RHEL5 Linux for zSeries (RHEL AS)
 116          */
 117         strncpy(sccb->evbuf.comp_id, CONFIG_SCLP_ASYNC_ID,
 118                 sizeof(sccb->evbuf.comp_id));
 119         sccb->evbuf.header.length = sizeof(sccb->evbuf);
 120         sccb->header.length = sizeof(sccb->evbuf) + sizeof(sccb->header);
 121         sccb->header.function_code = SCLP_NORMAL_WRITE;
 122         rc = sclp_add_request(request);
 123         if (rc)
 124                 return rc;
 125         spin_lock_irqsave(&sclp_async_lock, flags);
 126         while (request->status != SCLP_REQ_DONE &&
 127                 request->status != SCLP_REQ_FAILED) {
 128                  sclp_sync_wait();
 129         }
 130         spin_unlock_irqrestore(&sclp_async_lock, flags);
 131         if (request->status != SCLP_REQ_DONE)
 132                 return -EIO;
 133         rc = ((struct sclp_async_sccb *)
 134                request->sccb)->header.response_code;
 135         if (rc != 0x0020)
 136                 return -EIO;
 137         if (evb->header.flags != 0x80)
 138                 return -EIO;
 139         return rc;
 140 }
 141
 142 static int __init sclp_async_init(void)
 143 {
 144         int rc;
 145
 146         rc = sclp_register(&sclp_async_register);
 147         if (rc)
 148                 return rc;
 149         rc = -EOPNOTSUPP;
 150         if (!(sclp_async_register.sclp_receive_mask & EVTYP_ASYNC_MASK))
 151                 goto out_sclp;
 152         rc = -ENOMEM;
 153         callhome_sysctl_header = register_sysctl_table(kern_dir_table);
 154         if (!callhome_sysctl_header)
 155                 goto out_sclp;
 156         request = kzalloc(sizeof(struct sclp_req), GFP_KERNEL);
 157         sccb = (struct sclp_async_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 158         if (!request || !sccb)
 159                 goto out_mem;
 160         rc = atomic_notifier_chain_register(&panic_notifier_list,
 161                                             &call_home_panic_nb);
 162         if (!rc)
 163                 goto out;
 164 out_mem:
 165         kfree(request);
 166         free_page((unsigned long) sccb);
 167         unregister_sysctl_table(callhome_sysctl_header);
 168 out_sclp:
 169         sclp_unregister(&sclp_async_register);
 170 out:
 171         return rc;
 172 }
 173 module_init(sclp_async_init);
 174
 175 static void __exit sclp_async_exit(void)
 176 {
 177         atomic_notifier_chain_unregister(&panic_notifier_list,
 178                                          &call_home_panic_nb);
 179         unregister_sysctl_table(callhome_sysctl_header);
 180         sclp_unregister(&sclp_async_register);
 181         free_page((unsigned long) sccb);
 182         kfree(request);
 183 }
 184 module_exit(sclp_async_exit);
 185
 186 MODULE_AUTHOR("Copyright IBM Corp. 2009");
 187 MODULE_AUTHOR("Hans-Joachim Picht <hans@linux.vnet.ibm.com>");
 188 MODULE_LICENSE("GPL");
 189 MODULE_DESCRIPTION("SCLP Asynchronous Notification Records");