linux/drivers/s390/char/sclp_async.c
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   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
  24static int callhome_enabled;
  25static struct sclp_req *request;
  26static struct sclp_async_sccb *sccb;
  27static int sclp_async_send_wait(char *message);
  28static struct ctl_table_header *callhome_sysctl_header;
  29static DEFINE_SPINLOCK(sclp_async_lock);
  30#define SCLP_NORMAL_WRITE       0x00
  31
  32struct 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
  43struct sclp_async_sccb {
  44        struct sccb_header header;
  45        struct async_evbuf evbuf;
  46} __attribute__((packed));
  47
  48static struct sclp_register sclp_async_register = {
  49        .send_mask = EVTYP_ASYNC_MASK,
  50};
  51
  52static 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
  61static struct notifier_block call_home_panic_nb = {
  62        .notifier_call = call_home_on_panic,
  63        .priority = INT_MAX,
  64};
  65
  66static 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
  97static struct ctl_table callhome_table[] = {
  98        {
  99                .procname       = "callhome",
 100                .mode           = 0644,
 101                .proc_handler   = proc_handler_callhome,
 102        },
 103        {}
 104};
 105
 106static 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 */
 120static 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, "000000000", sizeof(sccb->evbuf.comp_id));
 141        sccb->evbuf.header.length = sizeof(sccb->evbuf);
 142        sccb->header.length = sizeof(sccb->evbuf) + sizeof(sccb->header);
 143        sccb->header.function_code = SCLP_NORMAL_WRITE;
 144        rc = sclp_add_request(request);
 145        if (rc)
 146                return rc;
 147        spin_lock_irqsave(&sclp_async_lock, flags);
 148        while (request->status != SCLP_REQ_DONE &&
 149                request->status != SCLP_REQ_FAILED) {
 150                 sclp_sync_wait();
 151        }
 152        spin_unlock_irqrestore(&sclp_async_lock, flags);
 153        if (request->status != SCLP_REQ_DONE)
 154                return -EIO;
 155        rc = ((struct sclp_async_sccb *)
 156               request->sccb)->header.response_code;
 157        if (rc != 0x0020)
 158                return -EIO;
 159        if (evb->header.flags != 0x80)
 160                return -EIO;
 161        return rc;
 162}
 163
 164static int __init sclp_async_init(void)
 165{
 166        int rc;
 167
 168        rc = sclp_register(&sclp_async_register);
 169        if (rc)
 170                return rc;
 171        rc = -EOPNOTSUPP;
 172        if (!(sclp_async_register.sclp_receive_mask & EVTYP_ASYNC_MASK))
 173                goto out_sclp;
 174        rc = -ENOMEM;
 175        callhome_sysctl_header = register_sysctl_table(kern_dir_table);
 176        if (!callhome_sysctl_header)
 177                goto out_sclp;
 178        request = kzalloc(sizeof(struct sclp_req), GFP_KERNEL);
 179        sccb = (struct sclp_async_sccb *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 180        if (!request || !sccb)
 181                goto out_mem;
 182        rc = atomic_notifier_chain_register(&panic_notifier_list,
 183                                            &call_home_panic_nb);
 184        if (!rc)
 185                goto out;
 186out_mem:
 187        kfree(request);
 188        free_page((unsigned long) sccb);
 189        unregister_sysctl_table(callhome_sysctl_header);
 190out_sclp:
 191        sclp_unregister(&sclp_async_register);
 192out:
 193        return rc;
 194}
 195module_init(sclp_async_init);
 196
 197static void __exit sclp_async_exit(void)
 198{
 199        atomic_notifier_chain_unregister(&panic_notifier_list,
 200                                         &call_home_panic_nb);
 201        unregister_sysctl_table(callhome_sysctl_header);
 202        sclp_unregister(&sclp_async_register);
 203        free_page((unsigned long) sccb);
 204        kfree(request);
 205}
 206module_exit(sclp_async_exit);
 207
 208MODULE_AUTHOR("Copyright IBM Corp. 2009");
 209MODULE_AUTHOR("Hans-Joachim Picht <hans@linux.vnet.ibm.com>");
 210MODULE_LICENSE("GPL");
 211MODULE_DESCRIPTION("SCLP Asynchronous Notification Records");
 212