linux/drivers/s390/char/sclp_async.c
<<
>>
Prefs
   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 = 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
 100static struct ctl_table callhome_table[] = {
 101        {
 102                .procname       = "callhome",
 103                .mode           = 0644,
 104                .proc_handler   = proc_handler_callhome,
 105        },
 106        {}
 107};
 108
 109static 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 */
 123static 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
 167static 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;
 189out_mem:
 190        kfree(request);
 191        free_page((unsigned long) sccb);
 192        unregister_sysctl_table(callhome_sysctl_header);
 193out_sclp:
 194        sclp_unregister(&sclp_async_register);
 195out:
 196        return rc;
 197}
 198module_init(sclp_async_init);
 199
 200static 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}
 209module_exit(sclp_async_exit);
 210
 211MODULE_AUTHOR("Copyright IBM Corp. 2009");
 212MODULE_AUTHOR("Hans-Joachim Picht <hans@linux.vnet.ibm.com>");
 213MODULE_LICENSE("GPL");
 214MODULE_DESCRIPTION("SCLP Asynchronous Notification Records");
 215