drivers/s390/s390mach.c

   1 /*
   2  *  drivers/s390/s390mach.c
   3  *   S/390 machine check handler
   4  *
   5  *  S390 version
   6  *    Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
   8  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/init.h>
  13 #include <linux/sched.h>
  14 #include <linux/errno.h>
  15 #include <linux/workqueue.h>
  16
  17 #include <asm/lowcore.h>
  18
  19 #include "s390mach.h"
  20
  21 #define DBG printk
  22 // #define DBG(args,...) do {} while (0);
  23
  24 static struct semaphore m_sem;
  25
  26 extern int css_process_crw(int);
  27 extern int chsc_process_crw(void);
  28 extern int chp_process_crw(int, int);
  29 extern void css_reiterate_subchannels(void);
  30
  31 extern struct workqueue_struct *slow_path_wq;
  32 extern struct work_struct slow_path_work;
  33
  34 static void
  35 s390_handle_damage(char *msg)
  36 {
  37         printk(KERN_EMERG "%s\n", msg);
  38 #ifdef CONFIG_SMP
  39         smp_send_stop();
  40 #endif
  41         disabled_wait((unsigned long) __builtin_return_address(0));
  42 }
  43
  44 /*
  45  * Retrieve CRWs and call function to handle event.
  46  *
  47  * Note : we currently process CRWs for io and chsc subchannels only
  48  */
  49 static int
  50 s390_collect_crw_info(void *param)
  51 {
  52         struct crw crw;
  53         int ccode, ret, slow;
  54         struct semaphore *sem;
  55
  56         sem = (struct semaphore *)param;
  57         /* Set a nice name. */
  58         daemonize("kmcheck");
  59 repeat:
  60         down_interruptible(sem);
  61         slow = 0;
  62         while (1) {
  63                 ccode = stcrw(&crw);
  64                 if (ccode != 0)
  65                         break;
  66                 DBG(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
  67                     "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
  68                     crw.slct, crw.oflw, crw.chn, crw.rsc, crw.anc,
  69                     crw.erc, crw.rsid);
  70                 /* Check for overflows. */
  71                 if (crw.oflw) {
  72                         pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
  73                         css_reiterate_subchannels();
  74                         slow = 1;
  75                         continue;
  76                 }
  77                 switch (crw.rsc) {
  78                 case CRW_RSC_SCH:
  79                         pr_debug("source is subchannel %04X\n", crw.rsid);
  80                         ret = css_process_crw (crw.rsid);
  81                         if (ret == -EAGAIN)
  82                                 slow = 1;
  83                         break;
  84                 case CRW_RSC_MONITOR:
  85                         pr_debug("source is monitoring facility\n");
  86                         break;
  87                 case CRW_RSC_CPATH:
  88                         pr_debug("source is channel path %02X\n", crw.rsid);
  89                         switch (crw.erc) {
  90                         case CRW_ERC_IPARM: /* Path has come. */
  91                                 ret = chp_process_crw(crw.rsid, 1);
  92                                 break;
  93                         case CRW_ERC_PERRI: /* Path has gone. */
  94                         case CRW_ERC_PERRN:
  95                                 ret = chp_process_crw(crw.rsid, 0);
  96                                 break;
  97                         default:
  98                                 pr_debug("Don't know how to handle erc=%x\n",
  99                                          crw.erc);
 100                                 ret = 0;
 101                         }
 102                         if (ret == -EAGAIN)
 103                                 slow = 1;
 104                         break;
 105                 case CRW_RSC_CONFIG:
 106                         pr_debug("source is configuration-alert facility\n");
 107                         break;
 108                 case CRW_RSC_CSS:
 109                         pr_debug("source is channel subsystem\n");
 110                         ret = chsc_process_crw();
 111                         if (ret == -EAGAIN)
 112                                 slow = 1;
 113                         break;
 114                 default:
 115                         pr_debug("unknown source\n");
 116                         break;
 117                 }
 118         }
 119         if (slow)
 120                 queue_work(slow_path_wq, &slow_path_work);
 121         goto repeat;
 122         return 0;
 123 }
 124
 125 /*
 126  * machine check handler.
 127  */
 128 void
 129 s390_do_machine_check(void)
 130 {
 131         struct mci *mci;
 132
 133         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
 134
 135         if (mci->sd)            /* system damage */
 136                 s390_handle_damage("received system damage machine check\n");
 137
 138         if (mci->pd)            /* instruction processing damage */
 139                 s390_handle_damage("received instruction processing "
 140                                    "damage machine check\n");
 141
 142         if (mci->se)            /* storage error uncorrected */
 143                 s390_handle_damage("received storage error uncorrected "
 144                                    "machine check\n");
 145
 146         if (mci->sc)            /* storage error corrected */
 147                 printk(KERN_WARNING
 148                        "received storage error corrected machine check\n");
 149
 150         if (mci->ke)            /* storage key-error uncorrected */
 151                 s390_handle_damage("received storage key-error uncorrected "
 152                                    "machine check\n");
 153
 154         if (mci->ds && mci->fa) /* storage degradation */
 155                 s390_handle_damage("received storage degradation machine "
 156                                    "check\n");
 157
 158         if (mci->cp)            /* channel report word pending */
 159                 up(&m_sem);
 160
 161 #ifdef CONFIG_MACHCHK_WARNING
 162 /*
 163  * The warning may remain for a prolonged period on the bare iron.
 164  * (actually till the machine is powered off, or until the problem is gone)
 165  * So we just stop listening for the WARNING MCH and prevent continuously
 166  * being interrupted.  One caveat is however, that we must do this per
 167  * processor and cannot use the smp version of ctl_clear_bit().
 168  * On VM we only get one interrupt per virtally presented machinecheck.
 169  * Though one suffices, we may get one interrupt per (virtual) processor.
 170  */
 171         if (mci->w) {   /* WARNING pending ? */
 172                 static int mchchk_wng_posted = 0;
 173                 /*
 174                  * Use single machine clear, as we cannot handle smp right now
 175                  */
 176                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
 177                 if (xchg(&mchchk_wng_posted, 1) == 0)
 178                         kill_proc(1, SIGPWR, 1);
 179         }
 180 #endif
 181 }
 182
 183 /*
 184  * s390_init_machine_check
 185  *
 186  * initialize machine check handling
 187  */
 188 static int
 189 machine_check_init(void)
 190 {
 191         init_MUTEX_LOCKED(&m_sem);
 192         ctl_clear_bit(14, 25);  /* disable damage MCH */
 193         ctl_set_bit(14, 26);    /* enable degradation MCH */
 194         ctl_set_bit(14, 27);    /* enable system recovery MCH */
 195 #ifdef CONFIG_MACHCHK_WARNING
 196         ctl_set_bit(14, 24);    /* enable warning MCH */
 197 #endif
 198         return 0;
 199 }
 200
 201 /*
 202  * Initialize the machine check handler really early to be able to
 203  * catch all machine checks that happen during boot
 204  */
 205 arch_initcall(machine_check_init);
 206
 207 /*
 208  * Machine checks for the channel subsystem must be enabled
 209  * after the channel subsystem is initialized
 210  */
 211 static int __init
 212 machine_check_crw_init (void)
 213 {
 214         kernel_thread(s390_collect_crw_info, &m_sem, CLONE_FS|CLONE_FILES);
 215         ctl_set_bit(14, 28);    /* enable channel report MCH */
 216         return 0;
 217 }
 218
 219 device_initcall (machine_check_crw_init);