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/init.h>
  12 #include <linux/sched.h>
  13 #include <linux/errno.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/time.h>
  16 #include <linux/device.h>
  17 #include <linux/kthread.h>
  18 #include <asm/etr.h>
  19 #include <asm/lowcore.h>
  20 #include <asm/cio.h>
  21 #include "cio/cio.h"
  22 #include "cio/chsc.h"
  23 #include "cio/css.h"
  24 #include "s390mach.h"
  25
  26 static struct semaphore m_sem;
  27
  28 static NORET_TYPE void
  29 s390_handle_damage(char *msg)
  30 {
  31 #ifdef CONFIG_SMP
  32         smp_send_stop();
  33 #endif
  34         disabled_wait((unsigned long) __builtin_return_address(0));
  35         for(;;);
  36 }
  37
  38 /*
  39  * Retrieve CRWs and call function to handle event.
  40  *
  41  * Note : we currently process CRWs for io and chsc subchannels only
  42  */
  43 static int
  44 s390_collect_crw_info(void *param)
  45 {
  46         struct crw crw[2];
  47         int ccode, ret, slow;
  48         struct semaphore *sem;
  49         unsigned int chain;
  50
  51         sem = (struct semaphore *)param;
  52 repeat:
  53         down_interruptible(sem);
  54         slow = 0;
  55         chain = 0;
  56         while (1) {
  57                 if (unlikely(chain > 1)) {
  58                         struct crw tmp_crw;
  59
  60                         printk(KERN_WARNING"%s: Code does not support more "
  61                                "than two chained crws; please report to "
  62                                "linux390@de.ibm.com!\n", __FUNCTION__);
  63                         ccode = stcrw(&tmp_crw);
  64                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
  65                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
  66                                __FUNCTION__, tmp_crw.slct, tmp_crw.oflw,
  67                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
  68                                tmp_crw.erc, tmp_crw.rsid);
  69                         printk(KERN_WARNING"%s: This was crw number %x in the "
  70                                "chain\n", __FUNCTION__, chain);
  71                         if (ccode != 0)
  72                                 break;
  73                         chain = tmp_crw.chn ? chain + 1 : 0;
  74                         continue;
  75                 }
  76                 ccode = stcrw(&crw[chain]);
  77                 if (ccode != 0)
  78                         break;
  79                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
  80                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
  81                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
  82                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
  83                        crw[chain].rsid);
  84                 /* Check for overflows. */
  85                 if (crw[chain].oflw) {
  86                         pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
  87                         css_reiterate_subchannels();
  88                         chain = 0;
  89                         slow = 1;
  90                         continue;
  91                 }
  92                 switch (crw[chain].rsc) {
  93                 case CRW_RSC_SCH:
  94                         if (crw[0].chn && !chain)
  95                                 break;
  96                         pr_debug("source is subchannel %04X\n", crw[0].rsid);
  97                         ret = css_process_crw (crw[0].rsid,
  98                                                chain ? crw[1].rsid : 0);
  99                         if (ret == -EAGAIN)
 100                                 slow = 1;
 101                         break;
 102                 case CRW_RSC_MONITOR:
 103                         pr_debug("source is monitoring facility\n");
 104                         break;
 105                 case CRW_RSC_CPATH:
 106                         pr_debug("source is channel path %02X\n", crw[0].rsid);
 107                         /*
 108                          * Check for solicited machine checks. These are
 109                          * created by reset channel path and need not be
 110                          * reported to the common I/O layer.
 111                          */
 112                         if (crw[chain].slct) {
 113                                 pr_debug("solicited machine check for "
 114                                          "channel path %02X\n", crw[0].rsid);
 115                                 break;
 116                         }
 117                         switch (crw[0].erc) {
 118                         case CRW_ERC_IPARM: /* Path has come. */
 119                                 ret = chp_process_crw(crw[0].rsid, 1);
 120                                 break;
 121                         case CRW_ERC_PERRI: /* Path has gone. */
 122                         case CRW_ERC_PERRN:
 123                                 ret = chp_process_crw(crw[0].rsid, 0);
 124                                 break;
 125                         default:
 126                                 pr_debug("Don't know how to handle erc=%x\n",
 127                                          crw[0].erc);
 128                                 ret = 0;
 129                         }
 130                         if (ret == -EAGAIN)
 131                                 slow = 1;
 132                         break;
 133                 case CRW_RSC_CONFIG:
 134                         pr_debug("source is configuration-alert facility\n");
 135                         break;
 136                 case CRW_RSC_CSS:
 137                         pr_debug("source is channel subsystem\n");
 138                         ret = chsc_process_crw();
 139                         if (ret == -EAGAIN)
 140                                 slow = 1;
 141                         break;
 142                 default:
 143                         pr_debug("unknown source\n");
 144                         break;
 145                 }
 146                 /* chain is always 0 or 1 here. */
 147                 chain = crw[chain].chn ? chain + 1 : 0;
 148         }
 149         if (slow)
 150                 queue_work(slow_path_wq, &slow_path_work);
 151         goto repeat;
 152         return 0;
 153 }
 154
 155 struct mcck_struct {
 156         int kill_task;
 157         int channel_report;
 158         int warning;
 159         unsigned long long mcck_code;
 160 };
 161
 162 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
 163
 164 /*
 165  * Main machine check handler function. Will be called with interrupts enabled
 166  * or disabled and machine checks enabled or disabled.
 167  */
 168 void
 169 s390_handle_mcck(void)
 170 {
 171         unsigned long flags;
 172         struct mcck_struct mcck;
 173
 174         /*
 175          * Disable machine checks and get the current state of accumulated
 176          * machine checks. Afterwards delete the old state and enable machine
 177          * checks again.
 178          */
 179         local_irq_save(flags);
 180         local_mcck_disable();
 181         mcck = __get_cpu_var(cpu_mcck);
 182         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
 183         clear_thread_flag(TIF_MCCK_PENDING);
 184         local_mcck_enable();
 185         local_irq_restore(flags);
 186
 187         if (mcck.channel_report)
 188                 up(&m_sem);
 189
 190 #ifdef CONFIG_MACHCHK_WARNING
 191 /*
 192  * The warning may remain for a prolonged period on the bare iron.
 193  * (actually till the machine is powered off, or until the problem is gone)
 194  * So we just stop listening for the WARNING MCH and prevent continuously
 195  * being interrupted.  One caveat is however, that we must do this per
 196  * processor and cannot use the smp version of ctl_clear_bit().
 197  * On VM we only get one interrupt per virtally presented machinecheck.
 198  * Though one suffices, we may get one interrupt per (virtual) processor.
 199  */
 200         if (mcck.warning) {     /* WARNING pending ? */
 201                 static int mchchk_wng_posted = 0;
 202                 /*
 203                  * Use single machine clear, as we cannot handle smp right now
 204                  */
 205                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
 206                 if (xchg(&mchchk_wng_posted, 1) == 0)
 207                         kill_cad_pid(SIGPWR, 1);
 208         }
 209 #endif
 210
 211         if (mcck.kill_task) {
 212                 local_irq_enable();
 213                 printk(KERN_EMERG "mcck: Terminating task because of machine "
 214                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
 215                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
 216                        current->comm, current->pid);
 217                 do_exit(SIGSEGV);
 218         }
 219 }
 220
 221 /*
 222  * returns 0 if all registers could be validated
 223  * returns 1 otherwise
 224  */
 225 static int
 226 s390_revalidate_registers(struct mci *mci)
 227 {
 228         int kill_task;
 229         u64 tmpclock;
 230         u64 zero;
 231         void *fpt_save_area, *fpt_creg_save_area;
 232
 233         kill_task = 0;
 234         zero = 0;
 235         /* General purpose registers */
 236         if (!mci->gr)
 237                 /*
 238                  * General purpose registers couldn't be restored and have
 239                  * unknown contents. Process needs to be terminated.
 240                  */
 241                 kill_task = 1;
 242
 243         /* Revalidate floating point registers */
 244         if (!mci->fp)
 245                 /*
 246                  * Floating point registers can't be restored and
 247                  * therefore the process needs to be terminated.
 248                  */
 249                 kill_task = 1;
 250
 251 #ifndef CONFIG_64BIT
 252         asm volatile(
 253                 "       ld      0,0(%0)\n"
 254                 "       ld      2,8(%0)\n"
 255                 "       ld      4,16(%0)\n"
 256                 "       ld      6,24(%0)"
 257                 : : "a" (&S390_lowcore.floating_pt_save_area));
 258 #endif
 259
 260         if (MACHINE_HAS_IEEE) {
 261 #ifdef CONFIG_64BIT
 262                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
 263                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
 264 #else
 265                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
 266                 fpt_creg_save_area = fpt_save_area+128;
 267 #endif
 268                 /* Floating point control register */
 269                 if (!mci->fc) {
 270                         /*
 271                          * Floating point control register can't be restored.
 272                          * Task will be terminated.
 273                          */
 274                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
 275                         kill_task = 1;
 276
 277                 } else
 278                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
 279
 280                 asm volatile(
 281                         "       ld      0,0(%0)\n"
 282                         "       ld      1,8(%0)\n"
 283                         "       ld      2,16(%0)\n"
 284                         "       ld      3,24(%0)\n"
 285                         "       ld      4,32(%0)\n"
 286                         "       ld      5,40(%0)\n"
 287                         "       ld      6,48(%0)\n"
 288                         "       ld      7,56(%0)\n"
 289                         "       ld      8,64(%0)\n"
 290                         "       ld      9,72(%0)\n"
 291                         "       ld      10,80(%0)\n"
 292                         "       ld      11,88(%0)\n"
 293                         "       ld      12,96(%0)\n"
 294                         "       ld      13,104(%0)\n"
 295                         "       ld      14,112(%0)\n"
 296                         "       ld      15,120(%0)\n"
 297                         : : "a" (fpt_save_area));
 298         }
 299
 300         /* Revalidate access registers */
 301         asm volatile(
 302                 "       lam     0,15,0(%0)"
 303                 : : "a" (&S390_lowcore.access_regs_save_area));
 304         if (!mci->ar)
 305                 /*
 306                  * Access registers have unknown contents.
 307                  * Terminating task.
 308                  */
 309                 kill_task = 1;
 310
 311         /* Revalidate control registers */
 312         if (!mci->cr)
 313                 /*
 314                  * Control registers have unknown contents.
 315                  * Can't recover and therefore stopping machine.
 316                  */
 317                 s390_handle_damage("invalid control registers.");
 318         else
 319 #ifdef CONFIG_64BIT
 320                 asm volatile(
 321                         "       lctlg   0,15,0(%0)"
 322                         : : "a" (&S390_lowcore.cregs_save_area));
 323 #else
 324                 asm volatile(
 325                         "       lctl    0,15,0(%0)"
 326                         : : "a" (&S390_lowcore.cregs_save_area));
 327 #endif
 328
 329         /*
 330          * We don't even try to revalidate the TOD register, since we simply
 331          * can't write something sensible into that register.
 332          */
 333
 334 #ifdef CONFIG_64BIT
 335         /*
 336          * See if we can revalidate the TOD programmable register with its
 337          * old contents (should be zero) otherwise set it to zero.
 338          */
 339         if (!mci->pr)
 340                 asm volatile(
 341                         "       sr      0,0\n"
 342                         "       sckpf"
 343                         : : : "0", "cc");
 344         else
 345                 asm volatile(
 346                         "       l       0,0(%0)\n"
 347                         "       sckpf"
 348                         : : "a" (&S390_lowcore.tod_progreg_save_area)
 349                         : "0", "cc");
 350 #endif
 351
 352         /* Revalidate clock comparator register */
 353         asm volatile(
 354                 "       stck    0(%1)\n"
 355                 "       sckc    0(%1)"
 356                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
 357
 358         /* Check if old PSW is valid */
 359         if (!mci->wp)
 360                 /*
 361                  * Can't tell if we come from user or kernel mode
 362                  * -> stopping machine.
 363                  */
 364                 s390_handle_damage("old psw invalid.");
 365
 366         if (!mci->ms || !mci->pm || !mci->ia)
 367                 kill_task = 1;
 368
 369         return kill_task;
 370 }
 371
 372 #define MAX_IPD_COUNT   29
 373 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
 374
 375 /*
 376  * machine check handler.
 377  */
 378 void
 379 s390_do_machine_check(struct pt_regs *regs)
 380 {
 381         static DEFINE_SPINLOCK(ipd_lock);
 382         static unsigned long long last_ipd;
 383         static int ipd_count;
 384         unsigned long long tmp;
 385         struct mci *mci;
 386         struct mcck_struct *mcck;
 387         int umode;
 388
 389         lockdep_off();
 390
 391         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
 392         mcck = &__get_cpu_var(cpu_mcck);
 393         umode = user_mode(regs);
 394
 395         if (mci->sd)
 396                 /* System damage -> stopping machine */
 397                 s390_handle_damage("received system damage machine check.");
 398
 399         if (mci->pd) {
 400                 if (mci->b) {
 401                         /* Processing backup -> verify if we can survive this */
 402                         u64 z_mcic, o_mcic, t_mcic;
 403 #ifdef CONFIG_64BIT
 404                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
 405                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 406                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 407                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
 408                                   1ULL<<16);
 409 #else
 410                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
 411                                   1ULL<<29);
 412                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 413                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 414                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
 415 #endif
 416                         t_mcic = *(u64 *)mci;
 417
 418                         if (((t_mcic & z_mcic) != 0) ||
 419                             ((t_mcic & o_mcic) != o_mcic)) {
 420                                 s390_handle_damage("processing backup machine "
 421                                                    "check with damage.");
 422                         }
 423
 424                         /*
 425                          * Nullifying exigent condition, therefore we might
 426                          * retry this instruction.
 427                          */
 428
 429                         spin_lock(&ipd_lock);
 430
 431                         tmp = get_clock();
 432
 433                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
 434                                 ipd_count++;
 435                         else
 436                                 ipd_count = 1;
 437
 438                         last_ipd = tmp;
 439
 440                         if (ipd_count == MAX_IPD_COUNT)
 441                                 s390_handle_damage("too many ipd retries.");
 442
 443                         spin_unlock(&ipd_lock);
 444                 }
 445                 else {
 446                         /* Processing damage -> stopping machine */
 447                         s390_handle_damage("received instruction processing "
 448                                            "damage machine check.");
 449                 }
 450         }
 451         if (s390_revalidate_registers(mci)) {
 452                 if (umode) {
 453                         /*
 454                          * Couldn't restore all register contents while in
 455                          * user mode -> mark task for termination.
 456                          */
 457                         mcck->kill_task = 1;
 458                         mcck->mcck_code = *(unsigned long long *) mci;
 459                         set_thread_flag(TIF_MCCK_PENDING);
 460                 }
 461                 else
 462                         /*
 463                          * Couldn't restore all register contents while in
 464                          * kernel mode -> stopping machine.
 465                          */
 466                         s390_handle_damage("unable to revalidate registers.");
 467         }
 468
 469         if (mci->cd) {
 470                 /* Timing facility damage */
 471                 s390_handle_damage("TOD clock damaged");
 472         }
 473
 474         if (mci->ed && mci->ec) {
 475                 /* External damage */
 476                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
 477                         etr_sync_check();
 478                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
 479                         etr_switch_to_local();
 480         }
 481
 482         if (mci->se)
 483                 /* Storage error uncorrected */
 484                 s390_handle_damage("received storage error uncorrected "
 485                                    "machine check.");
 486
 487         if (mci->ke)
 488                 /* Storage key-error uncorrected */
 489                 s390_handle_damage("received storage key-error uncorrected "
 490                                    "machine check.");
 491
 492         if (mci->ds && mci->fa)
 493                 /* Storage degradation */
 494                 s390_handle_damage("received storage degradation machine "
 495                                    "check.");
 496
 497         if (mci->cp) {
 498                 /* Channel report word pending */
 499                 mcck->channel_report = 1;
 500                 set_thread_flag(TIF_MCCK_PENDING);
 501         }
 502
 503         if (mci->w) {
 504                 /* Warning pending */
 505                 mcck->warning = 1;
 506                 set_thread_flag(TIF_MCCK_PENDING);
 507         }
 508         lockdep_on();
 509 }
 510
 511 /*
 512  * s390_init_machine_check
 513  *
 514  * initialize machine check handling
 515  */
 516 static int
 517 machine_check_init(void)
 518 {
 519         init_MUTEX_LOCKED(&m_sem);
 520         ctl_set_bit(14, 25);    /* enable external damage MCH */
 521         ctl_set_bit(14, 27);    /* enable system recovery MCH */
 522 #ifdef CONFIG_MACHCHK_WARNING
 523         ctl_set_bit(14, 24);    /* enable warning MCH */
 524 #endif
 525         return 0;
 526 }
 527
 528 /*
 529  * Initialize the machine check handler really early to be able to
 530  * catch all machine checks that happen during boot
 531  */
 532 arch_initcall(machine_check_init);
 533
 534 /*
 535  * Machine checks for the channel subsystem must be enabled
 536  * after the channel subsystem is initialized
 537  */
 538 static int __init
 539 machine_check_crw_init (void)
 540 {
 541         struct task_struct *task;
 542
 543         task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
 544         if (IS_ERR(task))
 545                 return PTR_ERR(task);
 546         ctl_set_bit(14, 28);    /* enable channel report MCH */
 547         return 0;
 548 }
 549
 550 device_initcall (machine_check_crw_init);