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