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