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