drivers/s390/s390mach.c

   1 /*
   2  *  drivers/s390/s390mach.c
   3  *   S/390 machine check handler
   4  *
   5  *    Copyright IBM Corp. 2000,2008
   6  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
   7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  *               Cornelia Huck <cornelia.huck@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 "s390mach.h"
  22
  23 static struct semaphore m_sem;
  24
  25 static NORET_TYPE void
  26 s390_handle_damage(char *msg)
  27 {
  28 #ifdef CONFIG_SMP
  29         smp_send_stop();
  30 #endif
  31         disabled_wait((unsigned long) __builtin_return_address(0));
  32         for(;;);
  33 }
  34
  35 static crw_handler_t crw_handlers[NR_RSCS];
  36
  37 /**
  38  * s390_register_crw_handler() - register a channel report word handler
  39  * @rsc: reporting source code to handle
  40  * @handler: handler to be registered
  41  *
  42  * Returns %0 on success and a negative error value otherwise.
  43  */
  44 int s390_register_crw_handler(int rsc, crw_handler_t handler)
  45 {
  46         if ((rsc < 0) || (rsc >= NR_RSCS))
  47                 return -EINVAL;
  48         if (!cmpxchg(&crw_handlers[rsc], NULL, handler))
  49                 return 0;
  50         return -EBUSY;
  51 }
  52
  53 /**
  54  * s390_unregister_crw_handler() - unregister a channel report word handler
  55  * @rsc: reporting source code to handle
  56  */
  57 void s390_unregister_crw_handler(int rsc)
  58 {
  59         if ((rsc < 0) || (rsc >= NR_RSCS))
  60                 return;
  61         xchg(&crw_handlers[rsc], NULL);
  62         synchronize_sched();
  63 }
  64
  65 /*
  66  * Retrieve CRWs and call function to handle event.
  67  */
  68 static int s390_collect_crw_info(void *param)
  69 {
  70         struct crw crw[2];
  71         int ccode;
  72         struct semaphore *sem;
  73         unsigned int chain;
  74         int ignore;
  75
  76         sem = (struct semaphore *)param;
  77 repeat:
  78         ignore = down_interruptible(sem);
  79         chain = 0;
  80         while (1) {
  81                 if (unlikely(chain > 1)) {
  82                         struct crw tmp_crw;
  83
  84                         printk(KERN_WARNING"%s: Code does not support more "
  85                                "than two chained crws; please report to "
  86                                "linux390@de.ibm.com!\n", __func__);
  87                         ccode = stcrw(&tmp_crw);
  88                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
  89                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
  90                                __func__, tmp_crw.slct, tmp_crw.oflw,
  91                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
  92                                tmp_crw.erc, tmp_crw.rsid);
  93                         printk(KERN_WARNING"%s: This was crw number %x in the "
  94                                "chain\n", __func__, chain);
  95                         if (ccode != 0)
  96                                 break;
  97                         chain = tmp_crw.chn ? chain + 1 : 0;
  98                         continue;
  99                 }
 100                 ccode = stcrw(&crw[chain]);
 101                 if (ccode != 0)
 102                         break;
 103                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
 104                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 105                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
 106                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
 107                        crw[chain].rsid);
 108                 /* Check for overflows. */
 109                 if (crw[chain].oflw) {
 110                         int i;
 111
 112                         pr_debug("%s: crw overflow detected!\n", __func__);
 113                         for (i = 0; i < NR_RSCS; i++) {
 114                                 if (crw_handlers[i])
 115                                         crw_handlers[i](NULL, NULL, 1);
 116                         }
 117                         chain = 0;
 118                         continue;
 119                 }
 120                 if (crw[0].chn && !chain) {
 121                         chain++;
 122                         continue;
 123                 }
 124                 if (crw_handlers[crw[chain].rsc])
 125                         crw_handlers[crw[chain].rsc](&crw[0],
 126                                                      chain ? &crw[1] : NULL,
 127                                                      0);
 128                 /* chain is always 0 or 1 here. */
 129                 chain = crw[chain].chn ? chain + 1 : 0;
 130         }
 131         goto repeat;
 132         return 0;
 133 }
 134
 135 struct mcck_struct {
 136         int kill_task;
 137         int channel_report;
 138         int warning;
 139         unsigned long long mcck_code;
 140 };
 141
 142 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
 143
 144 /*
 145  * Main machine check handler function. Will be called with interrupts enabled
 146  * or disabled and machine checks enabled or disabled.
 147  */
 148 void
 149 s390_handle_mcck(void)
 150 {
 151         unsigned long flags;
 152         struct mcck_struct mcck;
 153
 154         /*
 155          * Disable machine checks and get the current state of accumulated
 156          * machine checks. Afterwards delete the old state and enable machine
 157          * checks again.
 158          */
 159         local_irq_save(flags);
 160         local_mcck_disable();
 161         mcck = __get_cpu_var(cpu_mcck);
 162         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
 163         clear_thread_flag(TIF_MCCK_PENDING);
 164         local_mcck_enable();
 165         local_irq_restore(flags);
 166
 167         if (mcck.channel_report)
 168                 up(&m_sem);
 169
 170 #ifdef CONFIG_MACHCHK_WARNING
 171 /*
 172  * The warning may remain for a prolonged period on the bare iron.
 173  * (actually till the machine is powered off, or until the problem is gone)
 174  * So we just stop listening for the WARNING MCH and prevent continuously
 175  * being interrupted.  One caveat is however, that we must do this per
 176  * processor and cannot use the smp version of ctl_clear_bit().
 177  * On VM we only get one interrupt per virtally presented machinecheck.
 178  * Though one suffices, we may get one interrupt per (virtual) processor.
 179  */
 180         if (mcck.warning) {     /* WARNING pending ? */
 181                 static int mchchk_wng_posted = 0;
 182                 /*
 183                  * Use single machine clear, as we cannot handle smp right now
 184                  */
 185                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
 186                 if (xchg(&mchchk_wng_posted, 1) == 0)
 187                         kill_cad_pid(SIGPWR, 1);
 188         }
 189 #endif
 190
 191         if (mcck.kill_task) {
 192                 local_irq_enable();
 193                 printk(KERN_EMERG "mcck: Terminating task because of machine "
 194                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
 195                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
 196                        current->comm, current->pid);
 197                 do_exit(SIGSEGV);
 198         }
 199 }
 200 EXPORT_SYMBOL_GPL(s390_handle_mcck);
 201
 202 /*
 203  * returns 0 if all registers could be validated
 204  * returns 1 otherwise
 205  */
 206 static int
 207 s390_revalidate_registers(struct mci *mci)
 208 {
 209         int kill_task;
 210         u64 tmpclock;
 211         u64 zero;
 212         void *fpt_save_area, *fpt_creg_save_area;
 213
 214         kill_task = 0;
 215         zero = 0;
 216         /* General purpose registers */
 217         if (!mci->gr)
 218                 /*
 219                  * General purpose registers couldn't be restored and have
 220                  * unknown contents. Process needs to be terminated.
 221                  */
 222                 kill_task = 1;
 223
 224         /* Revalidate floating point registers */
 225         if (!mci->fp)
 226                 /*
 227                  * Floating point registers can't be restored and
 228                  * therefore the process needs to be terminated.
 229                  */
 230                 kill_task = 1;
 231
 232 #ifndef CONFIG_64BIT
 233         asm volatile(
 234                 "       ld      0,0(%0)\n"
 235                 "       ld      2,8(%0)\n"
 236                 "       ld      4,16(%0)\n"
 237                 "       ld      6,24(%0)"
 238                 : : "a" (&S390_lowcore.floating_pt_save_area));
 239 #endif
 240
 241         if (MACHINE_HAS_IEEE) {
 242 #ifdef CONFIG_64BIT
 243                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
 244                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
 245 #else
 246                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
 247                 fpt_creg_save_area = fpt_save_area+128;
 248 #endif
 249                 /* Floating point control register */
 250                 if (!mci->fc) {
 251                         /*
 252                          * Floating point control register can't be restored.
 253                          * Task will be terminated.
 254                          */
 255                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
 256                         kill_task = 1;
 257
 258                 } else
 259                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
 260
 261                 asm volatile(
 262                         "       ld      0,0(%0)\n"
 263                         "       ld      1,8(%0)\n"
 264                         "       ld      2,16(%0)\n"
 265                         "       ld      3,24(%0)\n"
 266                         "       ld      4,32(%0)\n"
 267                         "       ld      5,40(%0)\n"
 268                         "       ld      6,48(%0)\n"
 269                         "       ld      7,56(%0)\n"
 270                         "       ld      8,64(%0)\n"
 271                         "       ld      9,72(%0)\n"
 272                         "       ld      10,80(%0)\n"
 273                         "       ld      11,88(%0)\n"
 274                         "       ld      12,96(%0)\n"
 275                         "       ld      13,104(%0)\n"
 276                         "       ld      14,112(%0)\n"
 277                         "       ld      15,120(%0)\n"
 278                         : : "a" (fpt_save_area));
 279         }
 280
 281         /* Revalidate access registers */
 282         asm volatile(
 283                 "       lam     0,15,0(%0)"
 284                 : : "a" (&S390_lowcore.access_regs_save_area));
 285         if (!mci->ar)
 286                 /*
 287                  * Access registers have unknown contents.
 288                  * Terminating task.
 289                  */
 290                 kill_task = 1;
 291
 292         /* Revalidate control registers */
 293         if (!mci->cr)
 294                 /*
 295                  * Control registers have unknown contents.
 296                  * Can't recover and therefore stopping machine.
 297                  */
 298                 s390_handle_damage("invalid control registers.");
 299         else
 300 #ifdef CONFIG_64BIT
 301                 asm volatile(
 302                         "       lctlg   0,15,0(%0)"
 303                         : : "a" (&S390_lowcore.cregs_save_area));
 304 #else
 305                 asm volatile(
 306                         "       lctl    0,15,0(%0)"
 307                         : : "a" (&S390_lowcore.cregs_save_area));
 308 #endif
 309
 310         /*
 311          * We don't even try to revalidate the TOD register, since we simply
 312          * can't write something sensible into that register.
 313          */
 314
 315 #ifdef CONFIG_64BIT
 316         /*
 317          * See if we can revalidate the TOD programmable register with its
 318          * old contents (should be zero) otherwise set it to zero.
 319          */
 320         if (!mci->pr)
 321                 asm volatile(
 322                         "       sr      0,0\n"
 323                         "       sckpf"
 324                         : : : "0", "cc");
 325         else
 326                 asm volatile(
 327                         "       l       0,0(%0)\n"
 328                         "       sckpf"
 329                         : : "a" (&S390_lowcore.tod_progreg_save_area)
 330                         : "0", "cc");
 331 #endif
 332
 333         /* Revalidate clock comparator register */
 334         asm volatile(
 335                 "       stck    0(%1)\n"
 336                 "       sckc    0(%1)"
 337                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
 338
 339         /* Check if old PSW is valid */
 340         if (!mci->wp)
 341                 /*
 342                  * Can't tell if we come from user or kernel mode
 343                  * -> stopping machine.
 344                  */
 345                 s390_handle_damage("old psw invalid.");
 346
 347         if (!mci->ms || !mci->pm || !mci->ia)
 348                 kill_task = 1;
 349
 350         return kill_task;
 351 }
 352
 353 #define MAX_IPD_COUNT   29
 354 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
 355
 356 /*
 357  * machine check handler.
 358  */
 359 void
 360 s390_do_machine_check(struct pt_regs *regs)
 361 {
 362         static DEFINE_SPINLOCK(ipd_lock);
 363         static unsigned long long last_ipd;
 364         static int ipd_count;
 365         unsigned long long tmp;
 366         struct mci *mci;
 367         struct mcck_struct *mcck;
 368         int umode;
 369
 370         lockdep_off();
 371
 372         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
 373         mcck = &__get_cpu_var(cpu_mcck);
 374         umode = user_mode(regs);
 375
 376         if (mci->sd)
 377                 /* System damage -> stopping machine */
 378                 s390_handle_damage("received system damage machine check.");
 379
 380         if (mci->pd) {
 381                 if (mci->b) {
 382                         /* Processing backup -> verify if we can survive this */
 383                         u64 z_mcic, o_mcic, t_mcic;
 384 #ifdef CONFIG_64BIT
 385                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
 386                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 387                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 388                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
 389                                   1ULL<<16);
 390 #else
 391                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
 392                                   1ULL<<29);
 393                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 394                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 395                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
 396 #endif
 397                         t_mcic = *(u64 *)mci;
 398
 399                         if (((t_mcic & z_mcic) != 0) ||
 400                             ((t_mcic & o_mcic) != o_mcic)) {
 401                                 s390_handle_damage("processing backup machine "
 402                                                    "check with damage.");
 403                         }
 404
 405                         /*
 406                          * Nullifying exigent condition, therefore we might
 407                          * retry this instruction.
 408                          */
 409
 410                         spin_lock(&ipd_lock);
 411
 412                         tmp = get_clock();
 413
 414                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
 415                                 ipd_count++;
 416                         else
 417                                 ipd_count = 1;
 418
 419                         last_ipd = tmp;
 420
 421                         if (ipd_count == MAX_IPD_COUNT)
 422                                 s390_handle_damage("too many ipd retries.");
 423
 424                         spin_unlock(&ipd_lock);
 425                 }
 426                 else {
 427                         /* Processing damage -> stopping machine */
 428                         s390_handle_damage("received instruction processing "
 429                                            "damage machine check.");
 430                 }
 431         }
 432         if (s390_revalidate_registers(mci)) {
 433                 if (umode) {
 434                         /*
 435                          * Couldn't restore all register contents while in
 436                          * user mode -> mark task for termination.
 437                          */
 438                         mcck->kill_task = 1;
 439                         mcck->mcck_code = *(unsigned long long *) mci;
 440                         set_thread_flag(TIF_MCCK_PENDING);
 441                 }
 442                 else
 443                         /*
 444                          * Couldn't restore all register contents while in
 445                          * kernel mode -> stopping machine.
 446                          */
 447                         s390_handle_damage("unable to revalidate registers.");
 448         }
 449
 450         if (mci->cd) {
 451                 /* Timing facility damage */
 452                 s390_handle_damage("TOD clock damaged");
 453         }
 454
 455         if (mci->ed && mci->ec) {
 456                 /* External damage */
 457                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
 458                         etr_sync_check();
 459                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
 460                         etr_switch_to_local();
 461                 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
 462                         stp_sync_check();
 463                 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
 464                         stp_island_check();
 465         }
 466
 467         if (mci->se)
 468                 /* Storage error uncorrected */
 469                 s390_handle_damage("received storage error uncorrected "
 470                                    "machine check.");
 471
 472         if (mci->ke)
 473                 /* Storage key-error uncorrected */
 474                 s390_handle_damage("received storage key-error uncorrected "
 475                                    "machine check.");
 476
 477         if (mci->ds && mci->fa)
 478                 /* Storage degradation */
 479                 s390_handle_damage("received storage degradation machine "
 480                                    "check.");
 481
 482         if (mci->cp) {
 483                 /* Channel report word pending */
 484                 mcck->channel_report = 1;
 485                 set_thread_flag(TIF_MCCK_PENDING);
 486         }
 487
 488         if (mci->w) {
 489                 /* Warning pending */
 490                 mcck->warning = 1;
 491                 set_thread_flag(TIF_MCCK_PENDING);
 492         }
 493         lockdep_on();
 494 }
 495
 496 /*
 497  * s390_init_machine_check
 498  *
 499  * initialize machine check handling
 500  */
 501 static int
 502 machine_check_init(void)
 503 {
 504         init_MUTEX_LOCKED(&m_sem);
 505         ctl_set_bit(14, 25);    /* enable external damage MCH */
 506         ctl_set_bit(14, 27);    /* enable system recovery MCH */
 507 #ifdef CONFIG_MACHCHK_WARNING
 508         ctl_set_bit(14, 24);    /* enable warning MCH */
 509 #endif
 510         return 0;
 511 }
 512
 513 /*
 514  * Initialize the machine check handler really early to be able to
 515  * catch all machine checks that happen during boot
 516  */
 517 arch_initcall(machine_check_init);
 518
 519 /*
 520  * Machine checks for the channel subsystem must be enabled
 521  * after the channel subsystem is initialized
 522  */
 523 static int __init
 524 machine_check_crw_init (void)
 525 {
 526         struct task_struct *task;
 527
 528         task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
 529         if (IS_ERR(task))
 530                 return PTR_ERR(task);
 531         ctl_set_bit(14, 28);    /* enable channel report MCH */
 532         return 0;
 533 }
 534
 535 device_initcall (machine_check_crw_init);