git.oblomov.eu Git - linux-2.6/blob - 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 <asm/cpu.h>
  22 #include "s390mach.h"
  23
  24 static struct semaphore m_sem;
  25
  26 static NORET_TYPE void
  27 s390_handle_damage(char *msg)
  28 {
  29 #ifdef CONFIG_SMP
  30         smp_send_stop();
  31 #endif
  32         disabled_wait((unsigned long) __builtin_return_address(0));
  33         for(;;);
  34 }
  35
  36 static crw_handler_t crw_handlers[NR_RSCS];
  37
  38 /**
  39  * s390_register_crw_handler() - register a channel report word handler
  40  * @rsc: reporting source code to handle
  41  * @handler: handler to be registered
  42  *
  43  * Returns %0 on success and a negative error value otherwise.
  44  */
  45 int s390_register_crw_handler(int rsc, crw_handler_t handler)
  46 {
  47         if ((rsc < 0) || (rsc >= NR_RSCS))
  48                 return -EINVAL;
  49         if (!cmpxchg(&crw_handlers[rsc], NULL, handler))
  50                 return 0;
  51         return -EBUSY;
  52 }
  53
  54 /**
  55  * s390_unregister_crw_handler() - unregister a channel report word handler
  56  * @rsc: reporting source code to handle
  57  */
  58 void s390_unregister_crw_handler(int rsc)
  59 {
  60         if ((rsc < 0) || (rsc >= NR_RSCS))
  61                 return;
  62         xchg(&crw_handlers[rsc], NULL);
  63         synchronize_sched();
  64 }
  65
  66 /*
  67  * Retrieve CRWs and call function to handle event.
  68  */
  69 static int s390_collect_crw_info(void *param)
  70 {
  71         struct crw crw[2];
  72         int ccode;
  73         struct semaphore *sem;
  74         unsigned int chain;
  75         int ignore;
  76
  77         sem = (struct semaphore *)param;
  78 repeat:
  79         ignore = down_interruptible(sem);
  80         chain = 0;
  81         while (1) {
  82                 if (unlikely(chain > 1)) {
  83                         struct crw tmp_crw;
  84
  85                         printk(KERN_WARNING"%s: Code does not support more "
  86                                "than two chained crws; please report to "
  87                                "linux390@de.ibm.com!\n", __func__);
  88                         ccode = stcrw(&tmp_crw);
  89                         printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
  90                                "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
  91                                __func__, tmp_crw.slct, tmp_crw.oflw,
  92                                tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
  93                                tmp_crw.erc, tmp_crw.rsid);
  94                         printk(KERN_WARNING"%s: This was crw number %x in the "
  95                                "chain\n", __func__, chain);
  96                         if (ccode != 0)
  97                                 break;
  98                         chain = tmp_crw.chn ? chain + 1 : 0;
  99                         continue;
 100                 }
 101                 ccode = stcrw(&crw[chain]);
 102                 if (ccode != 0)
 103                         break;
 104                 printk(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
 105                        "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 106                        crw[chain].slct, crw[chain].oflw, crw[chain].chn,
 107                        crw[chain].rsc, crw[chain].anc, crw[chain].erc,
 108                        crw[chain].rsid);
 109                 /* Check for overflows. */
 110                 if (crw[chain].oflw) {
 111                         int i;
 112
 113                         pr_debug("%s: crw overflow detected!\n", __func__);
 114                         for (i = 0; i < NR_RSCS; i++) {
 115                                 if (crw_handlers[i])
 116                                         crw_handlers[i](NULL, NULL, 1);
 117                         }
 118                         chain = 0;
 119                         continue;
 120                 }
 121                 if (crw[0].chn && !chain) {
 122                         chain++;
 123                         continue;
 124                 }
 125                 if (crw_handlers[crw[chain].rsc])
 126                         crw_handlers[crw[chain].rsc](&crw[0],
 127                                                      chain ? &crw[1] : NULL,
 128                                                      0);
 129                 /* chain is always 0 or 1 here. */
 130                 chain = crw[chain].chn ? chain + 1 : 0;
 131         }
 132         goto repeat;
 133         return 0;
 134 }
 135
 136 struct mcck_struct {
 137         int kill_task;
 138         int channel_report;
 139         int warning;
 140         unsigned long long mcck_code;
 141 };
 142
 143 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
 144
 145 /*
 146  * Main machine check handler function. Will be called with interrupts enabled
 147  * or disabled and machine checks enabled or disabled.
 148  */
 149 void
 150 s390_handle_mcck(void)
 151 {
 152         unsigned long flags;
 153         struct mcck_struct mcck;
 154
 155         /*
 156          * Disable machine checks and get the current state of accumulated
 157          * machine checks. Afterwards delete the old state and enable machine
 158          * checks again.
 159          */
 160         local_irq_save(flags);
 161         local_mcck_disable();
 162         mcck = __get_cpu_var(cpu_mcck);
 163         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
 164         clear_thread_flag(TIF_MCCK_PENDING);
 165         local_mcck_enable();
 166         local_irq_restore(flags);
 167
 168         if (mcck.channel_report)
 169                 up(&m_sem);
 170
 171 #ifdef CONFIG_MACHCHK_WARNING
 172 /*
 173  * The warning may remain for a prolonged period on the bare iron.
 174  * (actually till the machine is powered off, or until the problem is gone)
 175  * So we just stop listening for the WARNING MCH and prevent continuously
 176  * being interrupted.  One caveat is however, that we must do this per
 177  * processor and cannot use the smp version of ctl_clear_bit().
 178  * On VM we only get one interrupt per virtally presented machinecheck.
 179  * Though one suffices, we may get one interrupt per (virtual) processor.
 180  */
 181         if (mcck.warning) {     /* WARNING pending ? */
 182                 static int mchchk_wng_posted = 0;
 183                 /*
 184                  * Use single machine clear, as we cannot handle smp right now
 185                  */
 186                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
 187                 if (xchg(&mchchk_wng_posted, 1) == 0)
 188                         kill_cad_pid(SIGPWR, 1);
 189         }
 190 #endif
 191
 192         if (mcck.kill_task) {
 193                 local_irq_enable();
 194                 printk(KERN_EMERG "mcck: Terminating task because of machine "
 195                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
 196                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
 197                        current->comm, current->pid);
 198                 do_exit(SIGSEGV);
 199         }
 200 }
 201 EXPORT_SYMBOL_GPL(s390_handle_mcck);
 202
 203 /*
 204  * returns 0 if all registers could be validated
 205  * returns 1 otherwise
 206  */
 207 static int
 208 s390_revalidate_registers(struct mci *mci)
 209 {
 210         int kill_task;
 211         u64 tmpclock;
 212         u64 zero;
 213         void *fpt_save_area, *fpt_creg_save_area;
 214
 215         kill_task = 0;
 216         zero = 0;
 217         /* General purpose registers */
 218         if (!mci->gr)
 219                 /*
 220                  * General purpose registers couldn't be restored and have
 221                  * unknown contents. Process needs to be terminated.
 222                  */
 223                 kill_task = 1;
 224
 225         /* Revalidate floating point registers */
 226         if (!mci->fp)
 227                 /*
 228                  * Floating point registers can't be restored and
 229                  * therefore the process needs to be terminated.
 230                  */
 231                 kill_task = 1;
 232
 233 #ifndef CONFIG_64BIT
 234         asm volatile(
 235                 "       ld      0,0(%0)\n"
 236                 "       ld      2,8(%0)\n"
 237                 "       ld      4,16(%0)\n"
 238                 "       ld      6,24(%0)"
 239                 : : "a" (&S390_lowcore.floating_pt_save_area));
 240 #endif
 241
 242         if (MACHINE_HAS_IEEE) {
 243 #ifdef CONFIG_64BIT
 244                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
 245                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
 246 #else
 247                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
 248                 fpt_creg_save_area = fpt_save_area+128;
 249 #endif
 250                 /* Floating point control register */
 251                 if (!mci->fc) {
 252                         /*
 253                          * Floating point control register can't be restored.
 254                          * Task will be terminated.
 255                          */
 256                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
 257                         kill_task = 1;
 258
 259                 } else
 260                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
 261
 262                 asm volatile(
 263                         "       ld      0,0(%0)\n"
 264                         "       ld      1,8(%0)\n"
 265                         "       ld      2,16(%0)\n"
 266                         "       ld      3,24(%0)\n"
 267                         "       ld      4,32(%0)\n"
 268                         "       ld      5,40(%0)\n"
 269                         "       ld      6,48(%0)\n"
 270                         "       ld      7,56(%0)\n"
 271                         "       ld      8,64(%0)\n"
 272                         "       ld      9,72(%0)\n"
 273                         "       ld      10,80(%0)\n"
 274                         "       ld      11,88(%0)\n"
 275                         "       ld      12,96(%0)\n"
 276                         "       ld      13,104(%0)\n"
 277                         "       ld      14,112(%0)\n"
 278                         "       ld      15,120(%0)\n"
 279                         : : "a" (fpt_save_area));
 280         }
 281
 282         /* Revalidate access registers */
 283         asm volatile(
 284                 "       lam     0,15,0(%0)"
 285                 : : "a" (&S390_lowcore.access_regs_save_area));
 286         if (!mci->ar)
 287                 /*
 288                  * Access registers have unknown contents.
 289                  * Terminating task.
 290                  */
 291                 kill_task = 1;
 292
 293         /* Revalidate control registers */
 294         if (!mci->cr)
 295                 /*
 296                  * Control registers have unknown contents.
 297                  * Can't recover and therefore stopping machine.
 298                  */
 299                 s390_handle_damage("invalid control registers.");
 300         else
 301 #ifdef CONFIG_64BIT
 302                 asm volatile(
 303                         "       lctlg   0,15,0(%0)"
 304                         : : "a" (&S390_lowcore.cregs_save_area));
 305 #else
 306                 asm volatile(
 307                         "       lctl    0,15,0(%0)"
 308                         : : "a" (&S390_lowcore.cregs_save_area));
 309 #endif
 310
 311         /*
 312          * We don't even try to revalidate the TOD register, since we simply
 313          * can't write something sensible into that register.
 314          */
 315
 316 #ifdef CONFIG_64BIT
 317         /*
 318          * See if we can revalidate the TOD programmable register with its
 319          * old contents (should be zero) otherwise set it to zero.
 320          */
 321         if (!mci->pr)
 322                 asm volatile(
 323                         "       sr      0,0\n"
 324                         "       sckpf"
 325                         : : : "0", "cc");
 326         else
 327                 asm volatile(
 328                         "       l       0,0(%0)\n"
 329                         "       sckpf"
 330                         : : "a" (&S390_lowcore.tod_progreg_save_area)
 331                         : "0", "cc");
 332 #endif
 333
 334         /* Revalidate clock comparator register */
 335         asm volatile(
 336                 "       stck    0(%1)\n"
 337                 "       sckc    0(%1)"
 338                 : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
 339
 340         /* Check if old PSW is valid */
 341         if (!mci->wp)
 342                 /*
 343                  * Can't tell if we come from user or kernel mode
 344                  * -> stopping machine.
 345                  */
 346                 s390_handle_damage("old psw invalid.");
 347
 348         if (!mci->ms || !mci->pm || !mci->ia)
 349                 kill_task = 1;
 350
 351         return kill_task;
 352 }
 353
 354 #define MAX_IPD_COUNT   29
 355 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
 356
 357 /*
 358  * machine check handler.
 359  */
 360 void
 361 s390_do_machine_check(struct pt_regs *regs)
 362 {
 363         static DEFINE_SPINLOCK(ipd_lock);
 364         static unsigned long long last_ipd;
 365         static int ipd_count;
 366         unsigned long long tmp;
 367         struct mci *mci;
 368         struct mcck_struct *mcck;
 369         int umode;
 370
 371         lockdep_off();
 372
 373         s390_idle_check();
 374
 375         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
 376         mcck = &__get_cpu_var(cpu_mcck);
 377         umode = user_mode(regs);
 378
 379         if (mci->sd)
 380                 /* System damage -> stopping machine */
 381                 s390_handle_damage("received system damage machine check.");
 382
 383         if (mci->pd) {
 384                 if (mci->b) {
 385                         /* Processing backup -> verify if we can survive this */
 386                         u64 z_mcic, o_mcic, t_mcic;
 387 #ifdef CONFIG_64BIT
 388                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
 389                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 390                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 391                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
 392                                   1ULL<<16);
 393 #else
 394                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
 395                                   1ULL<<29);
 396                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 397                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 398                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
 399 #endif
 400                         t_mcic = *(u64 *)mci;
 401
 402                         if (((t_mcic & z_mcic) != 0) ||
 403                             ((t_mcic & o_mcic) != o_mcic)) {
 404                                 s390_handle_damage("processing backup machine "
 405                                                    "check with damage.");
 406                         }
 407
 408                         /*
 409                          * Nullifying exigent condition, therefore we might
 410                          * retry this instruction.
 411                          */
 412
 413                         spin_lock(&ipd_lock);
 414
 415                         tmp = get_clock();
 416
 417                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
 418                                 ipd_count++;
 419                         else
 420                                 ipd_count = 1;
 421
 422                         last_ipd = tmp;
 423
 424                         if (ipd_count == MAX_IPD_COUNT)
 425                                 s390_handle_damage("too many ipd retries.");
 426
 427                         spin_unlock(&ipd_lock);
 428                 }
 429                 else {
 430                         /* Processing damage -> stopping machine */
 431                         s390_handle_damage("received instruction processing "
 432                                            "damage machine check.");
 433                 }
 434         }
 435         if (s390_revalidate_registers(mci)) {
 436                 if (umode) {
 437                         /*
 438                          * Couldn't restore all register contents while in
 439                          * user mode -> mark task for termination.
 440                          */
 441                         mcck->kill_task = 1;
 442                         mcck->mcck_code = *(unsigned long long *) mci;
 443                         set_thread_flag(TIF_MCCK_PENDING);
 444                 }
 445                 else
 446                         /*
 447                          * Couldn't restore all register contents while in
 448                          * kernel mode -> stopping machine.
 449                          */
 450                         s390_handle_damage("unable to revalidate registers.");
 451         }
 452
 453         if (mci->cd) {
 454                 /* Timing facility damage */
 455                 s390_handle_damage("TOD clock damaged");
 456         }
 457
 458         if (mci->ed && mci->ec) {
 459                 /* External damage */
 460                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
 461                         etr_sync_check();
 462                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
 463                         etr_switch_to_local();
 464                 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
 465                         stp_sync_check();
 466                 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
 467                         stp_island_check();
 468         }
 469
 470         if (mci->se)
 471                 /* Storage error uncorrected */
 472                 s390_handle_damage("received storage error uncorrected "
 473                                    "machine check.");
 474
 475         if (mci->ke)
 476                 /* Storage key-error uncorrected */
 477                 s390_handle_damage("received storage key-error uncorrected "
 478                                    "machine check.");
 479
 480         if (mci->ds && mci->fa)
 481                 /* Storage degradation */
 482                 s390_handle_damage("received storage degradation machine "
 483                                    "check.");
 484
 485         if (mci->cp) {
 486                 /* Channel report word pending */
 487                 mcck->channel_report = 1;
 488                 set_thread_flag(TIF_MCCK_PENDING);
 489         }
 490
 491         if (mci->w) {
 492                 /* Warning pending */
 493                 mcck->warning = 1;
 494                 set_thread_flag(TIF_MCCK_PENDING);
 495         }
 496         lockdep_on();
 497 }
 498
 499 /*
 500  * s390_init_machine_check
 501  *
 502  * initialize machine check handling
 503  */
 504 static int
 505 machine_check_init(void)
 506 {
 507         init_MUTEX_LOCKED(&m_sem);
 508         ctl_set_bit(14, 25);    /* enable external damage MCH */
 509         ctl_set_bit(14, 27);    /* enable system recovery MCH */
 510 #ifdef CONFIG_MACHCHK_WARNING
 511         ctl_set_bit(14, 24);    /* enable warning MCH */
 512 #endif
 513         return 0;
 514 }
 515
 516 /*
 517  * Initialize the machine check handler really early to be able to
 518  * catch all machine checks that happen during boot
 519  */
 520 arch_initcall(machine_check_init);
 521
 522 /*
 523  * Machine checks for the channel subsystem must be enabled
 524  * after the channel subsystem is initialized
 525  */
 526 static int __init
 527 machine_check_crw_init (void)
 528 {
 529         struct task_struct *task;
 530
 531         task = kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
 532         if (IS_ERR(task))
 533                 return PTR_ERR(task);
 534         ctl_set_bit(14, 28);    /* enable channel report MCH */
 535         return 0;
 536 }
 537
 538 device_initcall (machine_check_crw_init);