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