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