arch/s390/kernel/nmi.c

   1 /*
   2  *   Machine check handler
   3  *
   4  *    Copyright IBM Corp. 2000,2009
   5  *    Author(s): Ingo Adlung <adlung@de.ibm.com>,
   6  *               Martin Schwidefsky <schwidefsky@de.ibm.com>,
   7  *               Cornelia Huck <cornelia.huck@de.ibm.com>,
   8  *               Heiko Carstens <heiko.carstens@de.ibm.com>,
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/errno.h>
  13 #include <linux/hardirq.h>
  14 #include <linux/time.h>
  15 #include <linux/module.h>
  16 #include <asm/lowcore.h>
  17 #include <asm/smp.h>
  18 #include <asm/etr.h>
  19 #include <asm/cputime.h>
  20 #include <asm/nmi.h>
  21 #include <asm/crw.h>
  22
  23 struct mcck_struct {
  24         int kill_task;
  25         int channel_report;
  26         int warning;
  27         unsigned long long mcck_code;
  28 };
  29
  30 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
  31
  32 static NORET_TYPE void s390_handle_damage(char *msg)
  33 {
  34         smp_send_stop();
  35         disabled_wait((unsigned long) __builtin_return_address(0));
  36         while (1);
  37 }
  38
  39 /*
  40  * Main machine check handler function. Will be called with interrupts enabled
  41  * or disabled and machine checks enabled or disabled.
  42  */
  43 void s390_handle_mcck(void)
  44 {
  45         unsigned long flags;
  46         struct mcck_struct mcck;
  47
  48         /*
  49          * Disable machine checks and get the current state of accumulated
  50          * machine checks. Afterwards delete the old state and enable machine
  51          * checks again.
  52          */
  53         local_irq_save(flags);
  54         local_mcck_disable();
  55         mcck = __get_cpu_var(cpu_mcck);
  56         memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
  57         clear_thread_flag(TIF_MCCK_PENDING);
  58         local_mcck_enable();
  59         local_irq_restore(flags);
  60
  61         if (mcck.channel_report)
  62                 crw_handle_channel_report();
  63         /*
  64          * A warning may remain for a prolonged period on the bare iron.
  65          * (actually until the machine is powered off, or the problem is gone)
  66          * So we just stop listening for the WARNING MCH and avoid continuously
  67          * being interrupted.  One caveat is however, that we must do this per
  68          * processor and cannot use the smp version of ctl_clear_bit().
  69          * On VM we only get one interrupt per virtally presented machinecheck.
  70          * Though one suffices, we may get one interrupt per (virtual) cpu.
  71          */
  72         if (mcck.warning) {     /* WARNING pending ? */
  73                 static int mchchk_wng_posted = 0;
  74
  75                 /* Use single cpu clear, as we cannot handle smp here. */
  76                 __ctl_clear_bit(14, 24);        /* Disable WARNING MCH */
  77                 if (xchg(&mchchk_wng_posted, 1) == 0)
  78                         kill_cad_pid(SIGPWR, 1);
  79         }
  80         if (mcck.kill_task) {
  81                 local_irq_enable();
  82                 printk(KERN_EMERG "mcck: Terminating task because of machine "
  83                        "malfunction (code 0x%016llx).\n", mcck.mcck_code);
  84                 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
  85                        current->comm, current->pid);
  86                 do_exit(SIGSEGV);
  87         }
  88 }
  89 EXPORT_SYMBOL_GPL(s390_handle_mcck);
  90
  91 /*
  92  * returns 0 if all registers could be validated
  93  * returns 1 otherwise
  94  */
  95 static int notrace s390_revalidate_registers(struct mci *mci)
  96 {
  97         int kill_task;
  98         u64 zero;
  99         void *fpt_save_area, *fpt_creg_save_area;
 100
 101         kill_task = 0;
 102         zero = 0;
 103
 104         if (!mci->gr) {
 105                 /*
 106                  * General purpose registers couldn't be restored and have
 107                  * unknown contents. Process needs to be terminated.
 108                  */
 109                 kill_task = 1;
 110         }
 111         if (!mci->fp) {
 112                 /*
 113                  * Floating point registers can't be restored and
 114                  * therefore the process needs to be terminated.
 115                  */
 116                 kill_task = 1;
 117         }
 118 #ifndef CONFIG_64BIT
 119         asm volatile(
 120                 "       ld      0,0(%0)\n"
 121                 "       ld      2,8(%0)\n"
 122                 "       ld      4,16(%0)\n"
 123                 "       ld      6,24(%0)"
 124                 : : "a" (&S390_lowcore.floating_pt_save_area));
 125 #endif
 126
 127         if (MACHINE_HAS_IEEE) {
 128 #ifdef CONFIG_64BIT
 129                 fpt_save_area = &S390_lowcore.floating_pt_save_area;
 130                 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
 131 #else
 132                 fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
 133                 fpt_creg_save_area = fpt_save_area + 128;
 134 #endif
 135                 if (!mci->fc) {
 136                         /*
 137                          * Floating point control register can't be restored.
 138                          * Task will be terminated.
 139                          */
 140                         asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
 141                         kill_task = 1;
 142
 143                 } else
 144                         asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area));
 145
 146                 asm volatile(
 147                         "       ld      0,0(%0)\n"
 148                         "       ld      1,8(%0)\n"
 149                         "       ld      2,16(%0)\n"
 150                         "       ld      3,24(%0)\n"
 151                         "       ld      4,32(%0)\n"
 152                         "       ld      5,40(%0)\n"
 153                         "       ld      6,48(%0)\n"
 154                         "       ld      7,56(%0)\n"
 155                         "       ld      8,64(%0)\n"
 156                         "       ld      9,72(%0)\n"
 157                         "       ld      10,80(%0)\n"
 158                         "       ld      11,88(%0)\n"
 159                         "       ld      12,96(%0)\n"
 160                         "       ld      13,104(%0)\n"
 161                         "       ld      14,112(%0)\n"
 162                         "       ld      15,120(%0)\n"
 163                         : : "a" (fpt_save_area));
 164         }
 165         /* Revalidate access registers */
 166         asm volatile(
 167                 "       lam     0,15,0(%0)"
 168                 : : "a" (&S390_lowcore.access_regs_save_area));
 169         if (!mci->ar) {
 170                 /*
 171                  * Access registers have unknown contents.
 172                  * Terminating task.
 173                  */
 174                 kill_task = 1;
 175         }
 176         /* Revalidate control registers */
 177         if (!mci->cr) {
 178                 /*
 179                  * Control registers have unknown contents.
 180                  * Can't recover and therefore stopping machine.
 181                  */
 182                 s390_handle_damage("invalid control registers.");
 183         } else {
 184 #ifdef CONFIG_64BIT
 185                 asm volatile(
 186                         "       lctlg   0,15,0(%0)"
 187                         : : "a" (&S390_lowcore.cregs_save_area));
 188 #else
 189                 asm volatile(
 190                         "       lctl    0,15,0(%0)"
 191                         : : "a" (&S390_lowcore.cregs_save_area));
 192 #endif
 193         }
 194         /*
 195          * We don't even try to revalidate the TOD register, since we simply
 196          * can't write something sensible into that register.
 197          */
 198 #ifdef CONFIG_64BIT
 199         /*
 200          * See if we can revalidate the TOD programmable register with its
 201          * old contents (should be zero) otherwise set it to zero.
 202          */
 203         if (!mci->pr)
 204                 asm volatile(
 205                         "       sr      0,0\n"
 206                         "       sckpf"
 207                         : : : "0", "cc");
 208         else
 209                 asm volatile(
 210                         "       l       0,0(%0)\n"
 211                         "       sckpf"
 212                         : : "a" (&S390_lowcore.tod_progreg_save_area)
 213                         : "0", "cc");
 214 #endif
 215         /* Revalidate clock comparator register */
 216         if (S390_lowcore.clock_comparator == -1)
 217                 set_clock_comparator(S390_lowcore.mcck_clock);
 218         else
 219                 set_clock_comparator(S390_lowcore.clock_comparator);
 220         /* Check if old PSW is valid */
 221         if (!mci->wp)
 222                 /*
 223                  * Can't tell if we come from user or kernel mode
 224                  * -> stopping machine.
 225                  */
 226                 s390_handle_damage("old psw invalid.");
 227
 228         if (!mci->ms || !mci->pm || !mci->ia)
 229                 kill_task = 1;
 230
 231         return kill_task;
 232 }
 233
 234 #define MAX_IPD_COUNT   29
 235 #define MAX_IPD_TIME    (5 * 60 * USEC_PER_SEC) /* 5 minutes */
 236
 237 #define ED_STP_ISLAND   6       /* External damage STP island check */
 238 #define ED_STP_SYNC     7       /* External damage STP sync check */
 239 #define ED_ETR_SYNC     12      /* External damage ETR sync check */
 240 #define ED_ETR_SWITCH   13      /* External damage ETR switch to local */
 241
 242 /*
 243  * machine check handler.
 244  */
 245 void notrace s390_do_machine_check(struct pt_regs *regs)
 246 {
 247         static int ipd_count;
 248         static DEFINE_SPINLOCK(ipd_lock);
 249         static unsigned long long last_ipd;
 250         struct mcck_struct *mcck;
 251         unsigned long long tmp;
 252         struct mci *mci;
 253         int umode;
 254
 255         nmi_enter();
 256         s390_idle_check(regs, S390_lowcore.mcck_clock,
 257                         S390_lowcore.mcck_enter_timer);
 258
 259         mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
 260         mcck = &__get_cpu_var(cpu_mcck);
 261         umode = user_mode(regs);
 262
 263         if (mci->sd) {
 264                 /* System damage -> stopping machine */
 265                 s390_handle_damage("received system damage machine check.");
 266         }
 267         if (mci->pd) {
 268                 if (mci->b) {
 269                         /* Processing backup -> verify if we can survive this */
 270                         u64 z_mcic, o_mcic, t_mcic;
 271 #ifdef CONFIG_64BIT
 272                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
 273                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 274                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 275                                   1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
 276                                   1ULL<<16);
 277 #else
 278                         z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
 279                                   1ULL<<29);
 280                         o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
 281                                   1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
 282                                   1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
 283 #endif
 284                         t_mcic = *(u64 *)mci;
 285
 286                         if (((t_mcic & z_mcic) != 0) ||
 287                             ((t_mcic & o_mcic) != o_mcic)) {
 288                                 s390_handle_damage("processing backup machine "
 289                                                    "check with damage.");
 290                         }
 291
 292                         /*
 293                          * Nullifying exigent condition, therefore we might
 294                          * retry this instruction.
 295                          */
 296                         spin_lock(&ipd_lock);
 297                         tmp = get_clock();
 298                         if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
 299                                 ipd_count++;
 300                         else
 301                                 ipd_count = 1;
 302                         last_ipd = tmp;
 303                         if (ipd_count == MAX_IPD_COUNT)
 304                                 s390_handle_damage("too many ipd retries.");
 305                         spin_unlock(&ipd_lock);
 306                 } else {
 307                         /* Processing damage -> stopping machine */
 308                         s390_handle_damage("received instruction processing "
 309                                            "damage machine check.");
 310                 }
 311         }
 312         if (s390_revalidate_registers(mci)) {
 313                 if (umode) {
 314                         /*
 315                          * Couldn't restore all register contents while in
 316                          * user mode -> mark task for termination.
 317                          */
 318                         mcck->kill_task = 1;
 319                         mcck->mcck_code = *(unsigned long long *) mci;
 320                         set_thread_flag(TIF_MCCK_PENDING);
 321                 } else {
 322                         /*
 323                          * Couldn't restore all register contents while in
 324                          * kernel mode -> stopping machine.
 325                          */
 326                         s390_handle_damage("unable to revalidate registers.");
 327                 }
 328         }
 329         if (mci->cd) {
 330                 /* Timing facility damage */
 331                 s390_handle_damage("TOD clock damaged");
 332         }
 333         if (mci->ed && mci->ec) {
 334                 /* External damage */
 335                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
 336                         etr_sync_check();
 337                 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
 338                         etr_switch_to_local();
 339                 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
 340                         stp_sync_check();
 341                 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
 342                         stp_island_check();
 343         }
 344         if (mci->se)
 345                 /* Storage error uncorrected */
 346                 s390_handle_damage("received storage error uncorrected "
 347                                    "machine check.");
 348         if (mci->ke)
 349                 /* Storage key-error uncorrected */
 350                 s390_handle_damage("received storage key-error uncorrected "
 351                                    "machine check.");
 352         if (mci->ds && mci->fa)
 353                 /* Storage degradation */
 354                 s390_handle_damage("received storage degradation machine "
 355                                    "check.");
 356         if (mci->cp) {
 357                 /* Channel report word pending */
 358                 mcck->channel_report = 1;
 359                 set_thread_flag(TIF_MCCK_PENDING);
 360         }
 361         if (mci->w) {
 362                 /* Warning pending */
 363                 mcck->warning = 1;
 364                 set_thread_flag(TIF_MCCK_PENDING);
 365         }
 366         nmi_exit();
 367 }
 368
 369 static int __init machine_check_init(void)
 370 {
 371         ctl_set_bit(14, 25);    /* enable external damage MCH */
 372         ctl_set_bit(14, 27);    /* enable system recovery MCH */
 373         ctl_set_bit(14, 24);    /* enable warning MCH */
 374         return 0;
 375 }
 376 arch_initcall(machine_check_init);