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