arch/ia64/kernel/traps.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Architecture-specific trap handling.
   4  *
   5  * Copyright (C) 1998-2003 Hewlett-Packard Co
   6  *      David Mosberger-Tang <davidm@hpl.hp.com>
   7  *
   8  * 05/12/00 grao <goutham.rao@intel.com> : added isr in siginfo for SIGFPE
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/sched/signal.h>
  14 #include <linux/sched/debug.h>
  15 #include <linux/tty.h>
  16 #include <linux/vt_kern.h>              /* For unblank_screen() */
  17 #include <linux/export.h>
  18 #include <linux/extable.h>
  19 #include <linux/hardirq.h>
  20 #include <linux/kprobes.h>
  21 #include <linux/delay.h>                /* for ssleep() */
  22 #include <linux/kdebug.h>
  23 #include <linux/uaccess.h>
  24
  25 #include <asm/fpswa.h>
  26 #include <asm/intrinsics.h>
  27 #include <asm/processor.h>
  28 #include <asm/exception.h>
  29 #include <asm/setup.h>
  30
  31 fpswa_interface_t *fpswa_interface;
  32 EXPORT_SYMBOL(fpswa_interface);
  33
  34 void __init
  35 trap_init (void)
  36 {
  37         if (ia64_boot_param->fpswa)
  38                 /* FPSWA fixup: make the interface pointer a kernel virtual address: */
  39                 fpswa_interface = __va(ia64_boot_param->fpswa);
  40 }
  41
  42 int
  43 die (const char *str, struct pt_regs *regs, long err)
  44 {
  45         static struct {
  46                 spinlock_t lock;
  47                 u32 lock_owner;
  48                 int lock_owner_depth;
  49         } die = {
  50                 .lock = __SPIN_LOCK_UNLOCKED(die.lock),
  51                 .lock_owner = -1,
  52                 .lock_owner_depth = 0
  53         };
  54         static int die_counter;
  55         int cpu = get_cpu();
  56
  57         if (die.lock_owner != cpu) {
  58                 console_verbose();
  59                 spin_lock_irq(&die.lock);
  60                 die.lock_owner = cpu;
  61                 die.lock_owner_depth = 0;
  62                 bust_spinlocks(1);
  63         }
  64         put_cpu();
  65
  66         if (++die.lock_owner_depth < 3) {
  67                 printk("%s[%d]: %s %ld [%d]\n",
  68                 current->comm, task_pid_nr(current), str, err, ++die_counter);
  69                 if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV)
  70                     != NOTIFY_STOP)
  71                         show_regs(regs);
  72                 else
  73                         regs = NULL;
  74         } else
  75                 printk(KERN_ERR "Recursive die() failure, output suppressed\n");
  76
  77         bust_spinlocks(0);
  78         die.lock_owner = -1;
  79         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
  80         spin_unlock_irq(&die.lock);
  81
  82         if (!regs)
  83                 return 1;
  84
  85         if (panic_on_oops)
  86                 panic("Fatal exception");
  87
  88         do_exit(SIGSEGV);
  89         return 0;
  90 }
  91
  92 int
  93 die_if_kernel (char *str, struct pt_regs *regs, long err)
  94 {
  95         if (!user_mode(regs))
  96                 return die(str, regs, err);
  97         return 0;
  98 }
  99
 100 void
 101 __kprobes ia64_bad_break (unsigned long break_num, struct pt_regs *regs)
 102 {
 103         int sig, code;
 104
 105         switch (break_num) {
 106               case 0: /* unknown error (used by GCC for __builtin_abort()) */
 107                 if (notify_die(DIE_BREAK, "break 0", regs, break_num, TRAP_BRKPT, SIGTRAP)
 108                                 == NOTIFY_STOP)
 109                         return;
 110                 if (die_if_kernel("bugcheck!", regs, break_num))
 111                         return;
 112                 sig = SIGILL; code = ILL_ILLOPC;
 113                 break;
 114
 115               case 1: /* integer divide by zero */
 116                 sig = SIGFPE; code = FPE_INTDIV;
 117                 break;
 118
 119               case 2: /* integer overflow */
 120                 sig = SIGFPE; code = FPE_INTOVF;
 121                 break;
 122
 123               case 3: /* range check/bounds check */
 124                 sig = SIGFPE; code = FPE_FLTSUB;
 125                 break;
 126
 127               case 4: /* null pointer dereference */
 128                 sig = SIGSEGV; code = SEGV_MAPERR;
 129                 break;
 130
 131               case 5: /* misaligned data */
 132                 sig = SIGSEGV; code = BUS_ADRALN;
 133                 break;
 134
 135               case 6: /* decimal overflow */
 136                 sig = SIGFPE; code = __FPE_DECOVF;
 137                 break;
 138
 139               case 7: /* decimal divide by zero */
 140                 sig = SIGFPE; code = __FPE_DECDIV;
 141                 break;
 142
 143               case 8: /* packed decimal error */
 144                 sig = SIGFPE; code = __FPE_DECERR;
 145                 break;
 146
 147               case 9: /* invalid ASCII digit */
 148                 sig = SIGFPE; code = __FPE_INVASC;
 149                 break;
 150
 151               case 10: /* invalid decimal digit */
 152                 sig = SIGFPE; code = __FPE_INVDEC;
 153                 break;
 154
 155               case 11: /* paragraph stack overflow */
 156                 sig = SIGSEGV; code = __SEGV_PSTKOVF;
 157                 break;
 158
 159               case 0x3f000 ... 0x3ffff: /* bundle-update in progress */
 160                 sig = SIGILL; code = __ILL_BNDMOD;
 161                 break;
 162
 163               default:
 164                 if ((break_num < 0x40000 || break_num > 0x100000)
 165                     && die_if_kernel("Bad break", regs, break_num))
 166                         return;
 167
 168                 if (break_num < 0x80000) {
 169                         sig = SIGILL; code = __ILL_BREAK;
 170                 } else {
 171                         if (notify_die(DIE_BREAK, "bad break", regs, break_num, TRAP_BRKPT, SIGTRAP)
 172                                         == NOTIFY_STOP)
 173                                 return;
 174                         sig = SIGTRAP; code = TRAP_BRKPT;
 175                 }
 176         }
 177         force_sig_fault(sig, code,
 178                         (void __user *) (regs->cr_iip + ia64_psr(regs)->ri),
 179                         break_num, 0 /* clear __ISR_VALID */, 0);
 180 }
 181
 182 /*
 183  * disabled_fph_fault() is called when a user-level process attempts to access f32..f127
 184  * and it doesn't own the fp-high register partition.  When this happens, we save the
 185  * current fph partition in the task_struct of the fpu-owner (if necessary) and then load
 186  * the fp-high partition of the current task (if necessary).  Note that the kernel has
 187  * access to fph by the time we get here, as the IVT's "Disabled FP-Register" handler takes
 188  * care of clearing psr.dfh.
 189  */
 190 static inline void
 191 disabled_fph_fault (struct pt_regs *regs)
 192 {
 193         struct ia64_psr *psr = ia64_psr(regs);
 194
 195         /* first, grant user-level access to fph partition: */
 196         psr->dfh = 0;
 197
 198         /*
 199          * Make sure that no other task gets in on this processor
 200          * while we're claiming the FPU
 201          */
 202         preempt_disable();
 203 #ifndef CONFIG_SMP
 204         {
 205                 struct task_struct *fpu_owner
 206                         = (struct task_struct *)ia64_get_kr(IA64_KR_FPU_OWNER);
 207
 208                 if (ia64_is_local_fpu_owner(current)) {
 209                         preempt_enable_no_resched();
 210                         return;
 211                 }
 212
 213                 if (fpu_owner)
 214                         ia64_flush_fph(fpu_owner);
 215         }
 216 #endif /* !CONFIG_SMP */
 217         ia64_set_local_fpu_owner(current);
 218         if ((current->thread.flags & IA64_THREAD_FPH_VALID) != 0) {
 219                 __ia64_load_fpu(current->thread.fph);
 220                 psr->mfh = 0;
 221         } else {
 222                 __ia64_init_fpu();
 223                 /*
 224                  * Set mfh because the state in thread.fph does not match the state in
 225                  * the fph partition.
 226                  */
 227                 psr->mfh = 1;
 228         }
 229         preempt_enable_no_resched();
 230 }
 231
 232 static inline int
 233 fp_emulate (int fp_fault, void *bundle, long *ipsr, long *fpsr, long *isr, long *pr, long *ifs,
 234             struct pt_regs *regs)
 235 {
 236         fp_state_t fp_state;
 237         fpswa_ret_t ret;
 238
 239         if (!fpswa_interface)
 240                 return -1;
 241
 242         memset(&fp_state, 0, sizeof(fp_state_t));
 243
 244         /*
 245          * compute fp_state.  only FP registers f6 - f11 are used by the
 246          * kernel, so set those bits in the mask and set the low volatile
 247          * pointer to point to these registers.
 248          */
 249         fp_state.bitmask_low64 = 0xfc0;  /* bit6..bit11 */
 250
 251         fp_state.fp_state_low_volatile = (fp_state_low_volatile_t *) &regs->f6;
 252         /*
 253          * unsigned long (*EFI_FPSWA) (
 254          *      unsigned long    trap_type,
 255          *      void             *Bundle,
 256          *      unsigned long    *pipsr,
 257          *      unsigned long    *pfsr,
 258          *      unsigned long    *pisr,
 259          *      unsigned long    *ppreds,
 260          *      unsigned long    *pifs,
 261          *      void             *fp_state);
 262          */
 263         ret = (*fpswa_interface->fpswa)((unsigned long) fp_fault, bundle,
 264                                         (unsigned long *) ipsr, (unsigned long *) fpsr,
 265                                         (unsigned long *) isr, (unsigned long *) pr,
 266                                         (unsigned long *) ifs, &fp_state);
 267
 268         return ret.status;
 269 }
 270
 271 struct fpu_swa_msg {
 272         unsigned long count;
 273         unsigned long time;
 274 };
 275 static DEFINE_PER_CPU(struct fpu_swa_msg, cpulast);
 276 DECLARE_PER_CPU(struct fpu_swa_msg, cpulast);
 277 static struct fpu_swa_msg last __cacheline_aligned;
 278
 279
 280 /*
 281  * Handle floating-point assist faults and traps.
 282  */
 283 static int
 284 handle_fpu_swa (int fp_fault, struct pt_regs *regs, unsigned long isr)
 285 {
 286         long exception, bundle[2];
 287         unsigned long fault_ip;
 288
 289         fault_ip = regs->cr_iip;
 290         if (!fp_fault && (ia64_psr(regs)->ri == 0))
 291                 fault_ip -= 16;
 292         if (copy_from_user(bundle, (void __user *) fault_ip, sizeof(bundle)))
 293                 return -1;
 294
 295         if (!(current->thread.flags & IA64_THREAD_FPEMU_NOPRINT))  {
 296                 unsigned long count, current_jiffies = jiffies;
 297                 struct fpu_swa_msg *cp = this_cpu_ptr(&cpulast);
 298
 299                 if (unlikely(current_jiffies > cp->time))
 300                         cp->count = 0;
 301                 if (unlikely(cp->count < 5)) {
 302                         cp->count++;
 303                         cp->time = current_jiffies + 5 * HZ;
 304
 305                         /* minimize races by grabbing a copy of count BEFORE checking last.time. */
 306                         count = last.count;
 307                         barrier();
 308
 309                         /*
 310                          * Lower 4 bits are used as a count. Upper bits are a sequence
 311                          * number that is updated when count is reset. The cmpxchg will
 312                          * fail is seqno has changed. This minimizes mutiple cpus
 313                          * resetting the count.
 314                          */
 315                         if (current_jiffies > last.time)
 316                                 (void) cmpxchg_acq(&last.count, count, 16 + (count & ~15));
 317
 318                         /* used fetchadd to atomically update the count */
 319                         if ((last.count & 15) < 5 && (ia64_fetchadd(1, &last.count, acq) & 15) < 5) {
 320                                 last.time = current_jiffies + 5 * HZ;
 321                                 printk(KERN_WARNING
 322                                         "%s(%d): floating-point assist fault at ip %016lx, isr %016lx\n",
 323                                         current->comm, task_pid_nr(current), regs->cr_iip + ia64_psr(regs)->ri, isr);
 324                         }
 325                 }
 326         }
 327
 328         exception = fp_emulate(fp_fault, bundle, &regs->cr_ipsr, &regs->ar_fpsr, &isr, &regs->pr,
 329                                &regs->cr_ifs, regs);
 330         if (fp_fault) {
 331                 if (exception == 0) {
 332                         /* emulation was successful */
 333                         ia64_increment_ip(regs);
 334                 } else if (exception == -1) {
 335                         printk(KERN_ERR "handle_fpu_swa: fp_emulate() returned -1\n");
 336                         return -1;
 337                 } else {
 338                         /* is next instruction a trap? */
 339                         int si_code;
 340
 341                         if (exception & 2) {
 342                                 ia64_increment_ip(regs);
 343                         }
 344                         si_code = FPE_FLTUNK;   /* default code */
 345                         if (isr & 0x11) {
 346                                 si_code = FPE_FLTINV;
 347                         } else if (isr & 0x22) {
 348                                 /* denormal operand gets the same si_code as underflow
 349                                 * see arch/i386/kernel/traps.c:math_error()  */
 350                                 si_code = FPE_FLTUND;
 351                         } else if (isr & 0x44) {
 352                                 si_code = FPE_FLTDIV;
 353                         }
 354                         force_sig_fault(SIGFPE, si_code,
 355                                         (void __user *) (regs->cr_iip + ia64_psr(regs)->ri),
 356                                         0, __ISR_VALID, isr);
 357                 }
 358         } else {
 359                 if (exception == -1) {
 360                         printk(KERN_ERR "handle_fpu_swa: fp_emulate() returned -1\n");
 361                         return -1;
 362                 } else if (exception != 0) {
 363                         /* raise exception */
 364                         int si_code;
 365
 366                         si_code = FPE_FLTUNK;   /* default code */
 367                         if (isr & 0x880) {
 368                                 si_code = FPE_FLTOVF;
 369                         } else if (isr & 0x1100) {
 370                                 si_code = FPE_FLTUND;
 371                         } else if (isr & 0x2200) {
 372                                 si_code = FPE_FLTRES;
 373                         }
 374                         force_sig_fault(SIGFPE, si_code,
 375                                         (void __user *) (regs->cr_iip + ia64_psr(regs)->ri),
 376                                         0, __ISR_VALID, isr);
 377                 }
 378         }
 379         return 0;
 380 }
 381
 382 struct illegal_op_return {
 383         unsigned long fkt, arg1, arg2, arg3;
 384 };
 385
 386 struct illegal_op_return
 387 ia64_illegal_op_fault (unsigned long ec, long arg1, long arg2, long arg3,
 388                        long arg4, long arg5, long arg6, long arg7,
 389                        struct pt_regs regs)
 390 {
 391         struct illegal_op_return rv;
 392         char buf[128];
 393
 394 #ifdef CONFIG_IA64_BRL_EMU
 395         {
 396                 extern struct illegal_op_return ia64_emulate_brl (struct pt_regs *, unsigned long);
 397
 398                 rv = ia64_emulate_brl(&regs, ec);
 399                 if (rv.fkt != (unsigned long) -1)
 400                         return rv;
 401         }
 402 #endif
 403
 404         sprintf(buf, "IA-64 Illegal operation fault");
 405         rv.fkt = 0;
 406         if (die_if_kernel(buf, &regs, 0))
 407                 return rv;
 408
 409         force_sig_fault(SIGILL, ILL_ILLOPC,
 410                         (void __user *) (regs.cr_iip + ia64_psr(&regs)->ri),
 411                         0, 0, 0);
 412         return rv;
 413 }
 414
 415 void __kprobes
 416 ia64_fault (unsigned long vector, unsigned long isr, unsigned long ifa,
 417             unsigned long iim, unsigned long itir, long arg5, long arg6,
 418             long arg7, struct pt_regs regs)
 419 {
 420         unsigned long code, error = isr, iip;
 421         char buf[128];
 422         int result, sig, si_code;
 423         static const char *reason[] = {
 424                 "IA-64 Illegal Operation fault",
 425                 "IA-64 Privileged Operation fault",
 426                 "IA-64 Privileged Register fault",
 427                 "IA-64 Reserved Register/Field fault",
 428                 "Disabled Instruction Set Transition fault",
 429                 "Unknown fault 5", "Unknown fault 6", "Unknown fault 7", "Illegal Hazard fault",
 430                 "Unknown fault 9", "Unknown fault 10", "Unknown fault 11", "Unknown fault 12",
 431                 "Unknown fault 13", "Unknown fault 14", "Unknown fault 15"
 432         };
 433
 434         if ((isr & IA64_ISR_NA) && ((isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH)) {
 435                 /*
 436                  * This fault was due to lfetch.fault, set "ed" bit in the psr to cancel
 437                  * the lfetch.
 438                  */
 439                 ia64_psr(&regs)->ed = 1;
 440                 return;
 441         }
 442
 443         iip = regs.cr_iip + ia64_psr(&regs)->ri;
 444
 445         switch (vector) {
 446               case 24: /* General Exception */
 447                 code = (isr >> 4) & 0xf;
 448                 sprintf(buf, "General Exception: %s%s", reason[code],
 449                         (code == 3) ? ((isr & (1UL << 37))
 450                                        ? " (RSE access)" : " (data access)") : "");
 451                 if (code == 8) {
 452 # ifdef CONFIG_IA64_PRINT_HAZARDS
 453                         printk("%s[%d]: possible hazard @ ip=%016lx (pr = %016lx)\n",
 454                                current->comm, task_pid_nr(current),
 455                                regs.cr_iip + ia64_psr(&regs)->ri, regs.pr);
 456 # endif
 457                         return;
 458                 }
 459                 break;
 460
 461               case 25: /* Disabled FP-Register */
 462                 if (isr & 2) {
 463                         disabled_fph_fault(&regs);
 464                         return;
 465                 }
 466                 sprintf(buf, "Disabled FPL fault---not supposed to happen!");
 467                 break;
 468
 469               case 26: /* NaT Consumption */
 470                 if (user_mode(&regs)) {
 471                         void __user *addr;
 472
 473                         if (((isr >> 4) & 0xf) == 2) {
 474                                 /* NaT page consumption */
 475                                 sig = SIGSEGV;
 476                                 code = SEGV_ACCERR;
 477                                 addr = (void __user *) ifa;
 478                         } else {
 479                                 /* register NaT consumption */
 480                                 sig = SIGILL;
 481                                 code = ILL_ILLOPN;
 482                                 addr = (void __user *) (regs.cr_iip
 483                                                         + ia64_psr(&regs)->ri);
 484                         }
 485                         force_sig_fault(sig, code, addr,
 486                                         vector, __ISR_VALID, isr);
 487                         return;
 488                 } else if (ia64_done_with_exception(&regs))
 489                         return;
 490                 sprintf(buf, "NaT consumption");
 491                 break;
 492
 493               case 31: /* Unsupported Data Reference */
 494                 if (user_mode(&regs)) {
 495                         force_sig_fault(SIGILL, ILL_ILLOPN, (void __user *) iip,
 496                                         vector, __ISR_VALID, isr);
 497                         return;
 498                 }
 499                 sprintf(buf, "Unsupported data reference");
 500                 break;
 501
 502               case 29: /* Debug */
 503               case 35: /* Taken Branch Trap */
 504               case 36: /* Single Step Trap */
 505                 if (fsys_mode(current, &regs)) {
 506                         extern char __kernel_syscall_via_break[];
 507                         /*
 508                          * Got a trap in fsys-mode: Taken Branch Trap
 509                          * and Single Step trap need special handling;
 510                          * Debug trap is ignored (we disable it here
 511                          * and re-enable it in the lower-privilege trap).
 512                          */
 513                         if (unlikely(vector == 29)) {
 514                                 set_thread_flag(TIF_DB_DISABLED);
 515                                 ia64_psr(&regs)->db = 0;
 516                                 ia64_psr(&regs)->lp = 1;
 517                                 return;
 518                         }
 519                         /* re-do the system call via break 0x100000: */
 520                         regs.cr_iip = (unsigned long) __kernel_syscall_via_break;
 521                         ia64_psr(&regs)->ri = 0;
 522                         ia64_psr(&regs)->cpl = 3;
 523                         return;
 524                 }
 525                 switch (vector) {
 526                       default:
 527                       case 29:
 528                         si_code = TRAP_HWBKPT;
 529 #ifdef CONFIG_ITANIUM
 530                         /*
 531                          * Erratum 10 (IFA may contain incorrect address) now has
 532                          * "NoFix" status.  There are no plans for fixing this.
 533                          */
 534                         if (ia64_psr(&regs)->is == 0)
 535                           ifa = regs.cr_iip;
 536 #endif
 537                         break;
 538                       case 35: si_code = TRAP_BRANCH; ifa = 0; break;
 539                       case 36: si_code = TRAP_TRACE; ifa = 0; break;
 540                 }
 541                 if (notify_die(DIE_FAULT, "ia64_fault", &regs, vector, si_code, SIGTRAP)
 542                                 == NOTIFY_STOP)
 543                         return;
 544                 force_sig_fault(SIGTRAP, si_code, (void __user *) ifa,
 545                                 0, __ISR_VALID, isr);
 546                 return;
 547
 548               case 32: /* fp fault */
 549               case 33: /* fp trap */
 550                 result = handle_fpu_swa((vector == 32) ? 1 : 0, &regs, isr);
 551                 if ((result < 0) || (current->thread.flags & IA64_THREAD_FPEMU_SIGFPE)) {
 552                         force_sig_fault(SIGFPE, FPE_FLTINV, (void __user *) iip,
 553                                         0, __ISR_VALID, isr);
 554                 }
 555                 return;
 556
 557               case 34:
 558                 if (isr & 0x2) {
 559                         /* Lower-Privilege Transfer Trap */
 560
 561                         /* If we disabled debug traps during an fsyscall,
 562                          * re-enable them here.
 563                          */
 564                         if (test_thread_flag(TIF_DB_DISABLED)) {
 565                                 clear_thread_flag(TIF_DB_DISABLED);
 566                                 ia64_psr(&regs)->db = 1;
 567                         }
 568
 569                         /*
 570                          * Just clear PSR.lp and then return immediately:
 571                          * all the interesting work (e.g., signal delivery)
 572                          * is done in the kernel exit path.
 573                          */
 574                         ia64_psr(&regs)->lp = 0;
 575                         return;
 576                 } else {
 577                         /* Unimplemented Instr. Address Trap */
 578                         if (user_mode(&regs)) {
 579                                 force_sig_fault(SIGILL, ILL_BADIADDR,
 580                                                 (void __user *) iip,
 581                                                 0, 0, 0);
 582                                 return;
 583                         }
 584                         sprintf(buf, "Unimplemented Instruction Address fault");
 585                 }
 586                 break;
 587
 588               case 45:
 589                 printk(KERN_ERR "Unexpected IA-32 exception (Trap 45)\n");
 590                 printk(KERN_ERR "  iip - 0x%lx, ifa - 0x%lx, isr - 0x%lx\n",
 591                        iip, ifa, isr);
 592                 force_sig(SIGSEGV);
 593                 return;
 594
 595               case 46:
 596                 printk(KERN_ERR "Unexpected IA-32 intercept trap (Trap 46)\n");
 597                 printk(KERN_ERR "  iip - 0x%lx, ifa - 0x%lx, isr - 0x%lx, iim - 0x%lx\n",
 598                        iip, ifa, isr, iim);
 599                 force_sig(SIGSEGV);
 600                 return;
 601
 602               case 47:
 603                 sprintf(buf, "IA-32 Interruption Fault (int 0x%lx)", isr >> 16);
 604                 break;
 605
 606               default:
 607                 sprintf(buf, "Fault %lu", vector);
 608                 break;
 609         }
 610         if (!die_if_kernel(buf, &regs, error))
 611                 force_sig(SIGILL);
 612 }