arch/x86/kernel/traps.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   4  *
   5  *  Pentium III FXSR, SSE support
   6  *      Gareth Hughes <gareth@valinux.com>, May 2000
   7  */
   8
   9 /*
  10  * Handle hardware traps and faults.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/context_tracking.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kallsyms.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/kprobes.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/kdebug.h>
  22 #include <linux/kgdb.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/uprobes.h>
  27 #include <linux/string.h>
  28 #include <linux/delay.h>
  29 #include <linux/errno.h>
  30 #include <linux/kexec.h>
  31 #include <linux/sched.h>
  32 #include <linux/timer.h>
  33 #include <linux/init.h>
  34 #include <linux/bug.h>
  35 #include <linux/nmi.h>
  36 #include <linux/mm.h>
  37 #include <linux/smp.h>
  38 #include <linux/io.h>
  39
  40 #ifdef CONFIG_EISA
  41 #include <linux/ioport.h>
  42 #include <linux/eisa.h>
  43 #endif
  44
  45 #if defined(CONFIG_EDAC)
  46 #include <linux/edac.h>
  47 #endif
  48
  49 #include <asm/kmemcheck.h>
  50 #include <asm/stacktrace.h>
  51 #include <asm/processor.h>
  52 #include <asm/debugreg.h>
  53 #include <linux/atomic.h>
  54 #include <asm/ftrace.h>
  55 #include <asm/traps.h>
  56 #include <asm/desc.h>
  57 #include <asm/i387.h>
  58 #include <asm/fpu-internal.h>
  59 #include <asm/mce.h>
  60 #include <asm/fixmap.h>
  61 #include <asm/mach_traps.h>
  62 #include <asm/alternative.h>
  63
  64 #ifdef CONFIG_X86_64
  65 #include <asm/x86_init.h>
  66 #include <asm/pgalloc.h>
  67 #include <asm/proto.h>
  68
  69 /* No need to be aligned, but done to keep all IDTs defined the same way. */
  70 gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
  71 #else
  72 #include <asm/processor-flags.h>
  73 #include <asm/setup.h>
  74
  75 asmlinkage int system_call(void);
  76 #endif
  77
  78 /* Must be page-aligned because the real IDT is used in a fixmap. */
  79 gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
  80
  81 DECLARE_BITMAP(used_vectors, NR_VECTORS);
  82 EXPORT_SYMBOL_GPL(used_vectors);
  83
  84 static inline void conditional_sti(struct pt_regs *regs)
  85 {
  86         if (regs->flags & X86_EFLAGS_IF)
  87                 local_irq_enable();
  88 }
  89
  90 static inline void preempt_conditional_sti(struct pt_regs *regs)
  91 {
  92         preempt_count_inc();
  93         if (regs->flags & X86_EFLAGS_IF)
  94                 local_irq_enable();
  95 }
  96
  97 static inline void conditional_cli(struct pt_regs *regs)
  98 {
  99         if (regs->flags & X86_EFLAGS_IF)
 100                 local_irq_disable();
 101 }
 102
 103 static inline void preempt_conditional_cli(struct pt_regs *regs)
 104 {
 105         if (regs->flags & X86_EFLAGS_IF)
 106                 local_irq_disable();
 107         preempt_count_dec();
 108 }
 109
 110 static nokprobe_inline int
 111 do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
 112                   struct pt_regs *regs, long error_code)
 113 {
 114 #ifdef CONFIG_X86_32
 115         if (regs->flags & X86_VM_MASK) {
 116                 /*
 117                  * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
 118                  * On nmi (interrupt 2), do_trap should not be called.
 119                  */
 120                 if (trapnr < X86_TRAP_UD) {
 121                         if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
 122                                                 error_code, trapnr))
 123                                 return 0;
 124                 }
 125                 return -1;
 126         }
 127 #endif
 128         if (!user_mode(regs)) {
 129                 if (!fixup_exception(regs)) {
 130                         tsk->thread.error_code = error_code;
 131                         tsk->thread.trap_nr = trapnr;
 132                         die(str, regs, error_code);
 133                 }
 134                 return 0;
 135         }
 136
 137         return -1;
 138 }
 139
 140 static siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr,
 141                                 siginfo_t *info)
 142 {
 143         unsigned long siaddr;
 144         int sicode;
 145
 146         switch (trapnr) {
 147         default:
 148                 return SEND_SIG_PRIV;
 149
 150         case X86_TRAP_DE:
 151                 sicode = FPE_INTDIV;
 152                 siaddr = uprobe_get_trap_addr(regs);
 153                 break;
 154         case X86_TRAP_UD:
 155                 sicode = ILL_ILLOPN;
 156                 siaddr = uprobe_get_trap_addr(regs);
 157                 break;
 158         case X86_TRAP_AC:
 159                 sicode = BUS_ADRALN;
 160                 siaddr = 0;
 161                 break;
 162         }
 163
 164         info->si_signo = signr;
 165         info->si_errno = 0;
 166         info->si_code = sicode;
 167         info->si_addr = (void __user *)siaddr;
 168         return info;
 169 }
 170
 171 static void
 172 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
 173         long error_code, siginfo_t *info)
 174 {
 175         struct task_struct *tsk = current;
 176
 177
 178         if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
 179                 return;
 180         /*
 181          * We want error_code and trap_nr set for userspace faults and
 182          * kernelspace faults which result in die(), but not
 183          * kernelspace faults which are fixed up.  die() gives the
 184          * process no chance to handle the signal and notice the
 185          * kernel fault information, so that won't result in polluting
 186          * the information about previously queued, but not yet
 187          * delivered, faults.  See also do_general_protection below.
 188          */
 189         tsk->thread.error_code = error_code;
 190         tsk->thread.trap_nr = trapnr;
 191
 192 #ifdef CONFIG_X86_64
 193         if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
 194             printk_ratelimit()) {
 195                 pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
 196                         tsk->comm, tsk->pid, str,
 197                         regs->ip, regs->sp, error_code);
 198                 print_vma_addr(" in ", regs->ip);
 199                 pr_cont("\n");
 200         }
 201 #endif
 202
 203         force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);
 204 }
 205 NOKPROBE_SYMBOL(do_trap);
 206
 207 static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
 208                           unsigned long trapnr, int signr)
 209 {
 210         enum ctx_state prev_state = exception_enter();
 211         siginfo_t info;
 212
 213         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
 214                         NOTIFY_STOP) {
 215                 conditional_sti(regs);
 216                 do_trap(trapnr, signr, str, regs, error_code,
 217                         fill_trap_info(regs, signr, trapnr, &info));
 218         }
 219
 220         exception_exit(prev_state);
 221 }
 222
 223 #define DO_ERROR(trapnr, signr, str, name)                              \
 224 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 225 {                                                                       \
 226         do_error_trap(regs, error_code, str, trapnr, signr);            \
 227 }
 228
 229 DO_ERROR(X86_TRAP_DE,     SIGFPE,  "divide error",              divide_error)
 230 DO_ERROR(X86_TRAP_OF,     SIGSEGV, "overflow",                  overflow)
 231 DO_ERROR(X86_TRAP_BR,     SIGSEGV, "bounds",                    bounds)
 232 DO_ERROR(X86_TRAP_UD,     SIGILL,  "invalid opcode",            invalid_op)
 233 DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,  "coprocessor segment overrun",coprocessor_segment_overrun)
 234 DO_ERROR(X86_TRAP_TS,     SIGSEGV, "invalid TSS",               invalid_TSS)
 235 DO_ERROR(X86_TRAP_NP,     SIGBUS,  "segment not present",       segment_not_present)
 236 #ifdef CONFIG_X86_32
 237 DO_ERROR(X86_TRAP_SS,     SIGBUS,  "stack segment",             stack_segment)
 238 #endif
 239 DO_ERROR(X86_TRAP_AC,     SIGBUS,  "alignment check",           alignment_check)
 240
 241 #ifdef CONFIG_X86_64
 242 /* Runs on IST stack */
 243 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
 244 {
 245         enum ctx_state prev_state;
 246
 247         prev_state = exception_enter();
 248         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
 249                        X86_TRAP_SS, SIGBUS) != NOTIFY_STOP) {
 250                 preempt_conditional_sti(regs);
 251                 do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
 252                 preempt_conditional_cli(regs);
 253         }
 254         exception_exit(prev_state);
 255 }
 256
 257 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 258 {
 259         static const char str[] = "double fault";
 260         struct task_struct *tsk = current;
 261
 262         exception_enter();
 263         /* Return not checked because double check cannot be ignored */
 264         notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 265
 266         tsk->thread.error_code = error_code;
 267         tsk->thread.trap_nr = X86_TRAP_DF;
 268
 269 #ifdef CONFIG_DOUBLEFAULT
 270         df_debug(regs, error_code);
 271 #endif
 272         /*
 273          * This is always a kernel trap and never fixable (and thus must
 274          * never return).
 275          */
 276         for (;;)
 277                 die(str, regs, error_code);
 278 }
 279 #endif
 280
 281 dotraplinkage void
 282 do_general_protection(struct pt_regs *regs, long error_code)
 283 {
 284         struct task_struct *tsk;
 285         enum ctx_state prev_state;
 286
 287         prev_state = exception_enter();
 288         conditional_sti(regs);
 289
 290 #ifdef CONFIG_X86_32
 291         if (regs->flags & X86_VM_MASK) {
 292                 local_irq_enable();
 293                 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
 294                 goto exit;
 295         }
 296 #endif
 297
 298         tsk = current;
 299         if (!user_mode(regs)) {
 300                 if (fixup_exception(regs))
 301                         goto exit;
 302
 303                 tsk->thread.error_code = error_code;
 304                 tsk->thread.trap_nr = X86_TRAP_GP;
 305                 if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
 306                                X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
 307                         die("general protection fault", regs, error_code);
 308                 goto exit;
 309         }
 310
 311         tsk->thread.error_code = error_code;
 312         tsk->thread.trap_nr = X86_TRAP_GP;
 313
 314         if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
 315                         printk_ratelimit()) {
 316                 pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
 317                         tsk->comm, task_pid_nr(tsk),
 318                         regs->ip, regs->sp, error_code);
 319                 print_vma_addr(" in ", regs->ip);
 320                 pr_cont("\n");
 321         }
 322
 323         force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 324 exit:
 325         exception_exit(prev_state);
 326 }
 327 NOKPROBE_SYMBOL(do_general_protection);
 328
 329 /* May run on IST stack. */
 330 dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 331 {
 332         enum ctx_state prev_state;
 333
 334 #ifdef CONFIG_DYNAMIC_FTRACE
 335         /*
 336          * ftrace must be first, everything else may cause a recursive crash.
 337          * See note by declaration of modifying_ftrace_code in ftrace.c
 338          */
 339         if (unlikely(atomic_read(&modifying_ftrace_code)) &&
 340             ftrace_int3_handler(regs))
 341                 return;
 342 #endif
 343         if (poke_int3_handler(regs))
 344                 return;
 345
 346         prev_state = exception_enter();
 347 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 348         if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 349                                 SIGTRAP) == NOTIFY_STOP)
 350                 goto exit;
 351 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 352
 353 #ifdef CONFIG_KPROBES
 354         if (kprobe_int3_handler(regs))
 355                 goto exit;
 356 #endif
 357
 358         if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
 359                         SIGTRAP) == NOTIFY_STOP)
 360                 goto exit;
 361
 362         /*
 363          * Let others (NMI) know that the debug stack is in use
 364          * as we may switch to the interrupt stack.
 365          */
 366         debug_stack_usage_inc();
 367         preempt_conditional_sti(regs);
 368         do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
 369         preempt_conditional_cli(regs);
 370         debug_stack_usage_dec();
 371 exit:
 372         exception_exit(prev_state);
 373 }
 374 NOKPROBE_SYMBOL(do_int3);
 375
 376 #ifdef CONFIG_X86_64
 377 /*
 378  * Help handler running on IST stack to switch back to user stack
 379  * for scheduling or signal handling. The actual stack switch is done in
 380  * entry.S
 381  */
 382 asmlinkage __visible struct pt_regs *sync_regs(struct pt_regs *eregs)
 383 {
 384         struct pt_regs *regs = eregs;
 385         /* Did already sync */
 386         if (eregs == (struct pt_regs *)eregs->sp)
 387                 ;
 388         /* Exception from user space */
 389         else if (user_mode(eregs))
 390                 regs = task_pt_regs(current);
 391         /*
 392          * Exception from kernel and interrupts are enabled. Move to
 393          * kernel process stack.
 394          */
 395         else if (eregs->flags & X86_EFLAGS_IF)
 396                 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
 397         if (eregs != regs)
 398                 *regs = *eregs;
 399         return regs;
 400 }
 401 NOKPROBE_SYMBOL(sync_regs);
 402 #endif
 403
 404 /*
 405  * Our handling of the processor debug registers is non-trivial.
 406  * We do not clear them on entry and exit from the kernel. Therefore
 407  * it is possible to get a watchpoint trap here from inside the kernel.
 408  * However, the code in ./ptrace.c has ensured that the user can
 409  * only set watchpoints on userspace addresses. Therefore the in-kernel
 410  * watchpoint trap can only occur in code which is reading/writing
 411  * from user space. Such code must not hold kernel locks (since it
 412  * can equally take a page fault), therefore it is safe to call
 413  * force_sig_info even though that claims and releases locks.
 414  *
 415  * Code in ./signal.c ensures that the debug control register
 416  * is restored before we deliver any signal, and therefore that
 417  * user code runs with the correct debug control register even though
 418  * we clear it here.
 419  *
 420  * Being careful here means that we don't have to be as careful in a
 421  * lot of more complicated places (task switching can be a bit lazy
 422  * about restoring all the debug state, and ptrace doesn't have to
 423  * find every occurrence of the TF bit that could be saved away even
 424  * by user code)
 425  *
 426  * May run on IST stack.
 427  */
 428 dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 429 {
 430         struct task_struct *tsk = current;
 431         enum ctx_state prev_state;
 432         int user_icebp = 0;
 433         unsigned long dr6;
 434         int si_code;
 435
 436         prev_state = exception_enter();
 437
 438         get_debugreg(dr6, 6);
 439
 440         /* Filter out all the reserved bits which are preset to 1 */
 441         dr6 &= ~DR6_RESERVED;
 442
 443         /*
 444          * If dr6 has no reason to give us about the origin of this trap,
 445          * then it's very likely the result of an icebp/int01 trap.
 446          * User wants a sigtrap for that.
 447          */
 448         if (!dr6 && user_mode(regs))
 449                 user_icebp = 1;
 450
 451         /* Catch kmemcheck conditions first of all! */
 452         if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
 453                 goto exit;
 454
 455         /* DR6 may or may not be cleared by the CPU */
 456         set_debugreg(0, 6);
 457
 458         /*
 459          * The processor cleared BTF, so don't mark that we need it set.
 460          */
 461         clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
 462
 463         /* Store the virtualized DR6 value */
 464         tsk->thread.debugreg6 = dr6;
 465
 466 #ifdef CONFIG_KPROBES
 467         if (kprobe_debug_handler(regs))
 468                 goto exit;
 469 #endif
 470
 471         if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
 472                                                         SIGTRAP) == NOTIFY_STOP)
 473                 goto exit;
 474
 475         /*
 476          * Let others (NMI) know that the debug stack is in use
 477          * as we may switch to the interrupt stack.
 478          */
 479         debug_stack_usage_inc();
 480
 481         /* It's safe to allow irq's after DR6 has been saved */
 482         preempt_conditional_sti(regs);
 483
 484         if (regs->flags & X86_VM_MASK) {
 485                 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
 486                                         X86_TRAP_DB);
 487                 preempt_conditional_cli(regs);
 488                 debug_stack_usage_dec();
 489                 goto exit;
 490         }
 491
 492         /*
 493          * Single-stepping through system calls: ignore any exceptions in
 494          * kernel space, but re-enable TF when returning to user mode.
 495          *
 496          * We already checked v86 mode above, so we can check for kernel mode
 497          * by just checking the CPL of CS.
 498          */
 499         if ((dr6 & DR_STEP) && !user_mode(regs)) {
 500                 tsk->thread.debugreg6 &= ~DR_STEP;
 501                 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
 502                 regs->flags &= ~X86_EFLAGS_TF;
 503         }
 504         si_code = get_si_code(tsk->thread.debugreg6);
 505         if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
 506                 send_sigtrap(tsk, regs, error_code, si_code);
 507         preempt_conditional_cli(regs);
 508         debug_stack_usage_dec();
 509
 510 exit:
 511         exception_exit(prev_state);
 512 }
 513 NOKPROBE_SYMBOL(do_debug);
 514
 515 /*
 516  * Note that we play around with the 'TS' bit in an attempt to get
 517  * the correct behaviour even in the presence of the asynchronous
 518  * IRQ13 behaviour
 519  */
 520 static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 521 {
 522         struct task_struct *task = current;
 523         siginfo_t info;
 524         unsigned short err;
 525         char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
 526                                                 "simd exception";
 527
 528         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
 529                 return;
 530         conditional_sti(regs);
 531
 532         if (!user_mode_vm(regs))
 533         {
 534                 if (!fixup_exception(regs)) {
 535                         task->thread.error_code = error_code;
 536                         task->thread.trap_nr = trapnr;
 537                         die(str, regs, error_code);
 538                 }
 539                 return;
 540         }
 541
 542         /*
 543          * Save the info for the exception handler and clear the error.
 544          */
 545         save_init_fpu(task);
 546         task->thread.trap_nr = trapnr;
 547         task->thread.error_code = error_code;
 548         info.si_signo = SIGFPE;
 549         info.si_errno = 0;
 550         info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
 551         if (trapnr == X86_TRAP_MF) {
 552                 unsigned short cwd, swd;
 553                 /*
 554                  * (~cwd & swd) will mask out exceptions that are not set to unmasked
 555                  * status.  0x3f is the exception bits in these regs, 0x200 is the
 556                  * C1 reg you need in case of a stack fault, 0x040 is the stack
 557                  * fault bit.  We should only be taking one exception at a time,
 558                  * so if this combination doesn't produce any single exception,
 559                  * then we have a bad program that isn't synchronizing its FPU usage
 560                  * and it will suffer the consequences since we won't be able to
 561                  * fully reproduce the context of the exception
 562                  */
 563                 cwd = get_fpu_cwd(task);
 564                 swd = get_fpu_swd(task);
 565
 566                 err = swd & ~cwd;
 567         } else {
 568                 /*
 569                  * The SIMD FPU exceptions are handled a little differently, as there
 570                  * is only a single status/control register.  Thus, to determine which
 571                  * unmasked exception was caught we must mask the exception mask bits
 572                  * at 0x1f80, and then use these to mask the exception bits at 0x3f.
 573                  */
 574                 unsigned short mxcsr = get_fpu_mxcsr(task);
 575                 err = ~(mxcsr >> 7) & mxcsr;
 576         }
 577
 578         if (err & 0x001) {      /* Invalid op */
 579                 /*
 580                  * swd & 0x240 == 0x040: Stack Underflow
 581                  * swd & 0x240 == 0x240: Stack Overflow
 582                  * User must clear the SF bit (0x40) if set
 583                  */
 584                 info.si_code = FPE_FLTINV;
 585         } else if (err & 0x004) { /* Divide by Zero */
 586                 info.si_code = FPE_FLTDIV;
 587         } else if (err & 0x008) { /* Overflow */
 588                 info.si_code = FPE_FLTOVF;
 589         } else if (err & 0x012) { /* Denormal, Underflow */
 590                 info.si_code = FPE_FLTUND;
 591         } else if (err & 0x020) { /* Precision */
 592                 info.si_code = FPE_FLTRES;
 593         } else {
 594                 /*
 595                  * If we're using IRQ 13, or supposedly even some trap
 596                  * X86_TRAP_MF implementations, it's possible
 597                  * we get a spurious trap, which is not an error.
 598                  */
 599                 return;
 600         }
 601         force_sig_info(SIGFPE, &info, task);
 602 }
 603
 604 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 605 {
 606         enum ctx_state prev_state;
 607
 608         prev_state = exception_enter();
 609         math_error(regs, error_code, X86_TRAP_MF);
 610         exception_exit(prev_state);
 611 }
 612
 613 dotraplinkage void
 614 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 615 {
 616         enum ctx_state prev_state;
 617
 618         prev_state = exception_enter();
 619         math_error(regs, error_code, X86_TRAP_XF);
 620         exception_exit(prev_state);
 621 }
 622
 623 dotraplinkage void
 624 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 625 {
 626         conditional_sti(regs);
 627 #if 0
 628         /* No need to warn about this any longer. */
 629         pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
 630 #endif
 631 }
 632
 633 asmlinkage __visible void __attribute__((weak)) smp_thermal_interrupt(void)
 634 {
 635 }
 636
 637 asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void)
 638 {
 639 }
 640
 641 /*
 642  * 'math_state_restore()' saves the current math information in the
 643  * old math state array, and gets the new ones from the current task
 644  *
 645  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
 646  * Don't touch unless you *really* know how it works.
 647  *
 648  * Must be called with kernel preemption disabled (eg with local
 649  * local interrupts as in the case of do_device_not_available).
 650  */
 651 void math_state_restore(void)
 652 {
 653         struct task_struct *tsk = current;
 654
 655         if (!tsk_used_math(tsk)) {
 656                 local_irq_enable();
 657                 /*
 658                  * does a slab alloc which can sleep
 659                  */
 660                 if (init_fpu(tsk)) {
 661                         /*
 662                          * ran out of memory!
 663                          */
 664                         do_group_exit(SIGKILL);
 665                         return;
 666                 }
 667                 local_irq_disable();
 668         }
 669
 670         __thread_fpu_begin(tsk);
 671
 672         /*
 673          * Paranoid restore. send a SIGSEGV if we fail to restore the state.
 674          */
 675         if (unlikely(restore_fpu_checking(tsk))) {
 676                 drop_init_fpu(tsk);
 677                 force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 678                 return;
 679         }
 680
 681         tsk->thread.fpu_counter++;
 682 }
 683 EXPORT_SYMBOL_GPL(math_state_restore);
 684
 685 dotraplinkage void
 686 do_device_not_available(struct pt_regs *regs, long error_code)
 687 {
 688         enum ctx_state prev_state;
 689
 690         prev_state = exception_enter();
 691         BUG_ON(use_eager_fpu());
 692
 693 #ifdef CONFIG_MATH_EMULATION
 694         if (read_cr0() & X86_CR0_EM) {
 695                 struct math_emu_info info = { };
 696
 697                 conditional_sti(regs);
 698
 699                 info.regs = regs;
 700                 math_emulate(&info);
 701                 exception_exit(prev_state);
 702                 return;
 703         }
 704 #endif
 705         math_state_restore(); /* interrupts still off */
 706 #ifdef CONFIG_X86_32
 707         conditional_sti(regs);
 708 #endif
 709         exception_exit(prev_state);
 710 }
 711 NOKPROBE_SYMBOL(do_device_not_available);
 712
 713 #ifdef CONFIG_X86_32
 714 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 715 {
 716         siginfo_t info;
 717         enum ctx_state prev_state;
 718
 719         prev_state = exception_enter();
 720         local_irq_enable();
 721
 722         info.si_signo = SIGILL;
 723         info.si_errno = 0;
 724         info.si_code = ILL_BADSTK;
 725         info.si_addr = NULL;
 726         if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
 727                         X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
 728                 do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
 729                         &info);
 730         }
 731         exception_exit(prev_state);
 732 }
 733 #endif
 734
 735 /* Set of traps needed for early debugging. */
 736 void __init early_trap_init(void)
 737 {
 738         set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
 739         /* int3 can be called from all */
 740         set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
 741 #ifdef CONFIG_X86_32
 742         set_intr_gate(X86_TRAP_PF, page_fault);
 743 #endif
 744         load_idt(&idt_descr);
 745 }
 746
 747 void __init early_trap_pf_init(void)
 748 {
 749 #ifdef CONFIG_X86_64
 750         set_intr_gate(X86_TRAP_PF, page_fault);
 751 #endif
 752 }
 753
 754 void __init trap_init(void)
 755 {
 756         int i;
 757
 758 #ifdef CONFIG_EISA
 759         void __iomem *p = early_ioremap(0x0FFFD9, 4);
 760
 761         if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
 762                 EISA_bus = 1;
 763         early_iounmap(p, 4);
 764 #endif
 765
 766         set_intr_gate(X86_TRAP_DE, divide_error);
 767         set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
 768         /* int4 can be called from all */
 769         set_system_intr_gate(X86_TRAP_OF, &overflow);
 770         set_intr_gate(X86_TRAP_BR, bounds);
 771         set_intr_gate(X86_TRAP_UD, invalid_op);
 772         set_intr_gate(X86_TRAP_NM, device_not_available);
 773 #ifdef CONFIG_X86_32
 774         set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
 775 #else
 776         set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
 777 #endif
 778         set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
 779         set_intr_gate(X86_TRAP_TS, invalid_TSS);
 780         set_intr_gate(X86_TRAP_NP, segment_not_present);
 781         set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
 782         set_intr_gate(X86_TRAP_GP, general_protection);
 783         set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
 784         set_intr_gate(X86_TRAP_MF, coprocessor_error);
 785         set_intr_gate(X86_TRAP_AC, alignment_check);
 786 #ifdef CONFIG_X86_MCE
 787         set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
 788 #endif
 789         set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
 790
 791         /* Reserve all the builtin and the syscall vector: */
 792         for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
 793                 set_bit(i, used_vectors);
 794
 795 #ifdef CONFIG_IA32_EMULATION
 796         set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
 797         set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 798 #endif
 799
 800 #ifdef CONFIG_X86_32
 801         set_system_trap_gate(SYSCALL_VECTOR, &system_call);
 802         set_bit(SYSCALL_VECTOR, used_vectors);
 803 #endif
 804
 805         /*
 806          * Set the IDT descriptor to a fixed read-only location, so that the
 807          * "sidt" instruction will not leak the location of the kernel, and
 808          * to defend the IDT against arbitrary memory write vulnerabilities.
 809          * It will be reloaded in cpu_init() */
 810         __set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
 811         idt_descr.address = fix_to_virt(FIX_RO_IDT);
 812
 813         /*
 814          * Should be a barrier for any external CPU state:
 815          */
 816         cpu_init();
 817
 818         x86_init.irqs.trap_init();
 819
 820 #ifdef CONFIG_X86_64
 821         memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
 822         set_nmi_gate(X86_TRAP_DB, &debug);
 823         set_nmi_gate(X86_TRAP_BP, &int3);
 824 #endif
 825 }