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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 #include <linux/interrupt.h>
13 #include <linux/kallsyms.h>
14 #include <linux/spinlock.h>
15 #include <linux/kprobes.h>
16 #include <linux/uaccess.h>
17 #include <linux/kdebug.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/ptrace.h>
21 #include <linux/string.h>
22 #include <linux/delay.h>
23 #include <linux/errno.h>
24 #include <linux/kexec.h>
25 #include <linux/sched.h>
26 #include <linux/timer.h>
27 #include <linux/init.h>
28 #include <linux/bug.h>
29 #include <linux/nmi.h>
30 #include <linux/mm.h>
31 #include <linux/smp.h>
32 #include <linux/io.h>
33
34 #ifdef CONFIG_EISA
35 #include <linux/ioport.h>
36 #include <linux/eisa.h>
37 #endif
38
39 #ifdef CONFIG_MCA
40 #include <linux/mca.h>
41 #endif
42
43 #if defined(CONFIG_EDAC)
44 #include <linux/edac.h>
45 #endif
46
47 #include <asm/kmemcheck.h>
48 #include <asm/stacktrace.h>
49 #include <asm/processor.h>
50 #include <asm/debugreg.h>
51 #include <asm/atomic.h>
52 #include <asm/system.h>
53 #include <asm/traps.h>
54 #include <asm/desc.h>
55 #include <asm/i387.h>
56 #include <asm/mce.h>
57
58 #include <asm/mach_traps.h>
59
60 #ifdef CONFIG_X86_64
61 #include <asm/x86_init.h>
62 #include <asm/pgalloc.h>
63 #include <asm/proto.h>
64 #else
65 #include <asm/processor-flags.h>
66 #include <asm/setup.h>
67
68 asmlinkage int system_call(void);
69
70 /* Do we ignore FPU interrupts ? */
71 char ignore_fpu_irq;
72
73 /*
74 * The IDT has to be page-aligned to simplify the Pentium
75 * F0 0F bug workaround.
76 */
77 gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
78 #endif
79
80 DECLARE_BITMAP(used_vectors, NR_VECTORS);
81 EXPORT_SYMBOL_GPL(used_vectors);
82
83 static int ignore_nmis;
84
85 static inline void conditional_sti(struct pt_regs *regs)
86 {
87 if (regs->flags & X86_EFLAGS_IF)
88 local_irq_enable();
89 }
90
91 static inline void preempt_conditional_sti(struct pt_regs *regs)
92 {
93 inc_preempt_count();
94 if (regs->flags & X86_EFLAGS_IF)
95 local_irq_enable();
96 }
97
98 static inline void conditional_cli(struct pt_regs *regs)
99 {
100 if (regs->flags & X86_EFLAGS_IF)
101 local_irq_disable();
102 }
103
104 static inline void preempt_conditional_cli(struct pt_regs *regs)
105 {
106 if (regs->flags & X86_EFLAGS_IF)
107 local_irq_disable();
108 dec_preempt_count();
109 }
110
111 #ifdef CONFIG_X86_32
112 static inline void
113 die_if_kernel(const char *str, struct pt_regs *regs, long err)
114 {
115 if (!user_mode_vm(regs))
116 die(str, regs, err);
117 }
118 #endif
119
120 static void __kprobes
121 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
122 long error_code, siginfo_t *info)
123 {
124 struct task_struct *tsk = current;
125
126 #ifdef CONFIG_X86_32
127 if (regs->flags & X86_VM_MASK) {
128 /*
129 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
130 * On nmi (interrupt 2), do_trap should not be called.
131 */
132 if (trapnr < 6)
133 goto vm86_trap;
134 goto trap_signal;
135 }
136 #endif
137
138 if (!user_mode(regs))
139 goto kernel_trap;
140
141 #ifdef CONFIG_X86_32
142 trap_signal:
143 #endif
144 /*
145 * We want error_code and trap_no set for userspace faults and
146 * kernelspace faults which result in die(), but not
147 * kernelspace faults which are fixed up. die() gives the
148 * process no chance to handle the signal and notice the
149 * kernel fault information, so that won't result in polluting
150 * the information about previously queued, but not yet
151 * delivered, faults. See also do_general_protection below.
152 */
153 tsk->thread.error_code = error_code;
154 tsk->thread.trap_no = trapnr;
155
156 #ifdef CONFIG_X86_64
157 if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
158 printk_ratelimit()) {
159 printk(KERN_INFO
160 "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
161 tsk->comm, tsk->pid, str,
162 regs->ip, regs->sp, error_code);
163 print_vma_addr(" in ", regs->ip);
164 printk("\n");
165 }
166 #endif
167
168 if (info)
169 force_sig_info(signr, info, tsk);
170 else
171 force_sig(signr, tsk);
172 return;
173
174 kernel_trap:
175 if (!fixup_exception(regs)) {
176 tsk->thread.error_code = error_code;
177 tsk->thread.trap_no = trapnr;
178 die(str, regs, error_code);
179 }
180 return;
181
182 #ifdef CONFIG_X86_32
183 vm86_trap:
184 if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
185 error_code, trapnr))
186 goto trap_signal;
187 return;
188 #endif
189 }
190
191 #define DO_ERROR(trapnr, signr, str, name) \
192 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
193 { \
194 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
195 == NOTIFY_STOP) \
196 return; \
197 conditional_sti(regs); \
198 do_trap(trapnr, signr, str, regs, error_code, NULL); \
199 }
200
201 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
202 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
203 { \
204 siginfo_t info; \
205 info.si_signo = signr; \
206 info.si_errno = 0; \
207 info.si_code = sicode; \
208 info.si_addr = (void __user *)siaddr; \
209 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
210 == NOTIFY_STOP) \
211 return; \
212 conditional_sti(regs); \
213 do_trap(trapnr, signr, str, regs, error_code, &info); \
214 }
215
216 DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
217 DO_ERROR(4, SIGSEGV, "overflow", overflow)
218 DO_ERROR(5, SIGSEGV, "bounds", bounds)
219 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)
220 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
221 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
222 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
223 #ifdef CONFIG_X86_32
224 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
225 #endif
226 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
227
228 #ifdef CONFIG_X86_64
229 /* Runs on IST stack */
230 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
231 {
232 if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
233 12, SIGBUS) == NOTIFY_STOP)
234 return;
235 preempt_conditional_sti(regs);
236 do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
237 preempt_conditional_cli(regs);
238 }
239
240 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
241 {
242 static const char str[] = "double fault";
243 struct task_struct *tsk = current;
244
245 /* Return not checked because double check cannot be ignored */
246 notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
247
248 tsk->thread.error_code = error_code;
249 tsk->thread.trap_no = 8;
250
251 /*
252 * This is always a kernel trap and never fixable (and thus must
253 * never return).
254 */
255 for (;;)
256 die(str, regs, error_code);
257 }
258 #endif
259
260 dotraplinkage void __kprobes
261 do_general_protection(struct pt_regs *regs, long error_code)
262 {
263 struct task_struct *tsk;
264
265 conditional_sti(regs);
266
267 #ifdef CONFIG_X86_32
268 if (regs->flags & X86_VM_MASK)
269 goto gp_in_vm86;
270 #endif
271
272 tsk = current;
273 if (!user_mode(regs))
274 goto gp_in_kernel;
275
276 tsk->thread.error_code = error_code;
277 tsk->thread.trap_no = 13;
278
279 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
280 printk_ratelimit()) {
281 printk(KERN_INFO
282 "%s[%d] general protection ip:%lx sp:%lx error:%lx",
283 tsk->comm, task_pid_nr(tsk),
284 regs->ip, regs->sp, error_code);
285 print_vma_addr(" in ", regs->ip);
286 printk("\n");
287 }
288
289 force_sig(SIGSEGV, tsk);
290 return;
291
292 #ifdef CONFIG_X86_32
293 gp_in_vm86:
294 local_irq_enable();
295 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
296 return;
297 #endif
298
299 gp_in_kernel:
300 if (fixup_exception(regs))
301 return;
302
303 tsk->thread.error_code = error_code;
304 tsk->thread.trap_no = 13;
305 if (notify_die(DIE_GPF, "general protection fault", regs,
306 error_code, 13, SIGSEGV) == NOTIFY_STOP)
307 return;
308 die("general protection fault", regs, error_code);
309 }
310
311 static notrace __kprobes void
312 mem_parity_error(unsigned char reason, struct pt_regs *regs)
313 {
314 printk(KERN_EMERG
315 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
316 reason, smp_processor_id());
317
318 printk(KERN_EMERG
319 "You have some hardware problem, likely on the PCI bus.\n");
320
321 #if defined(CONFIG_EDAC)
322 if (edac_handler_set()) {
323 edac_atomic_assert_error();
324 return;
325 }
326 #endif
327
328 if (panic_on_unrecovered_nmi)
329 panic("NMI: Not continuing");
330
331 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
332
333 /* Clear and disable the memory parity error line. */
334 reason = (reason & 0xf) | 4;
335 outb(reason, 0x61);
336 }
337
338 static notrace __kprobes void
339 io_check_error(unsigned char reason, struct pt_regs *regs)
340 {
341 unsigned long i;
342
343 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
344 show_registers(regs);
345
346 if (panic_on_io_nmi)
347 panic("NMI IOCK error: Not continuing");
348
349 /* Re-enable the IOCK line, wait for a few seconds */
350 reason = (reason & 0xf) | 8;
351 outb(reason, 0x61);
352
353 i = 2000;
354 while (--i)
355 udelay(1000);
356
357 reason &= ~8;
358 outb(reason, 0x61);
359 }
360
361 static notrace __kprobes void
362 unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
363 {
364 if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) ==
365 NOTIFY_STOP)
366 return;
367 #ifdef CONFIG_MCA
368 /*
369 * Might actually be able to figure out what the guilty party
370 * is:
371 */
372 if (MCA_bus) {
373 mca_handle_nmi();
374 return;
375 }
376 #endif
377 printk(KERN_EMERG
378 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
379 reason, smp_processor_id());
380
381 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
382 if (panic_on_unrecovered_nmi)
383 panic("NMI: Not continuing");
384
385 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
386 }
387
388 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
389 {
390 unsigned char reason = 0;
391 int cpu;
392
393 cpu = smp_processor_id();
394
395 /* Only the BSP gets external NMIs from the system. */
396 if (!cpu)
397 reason = get_nmi_reason();
398
399 if (!(reason & 0xc0)) {
400 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
401 == NOTIFY_STOP)
402 return;
403 #ifdef CONFIG_X86_LOCAL_APIC
404 /*
405 * Ok, so this is none of the documented NMI sources,
406 * so it must be the NMI watchdog.
407 */
408 if (nmi_watchdog_tick(regs, reason))
409 return;
410 if (!do_nmi_callback(regs, cpu))
411 unknown_nmi_error(reason, regs);
412 #else
413 unknown_nmi_error(reason, regs);
414 #endif
415
416 return;
417 }
418 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
419 return;
420
421 /* AK: following checks seem to be broken on modern chipsets. FIXME */
422 if (reason & 0x80)
423 mem_parity_error(reason, regs);
424 if (reason & 0x40)
425 io_check_error(reason, regs);
426 #ifdef CONFIG_X86_32
427 /*
428 * Reassert NMI in case it became active meanwhile
429 * as it's edge-triggered:
430 */
431 reassert_nmi();
432 #endif
433 }
434
435 dotraplinkage notrace __kprobes void
436 do_nmi(struct pt_regs *regs, long error_code)
437 {
438 nmi_enter();
439
440 inc_irq_stat(__nmi_count);
441
442 if (!ignore_nmis)
443 default_do_nmi(regs);
444
445 nmi_exit();
446 }
447
448 void stop_nmi(void)
449 {
450 acpi_nmi_disable();
451 ignore_nmis++;
452 }
453
454 void restart_nmi(void)
455 {
456 ignore_nmis--;
457 acpi_nmi_enable();
458 }
459
460 /* May run on IST stack. */
461 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
462 {
463 #ifdef CONFIG_KPROBES
464 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
465 == NOTIFY_STOP)
466 return;
467 #else
468 if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
469 == NOTIFY_STOP)
470 return;
471 #endif
472
473 preempt_conditional_sti(regs);
474 do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
475 preempt_conditional_cli(regs);
476 }
477
478 #ifdef CONFIG_X86_64
479 /*
480 * Help handler running on IST stack to switch back to user stack
481 * for scheduling or signal handling. The actual stack switch is done in
482 * entry.S
483 */
484 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
485 {
486 struct pt_regs *regs = eregs;
487 /* Did already sync */
488 if (eregs == (struct pt_regs *)eregs->sp)
489 ;
490 /* Exception from user space */
491 else if (user_mode(eregs))
492 regs = task_pt_regs(current);
493 /*
494 * Exception from kernel and interrupts are enabled. Move to
495 * kernel process stack.
496 */
497 else if (eregs->flags & X86_EFLAGS_IF)
498 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
499 if (eregs != regs)
500 *regs = *eregs;
501 return regs;
502 }
503 #endif
504
505 /*
506 * Our handling of the processor debug registers is non-trivial.
507 * We do not clear them on entry and exit from the kernel. Therefore
508 * it is possible to get a watchpoint trap here from inside the kernel.
509 * However, the code in ./ptrace.c has ensured that the user can
510 * only set watchpoints on userspace addresses. Therefore the in-kernel
511 * watchpoint trap can only occur in code which is reading/writing
512 * from user space. Such code must not hold kernel locks (since it
513 * can equally take a page fault), therefore it is safe to call
514 * force_sig_info even though that claims and releases locks.
515 *
516 * Code in ./signal.c ensures that the debug control register
517 * is restored before we deliver any signal, and therefore that
518 * user code runs with the correct debug control register even though
519 * we clear it here.
520 *
521 * Being careful here means that we don't have to be as careful in a
522 * lot of more complicated places (task switching can be a bit lazy
523 * about restoring all the debug state, and ptrace doesn't have to
524 * find every occurrence of the TF bit that could be saved away even
525 * by user code)
526 *
527 * May run on IST stack.
528 */
529 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
530 {
531 struct task_struct *tsk = current;
532 unsigned long dr6;
533 int si_code;
534
535 get_debugreg(dr6, 6);
536
537 /* Filter out all the reserved bits which are preset to 1 */
538 dr6 &= ~DR6_RESERVED;
539
540 /* Catch kmemcheck conditions first of all! */
541 if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
542 return;
543
544 /* DR6 may or may not be cleared by the CPU */
545 set_debugreg(0, 6);
546 /*
547 * The processor cleared BTF, so don't mark that we need it set.
548 */
549 clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
550 tsk->thread.debugctlmsr = 0;
551
552 /* Store the virtualized DR6 value */
553 tsk->thread.debugreg6 = dr6;
554
555 if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
556 SIGTRAP) == NOTIFY_STOP)
557 return;
558
559 /* It's safe to allow irq's after DR6 has been saved */
560 preempt_conditional_sti(regs);
561
562 if (regs->flags & X86_VM_MASK) {
563 handle_vm86_trap((struct kernel_vm86_regs *) regs,
564 error_code, 1);
565 return;
566 }
567
568 /*
569 * Single-stepping through system calls: ignore any exceptions in
570 * kernel space, but re-enable TF when returning to user mode.
571 *
572 * We already checked v86 mode above, so we can check for kernel mode
573 * by just checking the CPL of CS.
574 */
575 if ((dr6 & DR_STEP) && !user_mode(regs)) {
576 tsk->thread.debugreg6 &= ~DR_STEP;
577 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
578 regs->flags &= ~X86_EFLAGS_TF;
579 }
580 si_code = get_si_code(tsk->thread.debugreg6);
581 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS))
582 send_sigtrap(tsk, regs, error_code, si_code);
583 preempt_conditional_cli(regs);
584
585 return;
586 }
587
588 #ifdef CONFIG_X86_64
589 static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr)
590 {
591 if (fixup_exception(regs))
592 return 1;
593
594 notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE);
595 /* Illegal floating point operation in the kernel */
596 current->thread.trap_no = trapnr;
597 die(str, regs, 0);
598 return 0;
599 }
600 #endif
601
602 /*
603 * Note that we play around with the 'TS' bit in an attempt to get
604 * the correct behaviour even in the presence of the asynchronous
605 * IRQ13 behaviour
606 */
607 void math_error(void __user *ip)
608 {
609 struct task_struct *task;
610 siginfo_t info;
611 unsigned short cwd, swd, err;
612
613 /*
614 * Save the info for the exception handler and clear the error.
615 */
616 task = current;
617 save_init_fpu(task);
618 task->thread.trap_no = 16;
619 task->thread.error_code = 0;
620 info.si_signo = SIGFPE;
621 info.si_errno = 0;
622 info.si_addr = ip;
623 /*
624 * (~cwd & swd) will mask out exceptions that are not set to unmasked
625 * status. 0x3f is the exception bits in these regs, 0x200 is the
626 * C1 reg you need in case of a stack fault, 0x040 is the stack
627 * fault bit. We should only be taking one exception at a time,
628 * so if this combination doesn't produce any single exception,
629 * then we have a bad program that isn't synchronizing its FPU usage
630 * and it will suffer the consequences since we won't be able to
631 * fully reproduce the context of the exception
632 */
633 cwd = get_fpu_cwd(task);
634 swd = get_fpu_swd(task);
635
636 err = swd & ~cwd;
637
638 if (err & 0x001) { /* Invalid op */
639 /*
640 * swd & 0x240 == 0x040: Stack Underflow
641 * swd & 0x240 == 0x240: Stack Overflow
642 * User must clear the SF bit (0x40) if set
643 */
644 info.si_code = FPE_FLTINV;
645 } else if (err & 0x004) { /* Divide by Zero */
646 info.si_code = FPE_FLTDIV;
647 } else if (err & 0x008) { /* Overflow */
648 info.si_code = FPE_FLTOVF;
649 } else if (err & 0x012) { /* Denormal, Underflow */
650 info.si_code = FPE_FLTUND;
651 } else if (err & 0x020) { /* Precision */
652 info.si_code = FPE_FLTRES;
653 } else {
654 /*
655 * If we're using IRQ 13, or supposedly even some trap 16
656 * implementations, it's possible we get a spurious trap...
657 */
658 return; /* Spurious trap, no error */
659 }
660 force_sig_info(SIGFPE, &info, task);
661 }
662
663 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
664 {
665 conditional_sti(regs);
666
667 #ifdef CONFIG_X86_32
668 ignore_fpu_irq = 1;
669 #else
670 if (!user_mode(regs) &&
671 kernel_math_error(regs, "kernel x87 math error", 16))
672 return;
673 #endif
674
675 math_error((void __user *)regs->ip);
676 }
677
678 static void simd_math_error(void __user *ip)
679 {
680 struct task_struct *task;
681 siginfo_t info;
682 unsigned short mxcsr;
683
684 /*
685 * Save the info for the exception handler and clear the error.
686 */
687 task = current;
688 save_init_fpu(task);
689 task->thread.trap_no = 19;
690 task->thread.error_code = 0;
691 info.si_signo = SIGFPE;
692 info.si_errno = 0;
693 info.si_code = __SI_FAULT;
694 info.si_addr = ip;
695 /*
696 * The SIMD FPU exceptions are handled a little differently, as there
697 * is only a single status/control register. Thus, to determine which
698 * unmasked exception was caught we must mask the exception mask bits
699 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
700 */
701 mxcsr = get_fpu_mxcsr(task);
702 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
703 case 0x000:
704 default:
705 break;
706 case 0x001: /* Invalid Op */
707 info.si_code = FPE_FLTINV;
708 break;
709 case 0x002: /* Denormalize */
710 case 0x010: /* Underflow */
711 info.si_code = FPE_FLTUND;
712 break;
713 case 0x004: /* Zero Divide */
714 info.si_code = FPE_FLTDIV;
715 break;
716 case 0x008: /* Overflow */
717 info.si_code = FPE_FLTOVF;
718 break;
719 case 0x020: /* Precision */
720 info.si_code = FPE_FLTRES;
721 break;
722 }
723 force_sig_info(SIGFPE, &info, task);
724 }
725
726 dotraplinkage void
727 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
728 {
729 conditional_sti(regs);
730
731 #ifdef CONFIG_X86_32
732 if (cpu_has_xmm) {
733 /* Handle SIMD FPU exceptions on PIII+ processors. */
734 ignore_fpu_irq = 1;
735 simd_math_error((void __user *)regs->ip);
736 return;
737 }
738 /*
739 * Handle strange cache flush from user space exception
740 * in all other cases. This is undocumented behaviour.
741 */
742 if (regs->flags & X86_VM_MASK) {
743 handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code);
744 return;
745 }
746 current->thread.trap_no = 19;
747 current->thread.error_code = error_code;
748 die_if_kernel("cache flush denied", regs, error_code);
749 force_sig(SIGSEGV, current);
750 #else
751 if (!user_mode(regs) &&
752 kernel_math_error(regs, "kernel simd math error", 19))
753 return;
754 simd_math_error((void __user *)regs->ip);
755 #endif
756 }
757
758 dotraplinkage void
759 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
760 {
761 conditional_sti(regs);
762 #if 0
763 /* No need to warn about this any longer. */
764 printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
765 #endif
766 }
767
768 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
769 {
770 }
771
772 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
773 {
774 }
775
776 /*
777 * __math_state_restore assumes that cr0.TS is already clear and the
778 * fpu state is all ready for use. Used during context switch.
779 */
780 void __math_state_restore(void)
781 {
782 struct thread_info *thread = current_thread_info();
783 struct task_struct *tsk = thread->task;
784
785 /*
786 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
787 */
788 if (unlikely(restore_fpu_checking(tsk))) {
789 stts();
790 force_sig(SIGSEGV, tsk);
791 return;
792 }
793
794 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
795 tsk->fpu_counter++;
796 }
797
798 /*
799 * 'math_state_restore()' saves the current math information in the
800 * old math state array, and gets the new ones from the current task
801 *
802 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
803 * Don't touch unless you *really* know how it works.
804 *
805 * Must be called with kernel preemption disabled (in this case,
806 * local interrupts are disabled at the call-site in entry.S).
807 */
808 asmlinkage void math_state_restore(void)
809 {
810 struct thread_info *thread = current_thread_info();
811 struct task_struct *tsk = thread->task;
812
813 if (!tsk_used_math(tsk)) {
814 local_irq_enable();
815 /*
816 * does a slab alloc which can sleep
817 */
818 if (init_fpu(tsk)) {
819 /*
820 * ran out of memory!
821 */
822 do_group_exit(SIGKILL);
823 return;
824 }
825 local_irq_disable();
826 }
827
828 clts(); /* Allow maths ops (or we recurse) */
829
830 __math_state_restore();
831 }
832 EXPORT_SYMBOL_GPL(math_state_restore);
833
834 #ifndef CONFIG_MATH_EMULATION
835 void math_emulate(struct math_emu_info *info)
836 {
837 printk(KERN_EMERG
838 "math-emulation not enabled and no coprocessor found.\n");
839 printk(KERN_EMERG "killing %s.\n", current->comm);
840 force_sig(SIGFPE, current);
841 schedule();
842 }
843 #endif /* CONFIG_MATH_EMULATION */
844
845 dotraplinkage void __kprobes
846 do_device_not_available(struct pt_regs *regs, long error_code)
847 {
848 #ifdef CONFIG_X86_32
849 if (read_cr0() & X86_CR0_EM) {
850 struct math_emu_info info = { };
851
852 conditional_sti(regs);
853
854 info.regs = regs;
855 math_emulate(&info);
856 } else {
857 math_state_restore(); /* interrupts still off */
858 conditional_sti(regs);
859 }
860 #else
861 math_state_restore();
862 #endif
863 }
864
865 #ifdef CONFIG_X86_32
866 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
867 {
868 siginfo_t info;
869 local_irq_enable();
870
871 info.si_signo = SIGILL;
872 info.si_errno = 0;
873 info.si_code = ILL_BADSTK;
874 info.si_addr = NULL;
875 if (notify_die(DIE_TRAP, "iret exception",
876 regs, error_code, 32, SIGILL) == NOTIFY_STOP)
877 return;
878 do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
879 }
880 #endif
881
882 void __init trap_init(void)
883 {
884 int i;
885
886 #ifdef CONFIG_EISA
887 void __iomem *p = early_ioremap(0x0FFFD9, 4);
888
889 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
890 EISA_bus = 1;
891 early_iounmap(p, 4);
892 #endif
893
894 set_intr_gate(0, &divide_error);
895 set_intr_gate_ist(1, &debug, DEBUG_STACK);
896 set_intr_gate_ist(2, &nmi, NMI_STACK);
897 /* int3 can be called from all */
898 set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
899 /* int4 can be called from all */
900 set_system_intr_gate(4, &overflow);
901 set_intr_gate(5, &bounds);
902 set_intr_gate(6, &invalid_op);
903 set_intr_gate(7, &device_not_available);
904 #ifdef CONFIG_X86_32
905 set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
906 #else
907 set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
908 #endif
909 set_intr_gate(9, &coprocessor_segment_overrun);
910 set_intr_gate(10, &invalid_TSS);
911 set_intr_gate(11, &segment_not_present);
912 set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
913 set_intr_gate(13, &general_protection);
914 set_intr_gate(14, &page_fault);
915 set_intr_gate(15, &spurious_interrupt_bug);
916 set_intr_gate(16, &coprocessor_error);
917 set_intr_gate(17, &alignment_check);
918 #ifdef CONFIG_X86_MCE
919 set_intr_gate_ist(18, &machine_check, MCE_STACK);
920 #endif
921 set_intr_gate(19, &simd_coprocessor_error);
922
923 /* Reserve all the builtin and the syscall vector: */
924 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
925 set_bit(i, used_vectors);
926
927 #ifdef CONFIG_IA32_EMULATION
928 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
929 set_bit(IA32_SYSCALL_VECTOR, used_vectors);
930 #endif
931
932 #ifdef CONFIG_X86_32
933 if (cpu_has_fxsr) {
934 printk(KERN_INFO "Enabling fast FPU save and restore... ");
935 set_in_cr4(X86_CR4_OSFXSR);
936 printk("done.\n");
937 }
938 if (cpu_has_xmm) {
939 printk(KERN_INFO
940 "Enabling unmasked SIMD FPU exception support... ");
941 set_in_cr4(X86_CR4_OSXMMEXCPT);
942 printk("done.\n");
943 }
944
945 set_system_trap_gate(SYSCALL_VECTOR, &system_call);
946 set_bit(SYSCALL_VECTOR, used_vectors);
947 #endif
948
949 /*
950 * Should be a barrier for any external CPU state:
951 */
952 cpu_init();
953
954 x86_init.irqs.trap_init();
955 }