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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/kgdb.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/ptrace.h>
22#include <linux/string.h>
23#include <linux/delay.h>
24#include <linux/errno.h>
25#include <linux/kexec.h>
26#include <linux/sched.h>
27#include <linux/timer.h>
28#include <linux/init.h>
29#include <linux/bug.h>
30#include <linux/nmi.h>
31#include <linux/mm.h>
32#include <linux/smp.h>
33#include <linux/io.h>
34
35#ifdef CONFIG_EISA
36#include <linux/ioport.h>
37#include <linux/eisa.h>
38#endif
39
40#if defined(CONFIG_EDAC)
41#include <linux/edac.h>
42#endif
43
44#include <asm/kmemcheck.h>
45#include <asm/stacktrace.h>
46#include <asm/processor.h>
47#include <asm/debugreg.h>
48#include <linux/atomic.h>
49#include <asm/ftrace.h>
50#include <asm/traps.h>
51#include <asm/desc.h>
52#include <asm/i387.h>
53#include <asm/fpu-internal.h>
54#include <asm/mce.h>
55
56#include <asm/mach_traps.h>
57
58#ifdef CONFIG_X86_64
59#include <asm/x86_init.h>
60#include <asm/pgalloc.h>
61#include <asm/proto.h>
62#else
63#include <asm/processor-flags.h>
64#include <asm/setup.h>
65
66asmlinkage int system_call(void);
67
68/* Do we ignore FPU interrupts ? */
69char ignore_fpu_irq;
70
71/*
72 * The IDT has to be page-aligned to simplify the Pentium
73 * F0 0F bug workaround.
74 */
75gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
76#endif
77
78DECLARE_BITMAP(used_vectors, NR_VECTORS);
79EXPORT_SYMBOL_GPL(used_vectors);
80
81static inline void conditional_sti(struct pt_regs *regs)
82{
83 if (regs->flags & X86_EFLAGS_IF)
84 local_irq_enable();
85}
86
87static inline void preempt_conditional_sti(struct pt_regs *regs)
88{
89 inc_preempt_count();
90 if (regs->flags & X86_EFLAGS_IF)
91 local_irq_enable();
92}
93
94static inline void conditional_cli(struct pt_regs *regs)
95{
96 if (regs->flags & X86_EFLAGS_IF)
97 local_irq_disable();
98}
99
100static inline void preempt_conditional_cli(struct pt_regs *regs)
101{
102 if (regs->flags & X86_EFLAGS_IF)
103 local_irq_disable();
104 dec_preempt_count();
105}
106
107static void __kprobes
108do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
109 long error_code, siginfo_t *info)
110{
111 struct task_struct *tsk = current;
112
113#ifdef CONFIG_X86_32
114 if (regs->flags & X86_VM_MASK) {
115 /*
116 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
117 * On nmi (interrupt 2), do_trap should not be called.
118 */
119 if (trapnr < X86_TRAP_UD)
120 goto vm86_trap;
121 goto trap_signal;
122 }
123#endif
124
125 if (!user_mode(regs))
126 goto kernel_trap;
127
128#ifdef CONFIG_X86_32
129trap_signal:
130#endif
131 /*
132 * We want error_code and trap_nr set for userspace faults and
133 * kernelspace faults which result in die(), but not
134 * kernelspace faults which are fixed up. die() gives the
135 * process no chance to handle the signal and notice the
136 * kernel fault information, so that won't result in polluting
137 * the information about previously queued, but not yet
138 * delivered, faults. See also do_general_protection below.
139 */
140 tsk->thread.error_code = error_code;
141 tsk->thread.trap_nr = trapnr;
142
143#ifdef CONFIG_X86_64
144 if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
145 printk_ratelimit()) {
146 printk(KERN_INFO
147 "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
148 tsk->comm, tsk->pid, str,
149 regs->ip, regs->sp, error_code);
150 print_vma_addr(" in ", regs->ip);
151 printk("\n");
152 }
153#endif
154
155 if (info)
156 force_sig_info(signr, info, tsk);
157 else
158 force_sig(signr, tsk);
159 return;
160
161kernel_trap:
162 if (!fixup_exception(regs)) {
163 tsk->thread.error_code = error_code;
164 tsk->thread.trap_nr = trapnr;
165 die(str, regs, error_code);
166 }
167 return;
168
169#ifdef CONFIG_X86_32
170vm86_trap:
171 if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
172 error_code, trapnr))
173 goto trap_signal;
174 return;
175#endif
176}
177
178#define DO_ERROR(trapnr, signr, str, name) \
179dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
180{ \
181 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
182 == NOTIFY_STOP) \
183 return; \
184 conditional_sti(regs); \
185 do_trap(trapnr, signr, str, regs, error_code, NULL); \
186}
187
188#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
189dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
190{ \
191 siginfo_t info; \
192 info.si_signo = signr; \
193 info.si_errno = 0; \
194 info.si_code = sicode; \
195 info.si_addr = (void __user *)siaddr; \
196 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
197 == NOTIFY_STOP) \
198 return; \
199 conditional_sti(regs); \
200 do_trap(trapnr, signr, str, regs, error_code, &info); \
201}
202
203DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
204 regs->ip)
205DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
206DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds)
207DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN,
208 regs->ip)
209DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",
210 coprocessor_segment_overrun)
211DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
212DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
213#ifdef CONFIG_X86_32
214DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
215#endif
216DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check,
217 BUS_ADRALN, 0)
218
219#ifdef CONFIG_X86_64
220/* Runs on IST stack */
221dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
222{
223 if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
224 X86_TRAP_SS, SIGBUS) == NOTIFY_STOP)
225 return;
226 preempt_conditional_sti(regs);
227 do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
228 preempt_conditional_cli(regs);
229}
230
231dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
232{
233 static const char str[] = "double fault";
234 struct task_struct *tsk = current;
235
236 /* Return not checked because double check cannot be ignored */
237 notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
238
239 tsk->thread.error_code = error_code;
240 tsk->thread.trap_nr = X86_TRAP_DF;
241
242 /*
243 * This is always a kernel trap and never fixable (and thus must
244 * never return).
245 */
246 for (;;)
247 die(str, regs, error_code);
248}
249#endif
250
251dotraplinkage void __kprobes
252do_general_protection(struct pt_regs *regs, long error_code)
253{
254 struct task_struct *tsk;
255
256 conditional_sti(regs);
257
258#ifdef CONFIG_X86_32
259 if (regs->flags & X86_VM_MASK)
260 goto gp_in_vm86;
261#endif
262
263 tsk = current;
264 if (!user_mode(regs))
265 goto gp_in_kernel;
266
267 tsk->thread.error_code = error_code;
268 tsk->thread.trap_nr = X86_TRAP_GP;
269
270 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
271 printk_ratelimit()) {
272 printk(KERN_INFO
273 "%s[%d] general protection ip:%lx sp:%lx error:%lx",
274 tsk->comm, task_pid_nr(tsk),
275 regs->ip, regs->sp, error_code);
276 print_vma_addr(" in ", regs->ip);
277 printk("\n");
278 }
279
280 force_sig(SIGSEGV, tsk);
281 return;
282
283#ifdef CONFIG_X86_32
284gp_in_vm86:
285 local_irq_enable();
286 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
287 return;
288#endif
289
290gp_in_kernel:
291 if (fixup_exception(regs))
292 return;
293
294 tsk->thread.error_code = error_code;
295 tsk->thread.trap_nr = X86_TRAP_GP;
296 if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
297 X86_TRAP_GP, SIGSEGV) == NOTIFY_STOP)
298 return;
299 die("general protection fault", regs, error_code);
300}
301
302/* May run on IST stack. */
303dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
304{
305#ifdef CONFIG_DYNAMIC_FTRACE
306 /*
307 * ftrace must be first, everything else may cause a recursive crash.
308 * See note by declaration of modifying_ftrace_code in ftrace.c
309 */
310 if (unlikely(atomic_read(&modifying_ftrace_code)) &&
311 ftrace_int3_handler(regs))
312 return;
313#endif
314#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
315 if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
316 SIGTRAP) == NOTIFY_STOP)
317 return;
318#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
319
320 if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
321 SIGTRAP) == NOTIFY_STOP)
322 return;
323
324 /*
325 * Let others (NMI) know that the debug stack is in use
326 * as we may switch to the interrupt stack.
327 */
328 debug_stack_usage_inc();
329 preempt_conditional_sti(regs);
330 do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
331 preempt_conditional_cli(regs);
332 debug_stack_usage_dec();
333}
334
335#ifdef CONFIG_X86_64
336/*
337 * Help handler running on IST stack to switch back to user stack
338 * for scheduling or signal handling. The actual stack switch is done in
339 * entry.S
340 */
341asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
342{
343 struct pt_regs *regs = eregs;
344 /* Did already sync */
345 if (eregs == (struct pt_regs *)eregs->sp)
346 ;
347 /* Exception from user space */
348 else if (user_mode(eregs))
349 regs = task_pt_regs(current);
350 /*
351 * Exception from kernel and interrupts are enabled. Move to
352 * kernel process stack.
353 */
354 else if (eregs->flags & X86_EFLAGS_IF)
355 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
356 if (eregs != regs)
357 *regs = *eregs;
358 return regs;
359}
360#endif
361
362/*
363 * Our handling of the processor debug registers is non-trivial.
364 * We do not clear them on entry and exit from the kernel. Therefore
365 * it is possible to get a watchpoint trap here from inside the kernel.
366 * However, the code in ./ptrace.c has ensured that the user can
367 * only set watchpoints on userspace addresses. Therefore the in-kernel
368 * watchpoint trap can only occur in code which is reading/writing
369 * from user space. Such code must not hold kernel locks (since it
370 * can equally take a page fault), therefore it is safe to call
371 * force_sig_info even though that claims and releases locks.
372 *
373 * Code in ./signal.c ensures that the debug control register
374 * is restored before we deliver any signal, and therefore that
375 * user code runs with the correct debug control register even though
376 * we clear it here.
377 *
378 * Being careful here means that we don't have to be as careful in a
379 * lot of more complicated places (task switching can be a bit lazy
380 * about restoring all the debug state, and ptrace doesn't have to
381 * find every occurrence of the TF bit that could be saved away even
382 * by user code)
383 *
384 * May run on IST stack.
385 */
386dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
387{
388 struct task_struct *tsk = current;
389 int user_icebp = 0;
390 unsigned long dr6;
391 int si_code;
392
393 get_debugreg(dr6, 6);
394
395 /* Filter out all the reserved bits which are preset to 1 */
396 dr6 &= ~DR6_RESERVED;
397
398 /*
399 * If dr6 has no reason to give us about the origin of this trap,
400 * then it's very likely the result of an icebp/int01 trap.
401 * User wants a sigtrap for that.
402 */
403 if (!dr6 && user_mode(regs))
404 user_icebp = 1;
405
406 /* Catch kmemcheck conditions first of all! */
407 if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
408 return;
409
410 /* DR6 may or may not be cleared by the CPU */
411 set_debugreg(0, 6);
412
413 /*
414 * The processor cleared BTF, so don't mark that we need it set.
415 */
416 clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
417
418 /* Store the virtualized DR6 value */
419 tsk->thread.debugreg6 = dr6;
420
421 if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
422 SIGTRAP) == NOTIFY_STOP)
423 return;
424
425 /*
426 * Let others (NMI) know that the debug stack is in use
427 * as we may switch to the interrupt stack.
428 */
429 debug_stack_usage_inc();
430
431 /* It's safe to allow irq's after DR6 has been saved */
432 preempt_conditional_sti(regs);
433
434 if (regs->flags & X86_VM_MASK) {
435 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
436 X86_TRAP_DB);
437 preempt_conditional_cli(regs);
438 debug_stack_usage_dec();
439 return;
440 }
441
442 /*
443 * Single-stepping through system calls: ignore any exceptions in
444 * kernel space, but re-enable TF when returning to user mode.
445 *
446 * We already checked v86 mode above, so we can check for kernel mode
447 * by just checking the CPL of CS.
448 */
449 if ((dr6 & DR_STEP) && !user_mode(regs)) {
450 tsk->thread.debugreg6 &= ~DR_STEP;
451 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
452 regs->flags &= ~X86_EFLAGS_TF;
453 }
454 si_code = get_si_code(tsk->thread.debugreg6);
455 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
456 send_sigtrap(tsk, regs, error_code, si_code);
457 preempt_conditional_cli(regs);
458 debug_stack_usage_dec();
459
460 return;
461}
462
463/*
464 * Note that we play around with the 'TS' bit in an attempt to get
465 * the correct behaviour even in the presence of the asynchronous
466 * IRQ13 behaviour
467 */
468void math_error(struct pt_regs *regs, int error_code, int trapnr)
469{
470 struct task_struct *task = current;
471 siginfo_t info;
472 unsigned short err;
473 char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
474 "simd exception";
475
476 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
477 return;
478 conditional_sti(regs);
479
480 if (!user_mode_vm(regs))
481 {
482 if (!fixup_exception(regs)) {
483 task->thread.error_code = error_code;
484 task->thread.trap_nr = trapnr;
485 die(str, regs, error_code);
486 }
487 return;
488 }
489
490 /*
491 * Save the info for the exception handler and clear the error.
492 */
493 save_init_fpu(task);
494 task->thread.trap_nr = trapnr;
495 task->thread.error_code = error_code;
496 info.si_signo = SIGFPE;
497 info.si_errno = 0;
498 info.si_addr = (void __user *)regs->ip;
499 if (trapnr == X86_TRAP_MF) {
500 unsigned short cwd, swd;
501 /*
502 * (~cwd & swd) will mask out exceptions that are not set to unmasked
503 * status. 0x3f is the exception bits in these regs, 0x200 is the
504 * C1 reg you need in case of a stack fault, 0x040 is the stack
505 * fault bit. We should only be taking one exception at a time,
506 * so if this combination doesn't produce any single exception,
507 * then we have a bad program that isn't synchronizing its FPU usage
508 * and it will suffer the consequences since we won't be able to
509 * fully reproduce the context of the exception
510 */
511 cwd = get_fpu_cwd(task);
512 swd = get_fpu_swd(task);
513
514 err = swd & ~cwd;
515 } else {
516 /*
517 * The SIMD FPU exceptions are handled a little differently, as there
518 * is only a single status/control register. Thus, to determine which
519 * unmasked exception was caught we must mask the exception mask bits
520 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
521 */
522 unsigned short mxcsr = get_fpu_mxcsr(task);
523 err = ~(mxcsr >> 7) & mxcsr;
524 }
525
526 if (err & 0x001) { /* Invalid op */
527 /*
528 * swd & 0x240 == 0x040: Stack Underflow
529 * swd & 0x240 == 0x240: Stack Overflow
530 * User must clear the SF bit (0x40) if set
531 */
532 info.si_code = FPE_FLTINV;
533 } else if (err & 0x004) { /* Divide by Zero */
534 info.si_code = FPE_FLTDIV;
535 } else if (err & 0x008) { /* Overflow */
536 info.si_code = FPE_FLTOVF;
537 } else if (err & 0x012) { /* Denormal, Underflow */
538 info.si_code = FPE_FLTUND;
539 } else if (err & 0x020) { /* Precision */
540 info.si_code = FPE_FLTRES;
541 } else {
542 /*
543 * If we're using IRQ 13, or supposedly even some trap
544 * X86_TRAP_MF implementations, it's possible
545 * we get a spurious trap, which is not an error.
546 */
547 return;
548 }
549 force_sig_info(SIGFPE, &info, task);
550}
551
552dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
553{
554#ifdef CONFIG_X86_32
555 ignore_fpu_irq = 1;
556#endif
557
558 math_error(regs, error_code, X86_TRAP_MF);
559}
560
561dotraplinkage void
562do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
563{
564 math_error(regs, error_code, X86_TRAP_XF);
565}
566
567dotraplinkage void
568do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
569{
570 conditional_sti(regs);
571#if 0
572 /* No need to warn about this any longer. */
573 printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
574#endif
575}
576
577asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
578{
579}
580
581asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
582{
583}
584
585/*
586 * 'math_state_restore()' saves the current math information in the
587 * old math state array, and gets the new ones from the current task
588 *
589 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
590 * Don't touch unless you *really* know how it works.
591 *
592 * Must be called with kernel preemption disabled (eg with local
593 * local interrupts as in the case of do_device_not_available).
594 */
595void math_state_restore(void)
596{
597 struct task_struct *tsk = current;
598
599 if (!tsk_used_math(tsk)) {
600 local_irq_enable();
601 /*
602 * does a slab alloc which can sleep
603 */
604 if (init_fpu(tsk)) {
605 /*
606 * ran out of memory!
607 */
608 do_group_exit(SIGKILL);
609 return;
610 }
611 local_irq_disable();
612 }
613
614 __thread_fpu_begin(tsk);
615 /*
616 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
617 */
618 if (unlikely(restore_fpu_checking(tsk))) {
619 __thread_fpu_end(tsk);
620 force_sig(SIGSEGV, tsk);
621 return;
622 }
623
624 tsk->fpu_counter++;
625}
626EXPORT_SYMBOL_GPL(math_state_restore);
627
628dotraplinkage void __kprobes
629do_device_not_available(struct pt_regs *regs, long error_code)
630{
631#ifdef CONFIG_MATH_EMULATION
632 if (read_cr0() & X86_CR0_EM) {
633 struct math_emu_info info = { };
634
635 conditional_sti(regs);
636
637 info.regs = regs;
638 math_emulate(&info);
639 return;
640 }
641#endif
642 math_state_restore(); /* interrupts still off */
643#ifdef CONFIG_X86_32
644 conditional_sti(regs);
645#endif
646}
647
648#ifdef CONFIG_X86_32
649dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
650{
651 siginfo_t info;
652 local_irq_enable();
653
654 info.si_signo = SIGILL;
655 info.si_errno = 0;
656 info.si_code = ILL_BADSTK;
657 info.si_addr = NULL;
658 if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
659 X86_TRAP_IRET, SIGILL) == NOTIFY_STOP)
660 return;
661 do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
662 &info);
663}
664#endif
665
666/* Set of traps needed for early debugging. */
667void __init early_trap_init(void)
668{
669 set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
670 /* int3 can be called from all */
671 set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
672 set_intr_gate(X86_TRAP_PF, &page_fault);
673 load_idt(&idt_descr);
674}
675
676void __init trap_init(void)
677{
678 int i;
679
680#ifdef CONFIG_EISA
681 void __iomem *p = early_ioremap(0x0FFFD9, 4);
682
683 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
684 EISA_bus = 1;
685 early_iounmap(p, 4);
686#endif
687
688 set_intr_gate(X86_TRAP_DE, ÷_error);
689 set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
690 /* int4 can be called from all */
691 set_system_intr_gate(X86_TRAP_OF, &overflow);
692 set_intr_gate(X86_TRAP_BR, &bounds);
693 set_intr_gate(X86_TRAP_UD, &invalid_op);
694 set_intr_gate(X86_TRAP_NM, &device_not_available);
695#ifdef CONFIG_X86_32
696 set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
697#else
698 set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
699#endif
700 set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
701 set_intr_gate(X86_TRAP_TS, &invalid_TSS);
702 set_intr_gate(X86_TRAP_NP, &segment_not_present);
703 set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
704 set_intr_gate(X86_TRAP_GP, &general_protection);
705 set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
706 set_intr_gate(X86_TRAP_MF, &coprocessor_error);
707 set_intr_gate(X86_TRAP_AC, &alignment_check);
708#ifdef CONFIG_X86_MCE
709 set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
710#endif
711 set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
712
713 /* Reserve all the builtin and the syscall vector: */
714 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
715 set_bit(i, used_vectors);
716
717#ifdef CONFIG_IA32_EMULATION
718 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
719 set_bit(IA32_SYSCALL_VECTOR, used_vectors);
720#endif
721
722#ifdef CONFIG_X86_32
723 set_system_trap_gate(SYSCALL_VECTOR, &system_call);
724 set_bit(SYSCALL_VECTOR, used_vectors);
725#endif
726
727 /*
728 * Should be a barrier for any external CPU state:
729 */
730 cpu_init();
731
732 x86_init.irqs.trap_init();
733
734#ifdef CONFIG_X86_64
735 memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
736 set_nmi_gate(X86_TRAP_DB, &debug);
737 set_nmi_gate(X86_TRAP_BP, &int3);
738#endif
739}
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/string.h>
27#include <linux/delay.h>
28#include <linux/errno.h>
29#include <linux/kexec.h>
30#include <linux/sched.h>
31#include <linux/timer.h>
32#include <linux/init.h>
33#include <linux/bug.h>
34#include <linux/nmi.h>
35#include <linux/mm.h>
36#include <linux/smp.h>
37#include <linux/io.h>
38
39#ifdef CONFIG_EISA
40#include <linux/ioport.h>
41#include <linux/eisa.h>
42#endif
43
44#if defined(CONFIG_EDAC)
45#include <linux/edac.h>
46#endif
47
48#include <asm/kmemcheck.h>
49#include <asm/stacktrace.h>
50#include <asm/processor.h>
51#include <asm/debugreg.h>
52#include <linux/atomic.h>
53#include <asm/ftrace.h>
54#include <asm/traps.h>
55#include <asm/desc.h>
56#include <asm/i387.h>
57#include <asm/fpu-internal.h>
58#include <asm/mce.h>
59#include <asm/fixmap.h>
60#include <asm/mach_traps.h>
61#include <asm/alternative.h>
62
63#ifdef CONFIG_X86_64
64#include <asm/x86_init.h>
65#include <asm/pgalloc.h>
66#include <asm/proto.h>
67
68/* No need to be aligned, but done to keep all IDTs defined the same way. */
69gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
70#else
71#include <asm/processor-flags.h>
72#include <asm/setup.h>
73
74asmlinkage int system_call(void);
75#endif
76
77/* Must be page-aligned because the real IDT is used in a fixmap. */
78gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
79
80DECLARE_BITMAP(used_vectors, NR_VECTORS);
81EXPORT_SYMBOL_GPL(used_vectors);
82
83static inline void conditional_sti(struct pt_regs *regs)
84{
85 if (regs->flags & X86_EFLAGS_IF)
86 local_irq_enable();
87}
88
89static inline void preempt_conditional_sti(struct pt_regs *regs)
90{
91 preempt_count_inc();
92 if (regs->flags & X86_EFLAGS_IF)
93 local_irq_enable();
94}
95
96static inline void conditional_cli(struct pt_regs *regs)
97{
98 if (regs->flags & X86_EFLAGS_IF)
99 local_irq_disable();
100}
101
102static inline void preempt_conditional_cli(struct pt_regs *regs)
103{
104 if (regs->flags & X86_EFLAGS_IF)
105 local_irq_disable();
106 preempt_count_dec();
107}
108
109static int __kprobes
110do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
111 struct pt_regs *regs, long error_code)
112{
113#ifdef CONFIG_X86_32
114 if (regs->flags & X86_VM_MASK) {
115 /*
116 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
117 * On nmi (interrupt 2), do_trap should not be called.
118 */
119 if (trapnr < X86_TRAP_UD) {
120 if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
121 error_code, trapnr))
122 return 0;
123 }
124 return -1;
125 }
126#endif
127 if (!user_mode(regs)) {
128 if (!fixup_exception(regs)) {
129 tsk->thread.error_code = error_code;
130 tsk->thread.trap_nr = trapnr;
131 die(str, regs, error_code);
132 }
133 return 0;
134 }
135
136 return -1;
137}
138
139static void __kprobes
140do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
141 long error_code, siginfo_t *info)
142{
143 struct task_struct *tsk = current;
144
145
146 if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
147 return;
148 /*
149 * We want error_code and trap_nr set for userspace faults and
150 * kernelspace faults which result in die(), but not
151 * kernelspace faults which are fixed up. die() gives the
152 * process no chance to handle the signal and notice the
153 * kernel fault information, so that won't result in polluting
154 * the information about previously queued, but not yet
155 * delivered, faults. See also do_general_protection below.
156 */
157 tsk->thread.error_code = error_code;
158 tsk->thread.trap_nr = trapnr;
159
160#ifdef CONFIG_X86_64
161 if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
162 printk_ratelimit()) {
163 pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
164 tsk->comm, tsk->pid, str,
165 regs->ip, regs->sp, error_code);
166 print_vma_addr(" in ", regs->ip);
167 pr_cont("\n");
168 }
169#endif
170
171 if (info)
172 force_sig_info(signr, info, tsk);
173 else
174 force_sig(signr, tsk);
175}
176
177#define DO_ERROR(trapnr, signr, str, name) \
178dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
179{ \
180 enum ctx_state prev_state; \
181 \
182 prev_state = exception_enter(); \
183 if (notify_die(DIE_TRAP, str, regs, error_code, \
184 trapnr, signr) == NOTIFY_STOP) { \
185 exception_exit(prev_state); \
186 return; \
187 } \
188 conditional_sti(regs); \
189 do_trap(trapnr, signr, str, regs, error_code, NULL); \
190 exception_exit(prev_state); \
191}
192
193#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
194dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
195{ \
196 siginfo_t info; \
197 enum ctx_state prev_state; \
198 \
199 info.si_signo = signr; \
200 info.si_errno = 0; \
201 info.si_code = sicode; \
202 info.si_addr = (void __user *)siaddr; \
203 prev_state = exception_enter(); \
204 if (notify_die(DIE_TRAP, str, regs, error_code, \
205 trapnr, signr) == NOTIFY_STOP) { \
206 exception_exit(prev_state); \
207 return; \
208 } \
209 conditional_sti(regs); \
210 do_trap(trapnr, signr, str, regs, error_code, &info); \
211 exception_exit(prev_state); \
212}
213
214DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip )
215DO_ERROR (X86_TRAP_OF, SIGSEGV, "overflow", overflow )
216DO_ERROR (X86_TRAP_BR, SIGSEGV, "bounds", bounds )
217DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip )
218DO_ERROR (X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun )
219DO_ERROR (X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS )
220DO_ERROR (X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present )
221#ifdef CONFIG_X86_32
222DO_ERROR (X86_TRAP_SS, SIGBUS, "stack segment", stack_segment )
223#endif
224DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0 )
225
226#ifdef CONFIG_X86_64
227/* Runs on IST stack */
228dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
229{
230 enum ctx_state prev_state;
231
232 prev_state = exception_enter();
233 if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
234 X86_TRAP_SS, SIGBUS) != NOTIFY_STOP) {
235 preempt_conditional_sti(regs);
236 do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
237 preempt_conditional_cli(regs);
238 }
239 exception_exit(prev_state);
240}
241
242dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
243{
244 static const char str[] = "double fault";
245 struct task_struct *tsk = current;
246
247 exception_enter();
248 /* Return not checked because double check cannot be ignored */
249 notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
250
251 tsk->thread.error_code = error_code;
252 tsk->thread.trap_nr = X86_TRAP_DF;
253
254#ifdef CONFIG_DOUBLEFAULT
255 df_debug(regs, error_code);
256#endif
257 /*
258 * This is always a kernel trap and never fixable (and thus must
259 * never return).
260 */
261 for (;;)
262 die(str, regs, error_code);
263}
264#endif
265
266dotraplinkage void __kprobes
267do_general_protection(struct pt_regs *regs, long error_code)
268{
269 struct task_struct *tsk;
270 enum ctx_state prev_state;
271
272 prev_state = exception_enter();
273 conditional_sti(regs);
274
275#ifdef CONFIG_X86_32
276 if (regs->flags & X86_VM_MASK) {
277 local_irq_enable();
278 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
279 goto exit;
280 }
281#endif
282
283 tsk = current;
284 if (!user_mode(regs)) {
285 if (fixup_exception(regs))
286 goto exit;
287
288 tsk->thread.error_code = error_code;
289 tsk->thread.trap_nr = X86_TRAP_GP;
290 if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
291 X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
292 die("general protection fault", regs, error_code);
293 goto exit;
294 }
295
296 tsk->thread.error_code = error_code;
297 tsk->thread.trap_nr = X86_TRAP_GP;
298
299 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
300 printk_ratelimit()) {
301 pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
302 tsk->comm, task_pid_nr(tsk),
303 regs->ip, regs->sp, error_code);
304 print_vma_addr(" in ", regs->ip);
305 pr_cont("\n");
306 }
307
308 force_sig(SIGSEGV, tsk);
309exit:
310 exception_exit(prev_state);
311}
312
313/* May run on IST stack. */
314dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
315{
316 enum ctx_state prev_state;
317
318#ifdef CONFIG_DYNAMIC_FTRACE
319 /*
320 * ftrace must be first, everything else may cause a recursive crash.
321 * See note by declaration of modifying_ftrace_code in ftrace.c
322 */
323 if (unlikely(atomic_read(&modifying_ftrace_code)) &&
324 ftrace_int3_handler(regs))
325 return;
326#endif
327 if (poke_int3_handler(regs))
328 return;
329
330 prev_state = exception_enter();
331#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
332 if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
333 SIGTRAP) == NOTIFY_STOP)
334 goto exit;
335#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
336
337 if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
338 SIGTRAP) == NOTIFY_STOP)
339 goto exit;
340
341 /*
342 * Let others (NMI) know that the debug stack is in use
343 * as we may switch to the interrupt stack.
344 */
345 debug_stack_usage_inc();
346 preempt_conditional_sti(regs);
347 do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
348 preempt_conditional_cli(regs);
349 debug_stack_usage_dec();
350exit:
351 exception_exit(prev_state);
352}
353
354#ifdef CONFIG_X86_64
355/*
356 * Help handler running on IST stack to switch back to user stack
357 * for scheduling or signal handling. The actual stack switch is done in
358 * entry.S
359 */
360asmlinkage __visible __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
361{
362 struct pt_regs *regs = eregs;
363 /* Did already sync */
364 if (eregs == (struct pt_regs *)eregs->sp)
365 ;
366 /* Exception from user space */
367 else if (user_mode(eregs))
368 regs = task_pt_regs(current);
369 /*
370 * Exception from kernel and interrupts are enabled. Move to
371 * kernel process stack.
372 */
373 else if (eregs->flags & X86_EFLAGS_IF)
374 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
375 if (eregs != regs)
376 *regs = *eregs;
377 return regs;
378}
379#endif
380
381/*
382 * Our handling of the processor debug registers is non-trivial.
383 * We do not clear them on entry and exit from the kernel. Therefore
384 * it is possible to get a watchpoint trap here from inside the kernel.
385 * However, the code in ./ptrace.c has ensured that the user can
386 * only set watchpoints on userspace addresses. Therefore the in-kernel
387 * watchpoint trap can only occur in code which is reading/writing
388 * from user space. Such code must not hold kernel locks (since it
389 * can equally take a page fault), therefore it is safe to call
390 * force_sig_info even though that claims and releases locks.
391 *
392 * Code in ./signal.c ensures that the debug control register
393 * is restored before we deliver any signal, and therefore that
394 * user code runs with the correct debug control register even though
395 * we clear it here.
396 *
397 * Being careful here means that we don't have to be as careful in a
398 * lot of more complicated places (task switching can be a bit lazy
399 * about restoring all the debug state, and ptrace doesn't have to
400 * find every occurrence of the TF bit that could be saved away even
401 * by user code)
402 *
403 * May run on IST stack.
404 */
405dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
406{
407 struct task_struct *tsk = current;
408 enum ctx_state prev_state;
409 int user_icebp = 0;
410 unsigned long dr6;
411 int si_code;
412
413 prev_state = exception_enter();
414
415 get_debugreg(dr6, 6);
416
417 /* Filter out all the reserved bits which are preset to 1 */
418 dr6 &= ~DR6_RESERVED;
419
420 /*
421 * If dr6 has no reason to give us about the origin of this trap,
422 * then it's very likely the result of an icebp/int01 trap.
423 * User wants a sigtrap for that.
424 */
425 if (!dr6 && user_mode(regs))
426 user_icebp = 1;
427
428 /* Catch kmemcheck conditions first of all! */
429 if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
430 goto exit;
431
432 /* DR6 may or may not be cleared by the CPU */
433 set_debugreg(0, 6);
434
435 /*
436 * The processor cleared BTF, so don't mark that we need it set.
437 */
438 clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
439
440 /* Store the virtualized DR6 value */
441 tsk->thread.debugreg6 = dr6;
442
443 if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
444 SIGTRAP) == NOTIFY_STOP)
445 goto exit;
446
447 /*
448 * Let others (NMI) know that the debug stack is in use
449 * as we may switch to the interrupt stack.
450 */
451 debug_stack_usage_inc();
452
453 /* It's safe to allow irq's after DR6 has been saved */
454 preempt_conditional_sti(regs);
455
456 if (regs->flags & X86_VM_MASK) {
457 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
458 X86_TRAP_DB);
459 preempt_conditional_cli(regs);
460 debug_stack_usage_dec();
461 goto exit;
462 }
463
464 /*
465 * Single-stepping through system calls: ignore any exceptions in
466 * kernel space, but re-enable TF when returning to user mode.
467 *
468 * We already checked v86 mode above, so we can check for kernel mode
469 * by just checking the CPL of CS.
470 */
471 if ((dr6 & DR_STEP) && !user_mode(regs)) {
472 tsk->thread.debugreg6 &= ~DR_STEP;
473 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
474 regs->flags &= ~X86_EFLAGS_TF;
475 }
476 si_code = get_si_code(tsk->thread.debugreg6);
477 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
478 send_sigtrap(tsk, regs, error_code, si_code);
479 preempt_conditional_cli(regs);
480 debug_stack_usage_dec();
481
482exit:
483 exception_exit(prev_state);
484}
485
486/*
487 * Note that we play around with the 'TS' bit in an attempt to get
488 * the correct behaviour even in the presence of the asynchronous
489 * IRQ13 behaviour
490 */
491void math_error(struct pt_regs *regs, int error_code, int trapnr)
492{
493 struct task_struct *task = current;
494 siginfo_t info;
495 unsigned short err;
496 char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
497 "simd exception";
498
499 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
500 return;
501 conditional_sti(regs);
502
503 if (!user_mode_vm(regs))
504 {
505 if (!fixup_exception(regs)) {
506 task->thread.error_code = error_code;
507 task->thread.trap_nr = trapnr;
508 die(str, regs, error_code);
509 }
510 return;
511 }
512
513 /*
514 * Save the info for the exception handler and clear the error.
515 */
516 save_init_fpu(task);
517 task->thread.trap_nr = trapnr;
518 task->thread.error_code = error_code;
519 info.si_signo = SIGFPE;
520 info.si_errno = 0;
521 info.si_addr = (void __user *)regs->ip;
522 if (trapnr == X86_TRAP_MF) {
523 unsigned short cwd, swd;
524 /*
525 * (~cwd & swd) will mask out exceptions that are not set to unmasked
526 * status. 0x3f is the exception bits in these regs, 0x200 is the
527 * C1 reg you need in case of a stack fault, 0x040 is the stack
528 * fault bit. We should only be taking one exception at a time,
529 * so if this combination doesn't produce any single exception,
530 * then we have a bad program that isn't synchronizing its FPU usage
531 * and it will suffer the consequences since we won't be able to
532 * fully reproduce the context of the exception
533 */
534 cwd = get_fpu_cwd(task);
535 swd = get_fpu_swd(task);
536
537 err = swd & ~cwd;
538 } else {
539 /*
540 * The SIMD FPU exceptions are handled a little differently, as there
541 * is only a single status/control register. Thus, to determine which
542 * unmasked exception was caught we must mask the exception mask bits
543 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
544 */
545 unsigned short mxcsr = get_fpu_mxcsr(task);
546 err = ~(mxcsr >> 7) & mxcsr;
547 }
548
549 if (err & 0x001) { /* Invalid op */
550 /*
551 * swd & 0x240 == 0x040: Stack Underflow
552 * swd & 0x240 == 0x240: Stack Overflow
553 * User must clear the SF bit (0x40) if set
554 */
555 info.si_code = FPE_FLTINV;
556 } else if (err & 0x004) { /* Divide by Zero */
557 info.si_code = FPE_FLTDIV;
558 } else if (err & 0x008) { /* Overflow */
559 info.si_code = FPE_FLTOVF;
560 } else if (err & 0x012) { /* Denormal, Underflow */
561 info.si_code = FPE_FLTUND;
562 } else if (err & 0x020) { /* Precision */
563 info.si_code = FPE_FLTRES;
564 } else {
565 /*
566 * If we're using IRQ 13, or supposedly even some trap
567 * X86_TRAP_MF implementations, it's possible
568 * we get a spurious trap, which is not an error.
569 */
570 return;
571 }
572 force_sig_info(SIGFPE, &info, task);
573}
574
575dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
576{
577 enum ctx_state prev_state;
578
579 prev_state = exception_enter();
580 math_error(regs, error_code, X86_TRAP_MF);
581 exception_exit(prev_state);
582}
583
584dotraplinkage void
585do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
586{
587 enum ctx_state prev_state;
588
589 prev_state = exception_enter();
590 math_error(regs, error_code, X86_TRAP_XF);
591 exception_exit(prev_state);
592}
593
594dotraplinkage void
595do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
596{
597 conditional_sti(regs);
598#if 0
599 /* No need to warn about this any longer. */
600 pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
601#endif
602}
603
604asmlinkage __visible void __attribute__((weak)) smp_thermal_interrupt(void)
605{
606}
607
608asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void)
609{
610}
611
612/*
613 * 'math_state_restore()' saves the current math information in the
614 * old math state array, and gets the new ones from the current task
615 *
616 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
617 * Don't touch unless you *really* know how it works.
618 *
619 * Must be called with kernel preemption disabled (eg with local
620 * local interrupts as in the case of do_device_not_available).
621 */
622void math_state_restore(void)
623{
624 struct task_struct *tsk = current;
625
626 if (!tsk_used_math(tsk)) {
627 local_irq_enable();
628 /*
629 * does a slab alloc which can sleep
630 */
631 if (init_fpu(tsk)) {
632 /*
633 * ran out of memory!
634 */
635 do_group_exit(SIGKILL);
636 return;
637 }
638 local_irq_disable();
639 }
640
641 __thread_fpu_begin(tsk);
642
643 /*
644 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
645 */
646 if (unlikely(restore_fpu_checking(tsk))) {
647 drop_init_fpu(tsk);
648 force_sig(SIGSEGV, tsk);
649 return;
650 }
651
652 tsk->thread.fpu_counter++;
653}
654EXPORT_SYMBOL_GPL(math_state_restore);
655
656dotraplinkage void __kprobes
657do_device_not_available(struct pt_regs *regs, long error_code)
658{
659 enum ctx_state prev_state;
660
661 prev_state = exception_enter();
662 BUG_ON(use_eager_fpu());
663
664#ifdef CONFIG_MATH_EMULATION
665 if (read_cr0() & X86_CR0_EM) {
666 struct math_emu_info info = { };
667
668 conditional_sti(regs);
669
670 info.regs = regs;
671 math_emulate(&info);
672 exception_exit(prev_state);
673 return;
674 }
675#endif
676 math_state_restore(); /* interrupts still off */
677#ifdef CONFIG_X86_32
678 conditional_sti(regs);
679#endif
680 exception_exit(prev_state);
681}
682
683#ifdef CONFIG_X86_32
684dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
685{
686 siginfo_t info;
687 enum ctx_state prev_state;
688
689 prev_state = exception_enter();
690 local_irq_enable();
691
692 info.si_signo = SIGILL;
693 info.si_errno = 0;
694 info.si_code = ILL_BADSTK;
695 info.si_addr = NULL;
696 if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
697 X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
698 do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
699 &info);
700 }
701 exception_exit(prev_state);
702}
703#endif
704
705/* Set of traps needed for early debugging. */
706void __init early_trap_init(void)
707{
708 set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
709 /* int3 can be called from all */
710 set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
711#ifdef CONFIG_X86_32
712 set_intr_gate(X86_TRAP_PF, page_fault);
713#endif
714 load_idt(&idt_descr);
715}
716
717void __init early_trap_pf_init(void)
718{
719#ifdef CONFIG_X86_64
720 set_intr_gate(X86_TRAP_PF, page_fault);
721#endif
722}
723
724void __init trap_init(void)
725{
726 int i;
727
728#ifdef CONFIG_EISA
729 void __iomem *p = early_ioremap(0x0FFFD9, 4);
730
731 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
732 EISA_bus = 1;
733 early_iounmap(p, 4);
734#endif
735
736 set_intr_gate(X86_TRAP_DE, divide_error);
737 set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
738 /* int4 can be called from all */
739 set_system_intr_gate(X86_TRAP_OF, &overflow);
740 set_intr_gate(X86_TRAP_BR, bounds);
741 set_intr_gate(X86_TRAP_UD, invalid_op);
742 set_intr_gate(X86_TRAP_NM, device_not_available);
743#ifdef CONFIG_X86_32
744 set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
745#else
746 set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
747#endif
748 set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
749 set_intr_gate(X86_TRAP_TS, invalid_TSS);
750 set_intr_gate(X86_TRAP_NP, segment_not_present);
751 set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
752 set_intr_gate(X86_TRAP_GP, general_protection);
753 set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
754 set_intr_gate(X86_TRAP_MF, coprocessor_error);
755 set_intr_gate(X86_TRAP_AC, alignment_check);
756#ifdef CONFIG_X86_MCE
757 set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
758#endif
759 set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
760
761 /* Reserve all the builtin and the syscall vector: */
762 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
763 set_bit(i, used_vectors);
764
765#ifdef CONFIG_IA32_EMULATION
766 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
767 set_bit(IA32_SYSCALL_VECTOR, used_vectors);
768#endif
769
770#ifdef CONFIG_X86_32
771 set_system_trap_gate(SYSCALL_VECTOR, &system_call);
772 set_bit(SYSCALL_VECTOR, used_vectors);
773#endif
774
775 /*
776 * Set the IDT descriptor to a fixed read-only location, so that the
777 * "sidt" instruction will not leak the location of the kernel, and
778 * to defend the IDT against arbitrary memory write vulnerabilities.
779 * It will be reloaded in cpu_init() */
780 __set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
781 idt_descr.address = fix_to_virt(FIX_RO_IDT);
782
783 /*
784 * Should be a barrier for any external CPU state:
785 */
786 cpu_init();
787
788 x86_init.irqs.trap_init();
789
790#ifdef CONFIG_X86_64
791 memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
792 set_nmi_gate(X86_TRAP_DB, &debug);
793 set_nmi_gate(X86_TRAP_BP, &int3);
794#endif
795}