xref: /linux/arch/x86/kernel/traps.c (revision d97b46a64674a267bc41c9e16132ee2a98c3347d)
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 
66 asmlinkage int system_call(void);
67 
68 /* Do we ignore FPU interrupts ? */
69 char ignore_fpu_irq;
70 
71 /*
72  * The IDT has to be page-aligned to simplify the Pentium
73  * F0 0F bug workaround.
74  */
75 gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
76 #endif
77 
78 DECLARE_BITMAP(used_vectors, NR_VECTORS);
79 EXPORT_SYMBOL_GPL(used_vectors);
80 
81 static inline void conditional_sti(struct pt_regs *regs)
82 {
83 	if (regs->flags & X86_EFLAGS_IF)
84 		local_irq_enable();
85 }
86 
87 static 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 
94 static inline void conditional_cli(struct pt_regs *regs)
95 {
96 	if (regs->flags & X86_EFLAGS_IF)
97 		local_irq_disable();
98 }
99 
100 static 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 
107 static void __kprobes
108 do_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
129 trap_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 
161 kernel_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
170 vm86_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)				\
179 dotraplinkage 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)		\
189 dotraplinkage 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 
203 DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
204 		regs->ip)
205 DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
206 DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds)
207 DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN,
208 		regs->ip)
209 DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",
210 		coprocessor_segment_overrun)
211 DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
212 DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
213 #ifdef CONFIG_X86_32
214 DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
215 #endif
216 DO_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 */
221 dotraplinkage 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 
231 dotraplinkage 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 
251 dotraplinkage void __kprobes
252 do_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
284 gp_in_vm86:
285 	local_irq_enable();
286 	handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
287 	return;
288 #endif
289 
290 gp_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. */
303 dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
304 {
305 #ifdef CONFIG_DYNAMIC_FTRACE
306 	/* ftrace must be first, everything else may cause a recursive crash */
307 	if (unlikely(modifying_ftrace_code) && ftrace_int3_handler(regs))
308 		return;
309 #endif
310 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
311 	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
312 				SIGTRAP) == NOTIFY_STOP)
313 		return;
314 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
315 
316 	if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
317 			SIGTRAP) == NOTIFY_STOP)
318 		return;
319 
320 	/*
321 	 * Let others (NMI) know that the debug stack is in use
322 	 * as we may switch to the interrupt stack.
323 	 */
324 	debug_stack_usage_inc();
325 	preempt_conditional_sti(regs);
326 	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
327 	preempt_conditional_cli(regs);
328 	debug_stack_usage_dec();
329 }
330 
331 #ifdef CONFIG_X86_64
332 /*
333  * Help handler running on IST stack to switch back to user stack
334  * for scheduling or signal handling. The actual stack switch is done in
335  * entry.S
336  */
337 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
338 {
339 	struct pt_regs *regs = eregs;
340 	/* Did already sync */
341 	if (eregs == (struct pt_regs *)eregs->sp)
342 		;
343 	/* Exception from user space */
344 	else if (user_mode(eregs))
345 		regs = task_pt_regs(current);
346 	/*
347 	 * Exception from kernel and interrupts are enabled. Move to
348 	 * kernel process stack.
349 	 */
350 	else if (eregs->flags & X86_EFLAGS_IF)
351 		regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
352 	if (eregs != regs)
353 		*regs = *eregs;
354 	return regs;
355 }
356 #endif
357 
358 /*
359  * Our handling of the processor debug registers is non-trivial.
360  * We do not clear them on entry and exit from the kernel. Therefore
361  * it is possible to get a watchpoint trap here from inside the kernel.
362  * However, the code in ./ptrace.c has ensured that the user can
363  * only set watchpoints on userspace addresses. Therefore the in-kernel
364  * watchpoint trap can only occur in code which is reading/writing
365  * from user space. Such code must not hold kernel locks (since it
366  * can equally take a page fault), therefore it is safe to call
367  * force_sig_info even though that claims and releases locks.
368  *
369  * Code in ./signal.c ensures that the debug control register
370  * is restored before we deliver any signal, and therefore that
371  * user code runs with the correct debug control register even though
372  * we clear it here.
373  *
374  * Being careful here means that we don't have to be as careful in a
375  * lot of more complicated places (task switching can be a bit lazy
376  * about restoring all the debug state, and ptrace doesn't have to
377  * find every occurrence of the TF bit that could be saved away even
378  * by user code)
379  *
380  * May run on IST stack.
381  */
382 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
383 {
384 	struct task_struct *tsk = current;
385 	int user_icebp = 0;
386 	unsigned long dr6;
387 	int si_code;
388 
389 	get_debugreg(dr6, 6);
390 
391 	/* Filter out all the reserved bits which are preset to 1 */
392 	dr6 &= ~DR6_RESERVED;
393 
394 	/*
395 	 * If dr6 has no reason to give us about the origin of this trap,
396 	 * then it's very likely the result of an icebp/int01 trap.
397 	 * User wants a sigtrap for that.
398 	 */
399 	if (!dr6 && user_mode(regs))
400 		user_icebp = 1;
401 
402 	/* Catch kmemcheck conditions first of all! */
403 	if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
404 		return;
405 
406 	/* DR6 may or may not be cleared by the CPU */
407 	set_debugreg(0, 6);
408 
409 	/*
410 	 * The processor cleared BTF, so don't mark that we need it set.
411 	 */
412 	clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
413 
414 	/* Store the virtualized DR6 value */
415 	tsk->thread.debugreg6 = dr6;
416 
417 	if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
418 							SIGTRAP) == NOTIFY_STOP)
419 		return;
420 
421 	/*
422 	 * Let others (NMI) know that the debug stack is in use
423 	 * as we may switch to the interrupt stack.
424 	 */
425 	debug_stack_usage_inc();
426 
427 	/* It's safe to allow irq's after DR6 has been saved */
428 	preempt_conditional_sti(regs);
429 
430 	if (regs->flags & X86_VM_MASK) {
431 		handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
432 					X86_TRAP_DB);
433 		preempt_conditional_cli(regs);
434 		debug_stack_usage_dec();
435 		return;
436 	}
437 
438 	/*
439 	 * Single-stepping through system calls: ignore any exceptions in
440 	 * kernel space, but re-enable TF when returning to user mode.
441 	 *
442 	 * We already checked v86 mode above, so we can check for kernel mode
443 	 * by just checking the CPL of CS.
444 	 */
445 	if ((dr6 & DR_STEP) && !user_mode(regs)) {
446 		tsk->thread.debugreg6 &= ~DR_STEP;
447 		set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
448 		regs->flags &= ~X86_EFLAGS_TF;
449 	}
450 	si_code = get_si_code(tsk->thread.debugreg6);
451 	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
452 		send_sigtrap(tsk, regs, error_code, si_code);
453 	preempt_conditional_cli(regs);
454 	debug_stack_usage_dec();
455 
456 	return;
457 }
458 
459 /*
460  * Note that we play around with the 'TS' bit in an attempt to get
461  * the correct behaviour even in the presence of the asynchronous
462  * IRQ13 behaviour
463  */
464 void math_error(struct pt_regs *regs, int error_code, int trapnr)
465 {
466 	struct task_struct *task = current;
467 	siginfo_t info;
468 	unsigned short err;
469 	char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
470 						"simd exception";
471 
472 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
473 		return;
474 	conditional_sti(regs);
475 
476 	if (!user_mode_vm(regs))
477 	{
478 		if (!fixup_exception(regs)) {
479 			task->thread.error_code = error_code;
480 			task->thread.trap_nr = trapnr;
481 			die(str, regs, error_code);
482 		}
483 		return;
484 	}
485 
486 	/*
487 	 * Save the info for the exception handler and clear the error.
488 	 */
489 	save_init_fpu(task);
490 	task->thread.trap_nr = trapnr;
491 	task->thread.error_code = error_code;
492 	info.si_signo = SIGFPE;
493 	info.si_errno = 0;
494 	info.si_addr = (void __user *)regs->ip;
495 	if (trapnr == X86_TRAP_MF) {
496 		unsigned short cwd, swd;
497 		/*
498 		 * (~cwd & swd) will mask out exceptions that are not set to unmasked
499 		 * status.  0x3f is the exception bits in these regs, 0x200 is the
500 		 * C1 reg you need in case of a stack fault, 0x040 is the stack
501 		 * fault bit.  We should only be taking one exception at a time,
502 		 * so if this combination doesn't produce any single exception,
503 		 * then we have a bad program that isn't synchronizing its FPU usage
504 		 * and it will suffer the consequences since we won't be able to
505 		 * fully reproduce the context of the exception
506 		 */
507 		cwd = get_fpu_cwd(task);
508 		swd = get_fpu_swd(task);
509 
510 		err = swd & ~cwd;
511 	} else {
512 		/*
513 		 * The SIMD FPU exceptions are handled a little differently, as there
514 		 * is only a single status/control register.  Thus, to determine which
515 		 * unmasked exception was caught we must mask the exception mask bits
516 		 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
517 		 */
518 		unsigned short mxcsr = get_fpu_mxcsr(task);
519 		err = ~(mxcsr >> 7) & mxcsr;
520 	}
521 
522 	if (err & 0x001) {	/* Invalid op */
523 		/*
524 		 * swd & 0x240 == 0x040: Stack Underflow
525 		 * swd & 0x240 == 0x240: Stack Overflow
526 		 * User must clear the SF bit (0x40) if set
527 		 */
528 		info.si_code = FPE_FLTINV;
529 	} else if (err & 0x004) { /* Divide by Zero */
530 		info.si_code = FPE_FLTDIV;
531 	} else if (err & 0x008) { /* Overflow */
532 		info.si_code = FPE_FLTOVF;
533 	} else if (err & 0x012) { /* Denormal, Underflow */
534 		info.si_code = FPE_FLTUND;
535 	} else if (err & 0x020) { /* Precision */
536 		info.si_code = FPE_FLTRES;
537 	} else {
538 		/*
539 		 * If we're using IRQ 13, or supposedly even some trap
540 		 * X86_TRAP_MF implementations, it's possible
541 		 * we get a spurious trap, which is not an error.
542 		 */
543 		return;
544 	}
545 	force_sig_info(SIGFPE, &info, task);
546 }
547 
548 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
549 {
550 #ifdef CONFIG_X86_32
551 	ignore_fpu_irq = 1;
552 #endif
553 
554 	math_error(regs, error_code, X86_TRAP_MF);
555 }
556 
557 dotraplinkage void
558 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
559 {
560 	math_error(regs, error_code, X86_TRAP_XF);
561 }
562 
563 dotraplinkage void
564 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
565 {
566 	conditional_sti(regs);
567 #if 0
568 	/* No need to warn about this any longer. */
569 	printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
570 #endif
571 }
572 
573 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
574 {
575 }
576 
577 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
578 {
579 }
580 
581 /*
582  * 'math_state_restore()' saves the current math information in the
583  * old math state array, and gets the new ones from the current task
584  *
585  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
586  * Don't touch unless you *really* know how it works.
587  *
588  * Must be called with kernel preemption disabled (eg with local
589  * local interrupts as in the case of do_device_not_available).
590  */
591 void math_state_restore(void)
592 {
593 	struct task_struct *tsk = current;
594 
595 	if (!tsk_used_math(tsk)) {
596 		local_irq_enable();
597 		/*
598 		 * does a slab alloc which can sleep
599 		 */
600 		if (init_fpu(tsk)) {
601 			/*
602 			 * ran out of memory!
603 			 */
604 			do_group_exit(SIGKILL);
605 			return;
606 		}
607 		local_irq_disable();
608 	}
609 
610 	__thread_fpu_begin(tsk);
611 	/*
612 	 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
613 	 */
614 	if (unlikely(restore_fpu_checking(tsk))) {
615 		__thread_fpu_end(tsk);
616 		force_sig(SIGSEGV, tsk);
617 		return;
618 	}
619 
620 	tsk->fpu_counter++;
621 }
622 EXPORT_SYMBOL_GPL(math_state_restore);
623 
624 dotraplinkage void __kprobes
625 do_device_not_available(struct pt_regs *regs, long error_code)
626 {
627 #ifdef CONFIG_MATH_EMULATION
628 	if (read_cr0() & X86_CR0_EM) {
629 		struct math_emu_info info = { };
630 
631 		conditional_sti(regs);
632 
633 		info.regs = regs;
634 		math_emulate(&info);
635 		return;
636 	}
637 #endif
638 	math_state_restore(); /* interrupts still off */
639 #ifdef CONFIG_X86_32
640 	conditional_sti(regs);
641 #endif
642 }
643 
644 #ifdef CONFIG_X86_32
645 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
646 {
647 	siginfo_t info;
648 	local_irq_enable();
649 
650 	info.si_signo = SIGILL;
651 	info.si_errno = 0;
652 	info.si_code = ILL_BADSTK;
653 	info.si_addr = NULL;
654 	if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
655 			X86_TRAP_IRET, SIGILL) == NOTIFY_STOP)
656 		return;
657 	do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
658 		&info);
659 }
660 #endif
661 
662 /* Set of traps needed for early debugging. */
663 void __init early_trap_init(void)
664 {
665 	set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
666 	/* int3 can be called from all */
667 	set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
668 	set_intr_gate(X86_TRAP_PF, &page_fault);
669 	load_idt(&idt_descr);
670 }
671 
672 void __init trap_init(void)
673 {
674 	int i;
675 
676 #ifdef CONFIG_EISA
677 	void __iomem *p = early_ioremap(0x0FFFD9, 4);
678 
679 	if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
680 		EISA_bus = 1;
681 	early_iounmap(p, 4);
682 #endif
683 
684 	set_intr_gate(X86_TRAP_DE, &divide_error);
685 	set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
686 	/* int4 can be called from all */
687 	set_system_intr_gate(X86_TRAP_OF, &overflow);
688 	set_intr_gate(X86_TRAP_BR, &bounds);
689 	set_intr_gate(X86_TRAP_UD, &invalid_op);
690 	set_intr_gate(X86_TRAP_NM, &device_not_available);
691 #ifdef CONFIG_X86_32
692 	set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
693 #else
694 	set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
695 #endif
696 	set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
697 	set_intr_gate(X86_TRAP_TS, &invalid_TSS);
698 	set_intr_gate(X86_TRAP_NP, &segment_not_present);
699 	set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
700 	set_intr_gate(X86_TRAP_GP, &general_protection);
701 	set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
702 	set_intr_gate(X86_TRAP_MF, &coprocessor_error);
703 	set_intr_gate(X86_TRAP_AC, &alignment_check);
704 #ifdef CONFIG_X86_MCE
705 	set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
706 #endif
707 	set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
708 
709 	/* Reserve all the builtin and the syscall vector: */
710 	for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
711 		set_bit(i, used_vectors);
712 
713 #ifdef CONFIG_IA32_EMULATION
714 	set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
715 	set_bit(IA32_SYSCALL_VECTOR, used_vectors);
716 #endif
717 
718 #ifdef CONFIG_X86_32
719 	set_system_trap_gate(SYSCALL_VECTOR, &system_call);
720 	set_bit(SYSCALL_VECTOR, used_vectors);
721 #endif
722 
723 	/*
724 	 * Should be a barrier for any external CPU state:
725 	 */
726 	cpu_init();
727 
728 	x86_init.irqs.trap_init();
729 
730 #ifdef CONFIG_X86_64
731 	memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
732 	set_nmi_gate(X86_TRAP_DB, &debug);
733 	set_nmi_gate(X86_TRAP_BP, &int3);
734 #endif
735 }
736