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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 #ifdef CONFIG_MCA
41 #include <linux/mca.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 <asm/atomic.h>
53 #include <asm/system.h>
54 #include <asm/traps.h>
55 #include <asm/desc.h>
56 #include <asm/i387.h>
57 #include <asm/mce.h>
58
59 #include <asm/mach_traps.h>
60
61 #ifdef CONFIG_X86_64
62 #include <asm/x86_init.h>
63 #include <asm/pgalloc.h>
64 #include <asm/proto.h>
65 #else
66 #include <asm/processor-flags.h>
67 #include <asm/setup.h>
68
69 asmlinkage int system_call(void);
70
71 /* Do we ignore FPU interrupts ? */
72 char ignore_fpu_irq;
73
74 /*
75 * The IDT has to be page-aligned to simplify the Pentium
76 * F0 0F bug workaround.
77 */
78 gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
79 #endif
80
81 DECLARE_BITMAP(used_vectors, NR_VECTORS);
82 EXPORT_SYMBOL_GPL(used_vectors);
83
84 static int ignore_nmis;
85
86 static inline void conditional_sti(struct pt_regs *regs)
87 {
88 if (regs->flags & X86_EFLAGS_IF)
89 local_irq_enable();
90 }
91
92 static inline void preempt_conditional_sti(struct pt_regs *regs)
93 {
94 inc_preempt_count();
95 if (regs->flags & X86_EFLAGS_IF)
96 local_irq_enable();
97 }
98
99 static inline void conditional_cli(struct pt_regs *regs)
100 {
101 if (regs->flags & X86_EFLAGS_IF)
102 local_irq_disable();
103 }
104
105 static inline void preempt_conditional_cli(struct pt_regs *regs)
106 {
107 if (regs->flags & X86_EFLAGS_IF)
108 local_irq_disable();
109 dec_preempt_count();
110 }
111
112 static void __kprobes
113 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
114 long error_code, siginfo_t *info)
115 {
116 struct task_struct *tsk = current;
117
118 #ifdef CONFIG_X86_32
119 if (regs->flags & X86_VM_MASK) {
120 /*
121 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
122 * On nmi (interrupt 2), do_trap should not be called.
123 */
124 if (trapnr < 6)
125 goto vm86_trap;
126 goto trap_signal;
127 }
128 #endif
129
130 if (!user_mode(regs))
131 goto kernel_trap;
132
133 #ifdef CONFIG_X86_32
134 trap_signal:
135 #endif
136 /*
137 * We want error_code and trap_no set for userspace faults and
138 * kernelspace faults which result in die(), but not
139 * kernelspace faults which are fixed up. die() gives the
140 * process no chance to handle the signal and notice the
141 * kernel fault information, so that won't result in polluting
142 * the information about previously queued, but not yet
143 * delivered, faults. See also do_general_protection below.
144 */
145 tsk->thread.error_code = error_code;
146 tsk->thread.trap_no = trapnr;
147
148 #ifdef CONFIG_X86_64
149 if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
150 printk_ratelimit()) {
151 printk(KERN_INFO
152 "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
153 tsk->comm, tsk->pid, str,
154 regs->ip, regs->sp, error_code);
155 print_vma_addr(" in ", regs->ip);
156 printk("\n");
157 }
158 #endif
159
160 if (info)
161 force_sig_info(signr, info, tsk);
162 else
163 force_sig(signr, tsk);
164 return;
165
166 kernel_trap:
167 if (!fixup_exception(regs)) {
168 tsk->thread.error_code = error_code;
169 tsk->thread.trap_no = trapnr;
170 die(str, regs, error_code);
171 }
172 return;
173
174 #ifdef CONFIG_X86_32
175 vm86_trap:
176 if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
177 error_code, trapnr))
178 goto trap_signal;
179 return;
180 #endif
181 }
182
183 #define DO_ERROR(trapnr, signr, str, name) \
184 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
185 { \
186 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
187 == NOTIFY_STOP) \
188 return; \
189 conditional_sti(regs); \
190 do_trap(trapnr, signr, str, regs, error_code, NULL); \
191 }
192
193 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
194 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
195 { \
196 siginfo_t info; \
197 info.si_signo = signr; \
198 info.si_errno = 0; \
199 info.si_code = sicode; \
200 info.si_addr = (void __user *)siaddr; \
201 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
202 == NOTIFY_STOP) \
203 return; \
204 conditional_sti(regs); \
205 do_trap(trapnr, signr, str, regs, error_code, &info); \
206 }
207
208 DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
209 DO_ERROR(4, SIGSEGV, "overflow", overflow)
210 DO_ERROR(5, SIGSEGV, "bounds", bounds)
211 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)
212 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
213 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
214 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
215 #ifdef CONFIG_X86_32
216 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
217 #endif
218 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
219
220 #ifdef CONFIG_X86_64
221 /* Runs on IST stack */
222 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
223 {
224 if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
225 12, SIGBUS) == NOTIFY_STOP)
226 return;
227 preempt_conditional_sti(regs);
228 do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
229 preempt_conditional_cli(regs);
230 }
231
232 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
233 {
234 static const char str[] = "double fault";
235 struct task_struct *tsk = current;
236
237 /* Return not checked because double check cannot be ignored */
238 notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
239
240 tsk->thread.error_code = error_code;
241 tsk->thread.trap_no = 8;
242
243 /*
244 * This is always a kernel trap and never fixable (and thus must
245 * never return).
246 */
247 for (;;)
248 die(str, regs, error_code);
249 }
250 #endif
251
252 dotraplinkage void __kprobes
253 do_general_protection(struct pt_regs *regs, long error_code)
254 {
255 struct task_struct *tsk;
256
257 conditional_sti(regs);
258
259 #ifdef CONFIG_X86_32
260 if (regs->flags & X86_VM_MASK)
261 goto gp_in_vm86;
262 #endif
263
264 tsk = current;
265 if (!user_mode(regs))
266 goto gp_in_kernel;
267
268 tsk->thread.error_code = error_code;
269 tsk->thread.trap_no = 13;
270
271 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
272 printk_ratelimit()) {
273 printk(KERN_INFO
274 "%s[%d] general protection ip:%lx sp:%lx error:%lx",
275 tsk->comm, task_pid_nr(tsk),
276 regs->ip, regs->sp, error_code);
277 print_vma_addr(" in ", regs->ip);
278 printk("\n");
279 }
280
281 force_sig(SIGSEGV, tsk);
282 return;
283
284 #ifdef CONFIG_X86_32
285 gp_in_vm86:
286 local_irq_enable();
287 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
288 return;
289 #endif
290
291 gp_in_kernel:
292 if (fixup_exception(regs))
293 return;
294
295 tsk->thread.error_code = error_code;
296 tsk->thread.trap_no = 13;
297 if (notify_die(DIE_GPF, "general protection fault", regs,
298 error_code, 13, SIGSEGV) == NOTIFY_STOP)
299 return;
300 die("general protection fault", regs, error_code);
301 }
302
303 static notrace __kprobes void
304 mem_parity_error(unsigned char reason, struct pt_regs *regs)
305 {
306 printk(KERN_EMERG
307 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
308 reason, smp_processor_id());
309
310 printk(KERN_EMERG
311 "You have some hardware problem, likely on the PCI bus.\n");
312
313 #if defined(CONFIG_EDAC)
314 if (edac_handler_set()) {
315 edac_atomic_assert_error();
316 return;
317 }
318 #endif
319
320 if (panic_on_unrecovered_nmi)
321 panic("NMI: Not continuing");
322
323 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
324
325 /* Clear and disable the memory parity error line. */
326 reason = (reason & 0xf) | 4;
327 outb(reason, 0x61);
328 }
329
330 static notrace __kprobes void
331 io_check_error(unsigned char reason, struct pt_regs *regs)
332 {
333 unsigned long i;
334
335 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
336 show_registers(regs);
337
338 if (panic_on_io_nmi)
339 panic("NMI IOCK error: Not continuing");
340
341 /* Re-enable the IOCK line, wait for a few seconds */
342 reason = (reason & 0xf) | 8;
343 outb(reason, 0x61);
344
345 i = 2000;
346 while (--i)
347 udelay(1000);
348
349 reason &= ~8;
350 outb(reason, 0x61);
351 }
352
353 static notrace __kprobes void
354 unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
355 {
356 if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) ==
357 NOTIFY_STOP)
358 return;
359 #ifdef CONFIG_MCA
360 /*
361 * Might actually be able to figure out what the guilty party
362 * is:
363 */
364 if (MCA_bus) {
365 mca_handle_nmi();
366 return;
367 }
368 #endif
369 printk(KERN_EMERG
370 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
371 reason, smp_processor_id());
372
373 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
374 if (panic_on_unrecovered_nmi)
375 panic("NMI: Not continuing");
376
377 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
378 }
379
380 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
381 {
382 unsigned char reason = 0;
383 int cpu;
384
385 cpu = smp_processor_id();
386
387 /* Only the BSP gets external NMIs from the system. */
388 if (!cpu)
389 reason = get_nmi_reason();
390
391 if (!(reason & 0xc0)) {
392 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
393 == NOTIFY_STOP)
394 return;
395
396 #ifdef CONFIG_X86_LOCAL_APIC
397 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
398 == NOTIFY_STOP)
399 return;
400
401 #ifndef CONFIG_LOCKUP_DETECTOR
402 /*
403 * Ok, so this is none of the documented NMI sources,
404 * so it must be the NMI watchdog.
405 */
406 if (nmi_watchdog_tick(regs, reason))
407 return;
408 if (!do_nmi_callback(regs, cpu))
409 #endif /* !CONFIG_LOCKUP_DETECTOR */
410 unknown_nmi_error(reason, regs);
411 #else
412 unknown_nmi_error(reason, regs);
413 #endif
414
415 return;
416 }
417 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
418 return;
419
420 /* AK: following checks seem to be broken on modern chipsets. FIXME */
421 if (reason & 0x80)
422 mem_parity_error(reason, regs);
423 if (reason & 0x40)
424 io_check_error(reason, regs);
425 #ifdef CONFIG_X86_32
426 /*
427 * Reassert NMI in case it became active meanwhile
428 * as it's edge-triggered:
429 */
430 reassert_nmi();
431 #endif
432 }
433
434 dotraplinkage notrace __kprobes void
435 do_nmi(struct pt_regs *regs, long error_code)
436 {
437 nmi_enter();
438
439 inc_irq_stat(__nmi_count);
440
441 if (!ignore_nmis)
442 default_do_nmi(regs);
443
444 nmi_exit();
445 }
446
447 void stop_nmi(void)
448 {
449 acpi_nmi_disable();
450 ignore_nmis++;
451 }
452
453 void restart_nmi(void)
454 {
455 ignore_nmis--;
456 acpi_nmi_enable();
457 }
458
459 /* May run on IST stack. */
460 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
461 {
462 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
463 if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
464 == NOTIFY_STOP)
465 return;
466 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
467 #ifdef CONFIG_KPROBES
468 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
469 == NOTIFY_STOP)
470 return;
471 #else
472 if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
473 == NOTIFY_STOP)
474 return;
475 #endif
476
477 preempt_conditional_sti(regs);
478 do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
479 preempt_conditional_cli(regs);
480 }
481
482 #ifdef CONFIG_X86_64
483 /*
484 * Help handler running on IST stack to switch back to user stack
485 * for scheduling or signal handling. The actual stack switch is done in
486 * entry.S
487 */
488 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
489 {
490 struct pt_regs *regs = eregs;
491 /* Did already sync */
492 if (eregs == (struct pt_regs *)eregs->sp)
493 ;
494 /* Exception from user space */
495 else if (user_mode(eregs))
496 regs = task_pt_regs(current);
497 /*
498 * Exception from kernel and interrupts are enabled. Move to
499 * kernel process stack.
500 */
501 else if (eregs->flags & X86_EFLAGS_IF)
502 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
503 if (eregs != regs)
504 *regs = *eregs;
505 return regs;
506 }
507 #endif
508
509 /*
510 * Our handling of the processor debug registers is non-trivial.
511 * We do not clear them on entry and exit from the kernel. Therefore
512 * it is possible to get a watchpoint trap here from inside the kernel.
513 * However, the code in ./ptrace.c has ensured that the user can
514 * only set watchpoints on userspace addresses. Therefore the in-kernel
515 * watchpoint trap can only occur in code which is reading/writing
516 * from user space. Such code must not hold kernel locks (since it
517 * can equally take a page fault), therefore it is safe to call
518 * force_sig_info even though that claims and releases locks.
519 *
520 * Code in ./signal.c ensures that the debug control register
521 * is restored before we deliver any signal, and therefore that
522 * user code runs with the correct debug control register even though
523 * we clear it here.
524 *
525 * Being careful here means that we don't have to be as careful in a
526 * lot of more complicated places (task switching can be a bit lazy
527 * about restoring all the debug state, and ptrace doesn't have to
528 * find every occurrence of the TF bit that could be saved away even
529 * by user code)
530 *
531 * May run on IST stack.
532 */
533 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
534 {
535 struct task_struct *tsk = current;
536 int user_icebp = 0;
537 unsigned long dr6;
538 int si_code;
539
540 get_debugreg(dr6, 6);
541
542 /* Filter out all the reserved bits which are preset to 1 */
543 dr6 &= ~DR6_RESERVED;
544
545 /*
546 * If dr6 has no reason to give us about the origin of this trap,
547 * then it's very likely the result of an icebp/int01 trap.
548 * User wants a sigtrap for that.
549 */
550 if (!dr6 && user_mode(regs))
551 user_icebp = 1;
552
553 /* Catch kmemcheck conditions first of all! */
554 if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
555 return;
556
557 /* DR6 may or may not be cleared by the CPU */
558 set_debugreg(0, 6);
559
560 /*
561 * The processor cleared BTF, so don't mark that we need it set.
562 */
563 clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
564
565 /* Store the virtualized DR6 value */
566 tsk->thread.debugreg6 = dr6;
567
568 if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
569 SIGTRAP) == NOTIFY_STOP)
570 return;
571
572 /* It's safe to allow irq's after DR6 has been saved */
573 preempt_conditional_sti(regs);
574
575 if (regs->flags & X86_VM_MASK) {
576 handle_vm86_trap((struct kernel_vm86_regs *) regs,
577 error_code, 1);
578 return;
579 }
580
581 /*
582 * Single-stepping through system calls: ignore any exceptions in
583 * kernel space, but re-enable TF when returning to user mode.
584 *
585 * We already checked v86 mode above, so we can check for kernel mode
586 * by just checking the CPL of CS.
587 */
588 if ((dr6 & DR_STEP) && !user_mode(regs)) {
589 tsk->thread.debugreg6 &= ~DR_STEP;
590 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
591 regs->flags &= ~X86_EFLAGS_TF;
592 }
593 si_code = get_si_code(tsk->thread.debugreg6);
594 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
595 send_sigtrap(tsk, regs, error_code, si_code);
596 preempt_conditional_cli(regs);
597
598 return;
599 }
600
601 /*
602 * Note that we play around with the 'TS' bit in an attempt to get
603 * the correct behaviour even in the presence of the asynchronous
604 * IRQ13 behaviour
605 */
606 void math_error(struct pt_regs *regs, int error_code, int trapnr)
607 {
608 struct task_struct *task = current;
609 siginfo_t info;
610 unsigned short err;
611 char *str = (trapnr == 16) ? "fpu exception" : "simd exception";
612
613 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
614 return;
615 conditional_sti(regs);
616
617 if (!user_mode_vm(regs))
618 {
619 if (!fixup_exception(regs)) {
620 task->thread.error_code = error_code;
621 task->thread.trap_no = trapnr;
622 die(str, regs, error_code);
623 }
624 return;
625 }
626
627 /*
628 * Save the info for the exception handler and clear the error.
629 */
630 save_init_fpu(task);
631 task->thread.trap_no = trapnr;
632 task->thread.error_code = error_code;
633 info.si_signo = SIGFPE;
634 info.si_errno = 0;
635 info.si_addr = (void __user *)regs->ip;
636 if (trapnr == 16) {
637 unsigned short cwd, swd;
638 /*
639 * (~cwd & swd) will mask out exceptions that are not set to unmasked
640 * status. 0x3f is the exception bits in these regs, 0x200 is the
641 * C1 reg you need in case of a stack fault, 0x040 is the stack
642 * fault bit. We should only be taking one exception at a time,
643 * so if this combination doesn't produce any single exception,
644 * then we have a bad program that isn't synchronizing its FPU usage
645 * and it will suffer the consequences since we won't be able to
646 * fully reproduce the context of the exception
647 */
648 cwd = get_fpu_cwd(task);
649 swd = get_fpu_swd(task);
650
651 err = swd & ~cwd;
652 } else {
653 /*
654 * The SIMD FPU exceptions are handled a little differently, as there
655 * is only a single status/control register. Thus, to determine which
656 * unmasked exception was caught we must mask the exception mask bits
657 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
658 */
659 unsigned short mxcsr = get_fpu_mxcsr(task);
660 err = ~(mxcsr >> 7) & mxcsr;
661 }
662
663 if (err & 0x001) { /* Invalid op */
664 /*
665 * swd & 0x240 == 0x040: Stack Underflow
666 * swd & 0x240 == 0x240: Stack Overflow
667 * User must clear the SF bit (0x40) if set
668 */
669 info.si_code = FPE_FLTINV;
670 } else if (err & 0x004) { /* Divide by Zero */
671 info.si_code = FPE_FLTDIV;
672 } else if (err & 0x008) { /* Overflow */
673 info.si_code = FPE_FLTOVF;
674 } else if (err & 0x012) { /* Denormal, Underflow */
675 info.si_code = FPE_FLTUND;
676 } else if (err & 0x020) { /* Precision */
677 info.si_code = FPE_FLTRES;
678 } else {
679 /*
680 * If we're using IRQ 13, or supposedly even some trap 16
681 * implementations, it's possible we get a spurious trap...
682 */
683 return; /* Spurious trap, no error */
684 }
685 force_sig_info(SIGFPE, &info, task);
686 }
687
688 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
689 {
690 #ifdef CONFIG_X86_32
691 ignore_fpu_irq = 1;
692 #endif
693
694 math_error(regs, error_code, 16);
695 }
696
697 dotraplinkage void
698 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
699 {
700 math_error(regs, error_code, 19);
701 }
702
703 dotraplinkage void
704 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
705 {
706 conditional_sti(regs);
707 #if 0
708 /* No need to warn about this any longer. */
709 printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
710 #endif
711 }
712
713 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
714 {
715 }
716
717 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
718 {
719 }
720
721 /*
722 * __math_state_restore assumes that cr0.TS is already clear and the
723 * fpu state is all ready for use. Used during context switch.
724 */
725 void __math_state_restore(void)
726 {
727 struct thread_info *thread = current_thread_info();
728 struct task_struct *tsk = thread->task;
729
730 /*
731 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
732 */
733 if (unlikely(restore_fpu_checking(tsk))) {
734 stts();
735 force_sig(SIGSEGV, tsk);
736 return;
737 }
738
739 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
740 tsk->fpu_counter++;
741 }
742
743 /*
744 * 'math_state_restore()' saves the current math information in the
745 * old math state array, and gets the new ones from the current task
746 *
747 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
748 * Don't touch unless you *really* know how it works.
749 *
750 * Must be called with kernel preemption disabled (in this case,
751 * local interrupts are disabled at the call-site in entry.S).
752 */
753 asmlinkage void math_state_restore(void)
754 {
755 struct thread_info *thread = current_thread_info();
756 struct task_struct *tsk = thread->task;
757
758 if (!tsk_used_math(tsk)) {
759 local_irq_enable();
760 /*
761 * does a slab alloc which can sleep
762 */
763 if (init_fpu(tsk)) {
764 /*
765 * ran out of memory!
766 */
767 do_group_exit(SIGKILL);
768 return;
769 }
770 local_irq_disable();
771 }
772
773 clts(); /* Allow maths ops (or we recurse) */
774
775 __math_state_restore();
776 }
777 EXPORT_SYMBOL_GPL(math_state_restore);
778
779 #ifndef CONFIG_MATH_EMULATION
780 void math_emulate(struct math_emu_info *info)
781 {
782 printk(KERN_EMERG
783 "math-emulation not enabled and no coprocessor found.\n");
784 printk(KERN_EMERG "killing %s.\n", current->comm);
785 force_sig(SIGFPE, current);
786 schedule();
787 }
788 #endif /* CONFIG_MATH_EMULATION */
789
790 dotraplinkage void __kprobes
791 do_device_not_available(struct pt_regs *regs, long error_code)
792 {
793 #ifdef CONFIG_X86_32
794 if (read_cr0() & X86_CR0_EM) {
795 struct math_emu_info info = { };
796
797 conditional_sti(regs);
798
799 info.regs = regs;
800 math_emulate(&info);
801 } else {
802 math_state_restore(); /* interrupts still off */
803 conditional_sti(regs);
804 }
805 #else
806 math_state_restore();
807 #endif
808 }
809
810 #ifdef CONFIG_X86_32
811 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
812 {
813 siginfo_t info;
814 local_irq_enable();
815
816 info.si_signo = SIGILL;
817 info.si_errno = 0;
818 info.si_code = ILL_BADSTK;
819 info.si_addr = NULL;
820 if (notify_die(DIE_TRAP, "iret exception",
821 regs, error_code, 32, SIGILL) == NOTIFY_STOP)
822 return;
823 do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
824 }
825 #endif
826
827 /* Set of traps needed for early debugging. */
828 void __init early_trap_init(void)
829 {
830 set_intr_gate_ist(1, &debug, DEBUG_STACK);
831 /* int3 can be called from all */
832 set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
833 set_intr_gate(14, &page_fault);
834 load_idt(&idt_descr);
835 }
836
837 void __init trap_init(void)
838 {
839 int i;
840
841 #ifdef CONFIG_EISA
842 void __iomem *p = early_ioremap(0x0FFFD9, 4);
843
844 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
845 EISA_bus = 1;
846 early_iounmap(p, 4);
847 #endif
848
849 set_intr_gate(0, &divide_error);
850 set_intr_gate_ist(2, &nmi, NMI_STACK);
851 /* int4 can be called from all */
852 set_system_intr_gate(4, &overflow);
853 set_intr_gate(5, &bounds);
854 set_intr_gate(6, &invalid_op);
855 set_intr_gate(7, &device_not_available);
856 #ifdef CONFIG_X86_32
857 set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
858 #else
859 set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
860 #endif
861 set_intr_gate(9, &coprocessor_segment_overrun);
862 set_intr_gate(10, &invalid_TSS);
863 set_intr_gate(11, &segment_not_present);
864 set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
865 set_intr_gate(13, &general_protection);
866 set_intr_gate(15, &spurious_interrupt_bug);
867 set_intr_gate(16, &coprocessor_error);
868 set_intr_gate(17, &alignment_check);
869 #ifdef CONFIG_X86_MCE
870 set_intr_gate_ist(18, &machine_check, MCE_STACK);
871 #endif
872 set_intr_gate(19, &simd_coprocessor_error);
873
874 /* Reserve all the builtin and the syscall vector: */
875 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
876 set_bit(i, used_vectors);
877
878 #ifdef CONFIG_IA32_EMULATION
879 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
880 set_bit(IA32_SYSCALL_VECTOR, used_vectors);
881 #endif
882
883 #ifdef CONFIG_X86_32
884 set_system_trap_gate(SYSCALL_VECTOR, &system_call);
885 set_bit(SYSCALL_VECTOR, used_vectors);
886 #endif
887
888 /*
889 * Should be a barrier for any external CPU state:
890 */
891 cpu_init();
892
893 x86_init.irqs.trap_init();
894 }