1 /*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
4 *
5 * Pentium III FXSR, SSE support
6 * Gareth Hughes <gareth@valinux.com>, May 2000
7 */
8
9 /*
10 * Handle hardware traps and faults.
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/context_tracking.h>
16 #include <linux/interrupt.h>
17 #include <linux/kallsyms.h>
18 #include <linux/spinlock.h>
19 #include <linux/kprobes.h>
20 #include <linux/uaccess.h>
21 #include <linux/kdebug.h>
22 #include <linux/kgdb.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/ptrace.h>
26 #include <linux/uprobes.h>
27 #include <linux/string.h>
28 #include <linux/delay.h>
29 #include <linux/errno.h>
30 #include <linux/kexec.h>
31 #include <linux/sched.h>
32 #include <linux/timer.h>
33 #include <linux/init.h>
34 #include <linux/bug.h>
35 #include <linux/nmi.h>
36 #include <linux/mm.h>
37 #include <linux/smp.h>
38 #include <linux/io.h>
39
40 #ifdef CONFIG_EISA
41 #include <linux/ioport.h>
42 #include <linux/eisa.h>
43 #endif
44
45 #if defined(CONFIG_EDAC)
46 #include <linux/edac.h>
47 #endif
48
49 #include <asm/kmemcheck.h>
50 #include <asm/stacktrace.h>
51 #include <asm/processor.h>
52 #include <asm/debugreg.h>
53 #include <linux/atomic.h>
54 #include <asm/ftrace.h>
55 #include <asm/traps.h>
56 #include <asm/desc.h>
57 #include <asm/i387.h>
58 #include <asm/fpu-internal.h>
59 #include <asm/mce.h>
60 #include <asm/fixmap.h>
61 #include <asm/mach_traps.h>
62 #include <asm/alternative.h>
63
64 #ifdef CONFIG_X86_64
65 #include <asm/x86_init.h>
66 #include <asm/pgalloc.h>
67 #include <asm/proto.h>
68
69 /* No need to be aligned, but done to keep all IDTs defined the same way. */
70 gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
71 #else
72 #include <asm/processor-flags.h>
73 #include <asm/setup.h>
74
75 asmlinkage int system_call(void);
76 #endif
77
78 /* Must be page-aligned because the real IDT is used in a fixmap. */
79 gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
80
81 DECLARE_BITMAP(used_vectors, NR_VECTORS);
82 EXPORT_SYMBOL_GPL(used_vectors);
83
conditional_sti(struct pt_regs * regs)84 static inline void conditional_sti(struct pt_regs *regs)
85 {
86 if (regs->flags & X86_EFLAGS_IF)
87 local_irq_enable();
88 }
89
preempt_conditional_sti(struct pt_regs * regs)90 static inline void preempt_conditional_sti(struct pt_regs *regs)
91 {
92 preempt_count_inc();
93 if (regs->flags & X86_EFLAGS_IF)
94 local_irq_enable();
95 }
96
conditional_cli(struct pt_regs * regs)97 static inline void conditional_cli(struct pt_regs *regs)
98 {
99 if (regs->flags & X86_EFLAGS_IF)
100 local_irq_disable();
101 }
102
preempt_conditional_cli(struct pt_regs * regs)103 static inline void preempt_conditional_cli(struct pt_regs *regs)
104 {
105 if (regs->flags & X86_EFLAGS_IF)
106 local_irq_disable();
107 preempt_count_dec();
108 }
109
110 static nokprobe_inline int
do_trap_no_signal(struct task_struct * tsk,int trapnr,char * str,struct pt_regs * regs,long error_code)111 do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
112 struct pt_regs *regs, long error_code)
113 {
114 #ifdef CONFIG_X86_32
115 if (regs->flags & X86_VM_MASK) {
116 /*
117 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
118 * On nmi (interrupt 2), do_trap should not be called.
119 */
120 if (trapnr < X86_TRAP_UD) {
121 if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
122 error_code, trapnr))
123 return 0;
124 }
125 return -1;
126 }
127 #endif
128 if (!user_mode(regs)) {
129 if (!fixup_exception(regs)) {
130 tsk->thread.error_code = error_code;
131 tsk->thread.trap_nr = trapnr;
132 die(str, regs, error_code);
133 }
134 return 0;
135 }
136
137 return -1;
138 }
139
fill_trap_info(struct pt_regs * regs,int signr,int trapnr,siginfo_t * info)140 static siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr,
141 siginfo_t *info)
142 {
143 unsigned long siaddr;
144 int sicode;
145
146 switch (trapnr) {
147 default:
148 return SEND_SIG_PRIV;
149
150 case X86_TRAP_DE:
151 sicode = FPE_INTDIV;
152 siaddr = uprobe_get_trap_addr(regs);
153 break;
154 case X86_TRAP_UD:
155 sicode = ILL_ILLOPN;
156 siaddr = uprobe_get_trap_addr(regs);
157 break;
158 case X86_TRAP_AC:
159 sicode = BUS_ADRALN;
160 siaddr = 0;
161 break;
162 }
163
164 info->si_signo = signr;
165 info->si_errno = 0;
166 info->si_code = sicode;
167 info->si_addr = (void __user *)siaddr;
168 return info;
169 }
170
171 static void
do_trap(int trapnr,int signr,char * str,struct pt_regs * regs,long error_code,siginfo_t * info)172 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
173 long error_code, siginfo_t *info)
174 {
175 struct task_struct *tsk = current;
176
177
178 if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
179 return;
180 /*
181 * We want error_code and trap_nr set for userspace faults and
182 * kernelspace faults which result in die(), but not
183 * kernelspace faults which are fixed up. die() gives the
184 * process no chance to handle the signal and notice the
185 * kernel fault information, so that won't result in polluting
186 * the information about previously queued, but not yet
187 * delivered, faults. See also do_general_protection below.
188 */
189 tsk->thread.error_code = error_code;
190 tsk->thread.trap_nr = trapnr;
191
192 #ifdef CONFIG_X86_64
193 if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
194 printk_ratelimit()) {
195 pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
196 tsk->comm, tsk->pid, str,
197 regs->ip, regs->sp, error_code);
198 print_vma_addr(" in ", regs->ip);
199 pr_cont("\n");
200 }
201 #endif
202
203 force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);
204 }
205 NOKPROBE_SYMBOL(do_trap);
206
do_error_trap(struct pt_regs * regs,long error_code,char * str,unsigned long trapnr,int signr)207 static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
208 unsigned long trapnr, int signr)
209 {
210 enum ctx_state prev_state = exception_enter();
211 siginfo_t info;
212
213 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
214 NOTIFY_STOP) {
215 conditional_sti(regs);
216 do_trap(trapnr, signr, str, regs, error_code,
217 fill_trap_info(regs, signr, trapnr, &info));
218 }
219
220 exception_exit(prev_state);
221 }
222
223 #define DO_ERROR(trapnr, signr, str, name) \
224 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
225 { \
226 do_error_trap(regs, error_code, str, trapnr, signr); \
227 }
228
229 DO_ERROR(X86_TRAP_DE, SIGFPE, "divide error", divide_error)
230 DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
231 DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds)
232 DO_ERROR(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op)
233 DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",coprocessor_segment_overrun)
234 DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
235 DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
236 DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
237 DO_ERROR(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check)
238
239 #ifdef CONFIG_X86_64
240 /* Runs on IST stack */
do_double_fault(struct pt_regs * regs,long error_code)241 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
242 {
243 static const char str[] = "double fault";
244 struct task_struct *tsk = current;
245
246 #ifdef CONFIG_X86_ESPFIX64
247 extern unsigned char native_irq_return_iret[];
248
249 /*
250 * If IRET takes a non-IST fault on the espfix64 stack, then we
251 * end up promoting it to a doublefault. In that case, modify
252 * the stack to make it look like we just entered the #GP
253 * handler from user space, similar to bad_iret.
254 */
255 if (((long)regs->sp >> PGDIR_SHIFT) == ESPFIX_PGD_ENTRY &&
256 regs->cs == __KERNEL_CS &&
257 regs->ip == (unsigned long)native_irq_return_iret)
258 {
259 struct pt_regs *normal_regs = task_pt_regs(current);
260
261 /* Fake a #GP(0) from userspace. */
262 memmove(&normal_regs->ip, (void *)regs->sp, 5*8);
263 normal_regs->orig_ax = 0; /* Missing (lost) #GP error code */
264 regs->ip = (unsigned long)general_protection;
265 regs->sp = (unsigned long)&normal_regs->orig_ax;
266 return;
267 }
268 #endif
269
270 exception_enter();
271 /* Return not checked because double check cannot be ignored */
272 notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
273
274 tsk->thread.error_code = error_code;
275 tsk->thread.trap_nr = X86_TRAP_DF;
276
277 #ifdef CONFIG_DOUBLEFAULT
278 df_debug(regs, error_code);
279 #endif
280 /*
281 * This is always a kernel trap and never fixable (and thus must
282 * never return).
283 */
284 for (;;)
285 die(str, regs, error_code);
286 }
287 #endif
288
289 dotraplinkage void
do_general_protection(struct pt_regs * regs,long error_code)290 do_general_protection(struct pt_regs *regs, long error_code)
291 {
292 struct task_struct *tsk;
293 enum ctx_state prev_state;
294
295 prev_state = exception_enter();
296 conditional_sti(regs);
297
298 #ifdef CONFIG_X86_32
299 if (regs->flags & X86_VM_MASK) {
300 local_irq_enable();
301 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
302 goto exit;
303 }
304 #endif
305
306 tsk = current;
307 if (!user_mode(regs)) {
308 if (fixup_exception(regs))
309 goto exit;
310
311 tsk->thread.error_code = error_code;
312 tsk->thread.trap_nr = X86_TRAP_GP;
313 if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
314 X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
315 die("general protection fault", regs, error_code);
316 goto exit;
317 }
318
319 tsk->thread.error_code = error_code;
320 tsk->thread.trap_nr = X86_TRAP_GP;
321
322 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
323 printk_ratelimit()) {
324 pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
325 tsk->comm, task_pid_nr(tsk),
326 regs->ip, regs->sp, error_code);
327 print_vma_addr(" in ", regs->ip);
328 pr_cont("\n");
329 }
330
331 force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
332 exit:
333 exception_exit(prev_state);
334 }
335 NOKPROBE_SYMBOL(do_general_protection);
336
337 /* May run on IST stack. */
do_int3(struct pt_regs * regs,long error_code)338 dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
339 {
340 enum ctx_state prev_state;
341
342 #ifdef CONFIG_DYNAMIC_FTRACE
343 /*
344 * ftrace must be first, everything else may cause a recursive crash.
345 * See note by declaration of modifying_ftrace_code in ftrace.c
346 */
347 if (unlikely(atomic_read(&modifying_ftrace_code)) &&
348 ftrace_int3_handler(regs))
349 return;
350 #endif
351 if (poke_int3_handler(regs))
352 return;
353
354 prev_state = exception_enter();
355 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
356 if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
357 SIGTRAP) == NOTIFY_STOP)
358 goto exit;
359 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
360
361 #ifdef CONFIG_KPROBES
362 if (kprobe_int3_handler(regs))
363 goto exit;
364 #endif
365
366 if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
367 SIGTRAP) == NOTIFY_STOP)
368 goto exit;
369
370 /*
371 * Let others (NMI) know that the debug stack is in use
372 * as we may switch to the interrupt stack.
373 */
374 debug_stack_usage_inc();
375 preempt_conditional_sti(regs);
376 do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
377 preempt_conditional_cli(regs);
378 debug_stack_usage_dec();
379 exit:
380 exception_exit(prev_state);
381 }
382 NOKPROBE_SYMBOL(do_int3);
383
384 #ifdef CONFIG_X86_64
385 /*
386 * Help handler running on IST stack to switch back to user stack
387 * for scheduling or signal handling. The actual stack switch is done in
388 * entry.S
389 */
sync_regs(struct pt_regs * eregs)390 asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs)
391 {
392 struct pt_regs *regs = eregs;
393 /* Did already sync */
394 if (eregs == (struct pt_regs *)eregs->sp)
395 ;
396 /* Exception from user space */
397 else if (user_mode(eregs))
398 regs = task_pt_regs(current);
399 /*
400 * Exception from kernel and interrupts are enabled. Move to
401 * kernel process stack.
402 */
403 else if (eregs->flags & X86_EFLAGS_IF)
404 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
405 if (eregs != regs)
406 *regs = *eregs;
407 return regs;
408 }
409 NOKPROBE_SYMBOL(sync_regs);
410
411 struct bad_iret_stack {
412 void *error_entry_ret;
413 struct pt_regs regs;
414 };
415
416 asmlinkage __visible notrace
fixup_bad_iret(struct bad_iret_stack * s)417 struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
418 {
419 /*
420 * This is called from entry_64.S early in handling a fault
421 * caused by a bad iret to user mode. To handle the fault
422 * correctly, we want move our stack frame to task_pt_regs
423 * and we want to pretend that the exception came from the
424 * iret target.
425 */
426 struct bad_iret_stack *new_stack =
427 container_of(task_pt_regs(current),
428 struct bad_iret_stack, regs);
429
430 /* Copy the IRET target to the new stack. */
431 memmove(&new_stack->regs.ip, (void *)s->regs.sp, 5*8);
432
433 /* Copy the remainder of the stack from the current stack. */
434 memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip));
435
436 BUG_ON(!user_mode_vm(&new_stack->regs));
437 return new_stack;
438 }
439 NOKPROBE_SYMBOL(fixup_bad_iret);
440 #endif
441
442 /*
443 * Our handling of the processor debug registers is non-trivial.
444 * We do not clear them on entry and exit from the kernel. Therefore
445 * it is possible to get a watchpoint trap here from inside the kernel.
446 * However, the code in ./ptrace.c has ensured that the user can
447 * only set watchpoints on userspace addresses. Therefore the in-kernel
448 * watchpoint trap can only occur in code which is reading/writing
449 * from user space. Such code must not hold kernel locks (since it
450 * can equally take a page fault), therefore it is safe to call
451 * force_sig_info even though that claims and releases locks.
452 *
453 * Code in ./signal.c ensures that the debug control register
454 * is restored before we deliver any signal, and therefore that
455 * user code runs with the correct debug control register even though
456 * we clear it here.
457 *
458 * Being careful here means that we don't have to be as careful in a
459 * lot of more complicated places (task switching can be a bit lazy
460 * about restoring all the debug state, and ptrace doesn't have to
461 * find every occurrence of the TF bit that could be saved away even
462 * by user code)
463 *
464 * May run on IST stack.
465 */
do_debug(struct pt_regs * regs,long error_code)466 dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
467 {
468 struct task_struct *tsk = current;
469 enum ctx_state prev_state;
470 int user_icebp = 0;
471 unsigned long dr6;
472 int si_code;
473
474 prev_state = exception_enter();
475
476 get_debugreg(dr6, 6);
477
478 /* Filter out all the reserved bits which are preset to 1 */
479 dr6 &= ~DR6_RESERVED;
480
481 /*
482 * If dr6 has no reason to give us about the origin of this trap,
483 * then it's very likely the result of an icebp/int01 trap.
484 * User wants a sigtrap for that.
485 */
486 if (!dr6 && user_mode(regs))
487 user_icebp = 1;
488
489 /* Catch kmemcheck conditions first of all! */
490 if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
491 goto exit;
492
493 /* DR6 may or may not be cleared by the CPU */
494 set_debugreg(0, 6);
495
496 /*
497 * The processor cleared BTF, so don't mark that we need it set.
498 */
499 clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP);
500
501 /* Store the virtualized DR6 value */
502 tsk->thread.debugreg6 = dr6;
503
504 #ifdef CONFIG_KPROBES
505 if (kprobe_debug_handler(regs))
506 goto exit;
507 #endif
508
509 if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
510 SIGTRAP) == NOTIFY_STOP)
511 goto exit;
512
513 /*
514 * Let others (NMI) know that the debug stack is in use
515 * as we may switch to the interrupt stack.
516 */
517 debug_stack_usage_inc();
518
519 /* It's safe to allow irq's after DR6 has been saved */
520 preempt_conditional_sti(regs);
521
522 if (regs->flags & X86_VM_MASK) {
523 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
524 X86_TRAP_DB);
525 preempt_conditional_cli(regs);
526 debug_stack_usage_dec();
527 goto exit;
528 }
529
530 /*
531 * Single-stepping through system calls: ignore any exceptions in
532 * kernel space, but re-enable TF when returning to user mode.
533 *
534 * We already checked v86 mode above, so we can check for kernel mode
535 * by just checking the CPL of CS.
536 */
537 if ((dr6 & DR_STEP) && !user_mode(regs)) {
538 tsk->thread.debugreg6 &= ~DR_STEP;
539 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
540 regs->flags &= ~X86_EFLAGS_TF;
541 }
542 si_code = get_si_code(tsk->thread.debugreg6);
543 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
544 send_sigtrap(tsk, regs, error_code, si_code);
545 preempt_conditional_cli(regs);
546 debug_stack_usage_dec();
547
548 exit:
549 exception_exit(prev_state);
550 }
551 NOKPROBE_SYMBOL(do_debug);
552
553 /*
554 * Note that we play around with the 'TS' bit in an attempt to get
555 * the correct behaviour even in the presence of the asynchronous
556 * IRQ13 behaviour
557 */
math_error(struct pt_regs * regs,int error_code,int trapnr)558 static void math_error(struct pt_regs *regs, int error_code, int trapnr)
559 {
560 struct task_struct *task = current;
561 siginfo_t info;
562 unsigned short err;
563 char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
564 "simd exception";
565
566 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP)
567 return;
568 conditional_sti(regs);
569
570 if (!user_mode_vm(regs))
571 {
572 if (!fixup_exception(regs)) {
573 task->thread.error_code = error_code;
574 task->thread.trap_nr = trapnr;
575 die(str, regs, error_code);
576 }
577 return;
578 }
579
580 /*
581 * Save the info for the exception handler and clear the error.
582 */
583 save_init_fpu(task);
584 task->thread.trap_nr = trapnr;
585 task->thread.error_code = error_code;
586 info.si_signo = SIGFPE;
587 info.si_errno = 0;
588 info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
589 if (trapnr == X86_TRAP_MF) {
590 unsigned short cwd, swd;
591 /*
592 * (~cwd & swd) will mask out exceptions that are not set to unmasked
593 * status. 0x3f is the exception bits in these regs, 0x200 is the
594 * C1 reg you need in case of a stack fault, 0x040 is the stack
595 * fault bit. We should only be taking one exception at a time,
596 * so if this combination doesn't produce any single exception,
597 * then we have a bad program that isn't synchronizing its FPU usage
598 * and it will suffer the consequences since we won't be able to
599 * fully reproduce the context of the exception
600 */
601 cwd = get_fpu_cwd(task);
602 swd = get_fpu_swd(task);
603
604 err = swd & ~cwd;
605 } else {
606 /*
607 * The SIMD FPU exceptions are handled a little differently, as there
608 * is only a single status/control register. Thus, to determine which
609 * unmasked exception was caught we must mask the exception mask bits
610 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
611 */
612 unsigned short mxcsr = get_fpu_mxcsr(task);
613 err = ~(mxcsr >> 7) & mxcsr;
614 }
615
616 if (err & 0x001) { /* Invalid op */
617 /*
618 * swd & 0x240 == 0x040: Stack Underflow
619 * swd & 0x240 == 0x240: Stack Overflow
620 * User must clear the SF bit (0x40) if set
621 */
622 info.si_code = FPE_FLTINV;
623 } else if (err & 0x004) { /* Divide by Zero */
624 info.si_code = FPE_FLTDIV;
625 } else if (err & 0x008) { /* Overflow */
626 info.si_code = FPE_FLTOVF;
627 } else if (err & 0x012) { /* Denormal, Underflow */
628 info.si_code = FPE_FLTUND;
629 } else if (err & 0x020) { /* Precision */
630 info.si_code = FPE_FLTRES;
631 } else {
632 /*
633 * If we're using IRQ 13, or supposedly even some trap
634 * X86_TRAP_MF implementations, it's possible
635 * we get a spurious trap, which is not an error.
636 */
637 return;
638 }
639 force_sig_info(SIGFPE, &info, task);
640 }
641
do_coprocessor_error(struct pt_regs * regs,long error_code)642 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
643 {
644 enum ctx_state prev_state;
645
646 prev_state = exception_enter();
647 math_error(regs, error_code, X86_TRAP_MF);
648 exception_exit(prev_state);
649 }
650
651 dotraplinkage void
do_simd_coprocessor_error(struct pt_regs * regs,long error_code)652 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
653 {
654 enum ctx_state prev_state;
655
656 prev_state = exception_enter();
657 math_error(regs, error_code, X86_TRAP_XF);
658 exception_exit(prev_state);
659 }
660
661 dotraplinkage void
do_spurious_interrupt_bug(struct pt_regs * regs,long error_code)662 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
663 {
664 conditional_sti(regs);
665 #if 0
666 /* No need to warn about this any longer. */
667 pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
668 #endif
669 }
670
smp_thermal_interrupt(void)671 asmlinkage __visible void __attribute__((weak)) smp_thermal_interrupt(void)
672 {
673 }
674
smp_threshold_interrupt(void)675 asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void)
676 {
677 }
678
679 /*
680 * 'math_state_restore()' saves the current math information in the
681 * old math state array, and gets the new ones from the current task
682 *
683 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
684 * Don't touch unless you *really* know how it works.
685 *
686 * Must be called with kernel preemption disabled (eg with local
687 * local interrupts as in the case of do_device_not_available).
688 */
math_state_restore(void)689 void math_state_restore(void)
690 {
691 struct task_struct *tsk = current;
692
693 if (!tsk_used_math(tsk)) {
694 local_irq_enable();
695 /*
696 * does a slab alloc which can sleep
697 */
698 if (init_fpu(tsk)) {
699 /*
700 * ran out of memory!
701 */
702 do_group_exit(SIGKILL);
703 return;
704 }
705 local_irq_disable();
706 }
707
708 __thread_fpu_begin(tsk);
709
710 /*
711 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
712 */
713 if (unlikely(restore_fpu_checking(tsk))) {
714 drop_init_fpu(tsk);
715 force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
716 return;
717 }
718
719 tsk->thread.fpu_counter++;
720 }
721 EXPORT_SYMBOL_GPL(math_state_restore);
722
723 dotraplinkage void
do_device_not_available(struct pt_regs * regs,long error_code)724 do_device_not_available(struct pt_regs *regs, long error_code)
725 {
726 enum ctx_state prev_state;
727
728 prev_state = exception_enter();
729 BUG_ON(use_eager_fpu());
730
731 #ifdef CONFIG_MATH_EMULATION
732 if (read_cr0() & X86_CR0_EM) {
733 struct math_emu_info info = { };
734
735 conditional_sti(regs);
736
737 info.regs = regs;
738 math_emulate(&info);
739 exception_exit(prev_state);
740 return;
741 }
742 #endif
743 math_state_restore(); /* interrupts still off */
744 #ifdef CONFIG_X86_32
745 conditional_sti(regs);
746 #endif
747 exception_exit(prev_state);
748 }
749 NOKPROBE_SYMBOL(do_device_not_available);
750
751 #ifdef CONFIG_X86_32
do_iret_error(struct pt_regs * regs,long error_code)752 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
753 {
754 siginfo_t info;
755 enum ctx_state prev_state;
756
757 prev_state = exception_enter();
758 local_irq_enable();
759
760 info.si_signo = SIGILL;
761 info.si_errno = 0;
762 info.si_code = ILL_BADSTK;
763 info.si_addr = NULL;
764 if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
765 X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
766 do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
767 &info);
768 }
769 exception_exit(prev_state);
770 }
771 #endif
772
773 /* Set of traps needed for early debugging. */
early_trap_init(void)774 void __init early_trap_init(void)
775 {
776 set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
777 /* int3 can be called from all */
778 set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
779 #ifdef CONFIG_X86_32
780 set_intr_gate(X86_TRAP_PF, page_fault);
781 #endif
782 load_idt(&idt_descr);
783 }
784
early_trap_pf_init(void)785 void __init early_trap_pf_init(void)
786 {
787 #ifdef CONFIG_X86_64
788 set_intr_gate(X86_TRAP_PF, page_fault);
789 #endif
790 }
791
trap_init(void)792 void __init trap_init(void)
793 {
794 int i;
795
796 #ifdef CONFIG_EISA
797 void __iomem *p = early_ioremap(0x0FFFD9, 4);
798
799 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
800 EISA_bus = 1;
801 early_iounmap(p, 4);
802 #endif
803
804 set_intr_gate(X86_TRAP_DE, divide_error);
805 set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
806 /* int4 can be called from all */
807 set_system_intr_gate(X86_TRAP_OF, &overflow);
808 set_intr_gate(X86_TRAP_BR, bounds);
809 set_intr_gate(X86_TRAP_UD, invalid_op);
810 set_intr_gate(X86_TRAP_NM, device_not_available);
811 #ifdef CONFIG_X86_32
812 set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
813 #else
814 set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
815 #endif
816 set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
817 set_intr_gate(X86_TRAP_TS, invalid_TSS);
818 set_intr_gate(X86_TRAP_NP, segment_not_present);
819 set_intr_gate(X86_TRAP_SS, stack_segment);
820 set_intr_gate(X86_TRAP_GP, general_protection);
821 set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
822 set_intr_gate(X86_TRAP_MF, coprocessor_error);
823 set_intr_gate(X86_TRAP_AC, alignment_check);
824 #ifdef CONFIG_X86_MCE
825 set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
826 #endif
827 set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
828
829 /* Reserve all the builtin and the syscall vector: */
830 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
831 set_bit(i, used_vectors);
832
833 #ifdef CONFIG_IA32_EMULATION
834 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
835 set_bit(IA32_SYSCALL_VECTOR, used_vectors);
836 #endif
837
838 #ifdef CONFIG_X86_32
839 set_system_trap_gate(SYSCALL_VECTOR, &system_call);
840 set_bit(SYSCALL_VECTOR, used_vectors);
841 #endif
842
843 /*
844 * Set the IDT descriptor to a fixed read-only location, so that the
845 * "sidt" instruction will not leak the location of the kernel, and
846 * to defend the IDT against arbitrary memory write vulnerabilities.
847 * It will be reloaded in cpu_init() */
848 __set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
849 idt_descr.address = fix_to_virt(FIX_RO_IDT);
850
851 /*
852 * Should be a barrier for any external CPU state:
853 */
854 cpu_init();
855
856 x86_init.irqs.trap_init();
857
858 #ifdef CONFIG_X86_64
859 memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
860 set_nmi_gate(X86_TRAP_DB, &debug);
861 set_nmi_gate(X86_TRAP_BP, &int3);
862 #endif
863 }
864