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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 | ||
13 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
14 | ||
15 | #include <linux/interrupt.h> | |
16 | #include <linux/kallsyms.h> | |
17 | #include <linux/spinlock.h> | |
18 | #include <linux/kprobes.h> | |
19 | #include <linux/uaccess.h> | |
20 | #include <linux/kdebug.h> | |
21 | #include <linux/kgdb.h> | |
22 | #include <linux/kernel.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/ptrace.h> | |
25 | #include <linux/string.h> | |
26 | #include <linux/delay.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/kexec.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/timer.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/bug.h> | |
33 | #include <linux/nmi.h> | |
34 | #include <linux/mm.h> | |
35 | #include <linux/smp.h> | |
36 | #include <linux/io.h> | |
37 | ||
38 | #ifdef CONFIG_EISA | |
39 | #include <linux/ioport.h> | |
40 | #include <linux/eisa.h> | |
41 | #endif | |
42 | ||
43 | #if defined(CONFIG_EDAC) | |
44 | #include <linux/edac.h> | |
45 | #endif | |
46 | ||
47 | #include <asm/kmemcheck.h> | |
48 | #include <asm/stacktrace.h> | |
49 | #include <asm/processor.h> | |
50 | #include <asm/debugreg.h> | |
51 | #include <linux/atomic.h> | |
52 | #include <asm/ftrace.h> | |
53 | #include <asm/traps.h> | |
54 | #include <asm/desc.h> | |
55 | #include <asm/i387.h> | |
56 | #include <asm/fpu-internal.h> | |
57 | #include <asm/mce.h> | |
58 | #include <asm/rcu.h> | |
59 | ||
60 | #include <asm/mach_traps.h> | |
61 | ||
62 | #ifdef CONFIG_X86_64 | |
63 | #include <asm/x86_init.h> | |
64 | #include <asm/pgalloc.h> | |
65 | #include <asm/proto.h> | |
66 | #else | |
67 | #include <asm/processor-flags.h> | |
68 | #include <asm/setup.h> | |
69 | ||
70 | asmlinkage int system_call(void); | |
71 | ||
72 | /* | |
73 | * The IDT has to be page-aligned to simplify the Pentium | |
74 | * F0 0F bug workaround. | |
75 | */ | |
76 | gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, }; | |
77 | #endif | |
78 | ||
79 | DECLARE_BITMAP(used_vectors, NR_VECTORS); | |
80 | EXPORT_SYMBOL_GPL(used_vectors); | |
81 | ||
82 | static inline void conditional_sti(struct pt_regs *regs) | |
83 | { | |
84 | if (regs->flags & X86_EFLAGS_IF) | |
85 | local_irq_enable(); | |
86 | } | |
87 | ||
88 | static inline void preempt_conditional_sti(struct pt_regs *regs) | |
89 | { | |
90 | inc_preempt_count(); | |
91 | if (regs->flags & X86_EFLAGS_IF) | |
92 | local_irq_enable(); | |
93 | } | |
94 | ||
95 | static inline void conditional_cli(struct pt_regs *regs) | |
96 | { | |
97 | if (regs->flags & X86_EFLAGS_IF) | |
98 | local_irq_disable(); | |
99 | } | |
100 | ||
101 | static inline void preempt_conditional_cli(struct pt_regs *regs) | |
102 | { | |
103 | if (regs->flags & X86_EFLAGS_IF) | |
104 | local_irq_disable(); | |
105 | dec_preempt_count(); | |
106 | } | |
107 | ||
108 | static int __kprobes | |
109 | do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str, | |
110 | struct pt_regs *regs, long error_code) | |
111 | { | |
112 | #ifdef CONFIG_X86_32 | |
113 | if (regs->flags & X86_VM_MASK) { | |
114 | /* | |
115 | * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86. | |
116 | * On nmi (interrupt 2), do_trap should not be called. | |
117 | */ | |
118 | if (trapnr < X86_TRAP_UD) { | |
119 | if (!handle_vm86_trap((struct kernel_vm86_regs *) regs, | |
120 | error_code, trapnr)) | |
121 | return 0; | |
122 | } | |
123 | return -1; | |
124 | } | |
125 | #endif | |
126 | if (!user_mode(regs)) { | |
127 | if (!fixup_exception(regs)) { | |
128 | tsk->thread.error_code = error_code; | |
129 | tsk->thread.trap_nr = trapnr; | |
130 | die(str, regs, error_code); | |
131 | } | |
132 | return 0; | |
133 | } | |
134 | ||
135 | return -1; | |
136 | } | |
137 | ||
138 | static void __kprobes | |
139 | do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, | |
140 | long error_code, siginfo_t *info) | |
141 | { | |
142 | struct task_struct *tsk = current; | |
143 | ||
144 | ||
145 | if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code)) | |
146 | return; | |
147 | /* | |
148 | * We want error_code and trap_nr set for userspace faults and | |
149 | * kernelspace faults which result in die(), but not | |
150 | * kernelspace faults which are fixed up. die() gives the | |
151 | * process no chance to handle the signal and notice the | |
152 | * kernel fault information, so that won't result in polluting | |
153 | * the information about previously queued, but not yet | |
154 | * delivered, faults. See also do_general_protection below. | |
155 | */ | |
156 | tsk->thread.error_code = error_code; | |
157 | tsk->thread.trap_nr = trapnr; | |
158 | ||
159 | #ifdef CONFIG_X86_64 | |
160 | if (show_unhandled_signals && unhandled_signal(tsk, signr) && | |
161 | printk_ratelimit()) { | |
162 | pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx", | |
163 | tsk->comm, tsk->pid, str, | |
164 | regs->ip, regs->sp, error_code); | |
165 | print_vma_addr(" in ", regs->ip); | |
166 | pr_cont("\n"); | |
167 | } | |
168 | #endif | |
169 | ||
170 | if (info) | |
171 | force_sig_info(signr, info, tsk); | |
172 | else | |
173 | force_sig(signr, tsk); | |
174 | } | |
175 | ||
176 | #define DO_ERROR(trapnr, signr, str, name) \ | |
177 | dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ | |
178 | { \ | |
179 | exception_enter(regs); \ | |
180 | if (notify_die(DIE_TRAP, str, regs, error_code, \ | |
181 | trapnr, signr) == NOTIFY_STOP) { \ | |
182 | exception_exit(regs); \ | |
183 | return; \ | |
184 | } \ | |
185 | conditional_sti(regs); \ | |
186 | do_trap(trapnr, signr, str, regs, error_code, NULL); \ | |
187 | exception_exit(regs); \ | |
188 | } | |
189 | ||
190 | #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ | |
191 | dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ | |
192 | { \ | |
193 | siginfo_t info; \ | |
194 | info.si_signo = signr; \ | |
195 | info.si_errno = 0; \ | |
196 | info.si_code = sicode; \ | |
197 | info.si_addr = (void __user *)siaddr; \ | |
198 | exception_enter(regs); \ | |
199 | if (notify_die(DIE_TRAP, str, regs, error_code, \ | |
200 | trapnr, signr) == NOTIFY_STOP) { \ | |
201 | exception_exit(regs); \ | |
202 | return; \ | |
203 | } \ | |
204 | conditional_sti(regs); \ | |
205 | do_trap(trapnr, signr, str, regs, error_code, &info); \ | |
206 | exception_exit(regs); \ | |
207 | } | |
208 | ||
209 | DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV, | |
210 | regs->ip) | |
211 | DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow) | |
212 | DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds) | |
213 | DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, | |
214 | regs->ip) | |
215 | DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun", | |
216 | coprocessor_segment_overrun) | |
217 | DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS) | |
218 | DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present) | |
219 | #ifdef CONFIG_X86_32 | |
220 | DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment) | |
221 | #endif | |
222 | DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check, | |
223 | BUS_ADRALN, 0) | |
224 | ||
225 | #ifdef CONFIG_X86_64 | |
226 | /* Runs on IST stack */ | |
227 | dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code) | |
228 | { | |
229 | exception_enter(regs); | |
230 | if (notify_die(DIE_TRAP, "stack segment", regs, error_code, | |
231 | X86_TRAP_SS, SIGBUS) != NOTIFY_STOP) { | |
232 | preempt_conditional_sti(regs); | |
233 | do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL); | |
234 | preempt_conditional_cli(regs); | |
235 | } | |
236 | exception_exit(regs); | |
237 | } | |
238 | ||
239 | dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) | |
240 | { | |
241 | static const char str[] = "double fault"; | |
242 | struct task_struct *tsk = current; | |
243 | ||
244 | exception_enter(regs); | |
245 | /* Return not checked because double check cannot be ignored */ | |
246 | notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV); | |
247 | ||
248 | tsk->thread.error_code = error_code; | |
249 | tsk->thread.trap_nr = X86_TRAP_DF; | |
250 | ||
251 | /* | |
252 | * This is always a kernel trap and never fixable (and thus must | |
253 | * never return). | |
254 | */ | |
255 | for (;;) | |
256 | die(str, regs, error_code); | |
257 | } | |
258 | #endif | |
259 | ||
260 | dotraplinkage void __kprobes | |
261 | do_general_protection(struct pt_regs *regs, long error_code) | |
262 | { | |
263 | struct task_struct *tsk; | |
264 | ||
265 | exception_enter(regs); | |
266 | conditional_sti(regs); | |
267 | ||
268 | #ifdef CONFIG_X86_32 | |
269 | if (regs->flags & X86_VM_MASK) { | |
270 | local_irq_enable(); | |
271 | handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code); | |
272 | goto exit; | |
273 | } | |
274 | #endif | |
275 | ||
276 | tsk = current; | |
277 | if (!user_mode(regs)) { | |
278 | if (fixup_exception(regs)) | |
279 | goto exit; | |
280 | ||
281 | tsk->thread.error_code = error_code; | |
282 | tsk->thread.trap_nr = X86_TRAP_GP; | |
283 | if (notify_die(DIE_GPF, "general protection fault", regs, error_code, | |
284 | X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP) | |
285 | die("general protection fault", regs, error_code); | |
286 | goto exit; | |
287 | } | |
288 | ||
289 | tsk->thread.error_code = error_code; | |
290 | tsk->thread.trap_nr = X86_TRAP_GP; | |
291 | ||
292 | if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && | |
293 | printk_ratelimit()) { | |
294 | pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx", | |
295 | tsk->comm, task_pid_nr(tsk), | |
296 | regs->ip, regs->sp, error_code); | |
297 | print_vma_addr(" in ", regs->ip); | |
298 | pr_cont("\n"); | |
299 | } | |
300 | ||
301 | force_sig(SIGSEGV, tsk); | |
302 | exit: | |
303 | exception_exit(regs); | |
304 | } | |
305 | ||
306 | /* May run on IST stack. */ | |
307 | dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code) | |
308 | { | |
309 | #ifdef CONFIG_DYNAMIC_FTRACE | |
310 | /* | |
311 | * ftrace must be first, everything else may cause a recursive crash. | |
312 | * See note by declaration of modifying_ftrace_code in ftrace.c | |
313 | */ | |
314 | if (unlikely(atomic_read(&modifying_ftrace_code)) && | |
315 | ftrace_int3_handler(regs)) | |
316 | return; | |
317 | #endif | |
318 | exception_enter(regs); | |
319 | #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP | |
320 | if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, | |
321 | SIGTRAP) == NOTIFY_STOP) | |
322 | goto exit; | |
323 | #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */ | |
324 | ||
325 | if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, | |
326 | SIGTRAP) == NOTIFY_STOP) | |
327 | goto exit; | |
328 | ||
329 | /* | |
330 | * Let others (NMI) know that the debug stack is in use | |
331 | * as we may switch to the interrupt stack. | |
332 | */ | |
333 | debug_stack_usage_inc(); | |
334 | preempt_conditional_sti(regs); | |
335 | do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL); | |
336 | preempt_conditional_cli(regs); | |
337 | debug_stack_usage_dec(); | |
338 | exit: | |
339 | exception_exit(regs); | |
340 | } | |
341 | ||
342 | #ifdef CONFIG_X86_64 | |
343 | /* | |
344 | * Help handler running on IST stack to switch back to user stack | |
345 | * for scheduling or signal handling. The actual stack switch is done in | |
346 | * entry.S | |
347 | */ | |
348 | asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs) | |
349 | { | |
350 | struct pt_regs *regs = eregs; | |
351 | /* Did already sync */ | |
352 | if (eregs == (struct pt_regs *)eregs->sp) | |
353 | ; | |
354 | /* Exception from user space */ | |
355 | else if (user_mode(eregs)) | |
356 | regs = task_pt_regs(current); | |
357 | /* | |
358 | * Exception from kernel and interrupts are enabled. Move to | |
359 | * kernel process stack. | |
360 | */ | |
361 | else if (eregs->flags & X86_EFLAGS_IF) | |
362 | regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs)); | |
363 | if (eregs != regs) | |
364 | *regs = *eregs; | |
365 | return regs; | |
366 | } | |
367 | #endif | |
368 | ||
369 | /* | |
370 | * Our handling of the processor debug registers is non-trivial. | |
371 | * We do not clear them on entry and exit from the kernel. Therefore | |
372 | * it is possible to get a watchpoint trap here from inside the kernel. | |
373 | * However, the code in ./ptrace.c has ensured that the user can | |
374 | * only set watchpoints on userspace addresses. Therefore the in-kernel | |
375 | * watchpoint trap can only occur in code which is reading/writing | |
376 | * from user space. Such code must not hold kernel locks (since it | |
377 | * can equally take a page fault), therefore it is safe to call | |
378 | * force_sig_info even though that claims and releases locks. | |
379 | * | |
380 | * Code in ./signal.c ensures that the debug control register | |
381 | * is restored before we deliver any signal, and therefore that | |
382 | * user code runs with the correct debug control register even though | |
383 | * we clear it here. | |
384 | * | |
385 | * Being careful here means that we don't have to be as careful in a | |
386 | * lot of more complicated places (task switching can be a bit lazy | |
387 | * about restoring all the debug state, and ptrace doesn't have to | |
388 | * find every occurrence of the TF bit that could be saved away even | |
389 | * by user code) | |
390 | * | |
391 | * May run on IST stack. | |
392 | */ | |
393 | dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) | |
394 | { | |
395 | struct task_struct *tsk = current; | |
396 | int user_icebp = 0; | |
397 | unsigned long dr6; | |
398 | int si_code; | |
399 | ||
400 | exception_enter(regs); | |
401 | ||
402 | get_debugreg(dr6, 6); | |
403 | ||
404 | /* Filter out all the reserved bits which are preset to 1 */ | |
405 | dr6 &= ~DR6_RESERVED; | |
406 | ||
407 | /* | |
408 | * If dr6 has no reason to give us about the origin of this trap, | |
409 | * then it's very likely the result of an icebp/int01 trap. | |
410 | * User wants a sigtrap for that. | |
411 | */ | |
412 | if (!dr6 && user_mode(regs)) | |
413 | user_icebp = 1; | |
414 | ||
415 | /* Catch kmemcheck conditions first of all! */ | |
416 | if ((dr6 & DR_STEP) && kmemcheck_trap(regs)) | |
417 | goto exit; | |
418 | ||
419 | /* DR6 may or may not be cleared by the CPU */ | |
420 | set_debugreg(0, 6); | |
421 | ||
422 | /* | |
423 | * The processor cleared BTF, so don't mark that we need it set. | |
424 | */ | |
425 | clear_tsk_thread_flag(tsk, TIF_BLOCKSTEP); | |
426 | ||
427 | /* Store the virtualized DR6 value */ | |
428 | tsk->thread.debugreg6 = dr6; | |
429 | ||
430 | if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code, | |
431 | SIGTRAP) == NOTIFY_STOP) | |
432 | goto exit; | |
433 | ||
434 | /* | |
435 | * Let others (NMI) know that the debug stack is in use | |
436 | * as we may switch to the interrupt stack. | |
437 | */ | |
438 | debug_stack_usage_inc(); | |
439 | ||
440 | /* It's safe to allow irq's after DR6 has been saved */ | |
441 | preempt_conditional_sti(regs); | |
442 | ||
443 | if (regs->flags & X86_VM_MASK) { | |
444 | handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, | |
445 | X86_TRAP_DB); | |
446 | preempt_conditional_cli(regs); | |
447 | debug_stack_usage_dec(); | |
448 | goto exit; | |
449 | } | |
450 | ||
451 | /* | |
452 | * Single-stepping through system calls: ignore any exceptions in | |
453 | * kernel space, but re-enable TF when returning to user mode. | |
454 | * | |
455 | * We already checked v86 mode above, so we can check for kernel mode | |
456 | * by just checking the CPL of CS. | |
457 | */ | |
458 | if ((dr6 & DR_STEP) && !user_mode(regs)) { | |
459 | tsk->thread.debugreg6 &= ~DR_STEP; | |
460 | set_tsk_thread_flag(tsk, TIF_SINGLESTEP); | |
461 | regs->flags &= ~X86_EFLAGS_TF; | |
462 | } | |
463 | si_code = get_si_code(tsk->thread.debugreg6); | |
464 | if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp) | |
465 | send_sigtrap(tsk, regs, error_code, si_code); | |
466 | preempt_conditional_cli(regs); | |
467 | debug_stack_usage_dec(); | |
468 | ||
469 | exit: | |
470 | exception_exit(regs); | |
471 | } | |
472 | ||
473 | /* | |
474 | * Note that we play around with the 'TS' bit in an attempt to get | |
475 | * the correct behaviour even in the presence of the asynchronous | |
476 | * IRQ13 behaviour | |
477 | */ | |
478 | void math_error(struct pt_regs *regs, int error_code, int trapnr) | |
479 | { | |
480 | struct task_struct *task = current; | |
481 | siginfo_t info; | |
482 | unsigned short err; | |
483 | char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" : | |
484 | "simd exception"; | |
485 | ||
486 | if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, SIGFPE) == NOTIFY_STOP) | |
487 | return; | |
488 | conditional_sti(regs); | |
489 | ||
490 | if (!user_mode_vm(regs)) | |
491 | { | |
492 | if (!fixup_exception(regs)) { | |
493 | task->thread.error_code = error_code; | |
494 | task->thread.trap_nr = trapnr; | |
495 | die(str, regs, error_code); | |
496 | } | |
497 | return; | |
498 | } | |
499 | ||
500 | /* | |
501 | * Save the info for the exception handler and clear the error. | |
502 | */ | |
503 | save_init_fpu(task); | |
504 | task->thread.trap_nr = trapnr; | |
505 | task->thread.error_code = error_code; | |
506 | info.si_signo = SIGFPE; | |
507 | info.si_errno = 0; | |
508 | info.si_addr = (void __user *)regs->ip; | |
509 | if (trapnr == X86_TRAP_MF) { | |
510 | unsigned short cwd, swd; | |
511 | /* | |
512 | * (~cwd & swd) will mask out exceptions that are not set to unmasked | |
513 | * status. 0x3f is the exception bits in these regs, 0x200 is the | |
514 | * C1 reg you need in case of a stack fault, 0x040 is the stack | |
515 | * fault bit. We should only be taking one exception at a time, | |
516 | * so if this combination doesn't produce any single exception, | |
517 | * then we have a bad program that isn't synchronizing its FPU usage | |
518 | * and it will suffer the consequences since we won't be able to | |
519 | * fully reproduce the context of the exception | |
520 | */ | |
521 | cwd = get_fpu_cwd(task); | |
522 | swd = get_fpu_swd(task); | |
523 | ||
524 | err = swd & ~cwd; | |
525 | } else { | |
526 | /* | |
527 | * The SIMD FPU exceptions are handled a little differently, as there | |
528 | * is only a single status/control register. Thus, to determine which | |
529 | * unmasked exception was caught we must mask the exception mask bits | |
530 | * at 0x1f80, and then use these to mask the exception bits at 0x3f. | |
531 | */ | |
532 | unsigned short mxcsr = get_fpu_mxcsr(task); | |
533 | err = ~(mxcsr >> 7) & mxcsr; | |
534 | } | |
535 | ||
536 | if (err & 0x001) { /* Invalid op */ | |
537 | /* | |
538 | * swd & 0x240 == 0x040: Stack Underflow | |
539 | * swd & 0x240 == 0x240: Stack Overflow | |
540 | * User must clear the SF bit (0x40) if set | |
541 | */ | |
542 | info.si_code = FPE_FLTINV; | |
543 | } else if (err & 0x004) { /* Divide by Zero */ | |
544 | info.si_code = FPE_FLTDIV; | |
545 | } else if (err & 0x008) { /* Overflow */ | |
546 | info.si_code = FPE_FLTOVF; | |
547 | } else if (err & 0x012) { /* Denormal, Underflow */ | |
548 | info.si_code = FPE_FLTUND; | |
549 | } else if (err & 0x020) { /* Precision */ | |
550 | info.si_code = FPE_FLTRES; | |
551 | } else { | |
552 | /* | |
553 | * If we're using IRQ 13, or supposedly even some trap | |
554 | * X86_TRAP_MF implementations, it's possible | |
555 | * we get a spurious trap, which is not an error. | |
556 | */ | |
557 | return; | |
558 | } | |
559 | force_sig_info(SIGFPE, &info, task); | |
560 | } | |
561 | ||
562 | dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) | |
563 | { | |
564 | exception_enter(regs); | |
565 | math_error(regs, error_code, X86_TRAP_MF); | |
566 | exception_exit(regs); | |
567 | } | |
568 | ||
569 | dotraplinkage void | |
570 | do_simd_coprocessor_error(struct pt_regs *regs, long error_code) | |
571 | { | |
572 | exception_enter(regs); | |
573 | math_error(regs, error_code, X86_TRAP_XF); | |
574 | exception_exit(regs); | |
575 | } | |
576 | ||
577 | dotraplinkage void | |
578 | do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) | |
579 | { | |
580 | conditional_sti(regs); | |
581 | #if 0 | |
582 | /* No need to warn about this any longer. */ | |
583 | pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n"); | |
584 | #endif | |
585 | } | |
586 | ||
587 | asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void) | |
588 | { | |
589 | } | |
590 | ||
591 | asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void) | |
592 | { | |
593 | } | |
594 | ||
595 | /* | |
596 | * 'math_state_restore()' saves the current math information in the | |
597 | * old math state array, and gets the new ones from the current task | |
598 | * | |
599 | * Careful.. There are problems with IBM-designed IRQ13 behaviour. | |
600 | * Don't touch unless you *really* know how it works. | |
601 | * | |
602 | * Must be called with kernel preemption disabled (eg with local | |
603 | * local interrupts as in the case of do_device_not_available). | |
604 | */ | |
605 | void math_state_restore(void) | |
606 | { | |
607 | struct task_struct *tsk = current; | |
608 | ||
609 | if (!tsk_used_math(tsk)) { | |
610 | local_irq_enable(); | |
611 | /* | |
612 | * does a slab alloc which can sleep | |
613 | */ | |
614 | if (init_fpu(tsk)) { | |
615 | /* | |
616 | * ran out of memory! | |
617 | */ | |
618 | do_group_exit(SIGKILL); | |
619 | return; | |
620 | } | |
621 | local_irq_disable(); | |
622 | } | |
623 | ||
624 | __thread_fpu_begin(tsk); | |
625 | ||
626 | /* | |
627 | * Paranoid restore. send a SIGSEGV if we fail to restore the state. | |
628 | */ | |
629 | if (unlikely(restore_fpu_checking(tsk))) { | |
630 | drop_init_fpu(tsk); | |
631 | force_sig(SIGSEGV, tsk); | |
632 | return; | |
633 | } | |
634 | ||
635 | tsk->fpu_counter++; | |
636 | } | |
637 | EXPORT_SYMBOL_GPL(math_state_restore); | |
638 | ||
639 | dotraplinkage void __kprobes | |
640 | do_device_not_available(struct pt_regs *regs, long error_code) | |
641 | { | |
642 | exception_enter(regs); | |
643 | BUG_ON(use_eager_fpu()); | |
644 | ||
645 | #ifdef CONFIG_MATH_EMULATION | |
646 | if (read_cr0() & X86_CR0_EM) { | |
647 | struct math_emu_info info = { }; | |
648 | ||
649 | conditional_sti(regs); | |
650 | ||
651 | info.regs = regs; | |
652 | math_emulate(&info); | |
653 | exception_exit(regs); | |
654 | return; | |
655 | } | |
656 | #endif | |
657 | math_state_restore(); /* interrupts still off */ | |
658 | #ifdef CONFIG_X86_32 | |
659 | conditional_sti(regs); | |
660 | #endif | |
661 | exception_exit(regs); | |
662 | } | |
663 | ||
664 | #ifdef CONFIG_X86_32 | |
665 | dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) | |
666 | { | |
667 | siginfo_t info; | |
668 | ||
669 | exception_enter(regs); | |
670 | local_irq_enable(); | |
671 | ||
672 | info.si_signo = SIGILL; | |
673 | info.si_errno = 0; | |
674 | info.si_code = ILL_BADSTK; | |
675 | info.si_addr = NULL; | |
676 | if (notify_die(DIE_TRAP, "iret exception", regs, error_code, | |
677 | X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) { | |
678 | do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code, | |
679 | &info); | |
680 | } | |
681 | exception_exit(regs); | |
682 | } | |
683 | #endif | |
684 | ||
685 | /* Set of traps needed for early debugging. */ | |
686 | void __init early_trap_init(void) | |
687 | { | |
688 | set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK); | |
689 | /* int3 can be called from all */ | |
690 | set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK); | |
691 | set_intr_gate(X86_TRAP_PF, &page_fault); | |
692 | load_idt(&idt_descr); | |
693 | } | |
694 | ||
695 | void __init trap_init(void) | |
696 | { | |
697 | int i; | |
698 | ||
699 | #ifdef CONFIG_EISA | |
700 | void __iomem *p = early_ioremap(0x0FFFD9, 4); | |
701 | ||
702 | if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24)) | |
703 | EISA_bus = 1; | |
704 | early_iounmap(p, 4); | |
705 | #endif | |
706 | ||
707 | set_intr_gate(X86_TRAP_DE, ÷_error); | |
708 | set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK); | |
709 | /* int4 can be called from all */ | |
710 | set_system_intr_gate(X86_TRAP_OF, &overflow); | |
711 | set_intr_gate(X86_TRAP_BR, &bounds); | |
712 | set_intr_gate(X86_TRAP_UD, &invalid_op); | |
713 | set_intr_gate(X86_TRAP_NM, &device_not_available); | |
714 | #ifdef CONFIG_X86_32 | |
715 | set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS); | |
716 | #else | |
717 | set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK); | |
718 | #endif | |
719 | set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun); | |
720 | set_intr_gate(X86_TRAP_TS, &invalid_TSS); | |
721 | set_intr_gate(X86_TRAP_NP, &segment_not_present); | |
722 | set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK); | |
723 | set_intr_gate(X86_TRAP_GP, &general_protection); | |
724 | set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug); | |
725 | set_intr_gate(X86_TRAP_MF, &coprocessor_error); | |
726 | set_intr_gate(X86_TRAP_AC, &alignment_check); | |
727 | #ifdef CONFIG_X86_MCE | |
728 | set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK); | |
729 | #endif | |
730 | set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error); | |
731 | ||
732 | /* Reserve all the builtin and the syscall vector: */ | |
733 | for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) | |
734 | set_bit(i, used_vectors); | |
735 | ||
736 | #ifdef CONFIG_IA32_EMULATION | |
737 | set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall); | |
738 | set_bit(IA32_SYSCALL_VECTOR, used_vectors); | |
739 | #endif | |
740 | ||
741 | #ifdef CONFIG_X86_32 | |
742 | set_system_trap_gate(SYSCALL_VECTOR, &system_call); | |
743 | set_bit(SYSCALL_VECTOR, used_vectors); | |
744 | #endif | |
745 | ||
746 | /* | |
747 | * Should be a barrier for any external CPU state: | |
748 | */ | |
749 | cpu_init(); | |
750 | ||
751 | x86_init.irqs.trap_init(); | |
752 | ||
753 | #ifdef CONFIG_X86_64 | |
754 | memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16); | |
755 | set_nmi_gate(X86_TRAP_DB, &debug); | |
756 | set_nmi_gate(X86_TRAP_BP, &int3); | |
757 | #endif | |
758 | } |