1 /*
2 * linux/arch/x86-64/traps.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
6 *
7 * Pentium III FXSR, SSE support
8 * Gareth Hughes <gareth@valinux.com>, May 2000
9 *
10 * $Id: traps.c,v 1.71 2004/02/27 22:07:36 ak Exp $
11 */
12
13 /*
14 * 'Traps.c' handles hardware traps and faults after we have saved some
15 * state in 'entry.S'.
16 */
17 #include <linux/config.h>
18 #include <linux/sched.h>
19 #include <linux/kernel.h>
20 #include <linux/string.h>
21 #include <linux/errno.h>
22 #include <linux/ptrace.h>
23 #include <linux/timer.h>
24 #include <linux/mm.h>
25 #include <linux/init.h>
26 #include <linux/delay.h>
27 #include <linux/spinlock.h>
28 #include <linux/interrupt.h>
29 #include <linux/module.h>
30
31 #include <asm/system.h>
32 #include <asm/uaccess.h>
33 #include <asm/io.h>
34 #include <asm/atomic.h>
35 #include <asm/debugreg.h>
36 #include <asm/desc.h>
37 #include <asm/i387.h>
38 #include <asm/kdebug.h>
39
40 #include <asm/smp.h>
41 #include <asm/pgalloc.h>
42 #include <asm/pda.h>
43 #include <asm/proto.h>
44
45 #include <linux/irq.h>
46
47 extern int exception_trace;
48
49 extern struct gate_struct idt_table[256];
50
51 asmlinkage void divide_error(void);
52 asmlinkage void debug(void);
53 asmlinkage void nmi(void);
54 asmlinkage void int3(void);
55 asmlinkage void overflow(void);
56 asmlinkage void bounds(void);
57 asmlinkage void invalid_op(void);
58 asmlinkage void device_not_available(void);
59 asmlinkage void double_fault(void);
60 asmlinkage void coprocessor_segment_overrun(void);
61 asmlinkage void invalid_TSS(void);
62 asmlinkage void segment_not_present(void);
63 asmlinkage void stack_segment(void);
64 asmlinkage void general_protection(void);
65 asmlinkage void page_fault(void);
66 asmlinkage void coprocessor_error(void);
67 asmlinkage void simd_coprocessor_error(void);
68 asmlinkage void reserved(void);
69 asmlinkage void alignment_check(void);
70 asmlinkage void machine_check(void);
71 asmlinkage void spurious_interrupt_bug(void);
72 asmlinkage void call_debug(void);
73
conditional_sti(struct pt_regs * regs)74 static inline void conditional_sti(struct pt_regs *regs)
75 {
76 if (regs->eflags & X86_EFLAGS_IF)
77 __sti();
78 }
79
80 extern char iret_address[];
81
82 struct notifier_block *die_chain;
83
84 int kstack_depth_to_print = 12;
85
86 #ifdef CONFIG_KALLSYMS
87 #include <linux/kallsyms.h>
printk_address(unsigned long address)88 int printk_address(unsigned long address)
89 {
90 unsigned long dummy;
91 const char *modname, *secname, *symname;
92 unsigned long symstart;
93 char *delim = ":";
94
95 /* What a function call! */
96 if (!kallsyms_address_to_symbol(address,
97 &modname, &dummy, &dummy,
98 &secname, &dummy, &dummy,
99 &symname, &symstart, &dummy)) {
100 return printk("[<%016lx>]", address);
101 }
102 if (!strcmp(modname, "kernel"))
103 modname = delim = "";
104 return printk("[<%016lx>]{%s%s%s%s%+ld}",
105 address,delim,modname,delim,symname,address-symstart);
106 }
107 #else
printk_address(unsigned long address)108 int printk_address(unsigned long address)
109 {
110 return printk("[<%016lx>]", address);
111 }
112 #endif
113
114
115 #ifdef CONFIG_MODULES
116
117 extern struct module *module_list;
118 extern struct module kernel_module;
119
kernel_text_address(unsigned long addr)120 static inline int kernel_text_address(unsigned long addr)
121 {
122 int retval = 0;
123 struct module *mod;
124
125 if (addr >= (unsigned long) &_stext &&
126 addr <= (unsigned long) &_etext)
127 return 1;
128
129 for (mod = module_list; mod != &kernel_module; mod = mod->next) {
130 /* mod_bound tests for addr being inside the vmalloc'ed
131 * module area. Of course it'd be better to test only
132 * for the .text subset... */
133 if (mod_bound(addr, 0, mod)) {
134 retval = 1;
135 break;
136 }
137 }
138
139 return retval;
140 }
141
142 #else
143
kernel_text_address(unsigned long addr)144 static inline int kernel_text_address(unsigned long addr)
145 {
146 return (addr >= (unsigned long) &_stext &&
147 addr <= (unsigned long) &_etext);
148 }
149
150 #endif
151
in_exception_stack(int cpu,unsigned long stack)152 unsigned long *in_exception_stack(int cpu, unsigned long stack)
153 {
154 int k;
155 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
156 unsigned long end = init_tss[cpu].ist[k] + EXCEPTION_STKSZ;
157
158 if (stack >= init_tss[cpu].ist[k] && stack <= end)
159 return (unsigned long *)end;
160 }
161 return 0;
162 }
163
show_trace(unsigned long * stack)164 void show_trace(unsigned long *stack)
165 {
166 unsigned long addr;
167 unsigned long *irqstack, *irqstack_end, *estack_end;
168 const int cpu = safe_smp_processor_id();
169 int i;
170
171 printk("\nCall Trace: ");
172
173 i = 12;
174 estack_end = in_exception_stack(cpu, (unsigned long)stack);
175 if (estack_end) {
176 while (stack < estack_end) {
177 addr = *stack++;
178 if (kernel_text_address(addr)) {
179 i += printk_address(addr);
180 i += printk(" ");
181 if (i > 50) {
182 printk("\n ");
183 i = 0;
184 }
185 }
186 }
187 printk(" <EOE> ");
188 i += 7;
189 stack = (unsigned long *) estack_end[-2];
190 }
191
192
193 irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr);
194 irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE + 8);
195
196 if (stack >= irqstack && stack < irqstack_end) {
197 while (stack < irqstack_end) {
198 addr = *stack++;
199 /*
200 * If the address is either in the text segment of the
201 * kernel, or in the region which contains vmalloc'ed
202 * memory, it *may* be the address of a calling
203 * routine; if so, print it so that someone tracing
204 * down the cause of the crash will be able to figure
205 * out the call path that was taken.
206 */
207 if (kernel_text_address(addr)) {
208 i += printk_address(addr);
209 i += printk(" ");
210 if (i > 50) {
211 printk("\n ");
212 i = 0;
213 }
214 }
215 }
216 stack = (unsigned long *) (irqstack_end[-1]);
217 i += 7;
218 printk(" <EOI> ");
219 }
220
221
222
223 while (((long) stack & (THREAD_SIZE-1)) != 0) {
224 addr = *stack++;
225 if (kernel_text_address(addr)) {
226 i += printk_address(addr);
227 i += printk(" ");
228 if (i > 50) {
229 printk("\n ");
230 i = 0;
231 }
232 }
233 }
234 printk("\n");
235 }
236
show_trace_task(struct task_struct * tsk)237 void show_trace_task(struct task_struct *tsk)
238 {
239 unsigned long rsp = tsk->thread.rsp;
240
241 /* User space on another CPU? */
242 if ((rsp ^ (unsigned long)tsk) & (PAGE_MASK<<1))
243 return;
244 show_trace((unsigned long *)rsp);
245 }
246
show_stack(unsigned long * rsp)247 void show_stack(unsigned long * rsp)
248 {
249 unsigned long *stack;
250 int i;
251 const int cpu = safe_smp_processor_id();
252 unsigned long *irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr);
253 unsigned long *irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE);
254
255 // debugging aid: "show_stack(NULL);" prints the
256 // back trace for this cpu.
257
258 if(rsp==NULL)
259 rsp=(unsigned long*)&rsp;
260
261 stack = rsp;
262 for(i=0; i < kstack_depth_to_print; i++) {
263 if (stack >= irqstack && stack <= irqstack_end) {
264 if (stack == irqstack_end) {
265 stack = (unsigned long *) (irqstack_end[-1]);
266 printk(" <EOI> ");
267 }
268 } else {
269 if (((long) stack & (THREAD_SIZE-1)) == 0)
270 break;
271 }
272 if (i && ((i % 4) == 0))
273 printk("\n ");
274 printk("%016lx ", *stack++);
275 }
276 show_trace((unsigned long *)rsp);
277 }
278
show_registers(struct pt_regs * regs)279 void show_registers(struct pt_regs *regs)
280 {
281 int i;
282 int in_kernel = 1;
283 unsigned long rsp;
284 const int cpu = safe_smp_processor_id();
285 struct task_struct *cur = cpu_pda[cpu].pcurrent;
286
287 rsp = (unsigned long) (®s->rsp);
288 if (regs->rsp < TASK_SIZE) {
289 in_kernel = 0;
290 rsp = regs->rsp;
291 }
292 printk("CPU %d ", cpu);
293 __show_regs(regs);
294 printk("Process %s (pid: %d, stackpage=%08lx)\n",
295 cur->comm, cur->pid, 4096+(unsigned long)cur);
296
297 /*
298 * When in-kernel, we also print out the stack and code at the
299 * time of the fault..
300 */
301 if (in_kernel) {
302
303 printk("Stack: ");
304 show_stack((unsigned long*)rsp);
305
306 printk("\nCode: ");
307 if(regs->rip < PAGE_OFFSET)
308 goto bad;
309
310 for(i=0;i<20;i++)
311 {
312 unsigned char c;
313 if(__get_user(c, &((unsigned char*)regs->rip)[i])) {
314 bad:
315 printk(" Bad RIP value.");
316 break;
317 }
318 printk("%02x ", c);
319 }
320 }
321 printk("\n");
322 }
323
handle_BUG(struct pt_regs * regs)324 void handle_BUG(struct pt_regs *regs)
325 {
326 struct bug_frame f;
327 char tmp;
328
329 if (regs->cs & 3)
330 return;
331 if (__copy_from_user(&f, (struct bug_frame *) regs->rip,
332 sizeof(struct bug_frame)))
333 return;
334 if ((unsigned long)f.filename < __PAGE_OFFSET ||
335 f.ud2[0] != 0x0f || f.ud2[1] != 0x0b)
336 return;
337 if (__get_user(tmp, f.filename))
338 f.filename = "unmapped filename";
339 printk(KERN_EMERG "Kernel BUG at %.50s:%d\n", f.filename, f.line);
340 }
341
342 spinlock_t die_lock = SPIN_LOCK_UNLOCKED;
343 int die_owner = -1;
344
__die(const char * str,struct pt_regs * regs,long err)345 void __die(const char * str, struct pt_regs * regs, long err)
346 {
347 printk(KERN_EMERG "%s: %04lx\n", str, err & 0xffff);
348 notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
349 show_registers(regs);
350 /* Execute summary in case the oops scrolled away */
351 printk(KERN_EMERG "RIP ");
352 printk_address(regs->rip);
353 printk(" RSP <%016lx>\n", regs->rsp);
354 }
355
prepare_die(unsigned long * flags)356 void prepare_die(unsigned long *flags)
357 {
358 int cpu;
359 console_verbose();
360 bust_spinlocks(1);
361 cpu = safe_smp_processor_id();
362 /* racy, but better than risking deadlock. */
363 __save_flags(*flags);
364 __cli();
365 if (!spin_trylock(&die_lock)) {
366 if (cpu == die_owner)
367 /* nested oops. should stop eventually */;
368 else
369 spin_lock(&die_lock);
370 }
371 die_owner = cpu;
372 }
373
exit_die(unsigned long flags)374 void exit_die(unsigned long flags)
375 {
376 die_owner = -1;
377 spin_unlock_irqrestore(&die_lock, flags);
378 __sti(); /* back scroll should work */
379 bust_spinlocks(0);
380 }
381
die(const char * str,struct pt_regs * regs,long err)382 void die(const char * str, struct pt_regs * regs, long err)
383 {
384 unsigned long flags;
385 prepare_die(&flags);
386 handle_BUG(regs);
387 __die(str, regs, err);
388 exit_die(flags);
389 do_exit(SIGSEGV);
390 }
391
die_if_kernel(const char * str,struct pt_regs * regs,long err)392 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
393 {
394 if (regs->cs == __KERNEL_CS)
395 die(str, regs, err);
396 }
397
get_cr2(void)398 static inline unsigned long get_cr2(void)
399 {
400 unsigned long address;
401
402 /* get the address */
403 __asm__("movq %%cr2,%0":"=r" (address));
404 return address;
405 }
406
do_trap(int trapnr,int signr,char * str,struct pt_regs * regs,long error_code,siginfo_t * info)407 static void do_trap(int trapnr, int signr, char *str,
408 struct pt_regs * regs, long error_code, siginfo_t *info)
409 {
410 conditional_sti(regs);
411
412 #if defined(CONFIG_CHECKING) && defined(CONFIG_LOCAL_APIC)
413 {
414 unsigned long gs;
415 struct x8664_pda *pda = cpu_pda + safe_smp_processor_id();
416 rdmsrl(MSR_GS_BASE, gs);
417 if (gs != (unsigned long)pda) {
418 wrmsrl(MSR_GS_BASE, pda);
419 printk("%s: wrong gs %lx expected %p\n", str, gs, pda);
420 }
421 }
422 #endif
423
424 if ((regs->cs & 3) != 0) {
425 struct task_struct *tsk = current;
426 tsk->thread.error_code = error_code;
427 tsk->thread.trap_no = trapnr;
428 if (exception_trace && !(tsk->ptrace & PT_PTRACED) &&
429 (tsk->sig->action[signr-1].sa.sa_handler == SIG_IGN ||
430 (tsk->sig->action[signr-1].sa.sa_handler == SIG_DFL)))
431 printk(KERN_INFO
432 "%s[%d] trap %s rip:%lx rsp:%lx error:%lx\n",
433 tsk->comm, tsk->pid, str,
434 regs->rip,regs->rsp,error_code);
435 if (info)
436 force_sig_info(signr, info, tsk);
437 else
438 force_sig(signr, tsk);
439 return;
440 }
441
442
443 /* kernel trap */
444 {
445 unsigned long fixup = search_exception_table(regs->rip);
446 if (fixup) {
447 regs->rip = fixup;
448 } else
449 die(str, regs, error_code);
450 return;
451 }
452 }
453
454 #define DO_ERROR(trapnr, signr, str, name) \
455 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
456 { \
457 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) == NOTIFY_BAD) \
458 return; \
459 do_trap(trapnr, signr, str, regs, error_code, NULL); \
460 }
461
462 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
463 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
464 { \
465 siginfo_t info; \
466 info.si_signo = signr; \
467 info.si_errno = 0; \
468 info.si_code = sicode; \
469 info.si_addr = (void *)siaddr; \
470 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)==NOTIFY_BAD) \
471 return; \
472 do_trap(trapnr, signr, str, regs, error_code, &info); \
473 }
474
475 DO_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->rip)
476 DO_ERROR( 3, SIGTRAP, "int3", int3);
477 DO_ERROR( 4, SIGSEGV, "overflow", overflow)
478 DO_ERROR( 5, SIGSEGV, "bounds", bounds)
479 DO_ERROR_INFO( 6, SIGILL, "invalid operand", invalid_op, ILL_ILLOPN, regs->rip)
480 DO_ERROR( 7, SIGSEGV, "device not available", device_not_available)
481 DO_ERROR( 8, SIGSEGV, "double fault", double_fault)
482 DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
483 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
484 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
485 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
486 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, get_cr2())
487 DO_ERROR(18, SIGSEGV, "reserved", reserved)
488
489 extern void dump_pagetable(unsigned long);
490
do_general_protection(struct pt_regs * regs,long error_code)491 asmlinkage void do_general_protection(struct pt_regs * regs, long error_code)
492 {
493 conditional_sti(regs);
494
495 #ifdef CONFIG_CHECKING
496 {
497 unsigned long gs;
498 struct x8664_pda *pda = cpu_pda + safe_smp_processor_id();
499 rdmsrl(MSR_GS_BASE, gs);
500 if (gs != (unsigned long)pda) {
501 wrmsrl(MSR_GS_BASE, pda);
502 /* Avoid wakeup in printk in case this was triggered
503 by the segment reloads in __switch_to. Otherwise
504 the wake_up could deadlock on scheduler locks. */
505 oops_in_progress++;
506 printk(KERN_EMERG
507 "general protection handler: wrong gs %lx expected %p\n", gs, pda);
508 oops_in_progress--;
509 }
510 }
511 #endif
512
513 if (regs->cs & 3) {
514 struct task_struct *tsk = current;
515 tsk->thread.error_code = error_code;
516 tsk->thread.trap_no = 13;
517 if (exception_trace && !(tsk->ptrace & PT_PTRACED) &&
518 (tsk->sig->action[SIGSEGV-1].sa.sa_handler == SIG_IGN ||
519 (tsk->sig->action[SIGSEGV-1].sa.sa_handler == SIG_DFL)))
520 printk(KERN_INFO
521 "%s[%d] general protection rip:%lx rsp:%lx error:%lx\n",
522 tsk->comm, tsk->pid,
523 regs->rip,regs->rsp,error_code);
524 force_sig(SIGSEGV, tsk);
525 return;
526 }
527
528 /* kernel gp */
529 {
530 unsigned long fixup;
531 fixup = search_exception_table(regs->rip);
532 if (fixup) {
533 regs->rip = fixup;
534 return;
535 }
536 notify_die(DIE_GPF, "general protection fault", regs, error_code,
537 13, SIGSEGV);
538 die("general protection fault", regs, error_code);
539 }
540 }
541
mem_parity_error(unsigned char reason,struct pt_regs * regs)542 static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
543 {
544 printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
545 printk("You probably have a hardware problem with your RAM chips\n");
546
547 /* Clear and disable the memory parity error line. */
548 reason = (reason & 0xf) | 4;
549 outb(reason, 0x61);
550 }
551
io_check_error(unsigned char reason,struct pt_regs * regs)552 static void io_check_error(unsigned char reason, struct pt_regs * regs)
553 {
554 printk("NMI: IOCK error (debug interrupt?)\n");
555 show_registers(regs);
556
557 /* Re-enable the IOCK line, wait for a few seconds */
558 reason = (reason & 0xf) | 8;
559 outb(reason, 0x61);
560 mdelay(2000);
561 reason &= ~8;
562 outb(reason, 0x61);
563 }
564
unknown_nmi_error(unsigned char reason,struct pt_regs * regs)565 static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
566 {
567 printk("Uhhuh. NMI received for unknown reason %02x.\n", reason);
568 printk("Dazed and confused, but trying to continue\n");
569 printk("Do you have a strange power saving mode enabled?\n");
570 }
571
do_nmi(struct pt_regs * regs)572 asmlinkage void do_nmi(struct pt_regs * regs)
573 {
574 unsigned char reason = inb(0x61);
575
576 ++nmi_count(safe_smp_processor_id());
577
578 if (!(reason & 0xc0)) {
579 #if CONFIG_X86_LOCAL_APIC
580 /*
581 * Ok, so this is none of the documented NMI sources,
582 * so it must be the NMI watchdog.
583 */
584 if (nmi_watchdog) {
585 nmi_watchdog_tick(regs, reason);
586 return;
587 }
588 #endif
589 unknown_nmi_error(reason, regs);
590 return;
591 }
592 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_BAD)
593 return;
594 if (reason & 0x80)
595 mem_parity_error(reason, regs);
596 if (reason & 0x40)
597 io_check_error(reason, regs);
598
599 /*
600 * Reassert NMI in case it became active meanwhile
601 * as it's edge-triggered.
602 */
603 outb(0x8f, 0x70);
604 inb(0x71); /* dummy */
605 outb(0x0f, 0x70);
606 inb(0x71); /* dummy */
607 }
608
do_debug(struct pt_regs * regs,long error_code)609 asmlinkage void do_debug(struct pt_regs * regs, long error_code)
610 {
611 unsigned long condition;
612 struct task_struct *tsk = current;
613 siginfo_t info;
614
615 asm("movq %%db6,%0" : "=r" (condition));
616
617 conditional_sti(regs);
618
619 #ifdef CONFIG_CHECKING
620 {
621 /* XXX: interaction with debugger - could destroy gs */
622 unsigned long gs;
623 struct x8664_pda *pda = cpu_pda + safe_smp_processor_id();
624 rdmsrl(MSR_GS_BASE, gs);
625 if (gs != (unsigned long)pda) {
626 wrmsrl(MSR_GS_BASE, pda);
627 printk(KERN_EMERG "debug handler: wrong gs %lx expected %p\n", gs, pda);
628 }
629 }
630 #endif
631
632 /* Mask out spurious debug traps due to lazy DR7 setting */
633 if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
634 if (!tsk->thread.debugreg[7]) {
635 goto clear_dr7;
636 }
637 }
638
639 tsk->thread.debugreg[6] = condition;
640
641 /* Mask out spurious TF errors due to lazy TF clearing */
642 if (condition & DR_STEP) {
643 /*
644 * The TF error should be masked out only if the current
645 * process is not traced and if the TRAP flag has been set
646 * previously by a tracing process (condition detected by
647 * the PT_DTRACE flag); remember that the i386 TRAP flag
648 * can be modified by the process itself in user mode,
649 * allowing programs to debug themselves without the ptrace()
650 * interface.
651 */
652 if ((regs->cs & 3) == 0)
653 goto clear_TF;
654 if ((tsk->ptrace & (PT_DTRACE|PT_PTRACED)) == PT_DTRACE)
655 goto clear_TF;
656 }
657
658 /* Ok, finally something we can handle */
659 tsk->thread.trap_no = 1;
660 tsk->thread.error_code = error_code;
661 info.si_signo = SIGTRAP;
662 info.si_errno = 0;
663 info.si_code = TRAP_BRKPT;
664 if ((regs->cs & 3) == 0)
665 goto clear_dr7;
666
667 info.si_addr = (void *)regs->rip;
668 force_sig_info(SIGTRAP, &info, tsk);
669 clear_dr7:
670 asm volatile("movq %0,%%db7"::"r"(0UL));
671 notify_die(DIE_DEBUG, "debug", regs, error_code, 1, SIGTRAP);
672 return;
673
674 clear_TF:
675 /* XXX: could cause spurious errors */
676 if (notify_die(DIE_DEBUG, "debug2", regs, error_code, 1, SIGTRAP) != NOTIFY_BAD)
677 regs->eflags &= ~TF_MASK;
678 return;
679 }
680
681 /*
682 * Note that we play around with the 'TS' bit in an attempt to get
683 * the correct behaviour even in the presence of the asynchronous
684 * IRQ13 behaviour
685 */
math_error(void * rip)686 void math_error(void *rip)
687 {
688 struct task_struct * task;
689 siginfo_t info;
690 unsigned short cwd, swd;
691
692 /*
693 * Save the info for the exception handler and clear the error.
694 */
695 task = current;
696 save_init_fpu(task);
697 task->thread.trap_no = 16;
698 task->thread.error_code = 0;
699 info.si_signo = SIGFPE;
700 info.si_errno = 0;
701 info.si_code = __SI_FAULT;
702 info.si_addr = rip;
703 /*
704 * (~cwd & swd) will mask out exceptions that are not set to unmasked
705 * status. 0x3f is the exception bits in these regs, 0x200 is the
706 * C1 reg you need in case of a stack fault, 0x040 is the stack
707 * fault bit. We should only be taking one exception at a time,
708 * so if this combination doesn't produce any single exception,
709 * then we have a bad program that isn't syncronizing its FPU usage
710 * and it will suffer the consequences since we won't be able to
711 * fully reproduce the context of the exception
712 */
713 cwd = get_fpu_cwd(task);
714 swd = get_fpu_swd(task);
715 switch (((~cwd) & swd & 0x3f) | (swd & 0x240)) {
716 case 0x000:
717 default:
718 break;
719 case 0x001: /* Invalid Op */
720 case 0x041: /* Stack Fault */
721 case 0x241: /* Stack Fault | Direction */
722 info.si_code = FPE_FLTINV;
723 break;
724 case 0x002: /* Denormalize */
725 case 0x010: /* Underflow */
726 info.si_code = FPE_FLTUND;
727 break;
728 case 0x004: /* Zero Divide */
729 info.si_code = FPE_FLTDIV;
730 break;
731 case 0x008: /* Overflow */
732 info.si_code = FPE_FLTOVF;
733 break;
734 case 0x020: /* Precision */
735 info.si_code = FPE_FLTRES;
736 break;
737 }
738 force_sig_info(SIGFPE, &info, task);
739 }
740
do_coprocessor_error(struct pt_regs * regs,long error_code)741 asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code)
742 {
743 conditional_sti(regs);
744 math_error((void *)regs->rip);
745 }
746
bad_intr(void)747 asmlinkage void bad_intr(void)
748 {
749 printk("bad interrupt");
750 }
751
simd_math_error(void * rip)752 static inline void simd_math_error(void *rip)
753 {
754 struct task_struct * task;
755 siginfo_t info;
756 unsigned short mxcsr;
757
758 /*
759 * Save the info for the exception handler and clear the error.
760 */
761 task = current;
762 save_init_fpu(task);
763 task->thread.trap_no = 19;
764 task->thread.error_code = 0;
765 info.si_signo = SIGFPE;
766 info.si_errno = 0;
767 info.si_code = __SI_FAULT;
768 info.si_addr = rip;
769 /*
770 * The SIMD FPU exceptions are handled a little differently, as there
771 * is only a single status/control register. Thus, to determine which
772 * unmasked exception was caught we must mask the exception mask bits
773 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
774 */
775 mxcsr = get_fpu_mxcsr(task);
776 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
777 case 0x000:
778 default:
779 break;
780 case 0x001: /* Invalid Op */
781 info.si_code = FPE_FLTINV;
782 break;
783 case 0x002: /* Denormalize */
784 case 0x010: /* Underflow */
785 info.si_code = FPE_FLTUND;
786 break;
787 case 0x004: /* Zero Divide */
788 info.si_code = FPE_FLTDIV;
789 break;
790 case 0x008: /* Overflow */
791 info.si_code = FPE_FLTOVF;
792 break;
793 case 0x020: /* Precision */
794 info.si_code = FPE_FLTRES;
795 break;
796 }
797 force_sig_info(SIGFPE, &info, task);
798 }
799
do_simd_coprocessor_error(struct pt_regs * regs,long error_code)800 asmlinkage void do_simd_coprocessor_error(struct pt_regs * regs,
801 long error_code)
802 {
803 conditional_sti(regs);
804 simd_math_error((void *)regs->rip);
805 }
806
do_spurious_interrupt_bug(struct pt_regs * regs)807 asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs)
808 {
809 }
810
811 /*
812 * 'math_state_restore()' saves the current math information in the
813 * old math state array, and gets the new ones from the current task
814 *
815 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
816 * Don't touch unless you *really* know how it works.
817 */
math_state_restore(void)818 asmlinkage void math_state_restore(void)
819 {
820 struct task_struct *me = current;
821 clts(); /* Allow maths ops (or we recurse) */
822
823 if (!me->used_math)
824 init_fpu(me);
825 restore_fpu_checking(&me->thread.i387.fxsave);
826 me->flags |= PF_USEDFPU; /* So we fxsave on switch_to() */
827 }
828
math_emulate(void)829 asmlinkage void math_emulate(void)
830 {
831 BUG();
832 }
833
do_call_debug(struct pt_regs * regs)834 void do_call_debug(struct pt_regs *regs)
835 {
836 notify_die(DIE_CALL, "debug call", regs, 0, 255, SIGINT);
837 }
838
839 #ifndef CONFIG_MCE
do_machine_check(struct pt_regs * regs)840 void do_machine_check(struct pt_regs *regs)
841 {
842 printk(KERN_INFO "Machine check ignored\n");
843 }
844 #endif
845
trap_init(void)846 void __init trap_init(void)
847 {
848 set_intr_gate(0,÷_error);
849 set_intr_gate(1,&debug);
850 set_intr_gate_ist(2,&nmi,NMI_STACK);
851 set_system_gate(3,&int3); /* int3-5 can be called from all */
852 set_system_gate(4,&overflow);
853 set_system_gate(5,&bounds);
854 set_intr_gate(6,&invalid_op);
855 set_intr_gate(7,&device_not_available);
856 set_intr_gate_ist(8,&double_fault, DOUBLEFAULT_STACK);
857 set_intr_gate(9,&coprocessor_segment_overrun);
858 set_intr_gate(10,&invalid_TSS);
859 set_intr_gate(11,&segment_not_present);
860 set_intr_gate(12,&stack_segment);
861 set_intr_gate(13,&general_protection);
862 set_intr_gate(14,&page_fault);
863 set_intr_gate(15,&spurious_interrupt_bug);
864 set_intr_gate(16,&coprocessor_error);
865 set_intr_gate(17,&alignment_check);
866 set_intr_gate(18,&machine_check);
867 set_intr_gate(19,&simd_coprocessor_error);
868
869 #ifdef CONFIG_IA32_EMULATION
870 set_system_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
871 #endif
872
873 /*
874 * Should be a barrier for any external CPU state.
875 */
876 cpu_init();
877 }
878