Merge branch 'master' of git://oak/home/sfr/kernels/iseries/work
[linux-2.6] / arch / x86_64 / kernel / traps.c
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
11 /*
12  * 'Traps.c' handles hardware traps and faults after we have saved some
13  * state in 'entry.S'.
14  */
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/ptrace.h>
20 #include <linux/timer.h>
21 #include <linux/mm.h>
22 #include <linux/init.h>
23 #include <linux/delay.h>
24 #include <linux/spinlock.h>
25 #include <linux/interrupt.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/nmi.h>
29 #include <linux/kprobes.h>
30 #include <linux/kexec.h>
31 #include <linux/unwind.h>
32
33 #include <asm/system.h>
34 #include <asm/uaccess.h>
35 #include <asm/io.h>
36 #include <asm/atomic.h>
37 #include <asm/debugreg.h>
38 #include <asm/desc.h>
39 #include <asm/i387.h>
40 #include <asm/kdebug.h>
41 #include <asm/processor.h>
42 #include <asm/unwind.h>
43 #include <asm/smp.h>
44 #include <asm/pgalloc.h>
45 #include <asm/pda.h>
46 #include <asm/proto.h>
47 #include <asm/nmi.h>
48 #include <asm/stacktrace.h>
49
50 asmlinkage void divide_error(void);
51 asmlinkage void debug(void);
52 asmlinkage void nmi(void);
53 asmlinkage void int3(void);
54 asmlinkage void overflow(void);
55 asmlinkage void bounds(void);
56 asmlinkage void invalid_op(void);
57 asmlinkage void device_not_available(void);
58 asmlinkage void double_fault(void);
59 asmlinkage void coprocessor_segment_overrun(void);
60 asmlinkage void invalid_TSS(void);
61 asmlinkage void segment_not_present(void);
62 asmlinkage void stack_segment(void);
63 asmlinkage void general_protection(void);
64 asmlinkage void page_fault(void);
65 asmlinkage void coprocessor_error(void);
66 asmlinkage void simd_coprocessor_error(void);
67 asmlinkage void reserved(void);
68 asmlinkage void alignment_check(void);
69 asmlinkage void machine_check(void);
70 asmlinkage void spurious_interrupt_bug(void);
71
72 ATOMIC_NOTIFIER_HEAD(die_chain);
73 EXPORT_SYMBOL(die_chain);
74
75 int register_die_notifier(struct notifier_block *nb)
76 {
77         vmalloc_sync_all();
78         return atomic_notifier_chain_register(&die_chain, nb);
79 }
80 EXPORT_SYMBOL(register_die_notifier); /* used modular by kdb */
81
82 int unregister_die_notifier(struct notifier_block *nb)
83 {
84         return atomic_notifier_chain_unregister(&die_chain, nb);
85 }
86 EXPORT_SYMBOL(unregister_die_notifier); /* used modular by kdb */
87
88 static inline void conditional_sti(struct pt_regs *regs)
89 {
90         if (regs->eflags & X86_EFLAGS_IF)
91                 local_irq_enable();
92 }
93
94 static inline void preempt_conditional_sti(struct pt_regs *regs)
95 {
96         preempt_disable();
97         if (regs->eflags & X86_EFLAGS_IF)
98                 local_irq_enable();
99 }
100
101 static inline void preempt_conditional_cli(struct pt_regs *regs)
102 {
103         if (regs->eflags & X86_EFLAGS_IF)
104                 local_irq_disable();
105         /* Make sure to not schedule here because we could be running
106            on an exception stack. */
107         preempt_enable_no_resched();
108 }
109
110 static int kstack_depth_to_print = 12;
111 #ifdef CONFIG_STACK_UNWIND
112 static int call_trace = 1;
113 #else
114 #define call_trace (-1)
115 #endif
116
117 #ifdef CONFIG_KALLSYMS
118 # include <linux/kallsyms.h>
119 void printk_address(unsigned long address)
120 {
121         unsigned long offset = 0, symsize;
122         const char *symname;
123         char *modname;
124         char *delim = ":";
125         char namebuf[128];
126
127         symname = kallsyms_lookup(address, &symsize, &offset,
128                                         &modname, namebuf);
129         if (!symname) {
130                 printk(" [<%016lx>]\n", address);
131                 return;
132         }
133         if (!modname)
134                 modname = delim = "";           
135         printk(" [<%016lx>] %s%s%s%s+0x%lx/0x%lx\n",
136                 address, delim, modname, delim, symname, offset, symsize);
137 }
138 #else
139 void printk_address(unsigned long address)
140 {
141         printk(" [<%016lx>]\n", address);
142 }
143 #endif
144
145 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
146                                         unsigned *usedp, char **idp)
147 {
148         static char ids[][8] = {
149                 [DEBUG_STACK - 1] = "#DB",
150                 [NMI_STACK - 1] = "NMI",
151                 [DOUBLEFAULT_STACK - 1] = "#DF",
152                 [STACKFAULT_STACK - 1] = "#SS",
153                 [MCE_STACK - 1] = "#MC",
154 #if DEBUG_STKSZ > EXCEPTION_STKSZ
155                 [N_EXCEPTION_STACKS ... N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]"
156 #endif
157         };
158         unsigned k;
159
160         /*
161          * Iterate over all exception stacks, and figure out whether
162          * 'stack' is in one of them:
163          */
164         for (k = 0; k < N_EXCEPTION_STACKS; k++) {
165                 unsigned long end = per_cpu(orig_ist, cpu).ist[k];
166                 /*
167                  * Is 'stack' above this exception frame's end?
168                  * If yes then skip to the next frame.
169                  */
170                 if (stack >= end)
171                         continue;
172                 /*
173                  * Is 'stack' above this exception frame's start address?
174                  * If yes then we found the right frame.
175                  */
176                 if (stack >= end - EXCEPTION_STKSZ) {
177                         /*
178                          * Make sure we only iterate through an exception
179                          * stack once. If it comes up for the second time
180                          * then there's something wrong going on - just
181                          * break out and return NULL:
182                          */
183                         if (*usedp & (1U << k))
184                                 break;
185                         *usedp |= 1U << k;
186                         *idp = ids[k];
187                         return (unsigned long *)end;
188                 }
189                 /*
190                  * If this is a debug stack, and if it has a larger size than
191                  * the usual exception stacks, then 'stack' might still
192                  * be within the lower portion of the debug stack:
193                  */
194 #if DEBUG_STKSZ > EXCEPTION_STKSZ
195                 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
196                         unsigned j = N_EXCEPTION_STACKS - 1;
197
198                         /*
199                          * Black magic. A large debug stack is composed of
200                          * multiple exception stack entries, which we
201                          * iterate through now. Dont look:
202                          */
203                         do {
204                                 ++j;
205                                 end -= EXCEPTION_STKSZ;
206                                 ids[j][4] = '1' + (j - N_EXCEPTION_STACKS);
207                         } while (stack < end - EXCEPTION_STKSZ);
208                         if (*usedp & (1U << j))
209                                 break;
210                         *usedp |= 1U << j;
211                         *idp = ids[j];
212                         return (unsigned long *)end;
213                 }
214 #endif
215         }
216         return NULL;
217 }
218
219 struct ops_and_data {
220         struct stacktrace_ops *ops;
221         void *data;
222 };
223
224 static int dump_trace_unwind(struct unwind_frame_info *info, void *context)
225 {
226         struct ops_and_data *oad = (struct ops_and_data *)context;
227         int n = 0;
228
229         while (unwind(info) == 0 && UNW_PC(info)) {
230                 n++;
231                 oad->ops->address(oad->data, UNW_PC(info));
232                 if (arch_unw_user_mode(info))
233                         break;
234         }
235         return n;
236 }
237
238 /*
239  * x86-64 can have upto three kernel stacks: 
240  * process stack
241  * interrupt stack
242  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
243  */
244
245 void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * stack,
246                 struct stacktrace_ops *ops, void *data)
247 {
248         const unsigned cpu = smp_processor_id();
249         unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
250         unsigned used = 0;
251
252         if (!tsk)
253                 tsk = current;
254
255         if (call_trace >= 0) {
256                 int unw_ret = 0;
257                 struct unwind_frame_info info;
258                 struct ops_and_data oad = { .ops = ops, .data = data };
259
260                 if (regs) {
261                         if (unwind_init_frame_info(&info, tsk, regs) == 0)
262                                 unw_ret = dump_trace_unwind(&info, &oad);
263                 } else if (tsk == current)
264                         unw_ret = unwind_init_running(&info, dump_trace_unwind, &oad);
265                 else {
266                         if (unwind_init_blocked(&info, tsk) == 0)
267                                 unw_ret = dump_trace_unwind(&info, &oad);
268                 }
269                 if (unw_ret > 0) {
270                         if (call_trace == 1 && !arch_unw_user_mode(&info)) {
271                                 ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",
272                                              UNW_PC(&info));
273                                 if ((long)UNW_SP(&info) < 0) {
274                                         ops->warning(data, "Leftover inexact backtrace:\n");
275                                         stack = (unsigned long *)UNW_SP(&info);
276                                         if (!stack)
277                                                 return;
278                                 } else
279                                         ops->warning(data, "Full inexact backtrace again:\n");
280                         } else if (call_trace >= 1)
281                                 return;
282                         else
283                                 ops->warning(data, "Full inexact backtrace again:\n");
284                 } else
285                         ops->warning(data, "Inexact backtrace:\n");
286         }
287         if (!stack) {
288                 unsigned long dummy;
289                 stack = &dummy;
290                 if (tsk && tsk != current)
291                         stack = (unsigned long *)tsk->thread.rsp;
292         }
293
294         /*
295          * Print function call entries within a stack. 'cond' is the
296          * "end of stackframe" condition, that the 'stack++'
297          * iteration will eventually trigger.
298          */
299 #define HANDLE_STACK(cond) \
300         do while (cond) { \
301                 unsigned long addr = *stack++; \
302                 if (oops_in_progress ?          \
303                         __kernel_text_address(addr) : \
304                         kernel_text_address(addr)) { \
305                         /* \
306                          * If the address is either in the text segment of the \
307                          * kernel, or in the region which contains vmalloc'ed \
308                          * memory, it *may* be the address of a calling \
309                          * routine; if so, print it so that someone tracing \
310                          * down the cause of the crash will be able to figure \
311                          * out the call path that was taken. \
312                          */ \
313                         ops->address(data, addr);   \
314                 } \
315         } while (0)
316
317         /*
318          * Print function call entries in all stacks, starting at the
319          * current stack address. If the stacks consist of nested
320          * exceptions
321          */
322         for (;;) {
323                 char *id;
324                 unsigned long *estack_end;
325                 estack_end = in_exception_stack(cpu, (unsigned long)stack,
326                                                 &used, &id);
327
328                 if (estack_end) {
329                         if (ops->stack(data, id) < 0)
330                                 break;
331                         HANDLE_STACK (stack < estack_end);
332                         ops->stack(data, "<EOE>");
333                         /*
334                          * We link to the next stack via the
335                          * second-to-last pointer (index -2 to end) in the
336                          * exception stack:
337                          */
338                         stack = (unsigned long *) estack_end[-2];
339                         continue;
340                 }
341                 if (irqstack_end) {
342                         unsigned long *irqstack;
343                         irqstack = irqstack_end -
344                                 (IRQSTACKSIZE - 64) / sizeof(*irqstack);
345
346                         if (stack >= irqstack && stack < irqstack_end) {
347                                 if (ops->stack(data, "IRQ") < 0)
348                                         break;
349                                 HANDLE_STACK (stack < irqstack_end);
350                                 /*
351                                  * We link to the next stack (which would be
352                                  * the process stack normally) the last
353                                  * pointer (index -1 to end) in the IRQ stack:
354                                  */
355                                 stack = (unsigned long *) (irqstack_end[-1]);
356                                 irqstack_end = NULL;
357                                 ops->stack(data, "EOI");
358                                 continue;
359                         }
360                 }
361                 break;
362         }
363
364         /*
365          * This handles the process stack:
366          */
367         HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0);
368 #undef HANDLE_STACK
369 }
370 EXPORT_SYMBOL(dump_trace);
371
372 static void
373 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
374 {
375         print_symbol(msg, symbol);
376         printk("\n");
377 }
378
379 static void print_trace_warning(void *data, char *msg)
380 {
381         printk("%s\n", msg);
382 }
383
384 static int print_trace_stack(void *data, char *name)
385 {
386         printk(" <%s> ", name);
387         return 0;
388 }
389
390 static void print_trace_address(void *data, unsigned long addr)
391 {
392         printk_address(addr);
393 }
394
395 static struct stacktrace_ops print_trace_ops = {
396         .warning = print_trace_warning,
397         .warning_symbol = print_trace_warning_symbol,
398         .stack = print_trace_stack,
399         .address = print_trace_address,
400 };
401
402 void
403 show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long *stack)
404 {
405         printk("\nCall Trace:\n");
406         dump_trace(tsk, regs, stack, &print_trace_ops, NULL);
407         printk("\n");
408 }
409
410 static void
411 _show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long *rsp)
412 {
413         unsigned long *stack;
414         int i;
415         const int cpu = smp_processor_id();
416         unsigned long *irqstack_end = (unsigned long *) (cpu_pda(cpu)->irqstackptr);
417         unsigned long *irqstack = (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE);
418
419         // debugging aid: "show_stack(NULL, NULL);" prints the
420         // back trace for this cpu.
421
422         if (rsp == NULL) {
423                 if (tsk)
424                         rsp = (unsigned long *)tsk->thread.rsp;
425                 else
426                         rsp = (unsigned long *)&rsp;
427         }
428
429         stack = rsp;
430         for(i=0; i < kstack_depth_to_print; i++) {
431                 if (stack >= irqstack && stack <= irqstack_end) {
432                         if (stack == irqstack_end) {
433                                 stack = (unsigned long *) (irqstack_end[-1]);
434                                 printk(" <EOI> ");
435                         }
436                 } else {
437                 if (((long) stack & (THREAD_SIZE-1)) == 0)
438                         break;
439                 }
440                 if (i && ((i % 4) == 0))
441                         printk("\n");
442                 printk(" %016lx", *stack++);
443                 touch_nmi_watchdog();
444         }
445         show_trace(tsk, regs, rsp);
446 }
447
448 void show_stack(struct task_struct *tsk, unsigned long * rsp)
449 {
450         _show_stack(tsk, NULL, rsp);
451 }
452
453 /*
454  * The architecture-independent dump_stack generator
455  */
456 void dump_stack(void)
457 {
458         unsigned long dummy;
459         show_trace(NULL, NULL, &dummy);
460 }
461
462 EXPORT_SYMBOL(dump_stack);
463
464 void show_registers(struct pt_regs *regs)
465 {
466         int i;
467         int in_kernel = !user_mode(regs);
468         unsigned long rsp;
469         const int cpu = smp_processor_id();
470         struct task_struct *cur = cpu_pda(cpu)->pcurrent;
471
472                 rsp = regs->rsp;
473
474         printk("CPU %d ", cpu);
475         __show_regs(regs);
476         printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
477                 cur->comm, cur->pid, task_thread_info(cur), cur);
478
479         /*
480          * When in-kernel, we also print out the stack and code at the
481          * time of the fault..
482          */
483         if (in_kernel) {
484
485                 printk("Stack: ");
486                 _show_stack(NULL, regs, (unsigned long*)rsp);
487
488                 printk("\nCode: ");
489                 if (regs->rip < PAGE_OFFSET)
490                         goto bad;
491
492                 for (i=0; i<20; i++) {
493                         unsigned char c;
494                         if (__get_user(c, &((unsigned char*)regs->rip)[i])) {
495 bad:
496                                 printk(" Bad RIP value.");
497                                 break;
498                         }
499                         printk("%02x ", c);
500                 }
501         }
502         printk("\n");
503 }       
504
505 void handle_BUG(struct pt_regs *regs)
506
507         struct bug_frame f;
508         long len;
509         const char *prefix = "";
510
511         if (user_mode(regs))
512                 return; 
513         if (__copy_from_user(&f, (const void __user *) regs->rip,
514                              sizeof(struct bug_frame)))
515                 return; 
516         if (f.filename >= 0 ||
517             f.ud2[0] != 0x0f || f.ud2[1] != 0x0b) 
518                 return;
519         len = __strnlen_user((char *)(long)f.filename, PATH_MAX) - 1;
520         if (len < 0 || len >= PATH_MAX)
521                 f.filename = (int)(long)"unmapped filename";
522         else if (len > 50) {
523                 f.filename += len - 50;
524                 prefix = "...";
525         }
526         printk("----------- [cut here ] --------- [please bite here ] ---------\n");
527         printk(KERN_ALERT "Kernel BUG at %s%.50s:%d\n", prefix, (char *)(long)f.filename, f.line);
528
529
530 #ifdef CONFIG_BUG
531 void out_of_line_bug(void)
532
533         BUG(); 
534
535 EXPORT_SYMBOL(out_of_line_bug);
536 #endif
537
538 static DEFINE_SPINLOCK(die_lock);
539 static int die_owner = -1;
540 static unsigned int die_nest_count;
541
542 unsigned __kprobes long oops_begin(void)
543 {
544         int cpu = smp_processor_id();
545         unsigned long flags;
546
547         oops_enter();
548
549         /* racy, but better than risking deadlock. */
550         local_irq_save(flags);
551         if (!spin_trylock(&die_lock)) { 
552                 if (cpu == die_owner) 
553                         /* nested oops. should stop eventually */;
554                 else
555                         spin_lock(&die_lock);
556         }
557         die_nest_count++;
558         die_owner = cpu;
559         console_verbose();
560         bust_spinlocks(1);
561         return flags;
562 }
563
564 void __kprobes oops_end(unsigned long flags)
565
566         die_owner = -1;
567         bust_spinlocks(0);
568         die_nest_count--;
569         if (die_nest_count)
570                 /* We still own the lock */
571                 local_irq_restore(flags);
572         else
573                 /* Nest count reaches zero, release the lock. */
574                 spin_unlock_irqrestore(&die_lock, flags);
575         if (panic_on_oops)
576                 panic("Fatal exception");
577         oops_exit();
578 }
579
580 void __kprobes __die(const char * str, struct pt_regs * regs, long err)
581 {
582         static int die_counter;
583         printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff,++die_counter);
584 #ifdef CONFIG_PREEMPT
585         printk("PREEMPT ");
586 #endif
587 #ifdef CONFIG_SMP
588         printk("SMP ");
589 #endif
590 #ifdef CONFIG_DEBUG_PAGEALLOC
591         printk("DEBUG_PAGEALLOC");
592 #endif
593         printk("\n");
594         notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);
595         show_registers(regs);
596         /* Executive summary in case the oops scrolled away */
597         printk(KERN_ALERT "RIP ");
598         printk_address(regs->rip); 
599         printk(" RSP <%016lx>\n", regs->rsp); 
600         if (kexec_should_crash(current))
601                 crash_kexec(regs);
602 }
603
604 void die(const char * str, struct pt_regs * regs, long err)
605 {
606         unsigned long flags = oops_begin();
607
608         handle_BUG(regs);
609         __die(str, regs, err);
610         oops_end(flags);
611         do_exit(SIGSEGV); 
612 }
613
614 void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
615 {
616         unsigned long flags = oops_begin();
617
618         /*
619          * We are in trouble anyway, lets at least try
620          * to get a message out.
621          */
622         printk(str, smp_processor_id());
623         show_registers(regs);
624         if (kexec_should_crash(current))
625                 crash_kexec(regs);
626         if (do_panic || panic_on_oops)
627                 panic("Non maskable interrupt");
628         oops_end(flags);
629         nmi_exit();
630         local_irq_enable();
631         do_exit(SIGSEGV);
632 }
633
634 static void __kprobes do_trap(int trapnr, int signr, char *str,
635                               struct pt_regs * regs, long error_code,
636                               siginfo_t *info)
637 {
638         struct task_struct *tsk = current;
639
640         tsk->thread.error_code = error_code;
641         tsk->thread.trap_no = trapnr;
642
643         if (user_mode(regs)) {
644                 if (exception_trace && unhandled_signal(tsk, signr))
645                         printk(KERN_INFO
646                                "%s[%d] trap %s rip:%lx rsp:%lx error:%lx\n",
647                                tsk->comm, tsk->pid, str,
648                                regs->rip, regs->rsp, error_code); 
649
650                 if (info)
651                         force_sig_info(signr, info, tsk);
652                 else
653                         force_sig(signr, tsk);
654                 return;
655         }
656
657
658         /* kernel trap */ 
659         {            
660                 const struct exception_table_entry *fixup;
661                 fixup = search_exception_tables(regs->rip);
662                 if (fixup)
663                         regs->rip = fixup->fixup;
664                 else    
665                         die(str, regs, error_code);
666                 return;
667         }
668 }
669
670 #define DO_ERROR(trapnr, signr, str, name) \
671 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
672 { \
673         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
674                                                         == NOTIFY_STOP) \
675                 return; \
676         conditional_sti(regs);                                          \
677         do_trap(trapnr, signr, str, regs, error_code, NULL); \
678 }
679
680 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
681 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
682 { \
683         siginfo_t info; \
684         info.si_signo = signr; \
685         info.si_errno = 0; \
686         info.si_code = sicode; \
687         info.si_addr = (void __user *)siaddr; \
688         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
689                                                         == NOTIFY_STOP) \
690                 return; \
691         conditional_sti(regs);                                          \
692         do_trap(trapnr, signr, str, regs, error_code, &info); \
693 }
694
695 DO_ERROR_INFO( 0, SIGFPE,  "divide error", divide_error, FPE_INTDIV, regs->rip)
696 DO_ERROR( 4, SIGSEGV, "overflow", overflow)
697 DO_ERROR( 5, SIGSEGV, "bounds", bounds)
698 DO_ERROR_INFO( 6, SIGILL,  "invalid opcode", invalid_op, ILL_ILLOPN, regs->rip)
699 DO_ERROR( 7, SIGSEGV, "device not available", device_not_available)
700 DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun)
701 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
702 DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present)
703 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
704 DO_ERROR(18, SIGSEGV, "reserved", reserved)
705
706 /* Runs on IST stack */
707 asmlinkage void do_stack_segment(struct pt_regs *regs, long error_code)
708 {
709         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
710                         12, SIGBUS) == NOTIFY_STOP)
711                 return;
712         preempt_conditional_sti(regs);
713         do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
714         preempt_conditional_cli(regs);
715 }
716
717 asmlinkage void do_double_fault(struct pt_regs * regs, long error_code)
718 {
719         static const char str[] = "double fault";
720         struct task_struct *tsk = current;
721
722         /* Return not checked because double check cannot be ignored */
723         notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
724
725         tsk->thread.error_code = error_code;
726         tsk->thread.trap_no = 8;
727
728         /* This is always a kernel trap and never fixable (and thus must
729            never return). */
730         for (;;)
731                 die(str, regs, error_code);
732 }
733
734 asmlinkage void __kprobes do_general_protection(struct pt_regs * regs,
735                                                 long error_code)
736 {
737         struct task_struct *tsk = current;
738
739         conditional_sti(regs);
740
741         tsk->thread.error_code = error_code;
742         tsk->thread.trap_no = 13;
743
744         if (user_mode(regs)) {
745                 if (exception_trace && unhandled_signal(tsk, SIGSEGV))
746                         printk(KERN_INFO
747                        "%s[%d] general protection rip:%lx rsp:%lx error:%lx\n",
748                                tsk->comm, tsk->pid,
749                                regs->rip, regs->rsp, error_code); 
750
751                 force_sig(SIGSEGV, tsk);
752                 return;
753         } 
754
755         /* kernel gp */
756         {
757                 const struct exception_table_entry *fixup;
758                 fixup = search_exception_tables(regs->rip);
759                 if (fixup) {
760                         regs->rip = fixup->fixup;
761                         return;
762                 }
763                 if (notify_die(DIE_GPF, "general protection fault", regs,
764                                         error_code, 13, SIGSEGV) == NOTIFY_STOP)
765                         return;
766                 die("general protection fault", regs, error_code);
767         }
768 }
769
770 static __kprobes void
771 mem_parity_error(unsigned char reason, struct pt_regs * regs)
772 {
773         printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
774                 reason);
775         printk(KERN_EMERG "You probably have a hardware problem with your "
776                 "RAM chips\n");
777
778         if (panic_on_unrecovered_nmi)
779                 panic("NMI: Not continuing");
780
781         printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
782
783         /* Clear and disable the memory parity error line. */
784         reason = (reason & 0xf) | 4;
785         outb(reason, 0x61);
786 }
787
788 static __kprobes void
789 io_check_error(unsigned char reason, struct pt_regs * regs)
790 {
791         printk("NMI: IOCK error (debug interrupt?)\n");
792         show_registers(regs);
793
794         /* Re-enable the IOCK line, wait for a few seconds */
795         reason = (reason & 0xf) | 8;
796         outb(reason, 0x61);
797         mdelay(2000);
798         reason &= ~8;
799         outb(reason, 0x61);
800 }
801
802 static __kprobes void
803 unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
804 {
805         printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
806                 reason);
807         printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
808
809         if (panic_on_unrecovered_nmi)
810                 panic("NMI: Not continuing");
811
812         printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
813 }
814
815 /* Runs on IST stack. This code must keep interrupts off all the time.
816    Nested NMIs are prevented by the CPU. */
817 asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
818 {
819         unsigned char reason = 0;
820         int cpu;
821
822         cpu = smp_processor_id();
823
824         /* Only the BSP gets external NMIs from the system.  */
825         if (!cpu)
826                 reason = get_nmi_reason();
827
828         if (!(reason & 0xc0)) {
829                 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
830                                                                 == NOTIFY_STOP)
831                         return;
832                 /*
833                  * Ok, so this is none of the documented NMI sources,
834                  * so it must be the NMI watchdog.
835                  */
836                 if (nmi_watchdog_tick(regs,reason))
837                         return;
838                 if (!do_nmi_callback(regs,cpu))
839                         unknown_nmi_error(reason, regs);
840
841                 return;
842         }
843         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
844                 return; 
845
846         /* AK: following checks seem to be broken on modern chipsets. FIXME */
847
848         if (reason & 0x80)
849                 mem_parity_error(reason, regs);
850         if (reason & 0x40)
851                 io_check_error(reason, regs);
852 }
853
854 /* runs on IST stack. */
855 asmlinkage void __kprobes do_int3(struct pt_regs * regs, long error_code)
856 {
857         if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) {
858                 return;
859         }
860         preempt_conditional_sti(regs);
861         do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
862         preempt_conditional_cli(regs);
863 }
864
865 /* Help handler running on IST stack to switch back to user stack
866    for scheduling or signal handling. The actual stack switch is done in
867    entry.S */
868 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
869 {
870         struct pt_regs *regs = eregs;
871         /* Did already sync */
872         if (eregs == (struct pt_regs *)eregs->rsp)
873                 ;
874         /* Exception from user space */
875         else if (user_mode(eregs))
876                 regs = task_pt_regs(current);
877         /* Exception from kernel and interrupts are enabled. Move to
878            kernel process stack. */
879         else if (eregs->eflags & X86_EFLAGS_IF)
880                 regs = (struct pt_regs *)(eregs->rsp -= sizeof(struct pt_regs));
881         if (eregs != regs)
882                 *regs = *eregs;
883         return regs;
884 }
885
886 /* runs on IST stack. */
887 asmlinkage void __kprobes do_debug(struct pt_regs * regs,
888                                    unsigned long error_code)
889 {
890         unsigned long condition;
891         struct task_struct *tsk = current;
892         siginfo_t info;
893
894         get_debugreg(condition, 6);
895
896         if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
897                                                 SIGTRAP) == NOTIFY_STOP)
898                 return;
899
900         preempt_conditional_sti(regs);
901
902         /* Mask out spurious debug traps due to lazy DR7 setting */
903         if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
904                 if (!tsk->thread.debugreg7) { 
905                         goto clear_dr7;
906                 }
907         }
908
909         tsk->thread.debugreg6 = condition;
910
911         /* Mask out spurious TF errors due to lazy TF clearing */
912         if (condition & DR_STEP) {
913                 /*
914                  * The TF error should be masked out only if the current
915                  * process is not traced and if the TRAP flag has been set
916                  * previously by a tracing process (condition detected by
917                  * the PT_DTRACE flag); remember that the i386 TRAP flag
918                  * can be modified by the process itself in user mode,
919                  * allowing programs to debug themselves without the ptrace()
920                  * interface.
921                  */
922                 if (!user_mode(regs))
923                        goto clear_TF_reenable;
924                 /*
925                  * Was the TF flag set by a debugger? If so, clear it now,
926                  * so that register information is correct.
927                  */
928                 if (tsk->ptrace & PT_DTRACE) {
929                         regs->eflags &= ~TF_MASK;
930                         tsk->ptrace &= ~PT_DTRACE;
931                 }
932         }
933
934         /* Ok, finally something we can handle */
935         tsk->thread.trap_no = 1;
936         tsk->thread.error_code = error_code;
937         info.si_signo = SIGTRAP;
938         info.si_errno = 0;
939         info.si_code = TRAP_BRKPT;
940         info.si_addr = user_mode(regs) ? (void __user *)regs->rip : NULL;
941         force_sig_info(SIGTRAP, &info, tsk);
942
943 clear_dr7:
944         set_debugreg(0UL, 7);
945         preempt_conditional_cli(regs);
946         return;
947
948 clear_TF_reenable:
949         set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
950         regs->eflags &= ~TF_MASK;
951         preempt_conditional_cli(regs);
952 }
953
954 static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr)
955 {
956         const struct exception_table_entry *fixup;
957         fixup = search_exception_tables(regs->rip);
958         if (fixup) {
959                 regs->rip = fixup->fixup;
960                 return 1;
961         }
962         notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE);
963         /* Illegal floating point operation in the kernel */
964         current->thread.trap_no = trapnr;
965         die(str, regs, 0);
966         return 0;
967 }
968
969 /*
970  * Note that we play around with the 'TS' bit in an attempt to get
971  * the correct behaviour even in the presence of the asynchronous
972  * IRQ13 behaviour
973  */
974 asmlinkage void do_coprocessor_error(struct pt_regs *regs)
975 {
976         void __user *rip = (void __user *)(regs->rip);
977         struct task_struct * task;
978         siginfo_t info;
979         unsigned short cwd, swd;
980
981         conditional_sti(regs);
982         if (!user_mode(regs) &&
983             kernel_math_error(regs, "kernel x87 math error", 16))
984                 return;
985
986         /*
987          * Save the info for the exception handler and clear the error.
988          */
989         task = current;
990         save_init_fpu(task);
991         task->thread.trap_no = 16;
992         task->thread.error_code = 0;
993         info.si_signo = SIGFPE;
994         info.si_errno = 0;
995         info.si_code = __SI_FAULT;
996         info.si_addr = rip;
997         /*
998          * (~cwd & swd) will mask out exceptions that are not set to unmasked
999          * status.  0x3f is the exception bits in these regs, 0x200 is the
1000          * C1 reg you need in case of a stack fault, 0x040 is the stack
1001          * fault bit.  We should only be taking one exception at a time,
1002          * so if this combination doesn't produce any single exception,
1003          * then we have a bad program that isn't synchronizing its FPU usage
1004          * and it will suffer the consequences since we won't be able to
1005          * fully reproduce the context of the exception
1006          */
1007         cwd = get_fpu_cwd(task);
1008         swd = get_fpu_swd(task);
1009         switch (swd & ~cwd & 0x3f) {
1010                 case 0x000:
1011                 default:
1012                         break;
1013                 case 0x001: /* Invalid Op */
1014                         /*
1015                          * swd & 0x240 == 0x040: Stack Underflow
1016                          * swd & 0x240 == 0x240: Stack Overflow
1017                          * User must clear the SF bit (0x40) if set
1018                          */
1019                         info.si_code = FPE_FLTINV;
1020                         break;
1021                 case 0x002: /* Denormalize */
1022                 case 0x010: /* Underflow */
1023                         info.si_code = FPE_FLTUND;
1024                         break;
1025                 case 0x004: /* Zero Divide */
1026                         info.si_code = FPE_FLTDIV;
1027                         break;
1028                 case 0x008: /* Overflow */
1029                         info.si_code = FPE_FLTOVF;
1030                         break;
1031                 case 0x020: /* Precision */
1032                         info.si_code = FPE_FLTRES;
1033                         break;
1034         }
1035         force_sig_info(SIGFPE, &info, task);
1036 }
1037
1038 asmlinkage void bad_intr(void)
1039 {
1040         printk("bad interrupt"); 
1041 }
1042
1043 asmlinkage void do_simd_coprocessor_error(struct pt_regs *regs)
1044 {
1045         void __user *rip = (void __user *)(regs->rip);
1046         struct task_struct * task;
1047         siginfo_t info;
1048         unsigned short mxcsr;
1049
1050         conditional_sti(regs);
1051         if (!user_mode(regs) &&
1052                 kernel_math_error(regs, "kernel simd math error", 19))
1053                 return;
1054
1055         /*
1056          * Save the info for the exception handler and clear the error.
1057          */
1058         task = current;
1059         save_init_fpu(task);
1060         task->thread.trap_no = 19;
1061         task->thread.error_code = 0;
1062         info.si_signo = SIGFPE;
1063         info.si_errno = 0;
1064         info.si_code = __SI_FAULT;
1065         info.si_addr = rip;
1066         /*
1067          * The SIMD FPU exceptions are handled a little differently, as there
1068          * is only a single status/control register.  Thus, to determine which
1069          * unmasked exception was caught we must mask the exception mask bits
1070          * at 0x1f80, and then use these to mask the exception bits at 0x3f.
1071          */
1072         mxcsr = get_fpu_mxcsr(task);
1073         switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
1074                 case 0x000:
1075                 default:
1076                         break;
1077                 case 0x001: /* Invalid Op */
1078                         info.si_code = FPE_FLTINV;
1079                         break;
1080                 case 0x002: /* Denormalize */
1081                 case 0x010: /* Underflow */
1082                         info.si_code = FPE_FLTUND;
1083                         break;
1084                 case 0x004: /* Zero Divide */
1085                         info.si_code = FPE_FLTDIV;
1086                         break;
1087                 case 0x008: /* Overflow */
1088                         info.si_code = FPE_FLTOVF;
1089                         break;
1090                 case 0x020: /* Precision */
1091                         info.si_code = FPE_FLTRES;
1092                         break;
1093         }
1094         force_sig_info(SIGFPE, &info, task);
1095 }
1096
1097 asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs)
1098 {
1099 }
1100
1101 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
1102 {
1103 }
1104
1105 asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void)
1106 {
1107 }
1108
1109 /*
1110  *  'math_state_restore()' saves the current math information in the
1111  * old math state array, and gets the new ones from the current task
1112  *
1113  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1114  * Don't touch unless you *really* know how it works.
1115  */
1116 asmlinkage void math_state_restore(void)
1117 {
1118         struct task_struct *me = current;
1119         clts();                 /* Allow maths ops (or we recurse) */
1120
1121         if (!used_math())
1122                 init_fpu(me);
1123         restore_fpu_checking(&me->thread.i387.fxsave);
1124         task_thread_info(me)->status |= TS_USEDFPU;
1125         me->fpu_counter++;
1126 }
1127
1128 void __init trap_init(void)
1129 {
1130         set_intr_gate(0,&divide_error);
1131         set_intr_gate_ist(1,&debug,DEBUG_STACK);
1132         set_intr_gate_ist(2,&nmi,NMI_STACK);
1133         set_system_gate_ist(3,&int3,DEBUG_STACK); /* int3 can be called from all */
1134         set_system_gate(4,&overflow);   /* int4 can be called from all */
1135         set_intr_gate(5,&bounds);
1136         set_intr_gate(6,&invalid_op);
1137         set_intr_gate(7,&device_not_available);
1138         set_intr_gate_ist(8,&double_fault, DOUBLEFAULT_STACK);
1139         set_intr_gate(9,&coprocessor_segment_overrun);
1140         set_intr_gate(10,&invalid_TSS);
1141         set_intr_gate(11,&segment_not_present);
1142         set_intr_gate_ist(12,&stack_segment,STACKFAULT_STACK);
1143         set_intr_gate(13,&general_protection);
1144         set_intr_gate(14,&page_fault);
1145         set_intr_gate(15,&spurious_interrupt_bug);
1146         set_intr_gate(16,&coprocessor_error);
1147         set_intr_gate(17,&alignment_check);
1148 #ifdef CONFIG_X86_MCE
1149         set_intr_gate_ist(18,&machine_check, MCE_STACK); 
1150 #endif
1151         set_intr_gate(19,&simd_coprocessor_error);
1152
1153 #ifdef CONFIG_IA32_EMULATION
1154         set_system_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
1155 #endif
1156        
1157         /*
1158          * Should be a barrier for any external CPU state.
1159          */
1160         cpu_init();
1161 }
1162
1163
1164 static int __init oops_setup(char *s)
1165
1166         if (!s)
1167                 return -EINVAL;
1168         if (!strcmp(s, "panic"))
1169                 panic_on_oops = 1;
1170         return 0;
1171
1172 early_param("oops", oops_setup);
1173
1174 static int __init kstack_setup(char *s)
1175 {
1176         if (!s)
1177                 return -EINVAL;
1178         kstack_depth_to_print = simple_strtoul(s,NULL,0);
1179         return 0;
1180 }
1181 early_param("kstack", kstack_setup);
1182
1183 #ifdef CONFIG_STACK_UNWIND
1184 static int __init call_trace_setup(char *s)
1185 {
1186         if (!s)
1187                 return -EINVAL;
1188         if (strcmp(s, "old") == 0)
1189                 call_trace = -1;
1190         else if (strcmp(s, "both") == 0)
1191                 call_trace = 0;
1192         else if (strcmp(s, "newfallback") == 0)
1193                 call_trace = 1;
1194         else if (strcmp(s, "new") == 0)
1195                 call_trace = 2;
1196         return 0;
1197 }
1198 early_param("call_trace", call_trace_setup);
1199 #endif