2 * linux/arch/i386/traps.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * Pentium III FXSR, SSE support
7 * Gareth Hughes <gareth@valinux.com>, May 2000
11 * 'Traps.c' handles hardware traps and faults after we have saved some
14 #include <linux/sched.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/timer.h>
20 #include <linux/init.h>
21 #include <linux/delay.h>
22 #include <linux/spinlock.h>
23 #include <linux/interrupt.h>
24 #include <linux/highmem.h>
25 #include <linux/kallsyms.h>
26 #include <linux/ptrace.h>
27 #include <linux/utsname.h>
28 #include <linux/kprobes.h>
29 #include <linux/kexec.h>
30 #include <linux/unwind.h>
33 #include <linux/ioport.h>
34 #include <linux/eisa.h>
38 #include <linux/mca.h>
41 #include <asm/processor.h>
42 #include <asm/system.h>
43 #include <asm/uaccess.h>
45 #include <asm/atomic.h>
46 #include <asm/debugreg.h>
50 #include <asm/unwind.h>
52 #include <asm/arch_hooks.h>
53 #include <asm/kdebug.h>
55 #include <linux/module.h>
57 #include "mach_traps.h"
59 asmlinkage int system_call(void);
61 struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
64 /* Do we ignore FPU interrupts ? */
65 char ignore_fpu_irq = 0;
68 * The IDT has to be page-aligned to simplify the Pentium
69 * F0 0F bug workaround.. We have a special link segment
72 struct desc_struct idt_table[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, };
74 asmlinkage void divide_error(void);
75 asmlinkage void debug(void);
76 asmlinkage void nmi(void);
77 asmlinkage void int3(void);
78 asmlinkage void overflow(void);
79 asmlinkage void bounds(void);
80 asmlinkage void invalid_op(void);
81 asmlinkage void device_not_available(void);
82 asmlinkage void coprocessor_segment_overrun(void);
83 asmlinkage void invalid_TSS(void);
84 asmlinkage void segment_not_present(void);
85 asmlinkage void stack_segment(void);
86 asmlinkage void general_protection(void);
87 asmlinkage void page_fault(void);
88 asmlinkage void coprocessor_error(void);
89 asmlinkage void simd_coprocessor_error(void);
90 asmlinkage void alignment_check(void);
91 asmlinkage void spurious_interrupt_bug(void);
92 asmlinkage void machine_check(void);
94 static int kstack_depth_to_print = 24;
95 static int call_trace = 1;
96 ATOMIC_NOTIFIER_HEAD(i386die_chain);
98 int register_die_notifier(struct notifier_block *nb)
101 return atomic_notifier_chain_register(&i386die_chain, nb);
103 EXPORT_SYMBOL(register_die_notifier); /* used modular by kdb */
105 int unregister_die_notifier(struct notifier_block *nb)
107 return atomic_notifier_chain_unregister(&i386die_chain, nb);
109 EXPORT_SYMBOL(unregister_die_notifier); /* used modular by kdb */
111 static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
113 return p > (void *)tinfo &&
114 p < (void *)tinfo + THREAD_SIZE - 3;
118 * Print one address/symbol entries per line.
120 static inline void print_addr_and_symbol(unsigned long addr, char *log_lvl)
122 printk(" [<%08lx>] ", addr);
124 print_symbol("%s\n", addr);
127 static inline unsigned long print_context_stack(struct thread_info *tinfo,
128 unsigned long *stack, unsigned long ebp,
133 #ifdef CONFIG_FRAME_POINTER
134 while (valid_stack_ptr(tinfo, (void *)ebp)) {
135 addr = *(unsigned long *)(ebp + 4);
136 print_addr_and_symbol(addr, log_lvl);
138 * break out of recursive entries (such as
139 * end_of_stack_stop_unwind_function):
141 if (ebp == *(unsigned long *)ebp)
143 ebp = *(unsigned long *)ebp;
146 while (valid_stack_ptr(tinfo, stack)) {
148 if (__kernel_text_address(addr))
149 print_addr_and_symbol(addr, log_lvl);
155 static asmlinkage int
156 show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
160 while (unwind(info) == 0 && UNW_PC(info)) {
162 print_addr_and_symbol(UNW_PC(info), log_lvl);
163 if (arch_unw_user_mode(info))
169 static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
170 unsigned long *stack, char *log_lvl)
177 if (call_trace >= 0) {
179 struct unwind_frame_info info;
182 if (unwind_init_frame_info(&info, task, regs) == 0)
183 unw_ret = show_trace_unwind(&info, log_lvl);
184 } else if (task == current)
185 unw_ret = unwind_init_running(&info, show_trace_unwind, log_lvl);
187 if (unwind_init_blocked(&info, task) == 0)
188 unw_ret = show_trace_unwind(&info, log_lvl);
193 printk("%sLegacy call trace:\n", log_lvl);
197 if (task == current) {
198 /* Grab ebp right from our regs */
199 asm ("movl %%ebp, %0" : "=r" (ebp) : );
201 /* ebp is the last reg pushed by switch_to */
202 ebp = *(unsigned long *) task->thread.esp;
206 struct thread_info *context;
207 context = (struct thread_info *)
208 ((unsigned long)stack & (~(THREAD_SIZE - 1)));
209 ebp = print_context_stack(context, stack, ebp, log_lvl);
210 stack = (unsigned long*)context->previous_esp;
213 printk("%s =======================\n", log_lvl);
217 void show_trace(struct task_struct *task, struct pt_regs *regs, unsigned long * stack)
219 show_trace_log_lvl(task, regs, stack, "");
222 static void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
223 unsigned long *esp, char *log_lvl)
225 unsigned long *stack;
230 esp = (unsigned long*)task->thread.esp;
232 esp = (unsigned long *)&esp;
236 for(i = 0; i < kstack_depth_to_print; i++) {
237 if (kstack_end(stack))
239 if (i && ((i % 8) == 0))
240 printk("\n%s ", log_lvl);
241 printk("%08lx ", *stack++);
243 printk("\n%sCall Trace:\n", log_lvl);
244 show_trace_log_lvl(task, regs, esp, log_lvl);
247 void show_stack(struct task_struct *task, unsigned long *esp)
250 show_stack_log_lvl(task, NULL, esp, "");
254 * The architecture-independent dump_stack generator
256 void dump_stack(void)
260 show_trace(current, NULL, &stack);
263 EXPORT_SYMBOL(dump_stack);
265 void show_registers(struct pt_regs *regs)
272 esp = (unsigned long) (®s->esp);
274 if (user_mode_vm(regs)) {
277 ss = regs->xss & 0xffff;
280 printk(KERN_EMERG "CPU: %d\nEIP: %04x:[<%08lx>] %s VLI\n"
281 "EFLAGS: %08lx (%s %.*s) \n",
282 smp_processor_id(), 0xffff & regs->xcs, regs->eip,
283 print_tainted(), regs->eflags, system_utsname.release,
284 (int)strcspn(system_utsname.version, " "),
285 system_utsname.version);
286 print_symbol(KERN_EMERG "EIP is at %s\n", regs->eip);
287 printk(KERN_EMERG "eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
288 regs->eax, regs->ebx, regs->ecx, regs->edx);
289 printk(KERN_EMERG "esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
290 regs->esi, regs->edi, regs->ebp, esp);
291 printk(KERN_EMERG "ds: %04x es: %04x ss: %04x\n",
292 regs->xds & 0xffff, regs->xes & 0xffff, ss);
293 printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
294 TASK_COMM_LEN, current->comm, current->pid,
295 current_thread_info(), current, current->thread_info);
297 * When in-kernel, we also print out the stack and code at the
298 * time of the fault..
303 printk("\n" KERN_EMERG "Stack: ");
304 show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG);
306 printk(KERN_EMERG "Code: ");
308 eip = (u8 __user *)regs->eip - 43;
309 for (i = 0; i < 64; i++, eip++) {
312 if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
313 printk(" Bad EIP value.");
316 if (eip == (u8 __user *)regs->eip)
317 printk("<%02x> ", c);
325 static void handle_BUG(struct pt_regs *regs)
335 if (eip < PAGE_OFFSET)
337 if (__get_user(ud2, (unsigned short __user *)eip))
341 if (__get_user(line, (unsigned short __user *)(eip + 2)))
343 if (__get_user(file, (char * __user *)(eip + 4)) ||
344 (unsigned long)file < PAGE_OFFSET || __get_user(c, file))
345 file = "<bad filename>";
347 printk(KERN_EMERG "------------[ cut here ]------------\n");
348 printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
353 /* Here we know it was a BUG but file-n-line is unavailable */
355 printk(KERN_EMERG "Kernel BUG\n");
358 /* This is gone through when something in the kernel
359 * has done something bad and is about to be terminated.
361 void die(const char * str, struct pt_regs * regs, long err)
366 int lock_owner_depth;
368 .lock = SPIN_LOCK_UNLOCKED,
370 .lock_owner_depth = 0
372 static int die_counter;
377 if (die.lock_owner != raw_smp_processor_id()) {
379 spin_lock_irqsave(&die.lock, flags);
380 die.lock_owner = smp_processor_id();
381 die.lock_owner_depth = 0;
385 local_save_flags(flags);
387 if (++die.lock_owner_depth < 3) {
393 printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
394 #ifdef CONFIG_PREEMPT
395 printk(KERN_EMERG "PREEMPT ");
404 #ifdef CONFIG_DEBUG_PAGEALLOC
407 printk("DEBUG_PAGEALLOC");
412 if (notify_die(DIE_OOPS, str, regs, err,
413 current->thread.trap_no, SIGSEGV) !=
415 show_registers(regs);
416 /* Executive summary in case the oops scrolled away */
417 esp = (unsigned long) (®s->esp);
419 if (user_mode(regs)) {
421 ss = regs->xss & 0xffff;
423 printk(KERN_EMERG "EIP: [<%08lx>] ", regs->eip);
424 print_symbol("%s", regs->eip);
425 printk(" SS:ESP %04x:%08lx\n", ss, esp);
430 printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
434 spin_unlock_irqrestore(&die.lock, flags);
439 if (kexec_should_crash(current))
443 panic("Fatal exception in interrupt");
446 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
448 panic("Fatal exception");
454 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
456 if (!user_mode_vm(regs))
460 static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
461 struct pt_regs * regs, long error_code,
464 struct task_struct *tsk = current;
465 tsk->thread.error_code = error_code;
466 tsk->thread.trap_no = trapnr;
468 if (regs->eflags & VM_MASK) {
474 if (!user_mode(regs))
479 force_sig_info(signr, info, tsk);
481 force_sig(signr, tsk);
486 if (!fixup_exception(regs))
487 die(str, regs, error_code);
492 int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
493 if (ret) goto trap_signal;
498 #define DO_ERROR(trapnr, signr, str, name) \
499 fastcall void do_##name(struct pt_regs * regs, long error_code) \
501 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
504 do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
507 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
508 fastcall void do_##name(struct pt_regs * regs, long error_code) \
511 info.si_signo = signr; \
513 info.si_code = sicode; \
514 info.si_addr = (void __user *)siaddr; \
515 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
518 do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
521 #define DO_VM86_ERROR(trapnr, signr, str, name) \
522 fastcall void do_##name(struct pt_regs * regs, long error_code) \
524 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
527 do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
530 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
531 fastcall void do_##name(struct pt_regs * regs, long error_code) \
534 info.si_signo = signr; \
536 info.si_code = sicode; \
537 info.si_addr = (void __user *)siaddr; \
538 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
541 do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
544 DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip)
545 #ifndef CONFIG_KPROBES
546 DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
548 DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
549 DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
550 DO_ERROR_INFO( 6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->eip)
551 DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
552 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
553 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
554 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
555 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
556 DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0)
558 fastcall void __kprobes do_general_protection(struct pt_regs * regs,
562 struct tss_struct *tss = &per_cpu(init_tss, cpu);
563 struct thread_struct *thread = ¤t->thread;
566 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
567 * invalid offset set (the LAZY one) and the faulting thread has
568 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
569 * and we set the offset field correctly. Then we let the CPU to
570 * restart the faulting instruction.
572 if (tss->io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
573 thread->io_bitmap_ptr) {
574 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
575 thread->io_bitmap_max);
577 * If the previously set map was extending to higher ports
578 * than the current one, pad extra space with 0xff (no access).
580 if (thread->io_bitmap_max < tss->io_bitmap_max)
581 memset((char *) tss->io_bitmap +
582 thread->io_bitmap_max, 0xff,
583 tss->io_bitmap_max - thread->io_bitmap_max);
584 tss->io_bitmap_max = thread->io_bitmap_max;
585 tss->io_bitmap_base = IO_BITMAP_OFFSET;
586 tss->io_bitmap_owner = thread;
592 current->thread.error_code = error_code;
593 current->thread.trap_no = 13;
595 if (regs->eflags & VM_MASK)
598 if (!user_mode(regs))
601 current->thread.error_code = error_code;
602 current->thread.trap_no = 13;
603 force_sig(SIGSEGV, current);
608 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
612 if (!fixup_exception(regs)) {
613 if (notify_die(DIE_GPF, "general protection fault", regs,
614 error_code, 13, SIGSEGV) == NOTIFY_STOP)
616 die("general protection fault", regs, error_code);
620 static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
622 printk(KERN_EMERG "Uhhuh. NMI received. Dazed and confused, but trying "
624 printk(KERN_EMERG "You probably have a hardware problem with your RAM "
627 /* Clear and disable the memory parity error line. */
628 clear_mem_error(reason);
631 static void io_check_error(unsigned char reason, struct pt_regs * regs)
635 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
636 show_registers(regs);
638 /* Re-enable the IOCK line, wait for a few seconds */
639 reason = (reason & 0xf) | 8;
642 while (--i) udelay(1000);
647 static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
650 /* Might actually be able to figure out what the guilty party
657 printk("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
658 reason, smp_processor_id());
659 printk("Dazed and confused, but trying to continue\n");
660 printk("Do you have a strange power saving mode enabled?\n");
663 static DEFINE_SPINLOCK(nmi_print_lock);
665 void die_nmi (struct pt_regs *regs, const char *msg)
667 if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 2, SIGINT) ==
671 spin_lock(&nmi_print_lock);
673 * We are in trouble anyway, lets at least try
674 * to get a message out.
677 printk(KERN_EMERG "%s", msg);
678 printk(" on CPU%d, eip %08lx, registers:\n",
679 smp_processor_id(), regs->eip);
680 show_registers(regs);
681 printk(KERN_EMERG "console shuts up ...\n");
683 spin_unlock(&nmi_print_lock);
686 /* If we are in kernel we are probably nested up pretty bad
687 * and might aswell get out now while we still can.
689 if (!user_mode_vm(regs)) {
690 current->thread.trap_no = 2;
697 static void default_do_nmi(struct pt_regs * regs)
699 unsigned char reason = 0;
701 /* Only the BSP gets external NMIs from the system. */
702 if (!smp_processor_id())
703 reason = get_nmi_reason();
705 if (!(reason & 0xc0)) {
706 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
709 #ifdef CONFIG_X86_LOCAL_APIC
711 * Ok, so this is none of the documented NMI sources,
712 * so it must be the NMI watchdog.
715 nmi_watchdog_tick(regs);
719 unknown_nmi_error(reason, regs);
722 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
725 mem_parity_error(reason, regs);
727 io_check_error(reason, regs);
729 * Reassert NMI in case it became active meanwhile
730 * as it's edge-triggered.
735 static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
740 static nmi_callback_t nmi_callback = dummy_nmi_callback;
742 fastcall void do_nmi(struct pt_regs * regs, long error_code)
748 cpu = smp_processor_id();
752 if (!rcu_dereference(nmi_callback)(regs, cpu))
753 default_do_nmi(regs);
758 void set_nmi_callback(nmi_callback_t callback)
761 rcu_assign_pointer(nmi_callback, callback);
763 EXPORT_SYMBOL_GPL(set_nmi_callback);
765 void unset_nmi_callback(void)
767 nmi_callback = dummy_nmi_callback;
769 EXPORT_SYMBOL_GPL(unset_nmi_callback);
771 #ifdef CONFIG_KPROBES
772 fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
774 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
777 /* This is an interrupt gate, because kprobes wants interrupts
778 disabled. Normal trap handlers don't. */
779 restore_interrupts(regs);
780 do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
785 * Our handling of the processor debug registers is non-trivial.
786 * We do not clear them on entry and exit from the kernel. Therefore
787 * it is possible to get a watchpoint trap here from inside the kernel.
788 * However, the code in ./ptrace.c has ensured that the user can
789 * only set watchpoints on userspace addresses. Therefore the in-kernel
790 * watchpoint trap can only occur in code which is reading/writing
791 * from user space. Such code must not hold kernel locks (since it
792 * can equally take a page fault), therefore it is safe to call
793 * force_sig_info even though that claims and releases locks.
795 * Code in ./signal.c ensures that the debug control register
796 * is restored before we deliver any signal, and therefore that
797 * user code runs with the correct debug control register even though
800 * Being careful here means that we don't have to be as careful in a
801 * lot of more complicated places (task switching can be a bit lazy
802 * about restoring all the debug state, and ptrace doesn't have to
803 * find every occurrence of the TF bit that could be saved away even
806 fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)
808 unsigned int condition;
809 struct task_struct *tsk = current;
811 get_debugreg(condition, 6);
813 if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
814 SIGTRAP) == NOTIFY_STOP)
816 /* It's safe to allow irq's after DR6 has been saved */
817 if (regs->eflags & X86_EFLAGS_IF)
820 /* Mask out spurious debug traps due to lazy DR7 setting */
821 if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
822 if (!tsk->thread.debugreg[7])
826 if (regs->eflags & VM_MASK)
829 /* Save debug status register where ptrace can see it */
830 tsk->thread.debugreg[6] = condition;
833 * Single-stepping through TF: make sure we ignore any events in
834 * kernel space (but re-enable TF when returning to user mode).
836 if (condition & DR_STEP) {
838 * We already checked v86 mode above, so we can
839 * check for kernel mode by just checking the CPL
842 if (!user_mode(regs))
843 goto clear_TF_reenable;
846 /* Ok, finally something we can handle */
847 send_sigtrap(tsk, regs, error_code);
849 /* Disable additional traps. They'll be re-enabled when
850 * the signal is delivered.
857 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
861 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
862 regs->eflags &= ~TF_MASK;
867 * Note that we play around with the 'TS' bit in an attempt to get
868 * the correct behaviour even in the presence of the asynchronous
871 void math_error(void __user *eip)
873 struct task_struct * task;
875 unsigned short cwd, swd;
878 * Save the info for the exception handler and clear the error.
882 task->thread.trap_no = 16;
883 task->thread.error_code = 0;
884 info.si_signo = SIGFPE;
886 info.si_code = __SI_FAULT;
889 * (~cwd & swd) will mask out exceptions that are not set to unmasked
890 * status. 0x3f is the exception bits in these regs, 0x200 is the
891 * C1 reg you need in case of a stack fault, 0x040 is the stack
892 * fault bit. We should only be taking one exception at a time,
893 * so if this combination doesn't produce any single exception,
894 * then we have a bad program that isn't syncronizing its FPU usage
895 * and it will suffer the consequences since we won't be able to
896 * fully reproduce the context of the exception
898 cwd = get_fpu_cwd(task);
899 swd = get_fpu_swd(task);
900 switch (swd & ~cwd & 0x3f) {
901 case 0x000: /* No unmasked exception */
903 default: /* Multiple exceptions */
905 case 0x001: /* Invalid Op */
907 * swd & 0x240 == 0x040: Stack Underflow
908 * swd & 0x240 == 0x240: Stack Overflow
909 * User must clear the SF bit (0x40) if set
911 info.si_code = FPE_FLTINV;
913 case 0x002: /* Denormalize */
914 case 0x010: /* Underflow */
915 info.si_code = FPE_FLTUND;
917 case 0x004: /* Zero Divide */
918 info.si_code = FPE_FLTDIV;
920 case 0x008: /* Overflow */
921 info.si_code = FPE_FLTOVF;
923 case 0x020: /* Precision */
924 info.si_code = FPE_FLTRES;
927 force_sig_info(SIGFPE, &info, task);
930 fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code)
933 math_error((void __user *)regs->eip);
936 static void simd_math_error(void __user *eip)
938 struct task_struct * task;
940 unsigned short mxcsr;
943 * Save the info for the exception handler and clear the error.
947 task->thread.trap_no = 19;
948 task->thread.error_code = 0;
949 info.si_signo = SIGFPE;
951 info.si_code = __SI_FAULT;
954 * The SIMD FPU exceptions are handled a little differently, as there
955 * is only a single status/control register. Thus, to determine which
956 * unmasked exception was caught we must mask the exception mask bits
957 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
959 mxcsr = get_fpu_mxcsr(task);
960 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
964 case 0x001: /* Invalid Op */
965 info.si_code = FPE_FLTINV;
967 case 0x002: /* Denormalize */
968 case 0x010: /* Underflow */
969 info.si_code = FPE_FLTUND;
971 case 0x004: /* Zero Divide */
972 info.si_code = FPE_FLTDIV;
974 case 0x008: /* Overflow */
975 info.si_code = FPE_FLTOVF;
977 case 0x020: /* Precision */
978 info.si_code = FPE_FLTRES;
981 force_sig_info(SIGFPE, &info, task);
984 fastcall void do_simd_coprocessor_error(struct pt_regs * regs,
988 /* Handle SIMD FPU exceptions on PIII+ processors. */
990 simd_math_error((void __user *)regs->eip);
993 * Handle strange cache flush from user space exception
994 * in all other cases. This is undocumented behaviour.
996 if (regs->eflags & VM_MASK) {
997 handle_vm86_fault((struct kernel_vm86_regs *)regs,
1001 current->thread.trap_no = 19;
1002 current->thread.error_code = error_code;
1003 die_if_kernel("cache flush denied", regs, error_code);
1004 force_sig(SIGSEGV, current);
1008 fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
1012 /* No need to warn about this any longer. */
1013 printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
1017 fastcall void setup_x86_bogus_stack(unsigned char * stk)
1019 unsigned long *switch16_ptr, *switch32_ptr;
1020 struct pt_regs *regs;
1021 unsigned long stack_top, stack_bot;
1022 unsigned short iret_frame16_off;
1023 int cpu = smp_processor_id();
1024 /* reserve the space on 32bit stack for the magic switch16 pointer */
1025 memmove(stk, stk + 8, sizeof(struct pt_regs));
1026 switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs));
1027 regs = (struct pt_regs *)stk;
1028 /* now the switch32 on 16bit stack */
1029 stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
1030 stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
1031 switch32_ptr = (unsigned long *)(stack_top - 8);
1032 iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20;
1033 /* copy iret frame on 16bit stack */
1034 memcpy((void *)(stack_bot + iret_frame16_off), ®s->eip, 20);
1035 /* fill in the switch pointers */
1036 switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off;
1037 switch16_ptr[1] = __ESPFIX_SS;
1038 switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) +
1039 8 - CPU_16BIT_STACK_SIZE;
1040 switch32_ptr[1] = __KERNEL_DS;
1043 fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp)
1045 unsigned long *switch32_ptr;
1046 unsigned char *stack16, *stack32;
1047 unsigned long stack_top, stack_bot;
1049 int cpu = smp_processor_id();
1050 stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
1051 stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
1052 switch32_ptr = (unsigned long *)(stack_top - 8);
1053 /* copy the data from 16bit stack to 32bit stack */
1054 len = CPU_16BIT_STACK_SIZE - 8 - sp;
1055 stack16 = (unsigned char *)(stack_bot + sp);
1056 stack32 = (unsigned char *)
1057 (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len);
1058 memcpy(stack32, stack16, len);
1063 * 'math_state_restore()' saves the current math information in the
1064 * old math state array, and gets the new ones from the current task
1066 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1067 * Don't touch unless you *really* know how it works.
1069 * Must be called with kernel preemption disabled (in this case,
1070 * local interrupts are disabled at the call-site in entry.S).
1072 asmlinkage void math_state_restore(struct pt_regs regs)
1074 struct thread_info *thread = current_thread_info();
1075 struct task_struct *tsk = thread->task;
1077 clts(); /* Allow maths ops (or we recurse) */
1078 if (!tsk_used_math(tsk))
1081 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
1084 #ifndef CONFIG_MATH_EMULATION
1086 asmlinkage void math_emulate(long arg)
1088 printk(KERN_EMERG "math-emulation not enabled and no coprocessor found.\n");
1089 printk(KERN_EMERG "killing %s.\n",current->comm);
1090 force_sig(SIGFPE,current);
1094 #endif /* CONFIG_MATH_EMULATION */
1096 #ifdef CONFIG_X86_F00F_BUG
1097 void __init trap_init_f00f_bug(void)
1099 __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
1102 * Update the IDT descriptor and reload the IDT so that
1103 * it uses the read-only mapped virtual address.
1105 idt_descr.address = fix_to_virt(FIX_F00F_IDT);
1106 load_idt(&idt_descr);
1110 #define _set_gate(gate_addr,type,dpl,addr,seg) \
1113 __asm__ __volatile__ ("movw %%dx,%%ax\n\t" \
1114 "movw %4,%%dx\n\t" \
1115 "movl %%eax,%0\n\t" \
1117 :"=m" (*((long *) (gate_addr))), \
1118 "=m" (*(1+(long *) (gate_addr))), "=&a" (__d0), "=&d" (__d1) \
1119 :"i" ((short) (0x8000+(dpl<<13)+(type<<8))), \
1120 "3" ((char *) (addr)),"2" ((seg) << 16)); \
1125 * This needs to use 'idt_table' rather than 'idt', and
1126 * thus use the _nonmapped_ version of the IDT, as the
1127 * Pentium F0 0F bugfix can have resulted in the mapped
1128 * IDT being write-protected.
1130 void set_intr_gate(unsigned int n, void *addr)
1132 _set_gate(idt_table+n,14,0,addr,__KERNEL_CS);
1136 * This routine sets up an interrupt gate at directory privilege level 3.
1138 static inline void set_system_intr_gate(unsigned int n, void *addr)
1140 _set_gate(idt_table+n, 14, 3, addr, __KERNEL_CS);
1143 static void __init set_trap_gate(unsigned int n, void *addr)
1145 _set_gate(idt_table+n,15,0,addr,__KERNEL_CS);
1148 static void __init set_system_gate(unsigned int n, void *addr)
1150 _set_gate(idt_table+n,15,3,addr,__KERNEL_CS);
1153 static void __init set_task_gate(unsigned int n, unsigned int gdt_entry)
1155 _set_gate(idt_table+n,5,0,0,(gdt_entry<<3));
1159 void __init trap_init(void)
1162 void __iomem *p = ioremap(0x0FFFD9, 4);
1163 if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
1169 #ifdef CONFIG_X86_LOCAL_APIC
1170 init_apic_mappings();
1173 set_trap_gate(0,÷_error);
1174 set_intr_gate(1,&debug);
1175 set_intr_gate(2,&nmi);
1176 set_system_intr_gate(3, &int3); /* int3/4 can be called from all */
1177 set_system_gate(4,&overflow);
1178 set_trap_gate(5,&bounds);
1179 set_trap_gate(6,&invalid_op);
1180 set_trap_gate(7,&device_not_available);
1181 set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS);
1182 set_trap_gate(9,&coprocessor_segment_overrun);
1183 set_trap_gate(10,&invalid_TSS);
1184 set_trap_gate(11,&segment_not_present);
1185 set_trap_gate(12,&stack_segment);
1186 set_trap_gate(13,&general_protection);
1187 set_intr_gate(14,&page_fault);
1188 set_trap_gate(15,&spurious_interrupt_bug);
1189 set_trap_gate(16,&coprocessor_error);
1190 set_trap_gate(17,&alignment_check);
1191 #ifdef CONFIG_X86_MCE
1192 set_trap_gate(18,&machine_check);
1194 set_trap_gate(19,&simd_coprocessor_error);
1198 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
1199 * Generates a compile-time "error: zero width for bit-field" if
1200 * the alignment is wrong.
1202 struct fxsrAlignAssert {
1203 int _:!(offsetof(struct task_struct,
1204 thread.i387.fxsave) & 15);
1207 printk(KERN_INFO "Enabling fast FPU save and restore... ");
1208 set_in_cr4(X86_CR4_OSFXSR);
1212 printk(KERN_INFO "Enabling unmasked SIMD FPU exception "
1214 set_in_cr4(X86_CR4_OSXMMEXCPT);
1218 set_system_gate(SYSCALL_VECTOR,&system_call);
1221 * Should be a barrier for any external CPU state.
1228 static int __init kstack_setup(char *s)
1230 kstack_depth_to_print = simple_strtoul(s, NULL, 0);
1233 __setup("kstack=", kstack_setup);
1235 static int __init call_trace_setup(char *s)
1237 if (strcmp(s, "old") == 0)
1239 else if (strcmp(s, "both") == 0)
1241 else if (strcmp(s, "new") == 0)
1245 __setup("call_trace=", call_trace_setup);