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/config.h>
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/timer.h>
21 #include <linux/init.h>
22 #include <linux/delay.h>
23 #include <linux/spinlock.h>
24 #include <linux/interrupt.h>
25 #include <linux/highmem.h>
26 #include <linux/kallsyms.h>
27 #include <linux/ptrace.h>
28 #include <linux/utsname.h>
29 #include <linux/kprobes.h>
30 #include <linux/kexec.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>
52 #include <asm/arch_hooks.h>
53 #include <asm/kdebug.h>
55 #include <linux/irq.h>
56 #include <linux/module.h>
58 #include "mach_traps.h"
60 asmlinkage int system_call(void);
62 struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
65 /* Do we ignore FPU interrupts ? */
66 char ignore_fpu_irq = 0;
69 * The IDT has to be page-aligned to simplify the Pentium
70 * F0 0F bug workaround.. We have a special link segment
73 struct desc_struct idt_table[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, };
75 asmlinkage void divide_error(void);
76 asmlinkage void debug(void);
77 asmlinkage void nmi(void);
78 asmlinkage void int3(void);
79 asmlinkage void overflow(void);
80 asmlinkage void bounds(void);
81 asmlinkage void invalid_op(void);
82 asmlinkage void device_not_available(void);
83 asmlinkage void coprocessor_segment_overrun(void);
84 asmlinkage void invalid_TSS(void);
85 asmlinkage void segment_not_present(void);
86 asmlinkage void stack_segment(void);
87 asmlinkage void general_protection(void);
88 asmlinkage void page_fault(void);
89 asmlinkage void coprocessor_error(void);
90 asmlinkage void simd_coprocessor_error(void);
91 asmlinkage void alignment_check(void);
92 asmlinkage void spurious_interrupt_bug(void);
93 asmlinkage void machine_check(void);
95 static int kstack_depth_to_print = 24;
96 struct notifier_block *i386die_chain;
97 static DEFINE_SPINLOCK(die_notifier_lock);
99 int register_die_notifier(struct notifier_block *nb)
103 spin_lock_irqsave(&die_notifier_lock, flags);
104 err = notifier_chain_register(&i386die_chain, nb);
105 spin_unlock_irqrestore(&die_notifier_lock, flags);
108 EXPORT_SYMBOL(register_die_notifier);
110 static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
112 return p > (void *)tinfo &&
113 p < (void *)tinfo + THREAD_SIZE - 3;
116 static inline unsigned long print_context_stack(struct thread_info *tinfo,
117 unsigned long *stack, unsigned long ebp)
121 #ifdef CONFIG_FRAME_POINTER
122 while (valid_stack_ptr(tinfo, (void *)ebp)) {
123 addr = *(unsigned long *)(ebp + 4);
124 printk(" [<%08lx>] ", addr);
125 print_symbol("%s", addr);
127 ebp = *(unsigned long *)ebp;
130 while (valid_stack_ptr(tinfo, stack)) {
132 if (__kernel_text_address(addr)) {
133 printk(" [<%08lx>]", addr);
134 print_symbol(" %s", addr);
142 void show_trace(struct task_struct *task, unsigned long * stack)
149 if (task == current) {
150 /* Grab ebp right from our regs */
151 asm ("movl %%ebp, %0" : "=r" (ebp) : );
153 /* ebp is the last reg pushed by switch_to */
154 ebp = *(unsigned long *) task->thread.esp;
158 struct thread_info *context;
159 context = (struct thread_info *)
160 ((unsigned long)stack & (~(THREAD_SIZE - 1)));
161 ebp = print_context_stack(context, stack, ebp);
162 stack = (unsigned long*)context->previous_esp;
165 printk(" =======================\n");
169 void show_stack(struct task_struct *task, unsigned long *esp)
171 unsigned long *stack;
176 esp = (unsigned long*)task->thread.esp;
178 esp = (unsigned long *)&esp;
182 for(i = 0; i < kstack_depth_to_print; i++) {
183 if (kstack_end(stack))
185 if (i && ((i % 8) == 0))
187 printk("%08lx ", *stack++);
189 printk("\nCall Trace:\n");
190 show_trace(task, esp);
194 * The architecture-independent dump_stack generator
196 void dump_stack(void)
200 show_trace(current, &stack);
203 EXPORT_SYMBOL(dump_stack);
205 void show_registers(struct pt_regs *regs)
212 esp = (unsigned long) (®s->esp);
214 if (user_mode(regs)) {
217 ss = regs->xss & 0xffff;
220 printk("CPU: %d\nEIP: %04x:[<%08lx>] %s VLI\nEFLAGS: %08lx"
222 smp_processor_id(), 0xffff & regs->xcs, regs->eip,
223 print_tainted(), regs->eflags, system_utsname.release);
224 print_symbol("EIP is at %s\n", regs->eip);
225 printk("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
226 regs->eax, regs->ebx, regs->ecx, regs->edx);
227 printk("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
228 regs->esi, regs->edi, regs->ebp, esp);
229 printk("ds: %04x es: %04x ss: %04x\n",
230 regs->xds & 0xffff, regs->xes & 0xffff, ss);
231 printk("Process %s (pid: %d, threadinfo=%p task=%p)",
232 current->comm, current->pid, current_thread_info(), current);
234 * When in-kernel, we also print out the stack and code at the
235 * time of the fault..
241 show_stack(NULL, (unsigned long*)esp);
245 eip = (u8 __user *)regs->eip - 43;
246 for (i = 0; i < 64; i++, eip++) {
249 if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
250 printk(" Bad EIP value.");
253 if (eip == (u8 __user *)regs->eip)
254 printk("<%02x> ", c);
262 static void handle_BUG(struct pt_regs *regs)
272 if (eip < PAGE_OFFSET)
274 if (__get_user(ud2, (unsigned short __user *)eip))
278 if (__get_user(line, (unsigned short __user *)(eip + 2)))
280 if (__get_user(file, (char * __user *)(eip + 4)) ||
281 (unsigned long)file < PAGE_OFFSET || __get_user(c, file))
282 file = "<bad filename>";
284 printk("------------[ cut here ]------------\n");
285 printk(KERN_ALERT "kernel BUG at %s:%d!\n", file, line);
290 /* Here we know it was a BUG but file-n-line is unavailable */
292 printk("Kernel BUG\n");
295 /* This is gone through when something in the kernel
296 * has done something bad and is about to be terminated.
298 void die(const char * str, struct pt_regs * regs, long err)
303 int lock_owner_depth;
305 .lock = SPIN_LOCK_UNLOCKED,
307 .lock_owner_depth = 0
309 static int die_counter;
311 if (die.lock_owner != raw_smp_processor_id()) {
313 spin_lock_irq(&die.lock);
314 die.lock_owner = smp_processor_id();
315 die.lock_owner_depth = 0;
319 if (++die.lock_owner_depth < 3) {
322 printk(KERN_ALERT "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
323 #ifdef CONFIG_PREEMPT
331 #ifdef CONFIG_DEBUG_PAGEALLOC
332 printk("DEBUG_PAGEALLOC");
337 notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
338 show_registers(regs);
340 printk(KERN_ERR "Recursive die() failure, output suppressed\n");
344 spin_unlock_irq(&die.lock);
346 if (kexec_should_crash(current))
350 panic("Fatal exception in interrupt");
353 printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
355 panic("Fatal exception");
360 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
362 if (!user_mode_vm(regs))
366 static void do_trap(int trapnr, int signr, char *str, int vm86,
367 struct pt_regs * regs, long error_code, siginfo_t *info)
369 struct task_struct *tsk = current;
370 tsk->thread.error_code = error_code;
371 tsk->thread.trap_no = trapnr;
373 if (regs->eflags & VM_MASK) {
379 if (!user_mode(regs))
384 force_sig_info(signr, info, tsk);
386 force_sig(signr, tsk);
391 if (!fixup_exception(regs))
392 die(str, regs, error_code);
397 int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
398 if (ret) goto trap_signal;
403 #define DO_ERROR(trapnr, signr, str, name) \
404 fastcall void do_##name(struct pt_regs * regs, long error_code) \
406 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
409 do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
412 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
413 fastcall void do_##name(struct pt_regs * regs, long error_code) \
416 info.si_signo = signr; \
418 info.si_code = sicode; \
419 info.si_addr = (void __user *)siaddr; \
420 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
423 do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
426 #define DO_VM86_ERROR(trapnr, signr, str, name) \
427 fastcall void do_##name(struct pt_regs * regs, long error_code) \
429 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
432 do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
435 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
436 fastcall void do_##name(struct pt_regs * regs, long error_code) \
439 info.si_signo = signr; \
441 info.si_code = sicode; \
442 info.si_addr = (void __user *)siaddr; \
443 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
446 do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
449 DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip)
450 #ifndef CONFIG_KPROBES
451 DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
453 DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
454 DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
455 DO_ERROR_INFO( 6, SIGILL, "invalid operand", invalid_op, ILL_ILLOPN, regs->eip)
456 DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
457 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
458 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
459 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
460 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
461 DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0)
463 fastcall void do_general_protection(struct pt_regs * regs, long error_code)
466 struct tss_struct *tss = &per_cpu(init_tss, cpu);
467 struct thread_struct *thread = ¤t->thread;
470 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
471 * invalid offset set (the LAZY one) and the faulting thread has
472 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
473 * and we set the offset field correctly. Then we let the CPU to
474 * restart the faulting instruction.
476 if (tss->io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
477 thread->io_bitmap_ptr) {
478 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
479 thread->io_bitmap_max);
481 * If the previously set map was extending to higher ports
482 * than the current one, pad extra space with 0xff (no access).
484 if (thread->io_bitmap_max < tss->io_bitmap_max)
485 memset((char *) tss->io_bitmap +
486 thread->io_bitmap_max, 0xff,
487 tss->io_bitmap_max - thread->io_bitmap_max);
488 tss->io_bitmap_max = thread->io_bitmap_max;
489 tss->io_bitmap_base = IO_BITMAP_OFFSET;
495 current->thread.error_code = error_code;
496 current->thread.trap_no = 13;
498 if (regs->eflags & VM_MASK)
501 if (!user_mode(regs))
504 current->thread.error_code = error_code;
505 current->thread.trap_no = 13;
506 force_sig(SIGSEGV, current);
511 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
515 if (!fixup_exception(regs)) {
516 if (notify_die(DIE_GPF, "general protection fault", regs,
517 error_code, 13, SIGSEGV) == NOTIFY_STOP)
519 die("general protection fault", regs, error_code);
523 static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
525 printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
526 printk("You probably have a hardware problem with your RAM chips\n");
528 /* Clear and disable the memory parity error line. */
529 clear_mem_error(reason);
532 static void io_check_error(unsigned char reason, struct pt_regs * regs)
536 printk("NMI: IOCK error (debug interrupt?)\n");
537 show_registers(regs);
539 /* Re-enable the IOCK line, wait for a few seconds */
540 reason = (reason & 0xf) | 8;
543 while (--i) udelay(1000);
548 static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
551 /* Might actually be able to figure out what the guilty party
558 printk("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
559 reason, smp_processor_id());
560 printk("Dazed and confused, but trying to continue\n");
561 printk("Do you have a strange power saving mode enabled?\n");
564 static DEFINE_SPINLOCK(nmi_print_lock);
566 void die_nmi (struct pt_regs *regs, const char *msg)
568 if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 0, SIGINT) ==
572 spin_lock(&nmi_print_lock);
574 * We are in trouble anyway, lets at least try
575 * to get a message out.
579 printk(" on CPU%d, eip %08lx, registers:\n",
580 smp_processor_id(), regs->eip);
581 show_registers(regs);
582 printk("console shuts up ...\n");
584 spin_unlock(&nmi_print_lock);
587 /* If we are in kernel we are probably nested up pretty bad
588 * and might aswell get out now while we still can.
590 if (!user_mode(regs)) {
591 current->thread.trap_no = 2;
598 static void default_do_nmi(struct pt_regs * regs)
600 unsigned char reason = 0;
602 /* Only the BSP gets external NMIs from the system. */
603 if (!smp_processor_id())
604 reason = get_nmi_reason();
606 if (!(reason & 0xc0)) {
607 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT)
610 #ifdef CONFIG_X86_LOCAL_APIC
612 * Ok, so this is none of the documented NMI sources,
613 * so it must be the NMI watchdog.
616 nmi_watchdog_tick(regs);
620 unknown_nmi_error(reason, regs);
623 if (notify_die(DIE_NMI, "nmi", regs, reason, 0, SIGINT) == NOTIFY_STOP)
626 mem_parity_error(reason, regs);
628 io_check_error(reason, regs);
630 * Reassert NMI in case it became active meanwhile
631 * as it's edge-triggered.
636 static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
641 static nmi_callback_t nmi_callback = dummy_nmi_callback;
643 fastcall void do_nmi(struct pt_regs * regs, long error_code)
649 cpu = smp_processor_id();
651 #ifdef CONFIG_HOTPLUG_CPU
652 if (!cpu_online(cpu)) {
660 if (!nmi_callback(regs, cpu))
661 default_do_nmi(regs);
666 void set_nmi_callback(nmi_callback_t callback)
668 nmi_callback = callback;
670 EXPORT_SYMBOL_GPL(set_nmi_callback);
672 void unset_nmi_callback(void)
674 nmi_callback = dummy_nmi_callback;
676 EXPORT_SYMBOL_GPL(unset_nmi_callback);
678 #ifdef CONFIG_KPROBES
679 fastcall void do_int3(struct pt_regs *regs, long error_code)
681 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
684 /* This is an interrupt gate, because kprobes wants interrupts
685 disabled. Normal trap handlers don't. */
686 restore_interrupts(regs);
687 do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
692 * Our handling of the processor debug registers is non-trivial.
693 * We do not clear them on entry and exit from the kernel. Therefore
694 * it is possible to get a watchpoint trap here from inside the kernel.
695 * However, the code in ./ptrace.c has ensured that the user can
696 * only set watchpoints on userspace addresses. Therefore the in-kernel
697 * watchpoint trap can only occur in code which is reading/writing
698 * from user space. Such code must not hold kernel locks (since it
699 * can equally take a page fault), therefore it is safe to call
700 * force_sig_info even though that claims and releases locks.
702 * Code in ./signal.c ensures that the debug control register
703 * is restored before we deliver any signal, and therefore that
704 * user code runs with the correct debug control register even though
707 * Being careful here means that we don't have to be as careful in a
708 * lot of more complicated places (task switching can be a bit lazy
709 * about restoring all the debug state, and ptrace doesn't have to
710 * find every occurrence of the TF bit that could be saved away even
713 fastcall void do_debug(struct pt_regs * regs, long error_code)
715 unsigned int condition;
716 struct task_struct *tsk = current;
718 get_debugreg(condition, 6);
720 if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
721 SIGTRAP) == NOTIFY_STOP)
723 /* It's safe to allow irq's after DR6 has been saved */
724 if (regs->eflags & X86_EFLAGS_IF)
727 /* Mask out spurious debug traps due to lazy DR7 setting */
728 if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
729 if (!tsk->thread.debugreg[7])
733 if (regs->eflags & VM_MASK)
736 /* Save debug status register where ptrace can see it */
737 tsk->thread.debugreg[6] = condition;
740 * Single-stepping through TF: make sure we ignore any events in
741 * kernel space (but re-enable TF when returning to user mode).
743 if (condition & DR_STEP) {
745 * We already checked v86 mode above, so we can
746 * check for kernel mode by just checking the CPL
749 if (!user_mode(regs))
750 goto clear_TF_reenable;
753 /* Ok, finally something we can handle */
754 send_sigtrap(tsk, regs, error_code);
756 /* Disable additional traps. They'll be re-enabled when
757 * the signal is delivered.
764 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
768 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
769 regs->eflags &= ~TF_MASK;
774 * Note that we play around with the 'TS' bit in an attempt to get
775 * the correct behaviour even in the presence of the asynchronous
778 void math_error(void __user *eip)
780 struct task_struct * task;
782 unsigned short cwd, swd;
785 * Save the info for the exception handler and clear the error.
789 task->thread.trap_no = 16;
790 task->thread.error_code = 0;
791 info.si_signo = SIGFPE;
793 info.si_code = __SI_FAULT;
796 * (~cwd & swd) will mask out exceptions that are not set to unmasked
797 * status. 0x3f is the exception bits in these regs, 0x200 is the
798 * C1 reg you need in case of a stack fault, 0x040 is the stack
799 * fault bit. We should only be taking one exception at a time,
800 * so if this combination doesn't produce any single exception,
801 * then we have a bad program that isn't syncronizing its FPU usage
802 * and it will suffer the consequences since we won't be able to
803 * fully reproduce the context of the exception
805 cwd = get_fpu_cwd(task);
806 swd = get_fpu_swd(task);
807 switch (swd & ~cwd & 0x3f) {
811 case 0x001: /* Invalid Op */
813 * swd & 0x240 == 0x040: Stack Underflow
814 * swd & 0x240 == 0x240: Stack Overflow
815 * User must clear the SF bit (0x40) if set
817 info.si_code = FPE_FLTINV;
819 case 0x002: /* Denormalize */
820 case 0x010: /* Underflow */
821 info.si_code = FPE_FLTUND;
823 case 0x004: /* Zero Divide */
824 info.si_code = FPE_FLTDIV;
826 case 0x008: /* Overflow */
827 info.si_code = FPE_FLTOVF;
829 case 0x020: /* Precision */
830 info.si_code = FPE_FLTRES;
833 force_sig_info(SIGFPE, &info, task);
836 fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code)
839 math_error((void __user *)regs->eip);
842 static void simd_math_error(void __user *eip)
844 struct task_struct * task;
846 unsigned short mxcsr;
849 * Save the info for the exception handler and clear the error.
853 task->thread.trap_no = 19;
854 task->thread.error_code = 0;
855 info.si_signo = SIGFPE;
857 info.si_code = __SI_FAULT;
860 * The SIMD FPU exceptions are handled a little differently, as there
861 * is only a single status/control register. Thus, to determine which
862 * unmasked exception was caught we must mask the exception mask bits
863 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
865 mxcsr = get_fpu_mxcsr(task);
866 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
870 case 0x001: /* Invalid Op */
871 info.si_code = FPE_FLTINV;
873 case 0x002: /* Denormalize */
874 case 0x010: /* Underflow */
875 info.si_code = FPE_FLTUND;
877 case 0x004: /* Zero Divide */
878 info.si_code = FPE_FLTDIV;
880 case 0x008: /* Overflow */
881 info.si_code = FPE_FLTOVF;
883 case 0x020: /* Precision */
884 info.si_code = FPE_FLTRES;
887 force_sig_info(SIGFPE, &info, task);
890 fastcall void do_simd_coprocessor_error(struct pt_regs * regs,
894 /* Handle SIMD FPU exceptions on PIII+ processors. */
896 simd_math_error((void __user *)regs->eip);
899 * Handle strange cache flush from user space exception
900 * in all other cases. This is undocumented behaviour.
902 if (regs->eflags & VM_MASK) {
903 handle_vm86_fault((struct kernel_vm86_regs *)regs,
907 current->thread.trap_no = 19;
908 current->thread.error_code = error_code;
909 die_if_kernel("cache flush denied", regs, error_code);
910 force_sig(SIGSEGV, current);
914 fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
918 /* No need to warn about this any longer. */
919 printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
923 fastcall void setup_x86_bogus_stack(unsigned char * stk)
925 unsigned long *switch16_ptr, *switch32_ptr;
926 struct pt_regs *regs;
927 unsigned long stack_top, stack_bot;
928 unsigned short iret_frame16_off;
929 int cpu = smp_processor_id();
930 /* reserve the space on 32bit stack for the magic switch16 pointer */
931 memmove(stk, stk + 8, sizeof(struct pt_regs));
932 switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs));
933 regs = (struct pt_regs *)stk;
934 /* now the switch32 on 16bit stack */
935 stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
936 stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
937 switch32_ptr = (unsigned long *)(stack_top - 8);
938 iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20;
939 /* copy iret frame on 16bit stack */
940 memcpy((void *)(stack_bot + iret_frame16_off), ®s->eip, 20);
941 /* fill in the switch pointers */
942 switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off;
943 switch16_ptr[1] = __ESPFIX_SS;
944 switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) +
945 8 - CPU_16BIT_STACK_SIZE;
946 switch32_ptr[1] = __KERNEL_DS;
949 fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp)
951 unsigned long *switch32_ptr;
952 unsigned char *stack16, *stack32;
953 unsigned long stack_top, stack_bot;
955 int cpu = smp_processor_id();
956 stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
957 stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
958 switch32_ptr = (unsigned long *)(stack_top - 8);
959 /* copy the data from 16bit stack to 32bit stack */
960 len = CPU_16BIT_STACK_SIZE - 8 - sp;
961 stack16 = (unsigned char *)(stack_bot + sp);
962 stack32 = (unsigned char *)
963 (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len);
964 memcpy(stack32, stack16, len);
969 * 'math_state_restore()' saves the current math information in the
970 * old math state array, and gets the new ones from the current task
972 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
973 * Don't touch unless you *really* know how it works.
975 * Must be called with kernel preemption disabled (in this case,
976 * local interrupts are disabled at the call-site in entry.S).
978 asmlinkage void math_state_restore(struct pt_regs regs)
980 struct thread_info *thread = current_thread_info();
981 struct task_struct *tsk = thread->task;
983 clts(); /* Allow maths ops (or we recurse) */
984 if (!tsk_used_math(tsk))
987 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
990 #ifndef CONFIG_MATH_EMULATION
992 asmlinkage void math_emulate(long arg)
994 printk("math-emulation not enabled and no coprocessor found.\n");
995 printk("killing %s.\n",current->comm);
996 force_sig(SIGFPE,current);
1000 #endif /* CONFIG_MATH_EMULATION */
1002 #ifdef CONFIG_X86_F00F_BUG
1003 void __init trap_init_f00f_bug(void)
1005 __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
1008 * Update the IDT descriptor and reload the IDT so that
1009 * it uses the read-only mapped virtual address.
1011 idt_descr.address = fix_to_virt(FIX_F00F_IDT);
1012 load_idt(&idt_descr);
1016 #define _set_gate(gate_addr,type,dpl,addr,seg) \
1019 __asm__ __volatile__ ("movw %%dx,%%ax\n\t" \
1020 "movw %4,%%dx\n\t" \
1021 "movl %%eax,%0\n\t" \
1023 :"=m" (*((long *) (gate_addr))), \
1024 "=m" (*(1+(long *) (gate_addr))), "=&a" (__d0), "=&d" (__d1) \
1025 :"i" ((short) (0x8000+(dpl<<13)+(type<<8))), \
1026 "3" ((char *) (addr)),"2" ((seg) << 16)); \
1031 * This needs to use 'idt_table' rather than 'idt', and
1032 * thus use the _nonmapped_ version of the IDT, as the
1033 * Pentium F0 0F bugfix can have resulted in the mapped
1034 * IDT being write-protected.
1036 void set_intr_gate(unsigned int n, void *addr)
1038 _set_gate(idt_table+n,14,0,addr,__KERNEL_CS);
1042 * This routine sets up an interrupt gate at directory privilege level 3.
1044 static inline void set_system_intr_gate(unsigned int n, void *addr)
1046 _set_gate(idt_table+n, 14, 3, addr, __KERNEL_CS);
1049 static void __init set_trap_gate(unsigned int n, void *addr)
1051 _set_gate(idt_table+n,15,0,addr,__KERNEL_CS);
1054 static void __init set_system_gate(unsigned int n, void *addr)
1056 _set_gate(idt_table+n,15,3,addr,__KERNEL_CS);
1059 static void __init set_task_gate(unsigned int n, unsigned int gdt_entry)
1061 _set_gate(idt_table+n,5,0,0,(gdt_entry<<3));
1065 void __init trap_init(void)
1068 void __iomem *p = ioremap(0x0FFFD9, 4);
1069 if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
1075 #ifdef CONFIG_X86_LOCAL_APIC
1076 init_apic_mappings();
1079 set_trap_gate(0,÷_error);
1080 set_intr_gate(1,&debug);
1081 set_intr_gate(2,&nmi);
1082 set_system_intr_gate(3, &int3); /* int3-5 can be called from all */
1083 set_system_gate(4,&overflow);
1084 set_system_gate(5,&bounds);
1085 set_trap_gate(6,&invalid_op);
1086 set_trap_gate(7,&device_not_available);
1087 set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS);
1088 set_trap_gate(9,&coprocessor_segment_overrun);
1089 set_trap_gate(10,&invalid_TSS);
1090 set_trap_gate(11,&segment_not_present);
1091 set_trap_gate(12,&stack_segment);
1092 set_trap_gate(13,&general_protection);
1093 set_intr_gate(14,&page_fault);
1094 set_trap_gate(15,&spurious_interrupt_bug);
1095 set_trap_gate(16,&coprocessor_error);
1096 set_trap_gate(17,&alignment_check);
1097 #ifdef CONFIG_X86_MCE
1098 set_trap_gate(18,&machine_check);
1100 set_trap_gate(19,&simd_coprocessor_error);
1102 set_system_gate(SYSCALL_VECTOR,&system_call);
1105 * Should be a barrier for any external CPU state.
1112 static int __init kstack_setup(char *s)
1114 kstack_depth_to_print = simple_strtoul(s, NULL, 0);
1117 __setup("kstack=", kstack_setup);