2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
5 * Pentium III FXSR, SSE support
6 * Gareth Hughes <gareth@valinux.com>, May 2000
10 * Handle hardware traps and faults.
12 #include <linux/interrupt.h>
13 #include <linux/kallsyms.h>
14 #include <linux/spinlock.h>
15 #include <linux/kprobes.h>
16 #include <linux/uaccess.h>
17 #include <linux/kdebug.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/ptrace.h>
21 #include <linux/string.h>
22 #include <linux/delay.h>
23 #include <linux/errno.h>
24 #include <linux/kexec.h>
25 #include <linux/sched.h>
26 #include <linux/timer.h>
27 #include <linux/init.h>
28 #include <linux/bug.h>
29 #include <linux/nmi.h>
31 #include <linux/smp.h>
35 #include <linux/ioport.h>
36 #include <linux/eisa.h>
40 #include <linux/mca.h>
43 #if defined(CONFIG_EDAC)
44 #include <linux/edac.h>
47 #include <asm/kmemcheck.h>
48 #include <asm/stacktrace.h>
49 #include <asm/processor.h>
50 #include <asm/debugreg.h>
51 #include <asm/atomic.h>
52 #include <asm/system.h>
53 #include <asm/traps.h>
58 #include <asm/mach_traps.h>
61 #include <asm/x86_init.h>
62 #include <asm/pgalloc.h>
63 #include <asm/proto.h>
65 #include <asm/processor-flags.h>
66 #include <asm/setup.h>
68 asmlinkage int system_call(void);
70 /* Do we ignore FPU interrupts ? */
74 * The IDT has to be page-aligned to simplify the Pentium
75 * F0 0F bug workaround.
77 gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
80 DECLARE_BITMAP(used_vectors, NR_VECTORS);
81 EXPORT_SYMBOL_GPL(used_vectors);
83 static int ignore_nmis;
85 static inline void conditional_sti(struct pt_regs *regs)
87 if (regs->flags & X86_EFLAGS_IF)
91 static inline void preempt_conditional_sti(struct pt_regs *regs)
94 if (regs->flags & X86_EFLAGS_IF)
98 static inline void conditional_cli(struct pt_regs *regs)
100 if (regs->flags & X86_EFLAGS_IF)
104 static inline void preempt_conditional_cli(struct pt_regs *regs)
106 if (regs->flags & X86_EFLAGS_IF)
113 die_if_kernel(const char *str, struct pt_regs *regs, long err)
115 if (!user_mode_vm(regs))
120 static void __kprobes
121 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
122 long error_code, siginfo_t *info)
124 struct task_struct *tsk = current;
127 if (regs->flags & X86_VM_MASK) {
129 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
130 * On nmi (interrupt 2), do_trap should not be called.
138 if (!user_mode(regs))
145 * We want error_code and trap_no set for userspace faults and
146 * kernelspace faults which result in die(), but not
147 * kernelspace faults which are fixed up. die() gives the
148 * process no chance to handle the signal and notice the
149 * kernel fault information, so that won't result in polluting
150 * the information about previously queued, but not yet
151 * delivered, faults. See also do_general_protection below.
153 tsk->thread.error_code = error_code;
154 tsk->thread.trap_no = trapnr;
157 if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
158 printk_ratelimit()) {
160 "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
161 tsk->comm, tsk->pid, str,
162 regs->ip, regs->sp, error_code);
163 print_vma_addr(" in ", regs->ip);
169 force_sig_info(signr, info, tsk);
171 force_sig(signr, tsk);
175 if (!fixup_exception(regs)) {
176 tsk->thread.error_code = error_code;
177 tsk->thread.trap_no = trapnr;
178 die(str, regs, error_code);
184 if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
191 #define DO_ERROR(trapnr, signr, str, name) \
192 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
194 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
197 conditional_sti(regs); \
198 do_trap(trapnr, signr, str, regs, error_code, NULL); \
201 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
202 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
205 info.si_signo = signr; \
207 info.si_code = sicode; \
208 info.si_addr = (void __user *)siaddr; \
209 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
212 conditional_sti(regs); \
213 do_trap(trapnr, signr, str, regs, error_code, &info); \
216 DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
217 DO_ERROR(4, SIGSEGV, "overflow", overflow)
218 DO_ERROR(5, SIGSEGV, "bounds", bounds)
219 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)
220 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
221 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
222 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
224 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
226 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
229 /* Runs on IST stack */
230 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
232 if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
233 12, SIGBUS) == NOTIFY_STOP)
235 preempt_conditional_sti(regs);
236 do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
237 preempt_conditional_cli(regs);
240 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
242 static const char str[] = "double fault";
243 struct task_struct *tsk = current;
245 /* Return not checked because double check cannot be ignored */
246 notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
248 tsk->thread.error_code = error_code;
249 tsk->thread.trap_no = 8;
252 * This is always a kernel trap and never fixable (and thus must
256 die(str, regs, error_code);
260 dotraplinkage void __kprobes
261 do_general_protection(struct pt_regs *regs, long error_code)
263 struct task_struct *tsk;
265 conditional_sti(regs);
268 if (regs->flags & X86_VM_MASK)
273 if (!user_mode(regs))
276 tsk->thread.error_code = error_code;
277 tsk->thread.trap_no = 13;
279 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
280 printk_ratelimit()) {
282 "%s[%d] general protection ip:%lx sp:%lx error:%lx",
283 tsk->comm, task_pid_nr(tsk),
284 regs->ip, regs->sp, error_code);
285 print_vma_addr(" in ", regs->ip);
289 force_sig(SIGSEGV, tsk);
295 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
300 if (fixup_exception(regs))
303 tsk->thread.error_code = error_code;
304 tsk->thread.trap_no = 13;
305 if (notify_die(DIE_GPF, "general protection fault", regs,
306 error_code, 13, SIGSEGV) == NOTIFY_STOP)
308 die("general protection fault", regs, error_code);
311 static notrace __kprobes void
312 mem_parity_error(unsigned char reason, struct pt_regs *regs)
315 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
316 reason, smp_processor_id());
319 "You have some hardware problem, likely on the PCI bus.\n");
321 #if defined(CONFIG_EDAC)
322 if (edac_handler_set()) {
323 edac_atomic_assert_error();
328 if (panic_on_unrecovered_nmi)
329 panic("NMI: Not continuing");
331 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
333 /* Clear and disable the memory parity error line. */
334 reason = (reason & 0xf) | 4;
338 static notrace __kprobes void
339 io_check_error(unsigned char reason, struct pt_regs *regs)
343 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
344 show_registers(regs);
347 panic("NMI IOCK error: Not continuing");
349 /* Re-enable the IOCK line, wait for a few seconds */
350 reason = (reason & 0xf) | 8;
361 static notrace __kprobes void
362 unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
364 if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) ==
369 * Might actually be able to figure out what the guilty party
378 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
379 reason, smp_processor_id());
381 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
382 if (panic_on_unrecovered_nmi)
383 panic("NMI: Not continuing");
385 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
388 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
390 unsigned char reason = 0;
393 cpu = smp_processor_id();
395 /* Only the BSP gets external NMIs from the system. */
397 reason = get_nmi_reason();
399 if (!(reason & 0xc0)) {
400 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
404 #ifdef CONFIG_X86_LOCAL_APIC
405 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
410 * Ok, so this is none of the documented NMI sources,
411 * so it must be the NMI watchdog.
413 if (nmi_watchdog_tick(regs, reason))
415 if (!do_nmi_callback(regs, cpu))
416 unknown_nmi_error(reason, regs);
418 unknown_nmi_error(reason, regs);
423 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
426 /* AK: following checks seem to be broken on modern chipsets. FIXME */
428 mem_parity_error(reason, regs);
430 io_check_error(reason, regs);
433 * Reassert NMI in case it became active meanwhile
434 * as it's edge-triggered:
440 dotraplinkage notrace __kprobes void
441 do_nmi(struct pt_regs *regs, long error_code)
445 inc_irq_stat(__nmi_count);
448 default_do_nmi(regs);
459 void restart_nmi(void)
465 /* May run on IST stack. */
466 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
468 #ifdef CONFIG_KPROBES
469 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
473 if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
478 preempt_conditional_sti(regs);
479 do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
480 preempt_conditional_cli(regs);
485 * Help handler running on IST stack to switch back to user stack
486 * for scheduling or signal handling. The actual stack switch is done in
489 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
491 struct pt_regs *regs = eregs;
492 /* Did already sync */
493 if (eregs == (struct pt_regs *)eregs->sp)
495 /* Exception from user space */
496 else if (user_mode(eregs))
497 regs = task_pt_regs(current);
499 * Exception from kernel and interrupts are enabled. Move to
500 * kernel process stack.
502 else if (eregs->flags & X86_EFLAGS_IF)
503 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
511 * Our handling of the processor debug registers is non-trivial.
512 * We do not clear them on entry and exit from the kernel. Therefore
513 * it is possible to get a watchpoint trap here from inside the kernel.
514 * However, the code in ./ptrace.c has ensured that the user can
515 * only set watchpoints on userspace addresses. Therefore the in-kernel
516 * watchpoint trap can only occur in code which is reading/writing
517 * from user space. Such code must not hold kernel locks (since it
518 * can equally take a page fault), therefore it is safe to call
519 * force_sig_info even though that claims and releases locks.
521 * Code in ./signal.c ensures that the debug control register
522 * is restored before we deliver any signal, and therefore that
523 * user code runs with the correct debug control register even though
526 * Being careful here means that we don't have to be as careful in a
527 * lot of more complicated places (task switching can be a bit lazy
528 * about restoring all the debug state, and ptrace doesn't have to
529 * find every occurrence of the TF bit that could be saved away even
532 * May run on IST stack.
534 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
536 struct task_struct *tsk = current;
540 get_debugreg(dr6, 6);
542 /* Filter out all the reserved bits which are preset to 1 */
543 dr6 &= ~DR6_RESERVED;
545 /* Catch kmemcheck conditions first of all! */
546 if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
549 /* DR6 may or may not be cleared by the CPU */
552 * The processor cleared BTF, so don't mark that we need it set.
554 clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
555 tsk->thread.debugctlmsr = 0;
557 /* Store the virtualized DR6 value */
558 tsk->thread.debugreg6 = dr6;
560 if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
561 SIGTRAP) == NOTIFY_STOP)
564 /* It's safe to allow irq's after DR6 has been saved */
565 preempt_conditional_sti(regs);
567 if (regs->flags & X86_VM_MASK) {
568 handle_vm86_trap((struct kernel_vm86_regs *) regs,
574 * Single-stepping through system calls: ignore any exceptions in
575 * kernel space, but re-enable TF when returning to user mode.
577 * We already checked v86 mode above, so we can check for kernel mode
578 * by just checking the CPL of CS.
580 if ((dr6 & DR_STEP) && !user_mode(regs)) {
581 tsk->thread.debugreg6 &= ~DR_STEP;
582 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
583 regs->flags &= ~X86_EFLAGS_TF;
585 si_code = get_si_code(tsk->thread.debugreg6);
586 if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS))
587 send_sigtrap(tsk, regs, error_code, si_code);
588 preempt_conditional_cli(regs);
594 static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr)
596 if (fixup_exception(regs))
599 notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE);
600 /* Illegal floating point operation in the kernel */
601 current->thread.trap_no = trapnr;
608 * Note that we play around with the 'TS' bit in an attempt to get
609 * the correct behaviour even in the presence of the asynchronous
612 void math_error(void __user *ip)
614 struct task_struct *task;
616 unsigned short cwd, swd, err;
619 * Save the info for the exception handler and clear the error.
623 task->thread.trap_no = 16;
624 task->thread.error_code = 0;
625 info.si_signo = SIGFPE;
629 * (~cwd & swd) will mask out exceptions that are not set to unmasked
630 * status. 0x3f is the exception bits in these regs, 0x200 is the
631 * C1 reg you need in case of a stack fault, 0x040 is the stack
632 * fault bit. We should only be taking one exception at a time,
633 * so if this combination doesn't produce any single exception,
634 * then we have a bad program that isn't synchronizing its FPU usage
635 * and it will suffer the consequences since we won't be able to
636 * fully reproduce the context of the exception
638 cwd = get_fpu_cwd(task);
639 swd = get_fpu_swd(task);
643 if (err & 0x001) { /* Invalid op */
645 * swd & 0x240 == 0x040: Stack Underflow
646 * swd & 0x240 == 0x240: Stack Overflow
647 * User must clear the SF bit (0x40) if set
649 info.si_code = FPE_FLTINV;
650 } else if (err & 0x004) { /* Divide by Zero */
651 info.si_code = FPE_FLTDIV;
652 } else if (err & 0x008) { /* Overflow */
653 info.si_code = FPE_FLTOVF;
654 } else if (err & 0x012) { /* Denormal, Underflow */
655 info.si_code = FPE_FLTUND;
656 } else if (err & 0x020) { /* Precision */
657 info.si_code = FPE_FLTRES;
660 * If we're using IRQ 13, or supposedly even some trap 16
661 * implementations, it's possible we get a spurious trap...
663 return; /* Spurious trap, no error */
665 force_sig_info(SIGFPE, &info, task);
668 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
670 conditional_sti(regs);
675 if (!user_mode(regs) &&
676 kernel_math_error(regs, "kernel x87 math error", 16))
680 math_error((void __user *)regs->ip);
683 static void simd_math_error(void __user *ip)
685 struct task_struct *task;
687 unsigned short mxcsr;
690 * Save the info for the exception handler and clear the error.
694 task->thread.trap_no = 19;
695 task->thread.error_code = 0;
696 info.si_signo = SIGFPE;
698 info.si_code = __SI_FAULT;
701 * The SIMD FPU exceptions are handled a little differently, as there
702 * is only a single status/control register. Thus, to determine which
703 * unmasked exception was caught we must mask the exception mask bits
704 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
706 mxcsr = get_fpu_mxcsr(task);
707 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
711 case 0x001: /* Invalid Op */
712 info.si_code = FPE_FLTINV;
714 case 0x002: /* Denormalize */
715 case 0x010: /* Underflow */
716 info.si_code = FPE_FLTUND;
718 case 0x004: /* Zero Divide */
719 info.si_code = FPE_FLTDIV;
721 case 0x008: /* Overflow */
722 info.si_code = FPE_FLTOVF;
724 case 0x020: /* Precision */
725 info.si_code = FPE_FLTRES;
728 force_sig_info(SIGFPE, &info, task);
732 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
734 conditional_sti(regs);
738 /* Handle SIMD FPU exceptions on PIII+ processors. */
740 simd_math_error((void __user *)regs->ip);
744 * Handle strange cache flush from user space exception
745 * in all other cases. This is undocumented behaviour.
747 if (regs->flags & X86_VM_MASK) {
748 handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code);
751 current->thread.trap_no = 19;
752 current->thread.error_code = error_code;
753 die_if_kernel("cache flush denied", regs, error_code);
754 force_sig(SIGSEGV, current);
756 if (!user_mode(regs) &&
757 kernel_math_error(regs, "kernel simd math error", 19))
759 simd_math_error((void __user *)regs->ip);
764 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
766 conditional_sti(regs);
768 /* No need to warn about this any longer. */
769 printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
773 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
777 asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
782 * __math_state_restore assumes that cr0.TS is already clear and the
783 * fpu state is all ready for use. Used during context switch.
785 void __math_state_restore(void)
787 struct thread_info *thread = current_thread_info();
788 struct task_struct *tsk = thread->task;
791 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
793 if (unlikely(restore_fpu_checking(tsk))) {
795 force_sig(SIGSEGV, tsk);
799 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
804 * 'math_state_restore()' saves the current math information in the
805 * old math state array, and gets the new ones from the current task
807 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
808 * Don't touch unless you *really* know how it works.
810 * Must be called with kernel preemption disabled (in this case,
811 * local interrupts are disabled at the call-site in entry.S).
813 asmlinkage void math_state_restore(void)
815 struct thread_info *thread = current_thread_info();
816 struct task_struct *tsk = thread->task;
818 if (!tsk_used_math(tsk)) {
821 * does a slab alloc which can sleep
827 do_group_exit(SIGKILL);
833 clts(); /* Allow maths ops (or we recurse) */
835 __math_state_restore();
837 EXPORT_SYMBOL_GPL(math_state_restore);
839 #ifndef CONFIG_MATH_EMULATION
840 void math_emulate(struct math_emu_info *info)
843 "math-emulation not enabled and no coprocessor found.\n");
844 printk(KERN_EMERG "killing %s.\n", current->comm);
845 force_sig(SIGFPE, current);
848 #endif /* CONFIG_MATH_EMULATION */
850 dotraplinkage void __kprobes
851 do_device_not_available(struct pt_regs *regs, long error_code)
854 if (read_cr0() & X86_CR0_EM) {
855 struct math_emu_info info = { };
857 conditional_sti(regs);
862 math_state_restore(); /* interrupts still off */
863 conditional_sti(regs);
866 math_state_restore();
871 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
876 info.si_signo = SIGILL;
878 info.si_code = ILL_BADSTK;
880 if (notify_die(DIE_TRAP, "iret exception",
881 regs, error_code, 32, SIGILL) == NOTIFY_STOP)
883 do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
887 void __init trap_init(void)
892 void __iomem *p = early_ioremap(0x0FFFD9, 4);
894 if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
899 set_intr_gate(0, ÷_error);
900 set_intr_gate_ist(1, &debug, DEBUG_STACK);
901 set_intr_gate_ist(2, &nmi, NMI_STACK);
902 /* int3 can be called from all */
903 set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
904 /* int4 can be called from all */
905 set_system_intr_gate(4, &overflow);
906 set_intr_gate(5, &bounds);
907 set_intr_gate(6, &invalid_op);
908 set_intr_gate(7, &device_not_available);
910 set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
912 set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
914 set_intr_gate(9, &coprocessor_segment_overrun);
915 set_intr_gate(10, &invalid_TSS);
916 set_intr_gate(11, &segment_not_present);
917 set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
918 set_intr_gate(13, &general_protection);
919 set_intr_gate(14, &page_fault);
920 set_intr_gate(15, &spurious_interrupt_bug);
921 set_intr_gate(16, &coprocessor_error);
922 set_intr_gate(17, &alignment_check);
923 #ifdef CONFIG_X86_MCE
924 set_intr_gate_ist(18, &machine_check, MCE_STACK);
926 set_intr_gate(19, &simd_coprocessor_error);
928 /* Reserve all the builtin and the syscall vector: */
929 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
930 set_bit(i, used_vectors);
932 #ifdef CONFIG_IA32_EMULATION
933 set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
934 set_bit(IA32_SYSCALL_VECTOR, used_vectors);
939 printk(KERN_INFO "Enabling fast FPU save and restore... ");
940 set_in_cr4(X86_CR4_OSFXSR);
945 "Enabling unmasked SIMD FPU exception support... ");
946 set_in_cr4(X86_CR4_OSXMMEXCPT);
950 set_system_trap_gate(SYSCALL_VECTOR, &system_call);
951 set_bit(SYSCALL_VECTOR, used_vectors);
955 * Should be a barrier for any external CPU state:
959 x86_init.irqs.trap_init();