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/kgdb.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/ptrace.h>
22 #include <linux/string.h>
23 #include <linux/delay.h>
24 #include <linux/errno.h>
25 #include <linux/kexec.h>
26 #include <linux/sched.h>
27 #include <linux/timer.h>
28 #include <linux/init.h>
29 #include <linux/bug.h>
30 #include <linux/nmi.h>
32 #include <linux/smp.h>
36 #include <linux/ioport.h>
37 #include <linux/eisa.h>
41 #include <linux/mca.h>
44 #if defined(CONFIG_EDAC)
45 #include <linux/edac.h>
48 #include <asm/kmemcheck.h>
49 #include <asm/stacktrace.h>
50 #include <asm/processor.h>
51 #include <asm/debugreg.h>
52 #include <asm/atomic.h>
53 #include <asm/system.h>
54 #include <asm/traps.h>
59 #include <asm/mach_traps.h>
62 #include <asm/x86_init.h>
63 #include <asm/pgalloc.h>
64 #include <asm/proto.h>
66 #include <asm/processor-flags.h>
67 #include <asm/setup.h>
69 asmlinkage
int system_call(void);
71 /* Do we ignore FPU interrupts ? */
75 * The IDT has to be page-aligned to simplify the Pentium
76 * F0 0F bug workaround.
78 gate_desc idt_table
[NR_VECTORS
] __page_aligned_data
= { { { { 0, 0 } } }, };
81 DECLARE_BITMAP(used_vectors
, NR_VECTORS
);
82 EXPORT_SYMBOL_GPL(used_vectors
);
84 static int ignore_nmis
;
86 int unknown_nmi_panic
;
88 static inline void conditional_sti(struct pt_regs
*regs
)
90 if (regs
->flags
& X86_EFLAGS_IF
)
94 static inline void preempt_conditional_sti(struct pt_regs
*regs
)
97 if (regs
->flags
& X86_EFLAGS_IF
)
101 static inline void conditional_cli(struct pt_regs
*regs
)
103 if (regs
->flags
& X86_EFLAGS_IF
)
107 static inline void preempt_conditional_cli(struct pt_regs
*regs
)
109 if (regs
->flags
& X86_EFLAGS_IF
)
114 static void __kprobes
115 do_trap(int trapnr
, int signr
, char *str
, struct pt_regs
*regs
,
116 long error_code
, siginfo_t
*info
)
118 struct task_struct
*tsk
= current
;
121 if (regs
->flags
& X86_VM_MASK
) {
123 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
124 * On nmi (interrupt 2), do_trap should not be called.
132 if (!user_mode(regs
))
139 * We want error_code and trap_no set for userspace faults and
140 * kernelspace faults which result in die(), but not
141 * kernelspace faults which are fixed up. die() gives the
142 * process no chance to handle the signal and notice the
143 * kernel fault information, so that won't result in polluting
144 * the information about previously queued, but not yet
145 * delivered, faults. See also do_general_protection below.
147 tsk
->thread
.error_code
= error_code
;
148 tsk
->thread
.trap_no
= trapnr
;
151 if (show_unhandled_signals
&& unhandled_signal(tsk
, signr
) &&
152 printk_ratelimit()) {
154 "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
155 tsk
->comm
, tsk
->pid
, str
,
156 regs
->ip
, regs
->sp
, error_code
);
157 print_vma_addr(" in ", regs
->ip
);
163 force_sig_info(signr
, info
, tsk
);
165 force_sig(signr
, tsk
);
169 if (!fixup_exception(regs
)) {
170 tsk
->thread
.error_code
= error_code
;
171 tsk
->thread
.trap_no
= trapnr
;
172 die(str
, regs
, error_code
);
178 if (handle_vm86_trap((struct kernel_vm86_regs
*) regs
,
185 #define DO_ERROR(trapnr, signr, str, name) \
186 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
188 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
191 conditional_sti(regs); \
192 do_trap(trapnr, signr, str, regs, error_code, NULL); \
195 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
196 dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
199 info.si_signo = signr; \
201 info.si_code = sicode; \
202 info.si_addr = (void __user *)siaddr; \
203 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
206 conditional_sti(regs); \
207 do_trap(trapnr, signr, str, regs, error_code, &info); \
210 DO_ERROR_INFO(0, SIGFPE
, "divide error", divide_error
, FPE_INTDIV
, regs
->ip
)
211 DO_ERROR(4, SIGSEGV
, "overflow", overflow
)
212 DO_ERROR(5, SIGSEGV
, "bounds", bounds
)
213 DO_ERROR_INFO(6, SIGILL
, "invalid opcode", invalid_op
, ILL_ILLOPN
, regs
->ip
)
214 DO_ERROR(9, SIGFPE
, "coprocessor segment overrun", coprocessor_segment_overrun
)
215 DO_ERROR(10, SIGSEGV
, "invalid TSS", invalid_TSS
)
216 DO_ERROR(11, SIGBUS
, "segment not present", segment_not_present
)
218 DO_ERROR(12, SIGBUS
, "stack segment", stack_segment
)
220 DO_ERROR_INFO(17, SIGBUS
, "alignment check", alignment_check
, BUS_ADRALN
, 0)
223 /* Runs on IST stack */
224 dotraplinkage
void do_stack_segment(struct pt_regs
*regs
, long error_code
)
226 if (notify_die(DIE_TRAP
, "stack segment", regs
, error_code
,
227 12, SIGBUS
) == NOTIFY_STOP
)
229 preempt_conditional_sti(regs
);
230 do_trap(12, SIGBUS
, "stack segment", regs
, error_code
, NULL
);
231 preempt_conditional_cli(regs
);
234 dotraplinkage
void do_double_fault(struct pt_regs
*regs
, long error_code
)
236 static const char str
[] = "double fault";
237 struct task_struct
*tsk
= current
;
239 /* Return not checked because double check cannot be ignored */
240 notify_die(DIE_TRAP
, str
, regs
, error_code
, 8, SIGSEGV
);
242 tsk
->thread
.error_code
= error_code
;
243 tsk
->thread
.trap_no
= 8;
246 * This is always a kernel trap and never fixable (and thus must
250 die(str
, regs
, error_code
);
254 dotraplinkage
void __kprobes
255 do_general_protection(struct pt_regs
*regs
, long error_code
)
257 struct task_struct
*tsk
;
259 conditional_sti(regs
);
262 if (regs
->flags
& X86_VM_MASK
)
267 if (!user_mode(regs
))
270 tsk
->thread
.error_code
= error_code
;
271 tsk
->thread
.trap_no
= 13;
273 if (show_unhandled_signals
&& unhandled_signal(tsk
, SIGSEGV
) &&
274 printk_ratelimit()) {
276 "%s[%d] general protection ip:%lx sp:%lx error:%lx",
277 tsk
->comm
, task_pid_nr(tsk
),
278 regs
->ip
, regs
->sp
, error_code
);
279 print_vma_addr(" in ", regs
->ip
);
283 force_sig(SIGSEGV
, tsk
);
289 handle_vm86_fault((struct kernel_vm86_regs
*) regs
, error_code
);
294 if (fixup_exception(regs
))
297 tsk
->thread
.error_code
= error_code
;
298 tsk
->thread
.trap_no
= 13;
299 if (notify_die(DIE_GPF
, "general protection fault", regs
,
300 error_code
, 13, SIGSEGV
) == NOTIFY_STOP
)
302 die("general protection fault", regs
, error_code
);
305 static int __init
setup_unknown_nmi_panic(char *str
)
307 unknown_nmi_panic
= 1;
310 __setup("unknown_nmi_panic", setup_unknown_nmi_panic
);
312 static notrace __kprobes
void
313 mem_parity_error(unsigned char reason
, struct pt_regs
*regs
)
316 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
317 reason
, smp_processor_id());
320 "You have some hardware problem, likely on the PCI bus.\n");
322 #if defined(CONFIG_EDAC)
323 if (edac_handler_set()) {
324 edac_atomic_assert_error();
329 if (panic_on_unrecovered_nmi
)
330 panic("NMI: Not continuing");
332 printk(KERN_EMERG
"Dazed and confused, but trying to continue\n");
334 /* Clear and disable the memory parity error line. */
335 reason
= (reason
& 0xf) | 4;
339 static notrace __kprobes
void
340 io_check_error(unsigned char reason
, struct pt_regs
*regs
)
344 printk(KERN_EMERG
"NMI: IOCK error (debug interrupt?)\n");
345 show_registers(regs
);
348 panic("NMI IOCK error: Not continuing");
350 /* Re-enable the IOCK line, wait for a few seconds */
351 reason
= (reason
& 0xf) | 8;
356 touch_nmi_watchdog();
364 static notrace __kprobes
void
365 unknown_nmi_error(unsigned char reason
, struct pt_regs
*regs
)
367 if (notify_die(DIE_NMIUNKNOWN
, "nmi", regs
, reason
, 2, SIGINT
) ==
372 * Might actually be able to figure out what the guilty party
381 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
382 reason
, smp_processor_id());
384 printk(KERN_EMERG
"Do you have a strange power saving mode enabled?\n");
385 if (unknown_nmi_panic
|| panic_on_unrecovered_nmi
)
386 panic("NMI: Not continuing");
388 printk(KERN_EMERG
"Dazed and confused, but trying to continue\n");
391 static notrace __kprobes
void default_do_nmi(struct pt_regs
*regs
)
393 unsigned char reason
= 0;
396 cpu
= smp_processor_id();
398 /* Only the BSP gets external NMIs from the system. */
400 reason
= get_nmi_reason();
402 if (!(reason
& 0xc0)) {
403 if (notify_die(DIE_NMI_IPI
, "nmi_ipi", regs
, reason
, 2, SIGINT
)
407 #ifdef CONFIG_X86_LOCAL_APIC
408 if (notify_die(DIE_NMI
, "nmi", regs
, reason
, 2, SIGINT
)
412 unknown_nmi_error(reason
, regs
);
416 if (notify_die(DIE_NMI
, "nmi", regs
, reason
, 2, SIGINT
) == NOTIFY_STOP
)
419 /* AK: following checks seem to be broken on modern chipsets. FIXME */
421 mem_parity_error(reason
, regs
);
423 io_check_error(reason
, regs
);
426 * Reassert NMI in case it became active meanwhile
427 * as it's edge-triggered:
433 dotraplinkage notrace __kprobes
void
434 do_nmi(struct pt_regs
*regs
, long error_code
)
438 inc_irq_stat(__nmi_count
);
441 default_do_nmi(regs
);
451 void restart_nmi(void)
456 /* May run on IST stack. */
457 dotraplinkage
void __kprobes
do_int3(struct pt_regs
*regs
, long error_code
)
459 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
460 if (kgdb_ll_trap(DIE_INT3
, "int3", regs
, error_code
, 3, SIGTRAP
)
463 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
464 #ifdef CONFIG_KPROBES
465 if (notify_die(DIE_INT3
, "int3", regs
, error_code
, 3, SIGTRAP
)
469 if (notify_die(DIE_TRAP
, "int3", regs
, error_code
, 3, SIGTRAP
)
474 preempt_conditional_sti(regs
);
475 do_trap(3, SIGTRAP
, "int3", regs
, error_code
, NULL
);
476 preempt_conditional_cli(regs
);
481 * Help handler running on IST stack to switch back to user stack
482 * for scheduling or signal handling. The actual stack switch is done in
485 asmlinkage __kprobes
struct pt_regs
*sync_regs(struct pt_regs
*eregs
)
487 struct pt_regs
*regs
= eregs
;
488 /* Did already sync */
489 if (eregs
== (struct pt_regs
*)eregs
->sp
)
491 /* Exception from user space */
492 else if (user_mode(eregs
))
493 regs
= task_pt_regs(current
);
495 * Exception from kernel and interrupts are enabled. Move to
496 * kernel process stack.
498 else if (eregs
->flags
& X86_EFLAGS_IF
)
499 regs
= (struct pt_regs
*)(eregs
->sp
-= sizeof(struct pt_regs
));
507 * Our handling of the processor debug registers is non-trivial.
508 * We do not clear them on entry and exit from the kernel. Therefore
509 * it is possible to get a watchpoint trap here from inside the kernel.
510 * However, the code in ./ptrace.c has ensured that the user can
511 * only set watchpoints on userspace addresses. Therefore the in-kernel
512 * watchpoint trap can only occur in code which is reading/writing
513 * from user space. Such code must not hold kernel locks (since it
514 * can equally take a page fault), therefore it is safe to call
515 * force_sig_info even though that claims and releases locks.
517 * Code in ./signal.c ensures that the debug control register
518 * is restored before we deliver any signal, and therefore that
519 * user code runs with the correct debug control register even though
522 * Being careful here means that we don't have to be as careful in a
523 * lot of more complicated places (task switching can be a bit lazy
524 * about restoring all the debug state, and ptrace doesn't have to
525 * find every occurrence of the TF bit that could be saved away even
528 * May run on IST stack.
530 dotraplinkage
void __kprobes
do_debug(struct pt_regs
*regs
, long error_code
)
532 struct task_struct
*tsk
= current
;
537 get_debugreg(dr6
, 6);
539 /* Filter out all the reserved bits which are preset to 1 */
540 dr6
&= ~DR6_RESERVED
;
543 * If dr6 has no reason to give us about the origin of this trap,
544 * then it's very likely the result of an icebp/int01 trap.
545 * User wants a sigtrap for that.
547 if (!dr6
&& user_mode(regs
))
550 /* Catch kmemcheck conditions first of all! */
551 if ((dr6
& DR_STEP
) && kmemcheck_trap(regs
))
554 /* DR6 may or may not be cleared by the CPU */
558 * The processor cleared BTF, so don't mark that we need it set.
560 clear_tsk_thread_flag(tsk
, TIF_BLOCKSTEP
);
562 /* Store the virtualized DR6 value */
563 tsk
->thread
.debugreg6
= dr6
;
565 if (notify_die(DIE_DEBUG
, "debug", regs
, PTR_ERR(&dr6
), error_code
,
566 SIGTRAP
) == NOTIFY_STOP
)
569 /* It's safe to allow irq's after DR6 has been saved */
570 preempt_conditional_sti(regs
);
572 if (regs
->flags
& X86_VM_MASK
) {
573 handle_vm86_trap((struct kernel_vm86_regs
*) regs
,
575 preempt_conditional_cli(regs
);
580 * Single-stepping through system calls: ignore any exceptions in
581 * kernel space, but re-enable TF when returning to user mode.
583 * We already checked v86 mode above, so we can check for kernel mode
584 * by just checking the CPL of CS.
586 if ((dr6
& DR_STEP
) && !user_mode(regs
)) {
587 tsk
->thread
.debugreg6
&= ~DR_STEP
;
588 set_tsk_thread_flag(tsk
, TIF_SINGLESTEP
);
589 regs
->flags
&= ~X86_EFLAGS_TF
;
591 si_code
= get_si_code(tsk
->thread
.debugreg6
);
592 if (tsk
->thread
.debugreg6
& (DR_STEP
| DR_TRAP_BITS
) || user_icebp
)
593 send_sigtrap(tsk
, regs
, error_code
, si_code
);
594 preempt_conditional_cli(regs
);
600 * Note that we play around with the 'TS' bit in an attempt to get
601 * the correct behaviour even in the presence of the asynchronous
604 void math_error(struct pt_regs
*regs
, int error_code
, int trapnr
)
606 struct task_struct
*task
= current
;
609 char *str
= (trapnr
== 16) ? "fpu exception" : "simd exception";
611 if (notify_die(DIE_TRAP
, str
, regs
, error_code
, trapnr
, SIGFPE
) == NOTIFY_STOP
)
613 conditional_sti(regs
);
615 if (!user_mode_vm(regs
))
617 if (!fixup_exception(regs
)) {
618 task
->thread
.error_code
= error_code
;
619 task
->thread
.trap_no
= trapnr
;
620 die(str
, regs
, error_code
);
626 * Save the info for the exception handler and clear the error.
629 task
->thread
.trap_no
= trapnr
;
630 task
->thread
.error_code
= error_code
;
631 info
.si_signo
= SIGFPE
;
633 info
.si_addr
= (void __user
*)regs
->ip
;
635 unsigned short cwd
, swd
;
637 * (~cwd & swd) will mask out exceptions that are not set to unmasked
638 * status. 0x3f is the exception bits in these regs, 0x200 is the
639 * C1 reg you need in case of a stack fault, 0x040 is the stack
640 * fault bit. We should only be taking one exception at a time,
641 * so if this combination doesn't produce any single exception,
642 * then we have a bad program that isn't synchronizing its FPU usage
643 * and it will suffer the consequences since we won't be able to
644 * fully reproduce the context of the exception
646 cwd
= get_fpu_cwd(task
);
647 swd
= get_fpu_swd(task
);
652 * The SIMD FPU exceptions are handled a little differently, as there
653 * is only a single status/control register. Thus, to determine which
654 * unmasked exception was caught we must mask the exception mask bits
655 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
657 unsigned short mxcsr
= get_fpu_mxcsr(task
);
658 err
= ~(mxcsr
>> 7) & mxcsr
;
661 if (err
& 0x001) { /* Invalid op */
663 * swd & 0x240 == 0x040: Stack Underflow
664 * swd & 0x240 == 0x240: Stack Overflow
665 * User must clear the SF bit (0x40) if set
667 info
.si_code
= FPE_FLTINV
;
668 } else if (err
& 0x004) { /* Divide by Zero */
669 info
.si_code
= FPE_FLTDIV
;
670 } else if (err
& 0x008) { /* Overflow */
671 info
.si_code
= FPE_FLTOVF
;
672 } else if (err
& 0x012) { /* Denormal, Underflow */
673 info
.si_code
= FPE_FLTUND
;
674 } else if (err
& 0x020) { /* Precision */
675 info
.si_code
= FPE_FLTRES
;
678 * If we're using IRQ 13, or supposedly even some trap 16
679 * implementations, it's possible we get a spurious trap...
681 return; /* Spurious trap, no error */
683 force_sig_info(SIGFPE
, &info
, task
);
686 dotraplinkage
void do_coprocessor_error(struct pt_regs
*regs
, long error_code
)
692 math_error(regs
, error_code
, 16);
696 do_simd_coprocessor_error(struct pt_regs
*regs
, long error_code
)
698 math_error(regs
, error_code
, 19);
702 do_spurious_interrupt_bug(struct pt_regs
*regs
, long error_code
)
704 conditional_sti(regs
);
706 /* No need to warn about this any longer. */
707 printk(KERN_INFO
"Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
711 asmlinkage
void __attribute__((weak
)) smp_thermal_interrupt(void)
715 asmlinkage
void __attribute__((weak
)) smp_threshold_interrupt(void)
720 * __math_state_restore assumes that cr0.TS is already clear and the
721 * fpu state is all ready for use. Used during context switch.
723 void __math_state_restore(void)
725 struct thread_info
*thread
= current_thread_info();
726 struct task_struct
*tsk
= thread
->task
;
729 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
731 if (unlikely(restore_fpu_checking(tsk
))) {
733 force_sig(SIGSEGV
, tsk
);
737 thread
->status
|= TS_USEDFPU
; /* So we fnsave on switch_to() */
742 * 'math_state_restore()' saves the current math information in the
743 * old math state array, and gets the new ones from the current task
745 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
746 * Don't touch unless you *really* know how it works.
748 * Must be called with kernel preemption disabled (in this case,
749 * local interrupts are disabled at the call-site in entry.S).
751 asmlinkage
void math_state_restore(void)
753 struct thread_info
*thread
= current_thread_info();
754 struct task_struct
*tsk
= thread
->task
;
756 if (!tsk_used_math(tsk
)) {
759 * does a slab alloc which can sleep
765 do_group_exit(SIGKILL
);
771 clts(); /* Allow maths ops (or we recurse) */
773 __math_state_restore();
775 EXPORT_SYMBOL_GPL(math_state_restore
);
777 dotraplinkage
void __kprobes
778 do_device_not_available(struct pt_regs
*regs
, long error_code
)
780 #ifdef CONFIG_MATH_EMULATION
781 if (read_cr0() & X86_CR0_EM
) {
782 struct math_emu_info info
= { };
784 conditional_sti(regs
);
791 math_state_restore(); /* interrupts still off */
793 conditional_sti(regs
);
798 dotraplinkage
void do_iret_error(struct pt_regs
*regs
, long error_code
)
803 info
.si_signo
= SIGILL
;
805 info
.si_code
= ILL_BADSTK
;
807 if (notify_die(DIE_TRAP
, "iret exception",
808 regs
, error_code
, 32, SIGILL
) == NOTIFY_STOP
)
810 do_trap(32, SIGILL
, "iret exception", regs
, error_code
, &info
);
814 /* Set of traps needed for early debugging. */
815 void __init
early_trap_init(void)
817 set_intr_gate_ist(1, &debug
, DEBUG_STACK
);
818 /* int3 can be called from all */
819 set_system_intr_gate_ist(3, &int3
, DEBUG_STACK
);
820 set_intr_gate(14, &page_fault
);
821 load_idt(&idt_descr
);
824 void __init
trap_init(void)
829 void __iomem
*p
= early_ioremap(0x0FFFD9, 4);
831 if (readl(p
) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
836 set_intr_gate(0, ÷_error
);
837 set_intr_gate_ist(2, &nmi
, NMI_STACK
);
838 /* int4 can be called from all */
839 set_system_intr_gate(4, &overflow
);
840 set_intr_gate(5, &bounds
);
841 set_intr_gate(6, &invalid_op
);
842 set_intr_gate(7, &device_not_available
);
844 set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS
);
846 set_intr_gate_ist(8, &double_fault
, DOUBLEFAULT_STACK
);
848 set_intr_gate(9, &coprocessor_segment_overrun
);
849 set_intr_gate(10, &invalid_TSS
);
850 set_intr_gate(11, &segment_not_present
);
851 set_intr_gate_ist(12, &stack_segment
, STACKFAULT_STACK
);
852 set_intr_gate(13, &general_protection
);
853 set_intr_gate(15, &spurious_interrupt_bug
);
854 set_intr_gate(16, &coprocessor_error
);
855 set_intr_gate(17, &alignment_check
);
856 #ifdef CONFIG_X86_MCE
857 set_intr_gate_ist(18, &machine_check
, MCE_STACK
);
859 set_intr_gate(19, &simd_coprocessor_error
);
861 /* Reserve all the builtin and the syscall vector: */
862 for (i
= 0; i
< FIRST_EXTERNAL_VECTOR
; i
++)
863 set_bit(i
, used_vectors
);
865 #ifdef CONFIG_IA32_EMULATION
866 set_system_intr_gate(IA32_SYSCALL_VECTOR
, ia32_syscall
);
867 set_bit(IA32_SYSCALL_VECTOR
, used_vectors
);
871 set_system_trap_gate(SYSCALL_VECTOR
, &system_call
);
872 set_bit(SYSCALL_VECTOR
, used_vectors
);
876 * Should be a barrier for any external CPU state:
880 x86_init
.irqs
.trap_init();