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>
31 #include <linux/uaccess.h>
34 #include <linux/ioport.h>
35 #include <linux/eisa.h>
39 #include <linux/mca.h>
42 #include <asm/processor.h>
43 #include <asm/system.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>
54 #include <asm/stacktrace.h>
56 #include <linux/module.h>
58 #include "mach_traps.h"
60 int panic_on_unrecovered_nmi
;
62 asmlinkage
int system_call(void);
64 struct desc_struct default_ldt
[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
67 /* Do we ignore FPU interrupts ? */
68 char ignore_fpu_irq
= 0;
71 * The IDT has to be page-aligned to simplify the Pentium
72 * F0 0F bug workaround.. We have a special link segment
75 struct desc_struct idt_table
[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, };
77 asmlinkage
void divide_error(void);
78 asmlinkage
void debug(void);
79 asmlinkage
void nmi(void);
80 asmlinkage
void int3(void);
81 asmlinkage
void overflow(void);
82 asmlinkage
void bounds(void);
83 asmlinkage
void invalid_op(void);
84 asmlinkage
void device_not_available(void);
85 asmlinkage
void coprocessor_segment_overrun(void);
86 asmlinkage
void invalid_TSS(void);
87 asmlinkage
void segment_not_present(void);
88 asmlinkage
void stack_segment(void);
89 asmlinkage
void general_protection(void);
90 asmlinkage
void page_fault(void);
91 asmlinkage
void coprocessor_error(void);
92 asmlinkage
void simd_coprocessor_error(void);
93 asmlinkage
void alignment_check(void);
94 asmlinkage
void spurious_interrupt_bug(void);
95 asmlinkage
void machine_check(void);
97 static int kstack_depth_to_print
= 24;
98 #ifdef CONFIG_STACK_UNWIND
99 static int call_trace
= 1;
101 #define call_trace (-1)
103 ATOMIC_NOTIFIER_HEAD(i386die_chain
);
105 int register_die_notifier(struct notifier_block
*nb
)
108 return atomic_notifier_chain_register(&i386die_chain
, nb
);
110 EXPORT_SYMBOL(register_die_notifier
); /* used modular by kdb */
112 int unregister_die_notifier(struct notifier_block
*nb
)
114 return atomic_notifier_chain_unregister(&i386die_chain
, nb
);
116 EXPORT_SYMBOL(unregister_die_notifier
); /* used modular by kdb */
118 static inline int valid_stack_ptr(struct thread_info
*tinfo
, void *p
)
120 return p
> (void *)tinfo
&&
121 p
< (void *)tinfo
+ THREAD_SIZE
- 3;
124 static inline unsigned long print_context_stack(struct thread_info
*tinfo
,
125 unsigned long *stack
, unsigned long ebp
,
126 struct stacktrace_ops
*ops
, void *data
)
130 #ifdef CONFIG_FRAME_POINTER
131 while (valid_stack_ptr(tinfo
, (void *)ebp
)) {
132 addr
= *(unsigned long *)(ebp
+ 4);
133 ops
->address(data
, addr
);
135 * break out of recursive entries (such as
136 * end_of_stack_stop_unwind_function):
138 if (ebp
== *(unsigned long *)ebp
)
140 ebp
= *(unsigned long *)ebp
;
143 while (valid_stack_ptr(tinfo
, stack
)) {
145 if (__kernel_text_address(addr
))
146 ops
->address(data
, addr
);
152 struct ops_and_data
{
153 struct stacktrace_ops
*ops
;
157 static asmlinkage
int
158 dump_trace_unwind(struct unwind_frame_info
*info
, void *data
)
160 struct ops_and_data
*oad
= (struct ops_and_data
*)data
;
163 while (unwind(info
) == 0 && UNW_PC(info
)) {
165 oad
->ops
->address(oad
->data
, UNW_PC(info
));
166 if (arch_unw_user_mode(info
))
172 void dump_trace(struct task_struct
*task
, struct pt_regs
*regs
,
173 unsigned long *stack
,
174 struct stacktrace_ops
*ops
, void *data
)
176 unsigned long ebp
= 0;
181 if (call_trace
>= 0) {
183 struct unwind_frame_info info
;
184 struct ops_and_data oad
= { .ops
= ops
, .data
= data
};
187 if (unwind_init_frame_info(&info
, task
, regs
) == 0)
188 unw_ret
= dump_trace_unwind(&info
, &oad
);
189 } else if (task
== current
)
190 unw_ret
= unwind_init_running(&info
, dump_trace_unwind
, &oad
);
192 if (unwind_init_blocked(&info
, task
) == 0)
193 unw_ret
= dump_trace_unwind(&info
, &oad
);
196 if (call_trace
== 1 && !arch_unw_user_mode(&info
)) {
197 ops
->warning_symbol(data
, "DWARF2 unwinder stuck at %s\n",
199 if (UNW_SP(&info
) >= PAGE_OFFSET
) {
200 ops
->warning(data
, "Leftover inexact backtrace:\n");
201 stack
= (void *)UNW_SP(&info
);
206 ops
->warning(data
, "Full inexact backtrace again:\n");
207 } else if (call_trace
>= 1)
210 ops
->warning(data
, "Full inexact backtrace again:\n");
212 ops
->warning(data
, "Inexact backtrace:\n");
217 if (task
&& task
!= current
)
218 stack
= (unsigned long *)task
->thread
.esp
;
221 #ifdef CONFIG_FRAME_POINTER
223 if (task
== current
) {
224 /* Grab ebp right from our regs */
225 asm ("movl %%ebp, %0" : "=r" (ebp
) : );
227 /* ebp is the last reg pushed by switch_to */
228 ebp
= *(unsigned long *) task
->thread
.esp
;
234 struct thread_info
*context
;
235 context
= (struct thread_info
*)
236 ((unsigned long)stack
& (~(THREAD_SIZE
- 1)));
237 ebp
= print_context_stack(context
, stack
, ebp
, ops
, data
);
238 /* Should be after the line below, but somewhere
239 in early boot context comes out corrupted and we
240 can't reference it -AK */
241 if (ops
->stack(data
, "IRQ") < 0)
243 stack
= (unsigned long*)context
->previous_esp
;
248 EXPORT_SYMBOL(dump_trace
);
251 print_trace_warning_symbol(void *data
, char *msg
, unsigned long symbol
)
254 print_symbol(msg
, symbol
);
258 static void print_trace_warning(void *data
, char *msg
)
260 printk("%s%s\n", (char *)data
, msg
);
263 static int print_trace_stack(void *data
, char *name
)
269 * Print one address/symbol entries per line.
271 static void print_trace_address(void *data
, unsigned long addr
)
273 printk("%s [<%08lx>] ", (char *)data
, addr
);
274 print_symbol("%s\n", addr
);
277 static struct stacktrace_ops print_trace_ops
= {
278 .warning
= print_trace_warning
,
279 .warning_symbol
= print_trace_warning_symbol
,
280 .stack
= print_trace_stack
,
281 .address
= print_trace_address
,
285 show_trace_log_lvl(struct task_struct
*task
, struct pt_regs
*regs
,
286 unsigned long * stack
, char *log_lvl
)
288 dump_trace(task
, regs
, stack
, &print_trace_ops
, log_lvl
);
289 printk("%s =======================\n", log_lvl
);
292 void show_trace(struct task_struct
*task
, struct pt_regs
*regs
,
293 unsigned long * stack
)
295 show_trace_log_lvl(task
, regs
, stack
, "");
298 static void show_stack_log_lvl(struct task_struct
*task
, struct pt_regs
*regs
,
299 unsigned long *esp
, char *log_lvl
)
301 unsigned long *stack
;
306 esp
= (unsigned long*)task
->thread
.esp
;
308 esp
= (unsigned long *)&esp
;
312 for(i
= 0; i
< kstack_depth_to_print
; i
++) {
313 if (kstack_end(stack
))
315 if (i
&& ((i
% 8) == 0))
316 printk("\n%s ", log_lvl
);
317 printk("%08lx ", *stack
++);
319 printk("\n%sCall Trace:\n", log_lvl
);
320 show_trace_log_lvl(task
, regs
, esp
, log_lvl
);
323 void show_stack(struct task_struct
*task
, unsigned long *esp
)
326 show_stack_log_lvl(task
, NULL
, esp
, "");
330 * The architecture-independent dump_stack generator
332 void dump_stack(void)
336 show_trace(current
, NULL
, &stack
);
339 EXPORT_SYMBOL(dump_stack
);
341 void show_registers(struct pt_regs
*regs
)
348 esp
= (unsigned long) (®s
->esp
);
350 if (user_mode_vm(regs
)) {
353 ss
= regs
->xss
& 0xffff;
356 printk(KERN_EMERG
"CPU: %d\n"
357 KERN_EMERG
"EIP: %04x:[<%08lx>] %s VLI\n"
358 KERN_EMERG
"EFLAGS: %08lx (%s %.*s)\n",
359 smp_processor_id(), 0xffff & regs
->xcs
, regs
->eip
,
360 print_tainted(), regs
->eflags
, init_utsname()->release
,
361 (int)strcspn(init_utsname()->version
, " "),
362 init_utsname()->version
);
363 print_symbol(KERN_EMERG
"EIP is at %s\n", regs
->eip
);
364 printk(KERN_EMERG
"eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
365 regs
->eax
, regs
->ebx
, regs
->ecx
, regs
->edx
);
366 printk(KERN_EMERG
"esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
367 regs
->esi
, regs
->edi
, regs
->ebp
, esp
);
368 printk(KERN_EMERG
"ds: %04x es: %04x ss: %04x\n",
369 regs
->xds
& 0xffff, regs
->xes
& 0xffff, ss
);
370 printk(KERN_EMERG
"Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
371 TASK_COMM_LEN
, current
->comm
, current
->pid
,
372 current_thread_info(), current
, current
->thread_info
);
374 * When in-kernel, we also print out the stack and code at the
375 * time of the fault..
382 printk("\n" KERN_EMERG
"Stack: ");
383 show_stack_log_lvl(NULL
, regs
, (unsigned long *)esp
, KERN_EMERG
);
385 printk(KERN_EMERG
"Code: ");
387 eip
= (u8 __user
*)regs
->eip
- 43;
388 if (eip
< (u8 __user
*)PAGE_OFFSET
|| __get_user(c
, eip
)) {
389 /* try starting at EIP */
390 eip
= (u8 __user
*)regs
->eip
;
393 for (i
= 0; i
< code_bytes
; i
++, eip
++) {
394 if (eip
< (u8 __user
*)PAGE_OFFSET
|| __get_user(c
, eip
)) {
395 printk(" Bad EIP value.");
398 if (eip
== (u8 __user
*)regs
->eip
)
399 printk("<%02x> ", c
);
407 static void handle_BUG(struct pt_regs
*regs
)
409 unsigned long eip
= regs
->eip
;
412 if (eip
< PAGE_OFFSET
)
414 if (probe_kernel_address((unsigned short __user
*)eip
, ud2
))
419 printk(KERN_EMERG
"------------[ cut here ]------------\n");
421 #ifdef CONFIG_DEBUG_BUGVERBOSE
427 if (probe_kernel_address((unsigned short __user
*)(eip
+ 2),
430 if (__get_user(file
, (char * __user
*)(eip
+ 4)) ||
431 (unsigned long)file
< PAGE_OFFSET
|| __get_user(c
, file
))
432 file
= "<bad filename>";
434 printk(KERN_EMERG
"kernel BUG at %s:%d!\n", file
, line
);
438 printk(KERN_EMERG
"Kernel BUG at [verbose debug info unavailable]\n");
441 /* This is gone through when something in the kernel
442 * has done something bad and is about to be terminated.
444 void die(const char * str
, struct pt_regs
* regs
, long err
)
449 int lock_owner_depth
;
451 .lock
= SPIN_LOCK_UNLOCKED
,
453 .lock_owner_depth
= 0
455 static int die_counter
;
460 if (die
.lock_owner
!= raw_smp_processor_id()) {
462 spin_lock_irqsave(&die
.lock
, flags
);
463 die
.lock_owner
= smp_processor_id();
464 die
.lock_owner_depth
= 0;
468 local_save_flags(flags
);
470 if (++die
.lock_owner_depth
< 3) {
476 printk(KERN_EMERG
"%s: %04lx [#%d]\n", str
, err
& 0xffff, ++die_counter
);
477 #ifdef CONFIG_PREEMPT
478 printk(KERN_EMERG
"PREEMPT ");
487 #ifdef CONFIG_DEBUG_PAGEALLOC
490 printk("DEBUG_PAGEALLOC");
495 if (notify_die(DIE_OOPS
, str
, regs
, err
,
496 current
->thread
.trap_no
, SIGSEGV
) !=
498 show_registers(regs
);
499 /* Executive summary in case the oops scrolled away */
500 esp
= (unsigned long) (®s
->esp
);
502 if (user_mode(regs
)) {
504 ss
= regs
->xss
& 0xffff;
506 printk(KERN_EMERG
"EIP: [<%08lx>] ", regs
->eip
);
507 print_symbol("%s", regs
->eip
);
508 printk(" SS:ESP %04x:%08lx\n", ss
, esp
);
513 printk(KERN_EMERG
"Recursive die() failure, output suppressed\n");
517 spin_unlock_irqrestore(&die
.lock
, flags
);
522 if (kexec_should_crash(current
))
526 panic("Fatal exception in interrupt");
529 panic("Fatal exception");
535 static inline void die_if_kernel(const char * str
, struct pt_regs
* regs
, long err
)
537 if (!user_mode_vm(regs
))
541 static void __kprobes
do_trap(int trapnr
, int signr
, char *str
, int vm86
,
542 struct pt_regs
* regs
, long error_code
,
545 struct task_struct
*tsk
= current
;
546 tsk
->thread
.error_code
= error_code
;
547 tsk
->thread
.trap_no
= trapnr
;
549 if (regs
->eflags
& VM_MASK
) {
555 if (!user_mode(regs
))
560 force_sig_info(signr
, info
, tsk
);
562 force_sig(signr
, tsk
);
567 if (!fixup_exception(regs
))
568 die(str
, regs
, error_code
);
573 int ret
= handle_vm86_trap((struct kernel_vm86_regs
*) regs
, error_code
, trapnr
);
574 if (ret
) goto trap_signal
;
579 #define DO_ERROR(trapnr, signr, str, name) \
580 fastcall void do_##name(struct pt_regs * regs, long error_code) \
582 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
585 do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
588 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
589 fastcall void do_##name(struct pt_regs * regs, long error_code) \
592 info.si_signo = signr; \
594 info.si_code = sicode; \
595 info.si_addr = (void __user *)siaddr; \
596 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
599 do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
602 #define DO_VM86_ERROR(trapnr, signr, str, name) \
603 fastcall void do_##name(struct pt_regs * regs, long error_code) \
605 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
608 do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
611 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
612 fastcall void do_##name(struct pt_regs * regs, long error_code) \
615 info.si_signo = signr; \
617 info.si_code = sicode; \
618 info.si_addr = (void __user *)siaddr; \
619 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
622 do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
625 DO_VM86_ERROR_INFO( 0, SIGFPE
, "divide error", divide_error
, FPE_INTDIV
, regs
->eip
)
626 #ifndef CONFIG_KPROBES
627 DO_VM86_ERROR( 3, SIGTRAP
, "int3", int3
)
629 DO_VM86_ERROR( 4, SIGSEGV
, "overflow", overflow
)
630 DO_VM86_ERROR( 5, SIGSEGV
, "bounds", bounds
)
631 DO_ERROR_INFO( 6, SIGILL
, "invalid opcode", invalid_op
, ILL_ILLOPN
, regs
->eip
)
632 DO_ERROR( 9, SIGFPE
, "coprocessor segment overrun", coprocessor_segment_overrun
)
633 DO_ERROR(10, SIGSEGV
, "invalid TSS", invalid_TSS
)
634 DO_ERROR(11, SIGBUS
, "segment not present", segment_not_present
)
635 DO_ERROR(12, SIGBUS
, "stack segment", stack_segment
)
636 DO_ERROR_INFO(17, SIGBUS
, "alignment check", alignment_check
, BUS_ADRALN
, 0)
637 DO_ERROR_INFO(32, SIGSEGV
, "iret exception", iret_error
, ILL_BADSTK
, 0)
639 fastcall
void __kprobes
do_general_protection(struct pt_regs
* regs
,
643 struct tss_struct
*tss
= &per_cpu(init_tss
, cpu
);
644 struct thread_struct
*thread
= ¤t
->thread
;
647 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
648 * invalid offset set (the LAZY one) and the faulting thread has
649 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
650 * and we set the offset field correctly. Then we let the CPU to
651 * restart the faulting instruction.
653 if (tss
->io_bitmap_base
== INVALID_IO_BITMAP_OFFSET_LAZY
&&
654 thread
->io_bitmap_ptr
) {
655 memcpy(tss
->io_bitmap
, thread
->io_bitmap_ptr
,
656 thread
->io_bitmap_max
);
658 * If the previously set map was extending to higher ports
659 * than the current one, pad extra space with 0xff (no access).
661 if (thread
->io_bitmap_max
< tss
->io_bitmap_max
)
662 memset((char *) tss
->io_bitmap
+
663 thread
->io_bitmap_max
, 0xff,
664 tss
->io_bitmap_max
- thread
->io_bitmap_max
);
665 tss
->io_bitmap_max
= thread
->io_bitmap_max
;
666 tss
->io_bitmap_base
= IO_BITMAP_OFFSET
;
667 tss
->io_bitmap_owner
= thread
;
673 current
->thread
.error_code
= error_code
;
674 current
->thread
.trap_no
= 13;
676 if (regs
->eflags
& VM_MASK
)
679 if (!user_mode(regs
))
682 current
->thread
.error_code
= error_code
;
683 current
->thread
.trap_no
= 13;
684 force_sig(SIGSEGV
, current
);
689 handle_vm86_fault((struct kernel_vm86_regs
*) regs
, error_code
);
693 if (!fixup_exception(regs
)) {
694 if (notify_die(DIE_GPF
, "general protection fault", regs
,
695 error_code
, 13, SIGSEGV
) == NOTIFY_STOP
)
697 die("general protection fault", regs
, error_code
);
701 static __kprobes
void
702 mem_parity_error(unsigned char reason
, struct pt_regs
* regs
)
704 printk(KERN_EMERG
"Uhhuh. NMI received for unknown reason %02x on "
705 "CPU %d.\n", reason
, smp_processor_id());
706 printk(KERN_EMERG
"You probably have a hardware problem with your RAM "
708 if (panic_on_unrecovered_nmi
)
709 panic("NMI: Not continuing");
711 printk(KERN_EMERG
"Dazed and confused, but trying to continue\n");
713 /* Clear and disable the memory parity error line. */
714 clear_mem_error(reason
);
717 static __kprobes
void
718 io_check_error(unsigned char reason
, struct pt_regs
* regs
)
722 printk(KERN_EMERG
"NMI: IOCK error (debug interrupt?)\n");
723 show_registers(regs
);
725 /* Re-enable the IOCK line, wait for a few seconds */
726 reason
= (reason
& 0xf) | 8;
729 while (--i
) udelay(1000);
734 static __kprobes
void
735 unknown_nmi_error(unsigned char reason
, struct pt_regs
* regs
)
738 /* Might actually be able to figure out what the guilty party
745 printk(KERN_EMERG
"Uhhuh. NMI received for unknown reason %02x on "
746 "CPU %d.\n", reason
, smp_processor_id());
747 printk(KERN_EMERG
"Do you have a strange power saving mode enabled?\n");
748 if (panic_on_unrecovered_nmi
)
749 panic("NMI: Not continuing");
751 printk(KERN_EMERG
"Dazed and confused, but trying to continue\n");
754 static DEFINE_SPINLOCK(nmi_print_lock
);
756 void __kprobes
die_nmi(struct pt_regs
*regs
, const char *msg
)
758 if (notify_die(DIE_NMIWATCHDOG
, msg
, regs
, 0, 2, SIGINT
) ==
762 spin_lock(&nmi_print_lock
);
764 * We are in trouble anyway, lets at least try
765 * to get a message out.
768 printk(KERN_EMERG
"%s", msg
);
769 printk(" on CPU%d, eip %08lx, registers:\n",
770 smp_processor_id(), regs
->eip
);
771 show_registers(regs
);
772 printk(KERN_EMERG
"console shuts up ...\n");
774 spin_unlock(&nmi_print_lock
);
777 /* If we are in kernel we are probably nested up pretty bad
778 * and might aswell get out now while we still can.
780 if (!user_mode_vm(regs
)) {
781 current
->thread
.trap_no
= 2;
788 static __kprobes
void default_do_nmi(struct pt_regs
* regs
)
790 unsigned char reason
= 0;
792 /* Only the BSP gets external NMIs from the system. */
793 if (!smp_processor_id())
794 reason
= get_nmi_reason();
796 if (!(reason
& 0xc0)) {
797 if (notify_die(DIE_NMI_IPI
, "nmi_ipi", regs
, reason
, 2, SIGINT
)
800 #ifdef CONFIG_X86_LOCAL_APIC
802 * Ok, so this is none of the documented NMI sources,
803 * so it must be the NMI watchdog.
805 if (nmi_watchdog_tick(regs
, reason
))
807 if (!do_nmi_callback(regs
, smp_processor_id()))
809 unknown_nmi_error(reason
, regs
);
813 if (notify_die(DIE_NMI
, "nmi", regs
, reason
, 2, SIGINT
) == NOTIFY_STOP
)
816 mem_parity_error(reason
, regs
);
818 io_check_error(reason
, regs
);
820 * Reassert NMI in case it became active meanwhile
821 * as it's edge-triggered.
826 fastcall __kprobes
void do_nmi(struct pt_regs
* regs
, long error_code
)
832 cpu
= smp_processor_id();
836 default_do_nmi(regs
);
841 #ifdef CONFIG_KPROBES
842 fastcall
void __kprobes
do_int3(struct pt_regs
*regs
, long error_code
)
844 if (notify_die(DIE_INT3
, "int3", regs
, error_code
, 3, SIGTRAP
)
847 /* This is an interrupt gate, because kprobes wants interrupts
848 disabled. Normal trap handlers don't. */
849 restore_interrupts(regs
);
850 do_trap(3, SIGTRAP
, "int3", 1, regs
, error_code
, NULL
);
855 * Our handling of the processor debug registers is non-trivial.
856 * We do not clear them on entry and exit from the kernel. Therefore
857 * it is possible to get a watchpoint trap here from inside the kernel.
858 * However, the code in ./ptrace.c has ensured that the user can
859 * only set watchpoints on userspace addresses. Therefore the in-kernel
860 * watchpoint trap can only occur in code which is reading/writing
861 * from user space. Such code must not hold kernel locks (since it
862 * can equally take a page fault), therefore it is safe to call
863 * force_sig_info even though that claims and releases locks.
865 * Code in ./signal.c ensures that the debug control register
866 * is restored before we deliver any signal, and therefore that
867 * user code runs with the correct debug control register even though
870 * Being careful here means that we don't have to be as careful in a
871 * lot of more complicated places (task switching can be a bit lazy
872 * about restoring all the debug state, and ptrace doesn't have to
873 * find every occurrence of the TF bit that could be saved away even
876 fastcall
void __kprobes
do_debug(struct pt_regs
* regs
, long error_code
)
878 unsigned int condition
;
879 struct task_struct
*tsk
= current
;
881 get_debugreg(condition
, 6);
883 if (notify_die(DIE_DEBUG
, "debug", regs
, condition
, error_code
,
884 SIGTRAP
) == NOTIFY_STOP
)
886 /* It's safe to allow irq's after DR6 has been saved */
887 if (regs
->eflags
& X86_EFLAGS_IF
)
890 /* Mask out spurious debug traps due to lazy DR7 setting */
891 if (condition
& (DR_TRAP0
|DR_TRAP1
|DR_TRAP2
|DR_TRAP3
)) {
892 if (!tsk
->thread
.debugreg
[7])
896 if (regs
->eflags
& VM_MASK
)
899 /* Save debug status register where ptrace can see it */
900 tsk
->thread
.debugreg
[6] = condition
;
903 * Single-stepping through TF: make sure we ignore any events in
904 * kernel space (but re-enable TF when returning to user mode).
906 if (condition
& DR_STEP
) {
908 * We already checked v86 mode above, so we can
909 * check for kernel mode by just checking the CPL
912 if (!user_mode(regs
))
913 goto clear_TF_reenable
;
916 /* Ok, finally something we can handle */
917 send_sigtrap(tsk
, regs
, error_code
);
919 /* Disable additional traps. They'll be re-enabled when
920 * the signal is delivered.
927 handle_vm86_trap((struct kernel_vm86_regs
*) regs
, error_code
, 1);
931 set_tsk_thread_flag(tsk
, TIF_SINGLESTEP
);
932 regs
->eflags
&= ~TF_MASK
;
937 * Note that we play around with the 'TS' bit in an attempt to get
938 * the correct behaviour even in the presence of the asynchronous
941 void math_error(void __user
*eip
)
943 struct task_struct
* task
;
945 unsigned short cwd
, swd
;
948 * Save the info for the exception handler and clear the error.
952 task
->thread
.trap_no
= 16;
953 task
->thread
.error_code
= 0;
954 info
.si_signo
= SIGFPE
;
956 info
.si_code
= __SI_FAULT
;
959 * (~cwd & swd) will mask out exceptions that are not set to unmasked
960 * status. 0x3f is the exception bits in these regs, 0x200 is the
961 * C1 reg you need in case of a stack fault, 0x040 is the stack
962 * fault bit. We should only be taking one exception at a time,
963 * so if this combination doesn't produce any single exception,
964 * then we have a bad program that isn't syncronizing its FPU usage
965 * and it will suffer the consequences since we won't be able to
966 * fully reproduce the context of the exception
968 cwd
= get_fpu_cwd(task
);
969 swd
= get_fpu_swd(task
);
970 switch (swd
& ~cwd
& 0x3f) {
971 case 0x000: /* No unmasked exception */
973 default: /* Multiple exceptions */
975 case 0x001: /* Invalid Op */
977 * swd & 0x240 == 0x040: Stack Underflow
978 * swd & 0x240 == 0x240: Stack Overflow
979 * User must clear the SF bit (0x40) if set
981 info
.si_code
= FPE_FLTINV
;
983 case 0x002: /* Denormalize */
984 case 0x010: /* Underflow */
985 info
.si_code
= FPE_FLTUND
;
987 case 0x004: /* Zero Divide */
988 info
.si_code
= FPE_FLTDIV
;
990 case 0x008: /* Overflow */
991 info
.si_code
= FPE_FLTOVF
;
993 case 0x020: /* Precision */
994 info
.si_code
= FPE_FLTRES
;
997 force_sig_info(SIGFPE
, &info
, task
);
1000 fastcall
void do_coprocessor_error(struct pt_regs
* regs
, long error_code
)
1003 math_error((void __user
*)regs
->eip
);
1006 static void simd_math_error(void __user
*eip
)
1008 struct task_struct
* task
;
1010 unsigned short mxcsr
;
1013 * Save the info for the exception handler and clear the error.
1016 save_init_fpu(task
);
1017 task
->thread
.trap_no
= 19;
1018 task
->thread
.error_code
= 0;
1019 info
.si_signo
= SIGFPE
;
1021 info
.si_code
= __SI_FAULT
;
1024 * The SIMD FPU exceptions are handled a little differently, as there
1025 * is only a single status/control register. Thus, to determine which
1026 * unmasked exception was caught we must mask the exception mask bits
1027 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
1029 mxcsr
= get_fpu_mxcsr(task
);
1030 switch (~((mxcsr
& 0x1f80) >> 7) & (mxcsr
& 0x3f)) {
1034 case 0x001: /* Invalid Op */
1035 info
.si_code
= FPE_FLTINV
;
1037 case 0x002: /* Denormalize */
1038 case 0x010: /* Underflow */
1039 info
.si_code
= FPE_FLTUND
;
1041 case 0x004: /* Zero Divide */
1042 info
.si_code
= FPE_FLTDIV
;
1044 case 0x008: /* Overflow */
1045 info
.si_code
= FPE_FLTOVF
;
1047 case 0x020: /* Precision */
1048 info
.si_code
= FPE_FLTRES
;
1051 force_sig_info(SIGFPE
, &info
, task
);
1054 fastcall
void do_simd_coprocessor_error(struct pt_regs
* regs
,
1058 /* Handle SIMD FPU exceptions on PIII+ processors. */
1060 simd_math_error((void __user
*)regs
->eip
);
1063 * Handle strange cache flush from user space exception
1064 * in all other cases. This is undocumented behaviour.
1066 if (regs
->eflags
& VM_MASK
) {
1067 handle_vm86_fault((struct kernel_vm86_regs
*)regs
,
1071 current
->thread
.trap_no
= 19;
1072 current
->thread
.error_code
= error_code
;
1073 die_if_kernel("cache flush denied", regs
, error_code
);
1074 force_sig(SIGSEGV
, current
);
1078 fastcall
void do_spurious_interrupt_bug(struct pt_regs
* regs
,
1082 /* No need to warn about this any longer. */
1083 printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
1087 fastcall
void setup_x86_bogus_stack(unsigned char * stk
)
1089 unsigned long *switch16_ptr
, *switch32_ptr
;
1090 struct pt_regs
*regs
;
1091 unsigned long stack_top
, stack_bot
;
1092 unsigned short iret_frame16_off
;
1093 int cpu
= smp_processor_id();
1094 /* reserve the space on 32bit stack for the magic switch16 pointer */
1095 memmove(stk
, stk
+ 8, sizeof(struct pt_regs
));
1096 switch16_ptr
= (unsigned long *)(stk
+ sizeof(struct pt_regs
));
1097 regs
= (struct pt_regs
*)stk
;
1098 /* now the switch32 on 16bit stack */
1099 stack_bot
= (unsigned long)&per_cpu(cpu_16bit_stack
, cpu
);
1100 stack_top
= stack_bot
+ CPU_16BIT_STACK_SIZE
;
1101 switch32_ptr
= (unsigned long *)(stack_top
- 8);
1102 iret_frame16_off
= CPU_16BIT_STACK_SIZE
- 8 - 20;
1103 /* copy iret frame on 16bit stack */
1104 memcpy((void *)(stack_bot
+ iret_frame16_off
), ®s
->eip
, 20);
1105 /* fill in the switch pointers */
1106 switch16_ptr
[0] = (regs
->esp
& 0xffff0000) | iret_frame16_off
;
1107 switch16_ptr
[1] = __ESPFIX_SS
;
1108 switch32_ptr
[0] = (unsigned long)stk
+ sizeof(struct pt_regs
) +
1109 8 - CPU_16BIT_STACK_SIZE
;
1110 switch32_ptr
[1] = __KERNEL_DS
;
1113 fastcall
unsigned char * fixup_x86_bogus_stack(unsigned short sp
)
1115 unsigned long *switch32_ptr
;
1116 unsigned char *stack16
, *stack32
;
1117 unsigned long stack_top
, stack_bot
;
1119 int cpu
= smp_processor_id();
1120 stack_bot
= (unsigned long)&per_cpu(cpu_16bit_stack
, cpu
);
1121 stack_top
= stack_bot
+ CPU_16BIT_STACK_SIZE
;
1122 switch32_ptr
= (unsigned long *)(stack_top
- 8);
1123 /* copy the data from 16bit stack to 32bit stack */
1124 len
= CPU_16BIT_STACK_SIZE
- 8 - sp
;
1125 stack16
= (unsigned char *)(stack_bot
+ sp
);
1126 stack32
= (unsigned char *)
1127 (switch32_ptr
[0] + CPU_16BIT_STACK_SIZE
- 8 - len
);
1128 memcpy(stack32
, stack16
, len
);
1133 * 'math_state_restore()' saves the current math information in the
1134 * old math state array, and gets the new ones from the current task
1136 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1137 * Don't touch unless you *really* know how it works.
1139 * Must be called with kernel preemption disabled (in this case,
1140 * local interrupts are disabled at the call-site in entry.S).
1142 asmlinkage
void math_state_restore(struct pt_regs regs
)
1144 struct thread_info
*thread
= current_thread_info();
1145 struct task_struct
*tsk
= thread
->task
;
1147 clts(); /* Allow maths ops (or we recurse) */
1148 if (!tsk_used_math(tsk
))
1151 thread
->status
|= TS_USEDFPU
; /* So we fnsave on switch_to() */
1154 #ifndef CONFIG_MATH_EMULATION
1156 asmlinkage
void math_emulate(long arg
)
1158 printk(KERN_EMERG
"math-emulation not enabled and no coprocessor found.\n");
1159 printk(KERN_EMERG
"killing %s.\n",current
->comm
);
1160 force_sig(SIGFPE
,current
);
1164 #endif /* CONFIG_MATH_EMULATION */
1166 #ifdef CONFIG_X86_F00F_BUG
1167 void __init
trap_init_f00f_bug(void)
1169 __set_fixmap(FIX_F00F_IDT
, __pa(&idt_table
), PAGE_KERNEL_RO
);
1172 * Update the IDT descriptor and reload the IDT so that
1173 * it uses the read-only mapped virtual address.
1175 idt_descr
.address
= fix_to_virt(FIX_F00F_IDT
);
1176 load_idt(&idt_descr
);
1181 * This needs to use 'idt_table' rather than 'idt', and
1182 * thus use the _nonmapped_ version of the IDT, as the
1183 * Pentium F0 0F bugfix can have resulted in the mapped
1184 * IDT being write-protected.
1186 void set_intr_gate(unsigned int n
, void *addr
)
1188 _set_gate(n
, DESCTYPE_INT
, addr
, __KERNEL_CS
);
1192 * This routine sets up an interrupt gate at directory privilege level 3.
1194 static inline void set_system_intr_gate(unsigned int n
, void *addr
)
1196 _set_gate(n
, DESCTYPE_INT
| DESCTYPE_DPL3
, addr
, __KERNEL_CS
);
1199 static void __init
set_trap_gate(unsigned int n
, void *addr
)
1201 _set_gate(n
, DESCTYPE_TRAP
, addr
, __KERNEL_CS
);
1204 static void __init
set_system_gate(unsigned int n
, void *addr
)
1206 _set_gate(n
, DESCTYPE_TRAP
| DESCTYPE_DPL3
, addr
, __KERNEL_CS
);
1209 static void __init
set_task_gate(unsigned int n
, unsigned int gdt_entry
)
1211 _set_gate(n
, DESCTYPE_TASK
, (void *)0, (gdt_entry
<<3));
1215 void __init
trap_init(void)
1218 void __iomem
*p
= ioremap(0x0FFFD9, 4);
1219 if (readl(p
) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
1225 #ifdef CONFIG_X86_LOCAL_APIC
1226 init_apic_mappings();
1229 set_trap_gate(0,÷_error
);
1230 set_intr_gate(1,&debug
);
1231 set_intr_gate(2,&nmi
);
1232 set_system_intr_gate(3, &int3
); /* int3/4 can be called from all */
1233 set_system_gate(4,&overflow
);
1234 set_trap_gate(5,&bounds
);
1235 set_trap_gate(6,&invalid_op
);
1236 set_trap_gate(7,&device_not_available
);
1237 set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS
);
1238 set_trap_gate(9,&coprocessor_segment_overrun
);
1239 set_trap_gate(10,&invalid_TSS
);
1240 set_trap_gate(11,&segment_not_present
);
1241 set_trap_gate(12,&stack_segment
);
1242 set_trap_gate(13,&general_protection
);
1243 set_intr_gate(14,&page_fault
);
1244 set_trap_gate(15,&spurious_interrupt_bug
);
1245 set_trap_gate(16,&coprocessor_error
);
1246 set_trap_gate(17,&alignment_check
);
1247 #ifdef CONFIG_X86_MCE
1248 set_trap_gate(18,&machine_check
);
1250 set_trap_gate(19,&simd_coprocessor_error
);
1254 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
1255 * Generates a compile-time "error: zero width for bit-field" if
1256 * the alignment is wrong.
1258 struct fxsrAlignAssert
{
1259 int _
:!(offsetof(struct task_struct
,
1260 thread
.i387
.fxsave
) & 15);
1263 printk(KERN_INFO
"Enabling fast FPU save and restore... ");
1264 set_in_cr4(X86_CR4_OSFXSR
);
1268 printk(KERN_INFO
"Enabling unmasked SIMD FPU exception "
1270 set_in_cr4(X86_CR4_OSXMMEXCPT
);
1274 set_system_gate(SYSCALL_VECTOR
,&system_call
);
1277 * Should be a barrier for any external CPU state.
1284 static int __init
kstack_setup(char *s
)
1286 kstack_depth_to_print
= simple_strtoul(s
, NULL
, 0);
1289 __setup("kstack=", kstack_setup
);
1291 #ifdef CONFIG_STACK_UNWIND
1292 static int __init
call_trace_setup(char *s
)
1294 if (strcmp(s
, "old") == 0)
1296 else if (strcmp(s
, "both") == 0)
1298 else if (strcmp(s
, "newfallback") == 0)
1300 else if (strcmp(s
, "new") == 2)
1304 __setup("call_trace=", call_trace_setup
);