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 unsigned long new_ebp;
133 addr = *(unsigned long *)(ebp + 4);
134 ops->address(data, addr);
136 * break out of recursive entries (such as
137 * end_of_stack_stop_unwind_function). Also,
138 * we can never allow a frame pointer to
141 new_ebp = *(unsigned long *)ebp;
147 while (valid_stack_ptr(tinfo, stack)) {
149 if (__kernel_text_address(addr))
150 ops->address(data, addr);
156 struct ops_and_data {
157 struct stacktrace_ops *ops;
161 static asmlinkage int
162 dump_trace_unwind(struct unwind_frame_info *info, void *data)
164 struct ops_and_data *oad = (struct ops_and_data *)data;
167 while (unwind(info) == 0 && UNW_PC(info)) {
169 oad->ops->address(oad->data, UNW_PC(info));
170 if (arch_unw_user_mode(info))
176 #define MSG(msg) ops->warning(data, msg)
178 void dump_trace(struct task_struct *task, struct pt_regs *regs,
179 unsigned long *stack,
180 struct stacktrace_ops *ops, void *data)
182 unsigned long ebp = 0;
187 if (call_trace >= 0) {
189 struct unwind_frame_info info;
190 struct ops_and_data oad = { .ops = ops, .data = data };
193 if (unwind_init_frame_info(&info, task, regs) == 0)
194 unw_ret = dump_trace_unwind(&info, &oad);
195 } else if (task == current)
196 unw_ret = unwind_init_running(&info, dump_trace_unwind,
199 if (unwind_init_blocked(&info, task) == 0)
200 unw_ret = dump_trace_unwind(&info, &oad);
203 if (call_trace == 1 && !arch_unw_user_mode(&info)) {
204 ops->warning_symbol(data,
205 "DWARF2 unwinder stuck at %s",
207 if (UNW_SP(&info) >= PAGE_OFFSET) {
208 MSG("Leftover inexact backtrace:");
209 stack = (void *)UNW_SP(&info);
214 MSG("Full inexact backtrace again:");
215 } else if (call_trace >= 1)
218 MSG("Full inexact backtrace again:");
220 MSG("Inexact backtrace:");
225 if (task && task != current)
226 stack = (unsigned long *)task->thread.esp;
229 #ifdef CONFIG_FRAME_POINTER
231 if (task == current) {
232 /* Grab ebp right from our regs */
233 asm ("movl %%ebp, %0" : "=r" (ebp) : );
235 /* ebp is the last reg pushed by switch_to */
236 ebp = *(unsigned long *) task->thread.esp;
242 struct thread_info *context;
243 context = (struct thread_info *)
244 ((unsigned long)stack & (~(THREAD_SIZE - 1)));
245 ebp = print_context_stack(context, stack, ebp, ops, data);
246 /* Should be after the line below, but somewhere
247 in early boot context comes out corrupted and we
248 can't reference it -AK */
249 if (ops->stack(data, "IRQ") < 0)
251 stack = (unsigned long*)context->previous_esp;
256 EXPORT_SYMBOL(dump_trace);
259 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
262 print_symbol(msg, symbol);
266 static void print_trace_warning(void *data, char *msg)
268 printk("%s%s\n", (char *)data, msg);
271 static int print_trace_stack(void *data, char *name)
277 * Print one address/symbol entries per line.
279 static void print_trace_address(void *data, unsigned long addr)
281 printk("%s [<%08lx>] ", (char *)data, addr);
282 print_symbol("%s\n", addr);
285 static struct stacktrace_ops print_trace_ops = {
286 .warning = print_trace_warning,
287 .warning_symbol = print_trace_warning_symbol,
288 .stack = print_trace_stack,
289 .address = print_trace_address,
293 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
294 unsigned long * stack, char *log_lvl)
296 dump_trace(task, regs, stack, &print_trace_ops, log_lvl);
297 printk("%s =======================\n", log_lvl);
300 void show_trace(struct task_struct *task, struct pt_regs *regs,
301 unsigned long * stack)
303 show_trace_log_lvl(task, regs, stack, "");
306 static void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
307 unsigned long *esp, char *log_lvl)
309 unsigned long *stack;
314 esp = (unsigned long*)task->thread.esp;
316 esp = (unsigned long *)&esp;
320 for(i = 0; i < kstack_depth_to_print; i++) {
321 if (kstack_end(stack))
323 if (i && ((i % 8) == 0))
324 printk("\n%s ", log_lvl);
325 printk("%08lx ", *stack++);
327 printk("\n%sCall Trace:\n", log_lvl);
328 show_trace_log_lvl(task, regs, esp, log_lvl);
331 void show_stack(struct task_struct *task, unsigned long *esp)
334 show_stack_log_lvl(task, NULL, esp, "");
338 * The architecture-independent dump_stack generator
340 void dump_stack(void)
344 show_trace(current, NULL, &stack);
347 EXPORT_SYMBOL(dump_stack);
349 void show_registers(struct pt_regs *regs)
356 esp = (unsigned long) (®s->esp);
358 if (user_mode_vm(regs)) {
361 ss = regs->xss & 0xffff;
364 printk(KERN_EMERG "CPU: %d\n"
365 KERN_EMERG "EIP: %04x:[<%08lx>] %s VLI\n"
366 KERN_EMERG "EFLAGS: %08lx (%s %.*s)\n",
367 smp_processor_id(), 0xffff & regs->xcs, regs->eip,
368 print_tainted(), regs->eflags, init_utsname()->release,
369 (int)strcspn(init_utsname()->version, " "),
370 init_utsname()->version);
371 print_symbol(KERN_EMERG "EIP is at %s\n", regs->eip);
372 printk(KERN_EMERG "eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
373 regs->eax, regs->ebx, regs->ecx, regs->edx);
374 printk(KERN_EMERG "esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
375 regs->esi, regs->edi, regs->ebp, esp);
376 printk(KERN_EMERG "ds: %04x es: %04x ss: %04x\n",
377 regs->xds & 0xffff, regs->xes & 0xffff, ss);
378 printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
379 TASK_COMM_LEN, current->comm, current->pid,
380 current_thread_info(), current, current->thread_info);
382 * When in-kernel, we also print out the stack and code at the
383 * time of the fault..
390 printk("\n" KERN_EMERG "Stack: ");
391 show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG);
393 printk(KERN_EMERG "Code: ");
395 eip = (u8 __user *)regs->eip - 43;
396 if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
397 /* try starting at EIP */
398 eip = (u8 __user *)regs->eip;
401 for (i = 0; i < code_bytes; i++, eip++) {
402 if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) {
403 printk(" Bad EIP value.");
406 if (eip == (u8 __user *)regs->eip)
407 printk("<%02x> ", c);
415 static void handle_BUG(struct pt_regs *regs)
417 unsigned long eip = regs->eip;
420 if (eip < PAGE_OFFSET)
422 if (probe_kernel_address((unsigned short __user *)eip, ud2))
427 printk(KERN_EMERG "------------[ cut here ]------------\n");
429 #ifdef CONFIG_DEBUG_BUGVERBOSE
435 if (probe_kernel_address((unsigned short __user *)(eip + 2),
438 if (__get_user(file, (char * __user *)(eip + 4)) ||
439 (unsigned long)file < PAGE_OFFSET || __get_user(c, file))
440 file = "<bad filename>";
442 printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
446 printk(KERN_EMERG "Kernel BUG at [verbose debug info unavailable]\n");
449 /* This is gone through when something in the kernel
450 * has done something bad and is about to be terminated.
452 void die(const char * str, struct pt_regs * regs, long err)
457 int lock_owner_depth;
459 .lock = SPIN_LOCK_UNLOCKED,
461 .lock_owner_depth = 0
463 static int die_counter;
468 if (die.lock_owner != raw_smp_processor_id()) {
470 spin_lock_irqsave(&die.lock, flags);
471 die.lock_owner = smp_processor_id();
472 die.lock_owner_depth = 0;
476 local_save_flags(flags);
478 if (++die.lock_owner_depth < 3) {
484 printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
485 #ifdef CONFIG_PREEMPT
486 printk(KERN_EMERG "PREEMPT ");
495 #ifdef CONFIG_DEBUG_PAGEALLOC
498 printk("DEBUG_PAGEALLOC");
503 if (notify_die(DIE_OOPS, str, regs, err,
504 current->thread.trap_no, SIGSEGV) !=
506 show_registers(regs);
507 /* Executive summary in case the oops scrolled away */
508 esp = (unsigned long) (®s->esp);
510 if (user_mode(regs)) {
512 ss = regs->xss & 0xffff;
514 printk(KERN_EMERG "EIP: [<%08lx>] ", regs->eip);
515 print_symbol("%s", regs->eip);
516 printk(" SS:ESP %04x:%08lx\n", ss, esp);
521 printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
525 spin_unlock_irqrestore(&die.lock, flags);
530 if (kexec_should_crash(current))
534 panic("Fatal exception in interrupt");
537 panic("Fatal exception");
543 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
545 if (!user_mode_vm(regs))
549 static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
550 struct pt_regs * regs, long error_code,
553 struct task_struct *tsk = current;
554 tsk->thread.error_code = error_code;
555 tsk->thread.trap_no = trapnr;
557 if (regs->eflags & VM_MASK) {
563 if (!user_mode(regs))
568 force_sig_info(signr, info, tsk);
570 force_sig(signr, tsk);
575 if (!fixup_exception(regs))
576 die(str, regs, error_code);
581 int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
582 if (ret) goto trap_signal;
587 #define DO_ERROR(trapnr, signr, str, name) \
588 fastcall void do_##name(struct pt_regs * regs, long error_code) \
590 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
593 do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
596 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
597 fastcall void do_##name(struct pt_regs * regs, long error_code) \
600 info.si_signo = signr; \
602 info.si_code = sicode; \
603 info.si_addr = (void __user *)siaddr; \
604 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
607 do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
610 #define DO_VM86_ERROR(trapnr, signr, str, name) \
611 fastcall void do_##name(struct pt_regs * regs, long error_code) \
613 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
616 do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
619 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
620 fastcall void do_##name(struct pt_regs * regs, long error_code) \
623 info.si_signo = signr; \
625 info.si_code = sicode; \
626 info.si_addr = (void __user *)siaddr; \
627 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
630 do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
633 DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip)
634 #ifndef CONFIG_KPROBES
635 DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
637 DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
638 DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
639 DO_ERROR_INFO( 6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->eip)
640 DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
641 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
642 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
643 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
644 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
645 DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0)
647 fastcall void __kprobes do_general_protection(struct pt_regs * regs,
651 struct tss_struct *tss = &per_cpu(init_tss, cpu);
652 struct thread_struct *thread = ¤t->thread;
655 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
656 * invalid offset set (the LAZY one) and the faulting thread has
657 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
658 * and we set the offset field correctly. Then we let the CPU to
659 * restart the faulting instruction.
661 if (tss->io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
662 thread->io_bitmap_ptr) {
663 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
664 thread->io_bitmap_max);
666 * If the previously set map was extending to higher ports
667 * than the current one, pad extra space with 0xff (no access).
669 if (thread->io_bitmap_max < tss->io_bitmap_max)
670 memset((char *) tss->io_bitmap +
671 thread->io_bitmap_max, 0xff,
672 tss->io_bitmap_max - thread->io_bitmap_max);
673 tss->io_bitmap_max = thread->io_bitmap_max;
674 tss->io_bitmap_base = IO_BITMAP_OFFSET;
675 tss->io_bitmap_owner = thread;
681 current->thread.error_code = error_code;
682 current->thread.trap_no = 13;
684 if (regs->eflags & VM_MASK)
687 if (!user_mode(regs))
690 current->thread.error_code = error_code;
691 current->thread.trap_no = 13;
692 force_sig(SIGSEGV, current);
697 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
701 if (!fixup_exception(regs)) {
702 if (notify_die(DIE_GPF, "general protection fault", regs,
703 error_code, 13, SIGSEGV) == NOTIFY_STOP)
705 die("general protection fault", regs, error_code);
709 static __kprobes void
710 mem_parity_error(unsigned char reason, struct pt_regs * regs)
712 printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
713 "CPU %d.\n", reason, smp_processor_id());
714 printk(KERN_EMERG "You probably have a hardware problem with your RAM "
716 if (panic_on_unrecovered_nmi)
717 panic("NMI: Not continuing");
719 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
721 /* Clear and disable the memory parity error line. */
722 clear_mem_error(reason);
725 static __kprobes void
726 io_check_error(unsigned char reason, struct pt_regs * regs)
730 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
731 show_registers(regs);
733 /* Re-enable the IOCK line, wait for a few seconds */
734 reason = (reason & 0xf) | 8;
737 while (--i) udelay(1000);
742 static __kprobes void
743 unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
746 /* Might actually be able to figure out what the guilty party
753 printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
754 "CPU %d.\n", reason, smp_processor_id());
755 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
756 if (panic_on_unrecovered_nmi)
757 panic("NMI: Not continuing");
759 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
762 static DEFINE_SPINLOCK(nmi_print_lock);
764 void __kprobes die_nmi(struct pt_regs *regs, const char *msg)
766 if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 2, SIGINT) ==
770 spin_lock(&nmi_print_lock);
772 * We are in trouble anyway, lets at least try
773 * to get a message out.
776 printk(KERN_EMERG "%s", msg);
777 printk(" on CPU%d, eip %08lx, registers:\n",
778 smp_processor_id(), regs->eip);
779 show_registers(regs);
780 printk(KERN_EMERG "console shuts up ...\n");
782 spin_unlock(&nmi_print_lock);
785 /* If we are in kernel we are probably nested up pretty bad
786 * and might aswell get out now while we still can.
788 if (!user_mode_vm(regs)) {
789 current->thread.trap_no = 2;
796 static __kprobes void default_do_nmi(struct pt_regs * regs)
798 unsigned char reason = 0;
800 /* Only the BSP gets external NMIs from the system. */
801 if (!smp_processor_id())
802 reason = get_nmi_reason();
804 if (!(reason & 0xc0)) {
805 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
808 #ifdef CONFIG_X86_LOCAL_APIC
810 * Ok, so this is none of the documented NMI sources,
811 * so it must be the NMI watchdog.
813 if (nmi_watchdog_tick(regs, reason))
815 if (!do_nmi_callback(regs, smp_processor_id()))
817 unknown_nmi_error(reason, regs);
821 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
824 mem_parity_error(reason, regs);
826 io_check_error(reason, regs);
828 * Reassert NMI in case it became active meanwhile
829 * as it's edge-triggered.
834 fastcall __kprobes void do_nmi(struct pt_regs * regs, long error_code)
840 cpu = smp_processor_id();
844 default_do_nmi(regs);
849 #ifdef CONFIG_KPROBES
850 fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
852 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
855 /* This is an interrupt gate, because kprobes wants interrupts
856 disabled. Normal trap handlers don't. */
857 restore_interrupts(regs);
858 do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
863 * Our handling of the processor debug registers is non-trivial.
864 * We do not clear them on entry and exit from the kernel. Therefore
865 * it is possible to get a watchpoint trap here from inside the kernel.
866 * However, the code in ./ptrace.c has ensured that the user can
867 * only set watchpoints on userspace addresses. Therefore the in-kernel
868 * watchpoint trap can only occur in code which is reading/writing
869 * from user space. Such code must not hold kernel locks (since it
870 * can equally take a page fault), therefore it is safe to call
871 * force_sig_info even though that claims and releases locks.
873 * Code in ./signal.c ensures that the debug control register
874 * is restored before we deliver any signal, and therefore that
875 * user code runs with the correct debug control register even though
878 * Being careful here means that we don't have to be as careful in a
879 * lot of more complicated places (task switching can be a bit lazy
880 * about restoring all the debug state, and ptrace doesn't have to
881 * find every occurrence of the TF bit that could be saved away even
884 fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)
886 unsigned int condition;
887 struct task_struct *tsk = current;
889 get_debugreg(condition, 6);
891 if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
892 SIGTRAP) == NOTIFY_STOP)
894 /* It's safe to allow irq's after DR6 has been saved */
895 if (regs->eflags & X86_EFLAGS_IF)
898 /* Mask out spurious debug traps due to lazy DR7 setting */
899 if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
900 if (!tsk->thread.debugreg[7])
904 if (regs->eflags & VM_MASK)
907 /* Save debug status register where ptrace can see it */
908 tsk->thread.debugreg[6] = condition;
911 * Single-stepping through TF: make sure we ignore any events in
912 * kernel space (but re-enable TF when returning to user mode).
914 if (condition & DR_STEP) {
916 * We already checked v86 mode above, so we can
917 * check for kernel mode by just checking the CPL
920 if (!user_mode(regs))
921 goto clear_TF_reenable;
924 /* Ok, finally something we can handle */
925 send_sigtrap(tsk, regs, error_code);
927 /* Disable additional traps. They'll be re-enabled when
928 * the signal is delivered.
935 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
939 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
940 regs->eflags &= ~TF_MASK;
945 * Note that we play around with the 'TS' bit in an attempt to get
946 * the correct behaviour even in the presence of the asynchronous
949 void math_error(void __user *eip)
951 struct task_struct * task;
953 unsigned short cwd, swd;
956 * Save the info for the exception handler and clear the error.
960 task->thread.trap_no = 16;
961 task->thread.error_code = 0;
962 info.si_signo = SIGFPE;
964 info.si_code = __SI_FAULT;
967 * (~cwd & swd) will mask out exceptions that are not set to unmasked
968 * status. 0x3f is the exception bits in these regs, 0x200 is the
969 * C1 reg you need in case of a stack fault, 0x040 is the stack
970 * fault bit. We should only be taking one exception at a time,
971 * so if this combination doesn't produce any single exception,
972 * then we have a bad program that isn't syncronizing its FPU usage
973 * and it will suffer the consequences since we won't be able to
974 * fully reproduce the context of the exception
976 cwd = get_fpu_cwd(task);
977 swd = get_fpu_swd(task);
978 switch (swd & ~cwd & 0x3f) {
979 case 0x000: /* No unmasked exception */
981 default: /* Multiple exceptions */
983 case 0x001: /* Invalid Op */
985 * swd & 0x240 == 0x040: Stack Underflow
986 * swd & 0x240 == 0x240: Stack Overflow
987 * User must clear the SF bit (0x40) if set
989 info.si_code = FPE_FLTINV;
991 case 0x002: /* Denormalize */
992 case 0x010: /* Underflow */
993 info.si_code = FPE_FLTUND;
995 case 0x004: /* Zero Divide */
996 info.si_code = FPE_FLTDIV;
998 case 0x008: /* Overflow */
999 info.si_code = FPE_FLTOVF;
1001 case 0x020: /* Precision */
1002 info.si_code = FPE_FLTRES;
1005 force_sig_info(SIGFPE, &info, task);
1008 fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code)
1011 math_error((void __user *)regs->eip);
1014 static void simd_math_error(void __user *eip)
1016 struct task_struct * task;
1018 unsigned short mxcsr;
1021 * Save the info for the exception handler and clear the error.
1024 save_init_fpu(task);
1025 task->thread.trap_no = 19;
1026 task->thread.error_code = 0;
1027 info.si_signo = SIGFPE;
1029 info.si_code = __SI_FAULT;
1032 * The SIMD FPU exceptions are handled a little differently, as there
1033 * is only a single status/control register. Thus, to determine which
1034 * unmasked exception was caught we must mask the exception mask bits
1035 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
1037 mxcsr = get_fpu_mxcsr(task);
1038 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
1042 case 0x001: /* Invalid Op */
1043 info.si_code = FPE_FLTINV;
1045 case 0x002: /* Denormalize */
1046 case 0x010: /* Underflow */
1047 info.si_code = FPE_FLTUND;
1049 case 0x004: /* Zero Divide */
1050 info.si_code = FPE_FLTDIV;
1052 case 0x008: /* Overflow */
1053 info.si_code = FPE_FLTOVF;
1055 case 0x020: /* Precision */
1056 info.si_code = FPE_FLTRES;
1059 force_sig_info(SIGFPE, &info, task);
1062 fastcall void do_simd_coprocessor_error(struct pt_regs * regs,
1066 /* Handle SIMD FPU exceptions on PIII+ processors. */
1068 simd_math_error((void __user *)regs->eip);
1071 * Handle strange cache flush from user space exception
1072 * in all other cases. This is undocumented behaviour.
1074 if (regs->eflags & VM_MASK) {
1075 handle_vm86_fault((struct kernel_vm86_regs *)regs,
1079 current->thread.trap_no = 19;
1080 current->thread.error_code = error_code;
1081 die_if_kernel("cache flush denied", regs, error_code);
1082 force_sig(SIGSEGV, current);
1086 fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
1090 /* No need to warn about this any longer. */
1091 printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
1095 fastcall void setup_x86_bogus_stack(unsigned char * stk)
1097 unsigned long *switch16_ptr, *switch32_ptr;
1098 struct pt_regs *regs;
1099 unsigned long stack_top, stack_bot;
1100 unsigned short iret_frame16_off;
1101 int cpu = smp_processor_id();
1102 /* reserve the space on 32bit stack for the magic switch16 pointer */
1103 memmove(stk, stk + 8, sizeof(struct pt_regs));
1104 switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs));
1105 regs = (struct pt_regs *)stk;
1106 /* now the switch32 on 16bit stack */
1107 stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
1108 stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
1109 switch32_ptr = (unsigned long *)(stack_top - 8);
1110 iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20;
1111 /* copy iret frame on 16bit stack */
1112 memcpy((void *)(stack_bot + iret_frame16_off), ®s->eip, 20);
1113 /* fill in the switch pointers */
1114 switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off;
1115 switch16_ptr[1] = __ESPFIX_SS;
1116 switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) +
1117 8 - CPU_16BIT_STACK_SIZE;
1118 switch32_ptr[1] = __KERNEL_DS;
1121 fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp)
1123 unsigned long *switch32_ptr;
1124 unsigned char *stack16, *stack32;
1125 unsigned long stack_top, stack_bot;
1127 int cpu = smp_processor_id();
1128 stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
1129 stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
1130 switch32_ptr = (unsigned long *)(stack_top - 8);
1131 /* copy the data from 16bit stack to 32bit stack */
1132 len = CPU_16BIT_STACK_SIZE - 8 - sp;
1133 stack16 = (unsigned char *)(stack_bot + sp);
1134 stack32 = (unsigned char *)
1135 (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len);
1136 memcpy(stack32, stack16, len);
1141 * 'math_state_restore()' saves the current math information in the
1142 * old math state array, and gets the new ones from the current task
1144 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1145 * Don't touch unless you *really* know how it works.
1147 * Must be called with kernel preemption disabled (in this case,
1148 * local interrupts are disabled at the call-site in entry.S).
1150 asmlinkage void math_state_restore(struct pt_regs regs)
1152 struct thread_info *thread = current_thread_info();
1153 struct task_struct *tsk = thread->task;
1155 clts(); /* Allow maths ops (or we recurse) */
1156 if (!tsk_used_math(tsk))
1159 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
1162 #ifndef CONFIG_MATH_EMULATION
1164 asmlinkage void math_emulate(long arg)
1166 printk(KERN_EMERG "math-emulation not enabled and no coprocessor found.\n");
1167 printk(KERN_EMERG "killing %s.\n",current->comm);
1168 force_sig(SIGFPE,current);
1172 #endif /* CONFIG_MATH_EMULATION */
1174 #ifdef CONFIG_X86_F00F_BUG
1175 void __init trap_init_f00f_bug(void)
1177 __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
1180 * Update the IDT descriptor and reload the IDT so that
1181 * it uses the read-only mapped virtual address.
1183 idt_descr.address = fix_to_virt(FIX_F00F_IDT);
1184 load_idt(&idt_descr);
1189 * This needs to use 'idt_table' rather than 'idt', and
1190 * thus use the _nonmapped_ version of the IDT, as the
1191 * Pentium F0 0F bugfix can have resulted in the mapped
1192 * IDT being write-protected.
1194 void set_intr_gate(unsigned int n, void *addr)
1196 _set_gate(n, DESCTYPE_INT, addr, __KERNEL_CS);
1200 * This routine sets up an interrupt gate at directory privilege level 3.
1202 static inline void set_system_intr_gate(unsigned int n, void *addr)
1204 _set_gate(n, DESCTYPE_INT | DESCTYPE_DPL3, addr, __KERNEL_CS);
1207 static void __init set_trap_gate(unsigned int n, void *addr)
1209 _set_gate(n, DESCTYPE_TRAP, addr, __KERNEL_CS);
1212 static void __init set_system_gate(unsigned int n, void *addr)
1214 _set_gate(n, DESCTYPE_TRAP | DESCTYPE_DPL3, addr, __KERNEL_CS);
1217 static void __init set_task_gate(unsigned int n, unsigned int gdt_entry)
1219 _set_gate(n, DESCTYPE_TASK, (void *)0, (gdt_entry<<3));
1223 void __init trap_init(void)
1226 void __iomem *p = ioremap(0x0FFFD9, 4);
1227 if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
1233 #ifdef CONFIG_X86_LOCAL_APIC
1234 init_apic_mappings();
1237 set_trap_gate(0,÷_error);
1238 set_intr_gate(1,&debug);
1239 set_intr_gate(2,&nmi);
1240 set_system_intr_gate(3, &int3); /* int3/4 can be called from all */
1241 set_system_gate(4,&overflow);
1242 set_trap_gate(5,&bounds);
1243 set_trap_gate(6,&invalid_op);
1244 set_trap_gate(7,&device_not_available);
1245 set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS);
1246 set_trap_gate(9,&coprocessor_segment_overrun);
1247 set_trap_gate(10,&invalid_TSS);
1248 set_trap_gate(11,&segment_not_present);
1249 set_trap_gate(12,&stack_segment);
1250 set_trap_gate(13,&general_protection);
1251 set_intr_gate(14,&page_fault);
1252 set_trap_gate(15,&spurious_interrupt_bug);
1253 set_trap_gate(16,&coprocessor_error);
1254 set_trap_gate(17,&alignment_check);
1255 #ifdef CONFIG_X86_MCE
1256 set_trap_gate(18,&machine_check);
1258 set_trap_gate(19,&simd_coprocessor_error);
1262 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
1263 * Generates a compile-time "error: zero width for bit-field" if
1264 * the alignment is wrong.
1266 struct fxsrAlignAssert {
1267 int _:!(offsetof(struct task_struct,
1268 thread.i387.fxsave) & 15);
1271 printk(KERN_INFO "Enabling fast FPU save and restore... ");
1272 set_in_cr4(X86_CR4_OSFXSR);
1276 printk(KERN_INFO "Enabling unmasked SIMD FPU exception "
1278 set_in_cr4(X86_CR4_OSXMMEXCPT);
1282 set_system_gate(SYSCALL_VECTOR,&system_call);
1285 * Should be a barrier for any external CPU state.
1292 static int __init kstack_setup(char *s)
1294 kstack_depth_to_print = simple_strtoul(s, NULL, 0);
1297 __setup("kstack=", kstack_setup);
1299 #ifdef CONFIG_STACK_UNWIND
1300 static int __init call_trace_setup(char *s)
1302 if (strcmp(s, "old") == 0)
1304 else if (strcmp(s, "both") == 0)
1306 else if (strcmp(s, "newfallback") == 0)
1308 else if (strcmp(s, "new") == 2)
1312 __setup("call_trace=", call_trace_setup);