2 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Pentium III FXSR, SSE support
5 * Gareth Hughes <gareth@valinux.com>, May 2000
9 * 'Traps.c' handles hardware traps and faults after we have saved some
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/errno.h>
16 #include <linux/timer.h>
18 #include <linux/init.h>
19 #include <linux/delay.h>
20 #include <linux/spinlock.h>
21 #include <linux/interrupt.h>
22 #include <linux/highmem.h>
23 #include <linux/kallsyms.h>
24 #include <linux/ptrace.h>
25 #include <linux/utsname.h>
26 #include <linux/kprobes.h>
27 #include <linux/kexec.h>
28 #include <linux/unwind.h>
29 #include <linux/uaccess.h>
30 #include <linux/nmi.h>
31 #include <linux/bug.h>
34 #include <linux/ioport.h>
35 #include <linux/eisa.h>
39 #include <linux/mca.h>
42 #if defined(CONFIG_EDAC)
43 #include <linux/edac.h>
46 #include <asm/processor.h>
47 #include <asm/system.h>
49 #include <asm/atomic.h>
50 #include <asm/debugreg.h>
54 #include <asm/unwind.h>
56 #include <asm/arch_hooks.h>
57 #include <linux/kdebug.h>
58 #include <asm/stacktrace.h>
60 #include <linux/module.h>
62 #include "mach_traps.h"
64 int panic_on_unrecovered_nmi;
66 DECLARE_BITMAP(used_vectors, NR_VECTORS);
67 EXPORT_SYMBOL_GPL(used_vectors);
69 asmlinkage int system_call(void);
71 /* Do we ignore FPU interrupts ? */
72 char ignore_fpu_irq = 0;
75 * The IDT has to be page-aligned to simplify the Pentium
76 * F0 0F bug workaround.. We have a special link segment
79 gate_desc idt_table[256]
80 __attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, };
82 asmlinkage void divide_error(void);
83 asmlinkage void debug(void);
84 asmlinkage void nmi(void);
85 asmlinkage void int3(void);
86 asmlinkage void overflow(void);
87 asmlinkage void bounds(void);
88 asmlinkage void invalid_op(void);
89 asmlinkage void device_not_available(void);
90 asmlinkage void coprocessor_segment_overrun(void);
91 asmlinkage void invalid_TSS(void);
92 asmlinkage void segment_not_present(void);
93 asmlinkage void stack_segment(void);
94 asmlinkage void general_protection(void);
95 asmlinkage void page_fault(void);
96 asmlinkage void coprocessor_error(void);
97 asmlinkage void simd_coprocessor_error(void);
98 asmlinkage void alignment_check(void);
99 asmlinkage void spurious_interrupt_bug(void);
100 asmlinkage void machine_check(void);
102 int kstack_depth_to_print = 24;
103 static unsigned int code_bytes = 64;
105 void printk_address(unsigned long address, int reliable)
107 #ifdef CONFIG_KALLSYMS
108 unsigned long offset = 0, symsize;
115 symname = kallsyms_lookup(address, &symsize, &offset,
118 printk(" [<%08lx>]\n", address);
122 strcpy(reliab, "? ");
125 modname = delim = "";
126 printk(" [<%08lx>] %s%s%s%s%s+0x%lx/0x%lx\n",
127 address, reliab, delim, modname, delim, symname, offset, symsize);
129 printk(" [<%08lx>]\n", address);
133 static inline int valid_stack_ptr(struct thread_info *tinfo, void *p, unsigned size)
135 return p > (void *)tinfo &&
136 p <= (void *)tinfo + THREAD_SIZE - size;
139 /* The form of the top of the frame on the stack */
141 struct stack_frame *next_frame;
142 unsigned long return_address;
145 static inline unsigned long print_context_stack(struct thread_info *tinfo,
146 unsigned long *stack, unsigned long bp,
147 const struct stacktrace_ops *ops, void *data)
149 struct stack_frame *frame = (struct stack_frame *)bp;
151 while (valid_stack_ptr(tinfo, stack, sizeof(*stack))) {
155 if (__kernel_text_address(addr)) {
156 if ((unsigned long) stack == bp + 4) {
157 ops->address(data, addr, 1);
158 frame = frame->next_frame;
159 bp = (unsigned long) frame;
161 ops->address(data, addr, bp == 0);
169 #define MSG(msg) ops->warning(data, msg)
171 void dump_trace(struct task_struct *task, struct pt_regs *regs,
172 unsigned long *stack, unsigned long bp,
173 const struct stacktrace_ops *ops, void *data)
182 stack = (unsigned long *)task->thread.sp;
185 #ifdef CONFIG_FRAME_POINTER
187 if (task == current) {
188 /* Grab bp right from our regs */
189 asm ("movl %%ebp, %0" : "=r" (bp) : );
191 /* bp is the last reg pushed by switch_to */
192 bp = *(unsigned long *) task->thread.sp;
198 struct thread_info *context;
199 context = (struct thread_info *)
200 ((unsigned long)stack & (~(THREAD_SIZE - 1)));
201 bp = print_context_stack(context, stack, bp, ops, data);
202 /* Should be after the line below, but somewhere
203 in early boot context comes out corrupted and we
204 can't reference it -AK */
205 if (ops->stack(data, "IRQ") < 0)
207 stack = (unsigned long*)context->previous_esp;
210 touch_nmi_watchdog();
213 EXPORT_SYMBOL(dump_trace);
216 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
219 print_symbol(msg, symbol);
223 static void print_trace_warning(void *data, char *msg)
225 printk("%s%s\n", (char *)data, msg);
228 static int print_trace_stack(void *data, char *name)
234 * Print one address/symbol entries per line.
236 static void print_trace_address(void *data, unsigned long addr, int reliable)
238 printk("%s [<%08lx>] ", (char *)data, addr);
241 print_symbol("%s\n", addr);
242 touch_nmi_watchdog();
245 static const struct stacktrace_ops print_trace_ops = {
246 .warning = print_trace_warning,
247 .warning_symbol = print_trace_warning_symbol,
248 .stack = print_trace_stack,
249 .address = print_trace_address,
253 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
254 unsigned long *stack, unsigned long bp, char *log_lvl)
256 dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
257 printk("%s =======================\n", log_lvl);
260 void show_trace(struct task_struct *task, struct pt_regs *regs,
261 unsigned long *stack, unsigned long bp)
263 show_trace_log_lvl(task, regs, stack, bp, "");
266 static void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
267 unsigned long *sp, unsigned long bp, char *log_lvl)
269 unsigned long *stack;
274 sp = (unsigned long*)task->thread.sp;
276 sp = (unsigned long *)&sp;
280 for(i = 0; i < kstack_depth_to_print; i++) {
281 if (kstack_end(stack))
283 if (i && ((i % 8) == 0))
284 printk("\n%s ", log_lvl);
285 printk("%08lx ", *stack++);
287 printk("\n%sCall Trace:\n", log_lvl);
288 show_trace_log_lvl(task, regs, sp, bp, log_lvl);
291 void show_stack(struct task_struct *task, unsigned long *sp)
294 show_stack_log_lvl(task, NULL, sp, 0, "");
298 * The architecture-independent dump_stack generator
300 void dump_stack(void)
303 unsigned long bp = 0;
305 #ifdef CONFIG_FRAME_POINTER
307 asm("movl %%ebp, %0" : "=r" (bp):);
310 printk("Pid: %d, comm: %.20s %s %s %.*s\n",
311 current->pid, current->comm, print_tainted(),
312 init_utsname()->release,
313 (int)strcspn(init_utsname()->version, " "),
314 init_utsname()->version);
315 show_trace(current, NULL, &stack, bp);
318 EXPORT_SYMBOL(dump_stack);
320 void show_registers(struct pt_regs *regs)
325 __show_registers(regs, 0);
326 printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
327 TASK_COMM_LEN, current->comm, task_pid_nr(current),
328 current_thread_info(), current, task_thread_info(current));
330 * When in-kernel, we also print out the stack and code at the
331 * time of the fault..
333 if (!user_mode_vm(regs)) {
335 unsigned int code_prologue = code_bytes * 43 / 64;
336 unsigned int code_len = code_bytes;
339 printk("\n" KERN_EMERG "Stack: ");
340 show_stack_log_lvl(NULL, regs, ®s->sp, 0, KERN_EMERG);
342 printk(KERN_EMERG "Code: ");
344 ip = (u8 *)regs->ip - code_prologue;
345 if (ip < (u8 *)PAGE_OFFSET ||
346 probe_kernel_address(ip, c)) {
347 /* try starting at EIP */
349 code_len = code_len - code_prologue + 1;
351 for (i = 0; i < code_len; i++, ip++) {
352 if (ip < (u8 *)PAGE_OFFSET ||
353 probe_kernel_address(ip, c)) {
354 printk(" Bad EIP value.");
357 if (ip == (u8 *)regs->ip)
358 printk("<%02x> ", c);
366 int is_valid_bugaddr(unsigned long ip)
370 if (ip < PAGE_OFFSET)
372 if (probe_kernel_address((unsigned short *)ip, ud2))
375 return ud2 == 0x0b0f;
378 static int die_counter;
380 int __kprobes __die(const char * str, struct pt_regs * regs, long err)
385 printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
386 #ifdef CONFIG_PREEMPT
392 #ifdef CONFIG_DEBUG_PAGEALLOC
393 printk("DEBUG_PAGEALLOC");
397 if (notify_die(DIE_OOPS, str, regs, err,
398 current->thread.trap_no, SIGSEGV) !=
400 show_registers(regs);
401 /* Executive summary in case the oops scrolled away */
402 sp = (unsigned long) (®s->sp);
404 if (user_mode(regs)) {
406 ss = regs->ss & 0xffff;
408 printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
409 print_symbol("%s", regs->ip);
410 printk(" SS:ESP %04x:%08lx\n", ss, sp);
418 * This is gone through when something in the kernel has done something bad and
419 * is about to be terminated.
421 void die(const char * str, struct pt_regs * regs, long err)
426 int lock_owner_depth;
428 .lock = __RAW_SPIN_LOCK_UNLOCKED,
430 .lock_owner_depth = 0
436 if (die.lock_owner != raw_smp_processor_id()) {
438 raw_local_irq_save(flags);
439 __raw_spin_lock(&die.lock);
440 die.lock_owner = smp_processor_id();
441 die.lock_owner_depth = 0;
444 raw_local_irq_save(flags);
446 if (++die.lock_owner_depth < 3) {
447 report_bug(regs->ip, regs);
449 if (__die(str, regs, err))
452 printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
457 add_taint(TAINT_DIE);
458 __raw_spin_unlock(&die.lock);
459 raw_local_irq_restore(flags);
464 if (kexec_should_crash(current))
468 panic("Fatal exception in interrupt");
471 panic("Fatal exception");
477 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
479 if (!user_mode_vm(regs))
483 static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
484 struct pt_regs * regs, long error_code,
487 struct task_struct *tsk = current;
489 if (regs->flags & VM_MASK) {
495 if (!user_mode(regs))
500 * We want error_code and trap_no set for userspace faults and
501 * kernelspace faults which result in die(), but not
502 * kernelspace faults which are fixed up. die() gives the
503 * process no chance to handle the signal and notice the
504 * kernel fault information, so that won't result in polluting
505 * the information about previously queued, but not yet
506 * delivered, faults. See also do_general_protection below.
508 tsk->thread.error_code = error_code;
509 tsk->thread.trap_no = trapnr;
512 force_sig_info(signr, info, tsk);
514 force_sig(signr, tsk);
519 if (!fixup_exception(regs)) {
520 tsk->thread.error_code = error_code;
521 tsk->thread.trap_no = trapnr;
522 die(str, regs, error_code);
528 int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
529 if (ret) goto trap_signal;
534 #define DO_ERROR(trapnr, signr, str, name) \
535 void do_##name(struct pt_regs * regs, long error_code) \
537 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
540 do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
543 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr, irq) \
544 void do_##name(struct pt_regs * regs, long error_code) \
548 local_irq_enable(); \
549 info.si_signo = signr; \
551 info.si_code = sicode; \
552 info.si_addr = (void __user *)siaddr; \
553 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
556 do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
559 #define DO_VM86_ERROR(trapnr, signr, str, name) \
560 void do_##name(struct pt_regs * regs, long error_code) \
562 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
565 do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
568 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
569 void do_##name(struct pt_regs * regs, long error_code) \
572 info.si_signo = signr; \
574 info.si_code = sicode; \
575 info.si_addr = (void __user *)siaddr; \
576 trace_hardirqs_fixup(); \
577 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
580 do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
583 DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
584 #ifndef CONFIG_KPROBES
585 DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
587 DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
588 DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
589 DO_ERROR_INFO( 6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip, 0)
590 DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
591 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
592 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
593 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
594 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
595 DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1)
597 void __kprobes do_general_protection(struct pt_regs * regs,
601 struct tss_struct *tss = &per_cpu(init_tss, cpu);
602 struct thread_struct *thread = ¤t->thread;
605 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
606 * invalid offset set (the LAZY one) and the faulting thread has
607 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
608 * and we set the offset field correctly. Then we let the CPU to
609 * restart the faulting instruction.
611 if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
612 thread->io_bitmap_ptr) {
613 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
614 thread->io_bitmap_max);
616 * If the previously set map was extending to higher ports
617 * than the current one, pad extra space with 0xff (no access).
619 if (thread->io_bitmap_max < tss->io_bitmap_max)
620 memset((char *) tss->io_bitmap +
621 thread->io_bitmap_max, 0xff,
622 tss->io_bitmap_max - thread->io_bitmap_max);
623 tss->io_bitmap_max = thread->io_bitmap_max;
624 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
625 tss->io_bitmap_owner = thread;
631 if (regs->flags & VM_MASK)
634 if (!user_mode(regs))
637 current->thread.error_code = error_code;
638 current->thread.trap_no = 13;
639 if (show_unhandled_signals && unhandled_signal(current, SIGSEGV) &&
640 printk_ratelimit()) {
642 "%s[%d] general protection ip:%lx sp:%lx error:%lx",
643 current->comm, task_pid_nr(current),
644 regs->ip, regs->sp, error_code);
645 print_vma_addr(" in ", regs->ip);
649 force_sig(SIGSEGV, current);
654 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
658 if (!fixup_exception(regs)) {
659 current->thread.error_code = error_code;
660 current->thread.trap_no = 13;
661 if (notify_die(DIE_GPF, "general protection fault", regs,
662 error_code, 13, SIGSEGV) == NOTIFY_STOP)
664 die("general protection fault", regs, error_code);
668 static __kprobes void
669 mem_parity_error(unsigned char reason, struct pt_regs * regs)
671 printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
672 "CPU %d.\n", reason, smp_processor_id());
673 printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n");
675 #if defined(CONFIG_EDAC)
676 if(edac_handler_set()) {
677 edac_atomic_assert_error();
682 if (panic_on_unrecovered_nmi)
683 panic("NMI: Not continuing");
685 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
687 /* Clear and disable the memory parity error line. */
688 clear_mem_error(reason);
691 static __kprobes void
692 io_check_error(unsigned char reason, struct pt_regs * regs)
696 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
697 show_registers(regs);
699 /* Re-enable the IOCK line, wait for a few seconds */
700 reason = (reason & 0xf) | 8;
703 while (--i) udelay(1000);
708 static __kprobes void
709 unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
711 if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
714 /* Might actually be able to figure out what the guilty party
721 printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
722 "CPU %d.\n", reason, smp_processor_id());
723 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
724 if (panic_on_unrecovered_nmi)
725 panic("NMI: Not continuing");
727 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
730 static DEFINE_SPINLOCK(nmi_print_lock);
732 void __kprobes die_nmi(struct pt_regs *regs, const char *msg)
734 if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 2, SIGINT) ==
738 spin_lock(&nmi_print_lock);
740 * We are in trouble anyway, lets at least try
741 * to get a message out.
744 printk(KERN_EMERG "%s", msg);
745 printk(" on CPU%d, ip %08lx, registers:\n",
746 smp_processor_id(), regs->ip);
747 show_registers(regs);
749 spin_unlock(&nmi_print_lock);
752 /* If we are in kernel we are probably nested up pretty bad
753 * and might aswell get out now while we still can.
755 if (!user_mode_vm(regs)) {
756 current->thread.trap_no = 2;
763 static __kprobes void default_do_nmi(struct pt_regs * regs)
765 unsigned char reason = 0;
767 /* Only the BSP gets external NMIs from the system. */
768 if (!smp_processor_id())
769 reason = get_nmi_reason();
771 if (!(reason & 0xc0)) {
772 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
775 #ifdef CONFIG_X86_LOCAL_APIC
777 * Ok, so this is none of the documented NMI sources,
778 * so it must be the NMI watchdog.
780 if (nmi_watchdog_tick(regs, reason))
782 if (!do_nmi_callback(regs, smp_processor_id()))
784 unknown_nmi_error(reason, regs);
788 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
791 mem_parity_error(reason, regs);
793 io_check_error(reason, regs);
795 * Reassert NMI in case it became active meanwhile
796 * as it's edge-triggered.
801 static int ignore_nmis;
803 __kprobes void do_nmi(struct pt_regs * regs, long error_code)
809 cpu = smp_processor_id();
814 default_do_nmi(regs);
825 void restart_nmi(void)
831 #ifdef CONFIG_KPROBES
832 void __kprobes do_int3(struct pt_regs *regs, long error_code)
834 trace_hardirqs_fixup();
836 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
839 /* This is an interrupt gate, because kprobes wants interrupts
840 disabled. Normal trap handlers don't. */
841 restore_interrupts(regs);
842 do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
847 * Our handling of the processor debug registers is non-trivial.
848 * We do not clear them on entry and exit from the kernel. Therefore
849 * it is possible to get a watchpoint trap here from inside the kernel.
850 * However, the code in ./ptrace.c has ensured that the user can
851 * only set watchpoints on userspace addresses. Therefore the in-kernel
852 * watchpoint trap can only occur in code which is reading/writing
853 * from user space. Such code must not hold kernel locks (since it
854 * can equally take a page fault), therefore it is safe to call
855 * force_sig_info even though that claims and releases locks.
857 * Code in ./signal.c ensures that the debug control register
858 * is restored before we deliver any signal, and therefore that
859 * user code runs with the correct debug control register even though
862 * Being careful here means that we don't have to be as careful in a
863 * lot of more complicated places (task switching can be a bit lazy
864 * about restoring all the debug state, and ptrace doesn't have to
865 * find every occurrence of the TF bit that could be saved away even
868 void __kprobes do_debug(struct pt_regs * regs, long error_code)
870 unsigned int condition;
871 struct task_struct *tsk = current;
873 trace_hardirqs_fixup();
875 get_debugreg(condition, 6);
878 * The processor cleared BTF, so don't mark that we need it set.
880 clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
881 tsk->thread.debugctlmsr = 0;
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->flags & 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.debugreg7)
896 if (regs->flags & VM_MASK)
899 /* Save debug status register where ptrace can see it */
900 tsk->thread.debugreg6 = 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->flags &= ~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 *ip)
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 void do_coprocessor_error(struct pt_regs * regs, long error_code)
1003 math_error((void __user *)regs->ip);
1006 static void simd_math_error(void __user *ip)
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 void do_simd_coprocessor_error(struct pt_regs * regs,
1058 /* Handle SIMD FPU exceptions on PIII+ processors. */
1060 simd_math_error((void __user *)regs->ip);
1063 * Handle strange cache flush from user space exception
1064 * in all other cases. This is undocumented behaviour.
1066 if (regs->flags & 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 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 unsigned long patch_espfix_desc(unsigned long uesp,
1090 struct desc_struct *gdt = __get_cpu_var(gdt_page).gdt;
1091 unsigned long base = (kesp - uesp) & -THREAD_SIZE;
1092 unsigned long new_kesp = kesp - base;
1093 unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
1094 __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
1095 /* Set up base for espfix segment */
1096 desc &= 0x00f0ff0000000000ULL;
1097 desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
1098 ((((__u64)base) << 32) & 0xff00000000000000ULL) |
1099 ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
1100 (lim_pages & 0xffff);
1101 *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
1106 * 'math_state_restore()' saves the current math information in the
1107 * old math state array, and gets the new ones from the current task
1109 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1110 * Don't touch unless you *really* know how it works.
1112 * Must be called with kernel preemption disabled (in this case,
1113 * local interrupts are disabled at the call-site in entry.S).
1115 asmlinkage void math_state_restore(void)
1117 struct thread_info *thread = current_thread_info();
1118 struct task_struct *tsk = thread->task;
1120 clts(); /* Allow maths ops (or we recurse) */
1121 if (!tsk_used_math(tsk))
1124 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
1127 EXPORT_SYMBOL_GPL(math_state_restore);
1129 #ifndef CONFIG_MATH_EMULATION
1131 asmlinkage void math_emulate(long arg)
1133 printk(KERN_EMERG "math-emulation not enabled and no coprocessor found.\n");
1134 printk(KERN_EMERG "killing %s.\n",current->comm);
1135 force_sig(SIGFPE,current);
1139 #endif /* CONFIG_MATH_EMULATION */
1142 void __init trap_init(void)
1147 void __iomem *p = early_ioremap(0x0FFFD9, 4);
1148 if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
1151 early_iounmap(p, 4);
1154 #ifdef CONFIG_X86_LOCAL_APIC
1155 init_apic_mappings();
1158 set_trap_gate(0,÷_error);
1159 set_intr_gate(1,&debug);
1160 set_intr_gate(2,&nmi);
1161 set_system_intr_gate(3, &int3); /* int3/4 can be called from all */
1162 set_system_gate(4,&overflow);
1163 set_trap_gate(5,&bounds);
1164 set_trap_gate(6,&invalid_op);
1165 set_trap_gate(7,&device_not_available);
1166 set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS);
1167 set_trap_gate(9,&coprocessor_segment_overrun);
1168 set_trap_gate(10,&invalid_TSS);
1169 set_trap_gate(11,&segment_not_present);
1170 set_trap_gate(12,&stack_segment);
1171 set_trap_gate(13,&general_protection);
1172 set_intr_gate(14,&page_fault);
1173 set_trap_gate(15,&spurious_interrupt_bug);
1174 set_trap_gate(16,&coprocessor_error);
1175 set_trap_gate(17,&alignment_check);
1176 #ifdef CONFIG_X86_MCE
1177 set_trap_gate(18,&machine_check);
1179 set_trap_gate(19,&simd_coprocessor_error);
1182 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
1183 * Generate a build-time error if the alignment is wrong.
1185 BUILD_BUG_ON(offsetof(struct task_struct, thread.i387.fxsave) & 15);
1187 printk(KERN_INFO "Enabling fast FPU save and restore... ");
1188 set_in_cr4(X86_CR4_OSFXSR);
1192 printk(KERN_INFO "Enabling unmasked SIMD FPU exception "
1194 set_in_cr4(X86_CR4_OSXMMEXCPT);
1198 set_system_gate(SYSCALL_VECTOR,&system_call);
1200 /* Reserve all the builtin and the syscall vector. */
1201 for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
1202 set_bit(i, used_vectors);
1203 set_bit(SYSCALL_VECTOR, used_vectors);
1206 * Should be a barrier for any external CPU state.
1213 static int __init kstack_setup(char *s)
1215 kstack_depth_to_print = simple_strtoul(s, NULL, 0);
1218 __setup("kstack=", kstack_setup);
1220 static int __init code_bytes_setup(char *s)
1222 code_bytes = simple_strtoul(s, NULL, 0);
1223 if (code_bytes > 8192)
1228 __setup("code_bytes=", code_bytes_setup);