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>
32 #include <linux/nmi.h>
33 #include <linux/bug.h>
36 #include <linux/ioport.h>
37 #include <linux/eisa.h>
41 #include <linux/mca.h>
44 #include <asm/processor.h>
45 #include <asm/system.h>
47 #include <asm/atomic.h>
48 #include <asm/debugreg.h>
52 #include <asm/unwind.h>
54 #include <asm/arch_hooks.h>
55 #include <linux/kdebug.h>
56 #include <asm/stacktrace.h>
58 #include <linux/module.h>
60 #include "mach_traps.h"
62 int panic_on_unrecovered_nmi;
64 asmlinkage int system_call(void);
66 /* Do we ignore FPU interrupts ? */
67 char ignore_fpu_irq = 0;
70 * The IDT has to be page-aligned to simplify the Pentium
71 * F0 0F bug workaround.. We have a special link segment
74 struct desc_struct idt_table[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, };
76 asmlinkage void divide_error(void);
77 asmlinkage void debug(void);
78 asmlinkage void nmi(void);
79 asmlinkage void int3(void);
80 asmlinkage void overflow(void);
81 asmlinkage void bounds(void);
82 asmlinkage void invalid_op(void);
83 asmlinkage void device_not_available(void);
84 asmlinkage void coprocessor_segment_overrun(void);
85 asmlinkage void invalid_TSS(void);
86 asmlinkage void segment_not_present(void);
87 asmlinkage void stack_segment(void);
88 asmlinkage void general_protection(void);
89 asmlinkage void page_fault(void);
90 asmlinkage void coprocessor_error(void);
91 asmlinkage void simd_coprocessor_error(void);
92 asmlinkage void alignment_check(void);
93 asmlinkage void spurious_interrupt_bug(void);
94 asmlinkage void machine_check(void);
96 int kstack_depth_to_print = 24;
97 static unsigned int code_bytes = 64;
99 static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
101 return p > (void *)tinfo &&
102 p < (void *)tinfo + THREAD_SIZE - 3;
105 static inline unsigned long print_context_stack(struct thread_info *tinfo,
106 unsigned long *stack, unsigned long ebp,
107 struct stacktrace_ops *ops, void *data)
111 #ifdef CONFIG_FRAME_POINTER
112 while (valid_stack_ptr(tinfo, (void *)ebp)) {
113 unsigned long new_ebp;
114 addr = *(unsigned long *)(ebp + 4);
115 ops->address(data, addr);
117 * break out of recursive entries (such as
118 * end_of_stack_stop_unwind_function). Also,
119 * we can never allow a frame pointer to
122 new_ebp = *(unsigned long *)ebp;
128 while (valid_stack_ptr(tinfo, stack)) {
130 if (__kernel_text_address(addr))
131 ops->address(data, addr);
137 #define MSG(msg) ops->warning(data, msg)
139 void dump_trace(struct task_struct *task, struct pt_regs *regs,
140 unsigned long *stack,
141 struct stacktrace_ops *ops, void *data)
143 unsigned long ebp = 0;
151 if (task && task != current)
152 stack = (unsigned long *)task->thread.esp;
155 #ifdef CONFIG_FRAME_POINTER
157 if (task == current) {
158 /* Grab ebp right from our regs */
159 asm ("movl %%ebp, %0" : "=r" (ebp) : );
161 /* ebp is the last reg pushed by switch_to */
162 ebp = *(unsigned long *) task->thread.esp;
168 struct thread_info *context;
169 context = (struct thread_info *)
170 ((unsigned long)stack & (~(THREAD_SIZE - 1)));
171 ebp = print_context_stack(context, stack, ebp, ops, data);
172 /* Should be after the line below, but somewhere
173 in early boot context comes out corrupted and we
174 can't reference it -AK */
175 if (ops->stack(data, "IRQ") < 0)
177 stack = (unsigned long*)context->previous_esp;
180 touch_nmi_watchdog();
183 EXPORT_SYMBOL(dump_trace);
186 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
189 print_symbol(msg, symbol);
193 static void print_trace_warning(void *data, char *msg)
195 printk("%s%s\n", (char *)data, msg);
198 static int print_trace_stack(void *data, char *name)
204 * Print one address/symbol entries per line.
206 static void print_trace_address(void *data, unsigned long addr)
208 printk("%s [<%08lx>] ", (char *)data, addr);
209 print_symbol("%s\n", addr);
212 static struct stacktrace_ops print_trace_ops = {
213 .warning = print_trace_warning,
214 .warning_symbol = print_trace_warning_symbol,
215 .stack = print_trace_stack,
216 .address = print_trace_address,
220 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
221 unsigned long * stack, char *log_lvl)
223 dump_trace(task, regs, stack, &print_trace_ops, log_lvl);
224 printk("%s =======================\n", log_lvl);
227 void show_trace(struct task_struct *task, struct pt_regs *regs,
228 unsigned long * stack)
230 show_trace_log_lvl(task, regs, stack, "");
233 static void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
234 unsigned long *esp, char *log_lvl)
236 unsigned long *stack;
241 esp = (unsigned long*)task->thread.esp;
243 esp = (unsigned long *)&esp;
247 for(i = 0; i < kstack_depth_to_print; i++) {
248 if (kstack_end(stack))
250 if (i && ((i % 8) == 0))
251 printk("\n%s ", log_lvl);
252 printk("%08lx ", *stack++);
254 printk("\n%sCall Trace:\n", log_lvl);
255 show_trace_log_lvl(task, regs, esp, log_lvl);
258 void show_stack(struct task_struct *task, unsigned long *esp)
261 show_stack_log_lvl(task, NULL, esp, "");
265 * The architecture-independent dump_stack generator
267 void dump_stack(void)
271 show_trace(current, NULL, &stack);
274 EXPORT_SYMBOL(dump_stack);
276 void show_registers(struct pt_regs *regs)
281 unsigned short ss, gs;
283 esp = (unsigned long) (®s->esp);
286 if (user_mode_vm(regs)) {
289 ss = regs->xss & 0xffff;
292 printk(KERN_EMERG "CPU: %d\n"
293 KERN_EMERG "EIP: %04x:[<%08lx>] %s VLI\n"
294 KERN_EMERG "EFLAGS: %08lx (%s %.*s)\n",
295 smp_processor_id(), 0xffff & regs->xcs, regs->eip,
296 print_tainted(), regs->eflags, init_utsname()->release,
297 (int)strcspn(init_utsname()->version, " "),
298 init_utsname()->version);
299 print_symbol(KERN_EMERG "EIP is at %s\n", regs->eip);
300 printk(KERN_EMERG "eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
301 regs->eax, regs->ebx, regs->ecx, regs->edx);
302 printk(KERN_EMERG "esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
303 regs->esi, regs->edi, regs->ebp, esp);
304 printk(KERN_EMERG "ds: %04x es: %04x fs: %04x gs: %04x ss: %04x\n",
305 regs->xds & 0xffff, regs->xes & 0xffff, regs->xfs & 0xffff, gs, ss);
306 printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
307 TASK_COMM_LEN, current->comm, current->pid,
308 current_thread_info(), current, task_thread_info(current));
310 * When in-kernel, we also print out the stack and code at the
311 * time of the fault..
315 unsigned int code_prologue = code_bytes * 43 / 64;
316 unsigned int code_len = code_bytes;
319 printk("\n" KERN_EMERG "Stack: ");
320 show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG);
322 printk(KERN_EMERG "Code: ");
324 eip = (u8 *)regs->eip - code_prologue;
325 if (eip < (u8 *)PAGE_OFFSET ||
326 probe_kernel_address(eip, c)) {
327 /* try starting at EIP */
328 eip = (u8 *)regs->eip;
329 code_len = code_len - code_prologue + 1;
331 for (i = 0; i < code_len; i++, eip++) {
332 if (eip < (u8 *)PAGE_OFFSET ||
333 probe_kernel_address(eip, c)) {
334 printk(" Bad EIP value.");
337 if (eip == (u8 *)regs->eip)
338 printk("<%02x> ", c);
346 int is_valid_bugaddr(unsigned long eip)
350 if (eip < PAGE_OFFSET)
352 if (probe_kernel_address((unsigned short *)eip, ud2))
355 return ud2 == 0x0b0f;
359 * This is gone through when something in the kernel has done something bad and
360 * is about to be terminated.
362 void die(const char * str, struct pt_regs * regs, long err)
367 int lock_owner_depth;
369 .lock = __SPIN_LOCK_UNLOCKED(die.lock),
371 .lock_owner_depth = 0
373 static int die_counter;
378 if (die.lock_owner != raw_smp_processor_id()) {
380 spin_lock_irqsave(&die.lock, flags);
381 die.lock_owner = smp_processor_id();
382 die.lock_owner_depth = 0;
386 local_save_flags(flags);
388 if (++die.lock_owner_depth < 3) {
393 report_bug(regs->eip, regs);
395 printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
396 #ifdef CONFIG_PREEMPT
397 printk(KERN_EMERG "PREEMPT ");
406 #ifdef CONFIG_DEBUG_PAGEALLOC
409 printk("DEBUG_PAGEALLOC");
414 if (notify_die(DIE_OOPS, str, regs, err,
415 current->thread.trap_no, SIGSEGV) !=
417 show_registers(regs);
418 /* Executive summary in case the oops scrolled away */
419 esp = (unsigned long) (®s->esp);
421 if (user_mode(regs)) {
423 ss = regs->xss & 0xffff;
425 printk(KERN_EMERG "EIP: [<%08lx>] ", regs->eip);
426 print_symbol("%s", regs->eip);
427 printk(" SS:ESP %04x:%08lx\n", ss, esp);
432 printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
436 add_taint(TAINT_DIE);
437 spin_unlock_irqrestore(&die.lock, flags);
442 if (kexec_should_crash(current))
446 panic("Fatal exception in interrupt");
449 panic("Fatal exception");
455 static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
457 if (!user_mode_vm(regs))
461 static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
462 struct pt_regs * regs, long error_code,
465 struct task_struct *tsk = current;
467 if (regs->eflags & VM_MASK) {
473 if (!user_mode(regs))
478 * We want error_code and trap_no set for userspace faults and
479 * kernelspace faults which result in die(), but not
480 * kernelspace faults which are fixed up. die() gives the
481 * process no chance to handle the signal and notice the
482 * kernel fault information, so that won't result in polluting
483 * the information about previously queued, but not yet
484 * delivered, faults. See also do_general_protection below.
486 tsk->thread.error_code = error_code;
487 tsk->thread.trap_no = trapnr;
490 force_sig_info(signr, info, tsk);
492 force_sig(signr, tsk);
497 if (!fixup_exception(regs)) {
498 tsk->thread.error_code = error_code;
499 tsk->thread.trap_no = trapnr;
500 die(str, regs, error_code);
506 int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
507 if (ret) goto trap_signal;
512 #define DO_ERROR(trapnr, signr, str, name) \
513 fastcall void do_##name(struct pt_regs * regs, long error_code) \
515 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
518 do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
521 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr, irq) \
522 fastcall void do_##name(struct pt_regs * regs, long error_code) \
526 local_irq_enable(); \
527 info.si_signo = signr; \
529 info.si_code = sicode; \
530 info.si_addr = (void __user *)siaddr; \
531 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
534 do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
537 #define DO_VM86_ERROR(trapnr, signr, str, name) \
538 fastcall void do_##name(struct pt_regs * regs, long error_code) \
540 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
543 do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
546 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
547 fastcall void do_##name(struct pt_regs * regs, long error_code) \
550 info.si_signo = signr; \
552 info.si_code = sicode; \
553 info.si_addr = (void __user *)siaddr; \
554 if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
557 do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
560 DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip)
561 #ifndef CONFIG_KPROBES
562 DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
564 DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
565 DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
566 DO_ERROR_INFO( 6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->eip, 0)
567 DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
568 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
569 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
570 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
571 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
572 DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1)
574 fastcall void __kprobes do_general_protection(struct pt_regs * regs,
578 struct tss_struct *tss = &per_cpu(init_tss, cpu);
579 struct thread_struct *thread = ¤t->thread;
582 * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
583 * invalid offset set (the LAZY one) and the faulting thread has
584 * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
585 * and we set the offset field correctly. Then we let the CPU to
586 * restart the faulting instruction.
588 if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
589 thread->io_bitmap_ptr) {
590 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
591 thread->io_bitmap_max);
593 * If the previously set map was extending to higher ports
594 * than the current one, pad extra space with 0xff (no access).
596 if (thread->io_bitmap_max < tss->io_bitmap_max)
597 memset((char *) tss->io_bitmap +
598 thread->io_bitmap_max, 0xff,
599 tss->io_bitmap_max - thread->io_bitmap_max);
600 tss->io_bitmap_max = thread->io_bitmap_max;
601 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
602 tss->io_bitmap_owner = thread;
608 if (regs->eflags & VM_MASK)
611 if (!user_mode(regs))
614 current->thread.error_code = error_code;
615 current->thread.trap_no = 13;
616 force_sig(SIGSEGV, current);
621 handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
625 if (!fixup_exception(regs)) {
626 current->thread.error_code = error_code;
627 current->thread.trap_no = 13;
628 if (notify_die(DIE_GPF, "general protection fault", regs,
629 error_code, 13, SIGSEGV) == NOTIFY_STOP)
631 die("general protection fault", regs, error_code);
635 static __kprobes void
636 mem_parity_error(unsigned char reason, struct pt_regs * regs)
638 printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
639 "CPU %d.\n", reason, smp_processor_id());
640 printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n");
641 if (panic_on_unrecovered_nmi)
642 panic("NMI: Not continuing");
644 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
646 /* Clear and disable the memory parity error line. */
647 clear_mem_error(reason);
650 static __kprobes void
651 io_check_error(unsigned char reason, struct pt_regs * regs)
655 printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
656 show_registers(regs);
658 /* Re-enable the IOCK line, wait for a few seconds */
659 reason = (reason & 0xf) | 8;
662 while (--i) udelay(1000);
667 static __kprobes void
668 unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
671 /* Might actually be able to figure out what the guilty party
678 printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on "
679 "CPU %d.\n", reason, smp_processor_id());
680 printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
681 if (panic_on_unrecovered_nmi)
682 panic("NMI: Not continuing");
684 printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
687 static DEFINE_SPINLOCK(nmi_print_lock);
689 void __kprobes die_nmi(struct pt_regs *regs, const char *msg)
691 if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 2, SIGINT) ==
695 spin_lock(&nmi_print_lock);
697 * We are in trouble anyway, lets at least try
698 * to get a message out.
701 printk(KERN_EMERG "%s", msg);
702 printk(" on CPU%d, eip %08lx, registers:\n",
703 smp_processor_id(), regs->eip);
704 show_registers(regs);
706 spin_unlock(&nmi_print_lock);
709 /* If we are in kernel we are probably nested up pretty bad
710 * and might aswell get out now while we still can.
712 if (!user_mode_vm(regs)) {
713 current->thread.trap_no = 2;
720 static __kprobes void default_do_nmi(struct pt_regs * regs)
722 unsigned char reason = 0;
724 /* Only the BSP gets external NMIs from the system. */
725 if (!smp_processor_id())
726 reason = get_nmi_reason();
728 if (!(reason & 0xc0)) {
729 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
732 #ifdef CONFIG_X86_LOCAL_APIC
734 * Ok, so this is none of the documented NMI sources,
735 * so it must be the NMI watchdog.
737 if (nmi_watchdog_tick(regs, reason))
739 if (!do_nmi_callback(regs, smp_processor_id()))
741 unknown_nmi_error(reason, regs);
745 if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
748 mem_parity_error(reason, regs);
750 io_check_error(reason, regs);
752 * Reassert NMI in case it became active meanwhile
753 * as it's edge-triggered.
758 fastcall __kprobes void do_nmi(struct pt_regs * regs, long error_code)
764 cpu = smp_processor_id();
768 default_do_nmi(regs);
773 #ifdef CONFIG_KPROBES
774 fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
776 if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
779 /* This is an interrupt gate, because kprobes wants interrupts
780 disabled. Normal trap handlers don't. */
781 restore_interrupts(regs);
782 do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
787 * Our handling of the processor debug registers is non-trivial.
788 * We do not clear them on entry and exit from the kernel. Therefore
789 * it is possible to get a watchpoint trap here from inside the kernel.
790 * However, the code in ./ptrace.c has ensured that the user can
791 * only set watchpoints on userspace addresses. Therefore the in-kernel
792 * watchpoint trap can only occur in code which is reading/writing
793 * from user space. Such code must not hold kernel locks (since it
794 * can equally take a page fault), therefore it is safe to call
795 * force_sig_info even though that claims and releases locks.
797 * Code in ./signal.c ensures that the debug control register
798 * is restored before we deliver any signal, and therefore that
799 * user code runs with the correct debug control register even though
802 * Being careful here means that we don't have to be as careful in a
803 * lot of more complicated places (task switching can be a bit lazy
804 * about restoring all the debug state, and ptrace doesn't have to
805 * find every occurrence of the TF bit that could be saved away even
808 fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)
810 unsigned int condition;
811 struct task_struct *tsk = current;
813 get_debugreg(condition, 6);
815 if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
816 SIGTRAP) == NOTIFY_STOP)
818 /* It's safe to allow irq's after DR6 has been saved */
819 if (regs->eflags & X86_EFLAGS_IF)
822 /* Mask out spurious debug traps due to lazy DR7 setting */
823 if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
824 if (!tsk->thread.debugreg[7])
828 if (regs->eflags & VM_MASK)
831 /* Save debug status register where ptrace can see it */
832 tsk->thread.debugreg[6] = condition;
835 * Single-stepping through TF: make sure we ignore any events in
836 * kernel space (but re-enable TF when returning to user mode).
838 if (condition & DR_STEP) {
840 * We already checked v86 mode above, so we can
841 * check for kernel mode by just checking the CPL
844 if (!user_mode(regs))
845 goto clear_TF_reenable;
848 /* Ok, finally something we can handle */
849 send_sigtrap(tsk, regs, error_code);
851 /* Disable additional traps. They'll be re-enabled when
852 * the signal is delivered.
859 handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
863 set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
864 regs->eflags &= ~TF_MASK;
869 * Note that we play around with the 'TS' bit in an attempt to get
870 * the correct behaviour even in the presence of the asynchronous
873 void math_error(void __user *eip)
875 struct task_struct * task;
877 unsigned short cwd, swd;
880 * Save the info for the exception handler and clear the error.
884 task->thread.trap_no = 16;
885 task->thread.error_code = 0;
886 info.si_signo = SIGFPE;
888 info.si_code = __SI_FAULT;
891 * (~cwd & swd) will mask out exceptions that are not set to unmasked
892 * status. 0x3f is the exception bits in these regs, 0x200 is the
893 * C1 reg you need in case of a stack fault, 0x040 is the stack
894 * fault bit. We should only be taking one exception at a time,
895 * so if this combination doesn't produce any single exception,
896 * then we have a bad program that isn't syncronizing its FPU usage
897 * and it will suffer the consequences since we won't be able to
898 * fully reproduce the context of the exception
900 cwd = get_fpu_cwd(task);
901 swd = get_fpu_swd(task);
902 switch (swd & ~cwd & 0x3f) {
903 case 0x000: /* No unmasked exception */
905 default: /* Multiple exceptions */
907 case 0x001: /* Invalid Op */
909 * swd & 0x240 == 0x040: Stack Underflow
910 * swd & 0x240 == 0x240: Stack Overflow
911 * User must clear the SF bit (0x40) if set
913 info.si_code = FPE_FLTINV;
915 case 0x002: /* Denormalize */
916 case 0x010: /* Underflow */
917 info.si_code = FPE_FLTUND;
919 case 0x004: /* Zero Divide */
920 info.si_code = FPE_FLTDIV;
922 case 0x008: /* Overflow */
923 info.si_code = FPE_FLTOVF;
925 case 0x020: /* Precision */
926 info.si_code = FPE_FLTRES;
929 force_sig_info(SIGFPE, &info, task);
932 fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code)
935 math_error((void __user *)regs->eip);
938 static void simd_math_error(void __user *eip)
940 struct task_struct * task;
942 unsigned short mxcsr;
945 * Save the info for the exception handler and clear the error.
949 task->thread.trap_no = 19;
950 task->thread.error_code = 0;
951 info.si_signo = SIGFPE;
953 info.si_code = __SI_FAULT;
956 * The SIMD FPU exceptions are handled a little differently, as there
957 * is only a single status/control register. Thus, to determine which
958 * unmasked exception was caught we must mask the exception mask bits
959 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
961 mxcsr = get_fpu_mxcsr(task);
962 switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
966 case 0x001: /* Invalid Op */
967 info.si_code = FPE_FLTINV;
969 case 0x002: /* Denormalize */
970 case 0x010: /* Underflow */
971 info.si_code = FPE_FLTUND;
973 case 0x004: /* Zero Divide */
974 info.si_code = FPE_FLTDIV;
976 case 0x008: /* Overflow */
977 info.si_code = FPE_FLTOVF;
979 case 0x020: /* Precision */
980 info.si_code = FPE_FLTRES;
983 force_sig_info(SIGFPE, &info, task);
986 fastcall void do_simd_coprocessor_error(struct pt_regs * regs,
990 /* Handle SIMD FPU exceptions on PIII+ processors. */
992 simd_math_error((void __user *)regs->eip);
995 * Handle strange cache flush from user space exception
996 * in all other cases. This is undocumented behaviour.
998 if (regs->eflags & VM_MASK) {
999 handle_vm86_fault((struct kernel_vm86_regs *)regs,
1003 current->thread.trap_no = 19;
1004 current->thread.error_code = error_code;
1005 die_if_kernel("cache flush denied", regs, error_code);
1006 force_sig(SIGSEGV, current);
1010 fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
1014 /* No need to warn about this any longer. */
1015 printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
1019 fastcall unsigned long patch_espfix_desc(unsigned long uesp,
1022 struct desc_struct *gdt = __get_cpu_var(gdt_page).gdt;
1023 unsigned long base = (kesp - uesp) & -THREAD_SIZE;
1024 unsigned long new_kesp = kesp - base;
1025 unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
1026 __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
1027 /* Set up base for espfix segment */
1028 desc &= 0x00f0ff0000000000ULL;
1029 desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
1030 ((((__u64)base) << 32) & 0xff00000000000000ULL) |
1031 ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
1032 (lim_pages & 0xffff);
1033 *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
1038 * 'math_state_restore()' saves the current math information in the
1039 * old math state array, and gets the new ones from the current task
1041 * Careful.. There are problems with IBM-designed IRQ13 behaviour.
1042 * Don't touch unless you *really* know how it works.
1044 * Must be called with kernel preemption disabled (in this case,
1045 * local interrupts are disabled at the call-site in entry.S).
1047 asmlinkage void math_state_restore(void)
1049 struct thread_info *thread = current_thread_info();
1050 struct task_struct *tsk = thread->task;
1052 clts(); /* Allow maths ops (or we recurse) */
1053 if (!tsk_used_math(tsk))
1056 thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
1059 EXPORT_SYMBOL_GPL(math_state_restore);
1061 #ifndef CONFIG_MATH_EMULATION
1063 asmlinkage void math_emulate(long arg)
1065 printk(KERN_EMERG "math-emulation not enabled and no coprocessor found.\n");
1066 printk(KERN_EMERG "killing %s.\n",current->comm);
1067 force_sig(SIGFPE,current);
1071 #endif /* CONFIG_MATH_EMULATION */
1073 #ifdef CONFIG_X86_F00F_BUG
1074 void __init trap_init_f00f_bug(void)
1076 __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
1079 * Update the IDT descriptor and reload the IDT so that
1080 * it uses the read-only mapped virtual address.
1082 idt_descr.address = fix_to_virt(FIX_F00F_IDT);
1083 load_idt(&idt_descr);
1088 * This needs to use 'idt_table' rather than 'idt', and
1089 * thus use the _nonmapped_ version of the IDT, as the
1090 * Pentium F0 0F bugfix can have resulted in the mapped
1091 * IDT being write-protected.
1093 void set_intr_gate(unsigned int n, void *addr)
1095 _set_gate(n, DESCTYPE_INT, addr, __KERNEL_CS);
1099 * This routine sets up an interrupt gate at directory privilege level 3.
1101 static inline void set_system_intr_gate(unsigned int n, void *addr)
1103 _set_gate(n, DESCTYPE_INT | DESCTYPE_DPL3, addr, __KERNEL_CS);
1106 static void __init set_trap_gate(unsigned int n, void *addr)
1108 _set_gate(n, DESCTYPE_TRAP, addr, __KERNEL_CS);
1111 static void __init set_system_gate(unsigned int n, void *addr)
1113 _set_gate(n, DESCTYPE_TRAP | DESCTYPE_DPL3, addr, __KERNEL_CS);
1116 static void __init set_task_gate(unsigned int n, unsigned int gdt_entry)
1118 _set_gate(n, DESCTYPE_TASK, (void *)0, (gdt_entry<<3));
1122 void __init trap_init(void)
1125 void __iomem *p = ioremap(0x0FFFD9, 4);
1126 if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
1132 #ifdef CONFIG_X86_LOCAL_APIC
1133 init_apic_mappings();
1136 set_trap_gate(0,÷_error);
1137 set_intr_gate(1,&debug);
1138 set_intr_gate(2,&nmi);
1139 set_system_intr_gate(3, &int3); /* int3/4 can be called from all */
1140 set_system_gate(4,&overflow);
1141 set_trap_gate(5,&bounds);
1142 set_trap_gate(6,&invalid_op);
1143 set_trap_gate(7,&device_not_available);
1144 set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS);
1145 set_trap_gate(9,&coprocessor_segment_overrun);
1146 set_trap_gate(10,&invalid_TSS);
1147 set_trap_gate(11,&segment_not_present);
1148 set_trap_gate(12,&stack_segment);
1149 set_trap_gate(13,&general_protection);
1150 set_intr_gate(14,&page_fault);
1151 set_trap_gate(15,&spurious_interrupt_bug);
1152 set_trap_gate(16,&coprocessor_error);
1153 set_trap_gate(17,&alignment_check);
1154 #ifdef CONFIG_X86_MCE
1155 set_trap_gate(18,&machine_check);
1157 set_trap_gate(19,&simd_coprocessor_error);
1161 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
1162 * Generates a compile-time "error: zero width for bit-field" if
1163 * the alignment is wrong.
1165 struct fxsrAlignAssert {
1166 int _:!(offsetof(struct task_struct,
1167 thread.i387.fxsave) & 15);
1170 printk(KERN_INFO "Enabling fast FPU save and restore... ");
1171 set_in_cr4(X86_CR4_OSFXSR);
1175 printk(KERN_INFO "Enabling unmasked SIMD FPU exception "
1177 set_in_cr4(X86_CR4_OSXMMEXCPT);
1181 set_system_gate(SYSCALL_VECTOR,&system_call);
1184 * Should be a barrier for any external CPU state.
1191 static int __init kstack_setup(char *s)
1193 kstack_depth_to_print = simple_strtoul(s, NULL, 0);
1196 __setup("kstack=", kstack_setup);
1198 static int __init code_bytes_setup(char *s)
1200 code_bytes = simple_strtoul(s, NULL, 0);
1201 if (code_bytes > 8192)
1206 __setup("code_bytes=", code_bytes_setup);