ClabureDB: Classified Bug-Reports Database

   /*
    *  Copyright (C) 1991, 1992  Linus Torvalds
    *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
    *
    *  Pentium III FXSR, SSE support
    *        Gareth Hughes <gareth@valinux.com>, May 2000
    */
   
   /*
   * Handle hardware traps and faults.
   */
  #include <linux/interrupt.h>
  #include <linux/kallsyms.h>
  #include <linux/spinlock.h>
  #include <linux/kprobes.h>
  #include <linux/uaccess.h>
  #include <linux/utsname.h>
  #include <linux/kdebug.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/ptrace.h>
  #include <linux/string.h>
  #include <linux/unwind.h>
  #include <linux/delay.h>
  #include <linux/errno.h>
  #include <linux/kexec.h>
  #include <linux/sched.h>
  #include <linux/timer.h>
  #include <linux/init.h>
  #include <linux/bug.h>
  #include <linux/nmi.h>
  #include <linux/mm.h>
  #include <linux/smp.h>
  #include <linux/io.h>
  
  #ifdef CONFIG_EISA
  #include <linux/ioport.h>
  #include <linux/eisa.h>
  #endif
  
  #ifdef CONFIG_MCA
  #include <linux/mca.h>
  #endif
  
  #if defined(CONFIG_EDAC)
  #include <linux/edac.h>
  #endif
  
  #include <asm/stacktrace.h>
  #include <asm/processor.h>
  #include <asm/debugreg.h>
  #include <asm/atomic.h>
  #include <asm/system.h>
  #include <asm/unwind.h>
  #include <asm/traps.h>
  #include <asm/desc.h>
  #include <asm/i387.h>
  
  #include <mach_traps.h>
  
  #ifdef CONFIG_X86_64
  #include <asm/pgalloc.h>
  #include <asm/proto.h>
  #include <asm/pda.h>
  #else
  #include <asm/processor-flags.h>
  #include <asm/arch_hooks.h>
  #include <asm/nmi.h>
  #include <asm/smp.h>
  #include <asm/io.h>
  #include <asm/traps.h>
  
  #include "cpu/mcheck/mce.h"
  
  DECLARE_BITMAP(used_vectors, NR_VECTORS);
  EXPORT_SYMBOL_GPL(used_vectors);
  
  asmlinkage int system_call(void);
  
  /* Do we ignore FPU interrupts ? */
  char ignore_fpu_irq;
  
  /*
   * The IDT has to be page-aligned to simplify the Pentium
   * F0 0F bug workaround.. We have a special link segment
   * for this.
   */
  gate_desc idt_table[256]
          __attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, };
  #endif
  
  static int ignore_nmis;
  
  static inline void conditional_sti(struct pt_regs *regs)
  {
          if (regs->flags & X86_EFLAGS_IF)
                  local_irq_enable();
  }
  
 static inline void preempt_conditional_sti(struct pt_regs *regs)
 {
         inc_preempt_count();
         if (regs->flags & X86_EFLAGS_IF)
                 local_irq_enable();
 }
 
 static inline void preempt_conditional_cli(struct pt_regs *regs)
 {
         if (regs->flags & X86_EFLAGS_IF)
                 local_irq_disable();
         dec_preempt_count();
 }
 
 #ifdef CONFIG_X86_32
 static inline void
 die_if_kernel(const char *str, struct pt_regs *regs, long err)
 {
         if (!user_mode_vm(regs))
                 die(str, regs, err);
 }
 
 /*
  * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
  * invalid offset set (the LAZY one) and the faulting thread has
  * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS,
  * we set the offset field correctly and return 1.
  */
 static int lazy_iobitmap_copy(void)
 {
         struct thread_struct *thread;
         struct tss_struct *tss;
         int cpu;
 
         cpu = get_cpu();
         tss = &per_cpu(init_tss, cpu);
         thread = &current->thread;
 
         if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
             thread->io_bitmap_ptr) {
                 memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
                        thread->io_bitmap_max);
                 /*
                  * If the previously set map was extending to higher ports
                  * than the current one, pad extra space with 0xff (no access).
                  */
                 if (thread->io_bitmap_max < tss->io_bitmap_max) {
                         memset((char *) tss->io_bitmap +
                                 thread->io_bitmap_max, 0xff,
                                 tss->io_bitmap_max - thread->io_bitmap_max);
                 }
                 tss->io_bitmap_max = thread->io_bitmap_max;
                 tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
                 tss->io_bitmap_owner = thread;
                 put_cpu();
 
                 return 1;
         }
         put_cpu();
 
         return 0;
 }
 #endif
 
 static void __kprobes
 do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
         long error_code, siginfo_t *info)
 {
         struct task_struct *tsk = current;
 
 #ifdef CONFIG_X86_32
         if (regs->flags & X86_VM_MASK) {
                 /*
                  * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
                  * On nmi (interrupt 2), do_trap should not be called.
                  */
                 if (trapnr < 6)
                         goto vm86_trap;
                 goto trap_signal;
         }
 #endif
 
         if (!user_mode(regs))
                 goto kernel_trap;
 
 #ifdef CONFIG_X86_32
 trap_signal:
 #endif
         /*
          * We want error_code and trap_no set for userspace faults and
          * kernelspace faults which result in die(), but not
          * kernelspace faults which are fixed up.  die() gives the
          * process no chance to handle the signal and notice the
          * kernel fault information, so that won't result in polluting
          * the information about previously queued, but not yet
          * delivered, faults.  See also do_general_protection below.
          */
         tsk->thread.error_code = error_code;
         tsk->thread.trap_no = trapnr;
 
 #ifdef CONFIG_X86_64
         if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
             printk_ratelimit()) {
                 printk(KERN_INFO
                        "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
                        tsk->comm, tsk->pid, str,
                        regs->ip, regs->sp, error_code);
                 print_vma_addr(" in ", regs->ip);
                 printk("\n");
         }
 #endif
 
         if (info)
                 force_sig_info(signr, info, tsk);
         else
                 force_sig(signr, tsk);
         return;
 
 kernel_trap:
         if (!fixup_exception(regs)) {
                 tsk->thread.error_code = error_code;
                 tsk->thread.trap_no = trapnr;
                 die(str, regs, error_code);
         }
         return;
 
 #ifdef CONFIG_X86_32
 vm86_trap:
         if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
                                                 error_code, trapnr))
                 goto trap_signal;
         return;
 #endif
 }
 
 #define DO_ERROR(trapnr, signr, str, name)                                \
 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)        \
 {                                                                        \
         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)        \
                                                         == NOTIFY_STOP)        \
                 return;                                                        \
         conditional_sti(regs);                                                \
         do_trap(trapnr, signr, str, regs, error_code, NULL);                \
 }
 
 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)                \
 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)        \
 {                                                                        \
         siginfo_t info;                                                        \
         info.si_signo = signr;                                                \
         info.si_errno = 0;                                                \
         info.si_code = sicode;                                                \
         info.si_addr = (void __user *)siaddr;                                \
         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)        \
                                                         == NOTIFY_STOP)        \
                 return;                                                        \
         conditional_sti(regs);                                                \
         do_trap(trapnr, signr, str, regs, error_code, &info);                \
 }
 
 DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
 DO_ERROR(4, SIGSEGV, "overflow", overflow)
 DO_ERROR(5, SIGSEGV, "bounds", bounds)
 DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)
 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
 #ifdef CONFIG_X86_32
 DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
 #endif
 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
 
 #ifdef CONFIG_X86_64
 /* Runs on IST stack */
 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
 {
         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
                         12, SIGBUS) == NOTIFY_STOP)
                 return;
         preempt_conditional_sti(regs);
         do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
         preempt_conditional_cli(regs);
 }
 
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 {
         static const char str[] = "double fault";
         struct task_struct *tsk = current;
 
         /* Return not checked because double check cannot be ignored */
         notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
 
         tsk->thread.error_code = error_code;
         tsk->thread.trap_no = 8;
 
         /* This is always a kernel trap and never fixable (and thus must
            never return). */
         for (;;)
                 die(str, regs, error_code);
 }
 #endif
 
 dotraplinkage void __kprobes
 do_general_protection(struct pt_regs *regs, long error_code)
 {
         struct task_struct *tsk;
 
         conditional_sti(regs);
 
 #ifdef CONFIG_X86_32
         if (lazy_iobitmap_copy()) {
                 /* restart the faulting instruction */
                 return;
         }
 
         if (regs->flags & X86_VM_MASK)
                 goto gp_in_vm86;
 #endif
 
         tsk = current;
         if (!user_mode(regs))
                 goto gp_in_kernel;
 
         tsk->thread.error_code = error_code;
         tsk->thread.trap_no = 13;
 
         if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
                         printk_ratelimit()) {
                 printk(KERN_INFO
                         "%s[%d] general protection ip:%lx sp:%lx error:%lx",
                         tsk->comm, task_pid_nr(tsk),
                         regs->ip, regs->sp, error_code);
                 print_vma_addr(" in ", regs->ip);
                 printk("\n");
         }
 
         force_sig(SIGSEGV, tsk);
         return;
 
 #ifdef CONFIG_X86_32
 gp_in_vm86:
         local_irq_enable();
         handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
         return;
 #endif
 
 gp_in_kernel:
         if (fixup_exception(regs))
                 return;
 
         tsk->thread.error_code = error_code;
         tsk->thread.trap_no = 13;
         if (notify_die(DIE_GPF, "general protection fault", regs,
                                 error_code, 13, SIGSEGV) == NOTIFY_STOP)
                 return;
         die("general protection fault", regs, error_code);
 }
 
 static notrace __kprobes void
 mem_parity_error(unsigned char reason, struct pt_regs *regs)
 {
         printk(KERN_EMERG
                 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
                         reason, smp_processor_id());
 
         printk(KERN_EMERG
                 "You have some hardware problem, likely on the PCI bus.\n");
 
 #if defined(CONFIG_EDAC)
         if (edac_handler_set()) {
                 edac_atomic_assert_error();
                 return;
         }
 #endif
 
         if (panic_on_unrecovered_nmi)
                 panic("NMI: Not continuing");
 
         printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
 
         /* Clear and disable the memory parity error line. */
         reason = (reason & 0xf) | 4;
         outb(reason, 0x61);
 }
 
 static notrace __kprobes void
 io_check_error(unsigned char reason, struct pt_regs *regs)
 {
         unsigned long i;
 
         printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
         show_registers(regs);
 
         /* Re-enable the IOCK line, wait for a few seconds */
         reason = (reason & 0xf) | 8;
         outb(reason, 0x61);
 
         i = 2000;
         while (--i)
                 udelay(1000);
 
         reason &= ~8;
         outb(reason, 0x61);
 }
 
 static notrace __kprobes void
 unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
 {
         if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) ==
                         NOTIFY_STOP)
                 return;
 #ifdef CONFIG_MCA
         /*
          * Might actually be able to figure out what the guilty party
          * is:
          */
         if (MCA_bus) {
                 mca_handle_nmi();
                 return;
         }
 #endif
         printk(KERN_EMERG
                 "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
                         reason, smp_processor_id());
 
         printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
         if (panic_on_unrecovered_nmi)
                 panic("NMI: Not continuing");
 
         printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
 }
 
 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 {
         unsigned char reason = 0;
         int cpu;
 
         cpu = smp_processor_id();
 
         /* Only the BSP gets external NMIs from the system. */
         if (!cpu)
                 reason = get_nmi_reason();
 
         if (!(reason & 0xc0)) {
                 if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
                                                                 == NOTIFY_STOP)
                         return;
 #ifdef CONFIG_X86_LOCAL_APIC
                 /*
                  * Ok, so this is none of the documented NMI sources,
                  * so it must be the NMI watchdog.
                  */
                 if (nmi_watchdog_tick(regs, reason))
                         return;
                 if (!do_nmi_callback(regs, cpu))
                         unknown_nmi_error(reason, regs);
 #else
                 unknown_nmi_error(reason, regs);
 #endif
 
                 return;
         }
         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
                 return;
 
         /* AK: following checks seem to be broken on modern chipsets. FIXME */
         if (reason & 0x80)
                 mem_parity_error(reason, regs);
         if (reason & 0x40)
                 io_check_error(reason, regs);
 #ifdef CONFIG_X86_32
         /*
          * Reassert NMI in case it became active meanwhile
          * as it's edge-triggered:
          */
         reassert_nmi();
 #endif
 }
 
 dotraplinkage notrace __kprobes void
 do_nmi(struct pt_regs *regs, long error_code)
 {
         nmi_enter();
 
 #ifdef CONFIG_X86_32
         { int cpu; cpu = smp_processor_id(); ++nmi_count(cpu); }
 #else
         add_pda(__nmi_count, 1);
 #endif
 
         if (!ignore_nmis)
                 default_do_nmi(regs);
 
         nmi_exit();
 }
 
 void stop_nmi(void)
 {
         acpi_nmi_disable();
         ignore_nmis++;
 }
 
 void restart_nmi(void)
 {
         ignore_nmis--;
         acpi_nmi_enable();
 }
 
 /* May run on IST stack. */
 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
 {
 #ifdef CONFIG_KPROBES
         if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
                         == NOTIFY_STOP)
                 return;
 #else
         if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
                         == NOTIFY_STOP)
                 return;
 #endif
 
         preempt_conditional_sti(regs);
         do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
         preempt_conditional_cli(regs);
 }
 
 #ifdef CONFIG_X86_64
 /* Help handler running on IST stack to switch back to user stack
    for scheduling or signal handling. The actual stack switch is done in
    entry.S */
 asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
 {
         struct pt_regs *regs = eregs;
         /* Did already sync */
         if (eregs == (struct pt_regs *)eregs->sp)
                 ;
         /* Exception from user space */
         else if (user_mode(eregs))
                 regs = task_pt_regs(current);
         /* Exception from kernel and interrupts are enabled. Move to
            kernel process stack. */
         else if (eregs->flags & X86_EFLAGS_IF)
                 regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
         if (eregs != regs)
                 *regs = *eregs;
         return regs;
 }
 #endif
 
 /*
  * Our handling of the processor debug registers is non-trivial.
  * We do not clear them on entry and exit from the kernel. Therefore
  * it is possible to get a watchpoint trap here from inside the kernel.
  * However, the code in ./ptrace.c has ensured that the user can
  * only set watchpoints on userspace addresses. Therefore the in-kernel
  * watchpoint trap can only occur in code which is reading/writing
  * from user space. Such code must not hold kernel locks (since it
  * can equally take a page fault), therefore it is safe to call
  * force_sig_info even though that claims and releases locks.
  *
  * Code in ./signal.c ensures that the debug control register
  * is restored before we deliver any signal, and therefore that
  * user code runs with the correct debug control register even though
  * we clear it here.
  *
  * Being careful here means that we don't have to be as careful in a
  * lot of more complicated places (task switching can be a bit lazy
  * about restoring all the debug state, and ptrace doesn't have to
  * find every occurrence of the TF bit that could be saved away even
  * by user code)
  *
  * May run on IST stack.
  */
 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 {
         struct task_struct *tsk = current;
         unsigned long condition;
         int si_code;
 
         get_debugreg(condition, 6);
 
         /*
          * The processor cleared BTF, so don't mark that we need it set.
          */
         clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
         tsk->thread.debugctlmsr = 0;
 
         if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
                                                 SIGTRAP) == NOTIFY_STOP)
                 return;
 
         /* It's safe to allow irq's after DR6 has been saved */
         preempt_conditional_sti(regs);
 
         /* Mask out spurious debug traps due to lazy DR7 setting */
         if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
                 if (!tsk->thread.debugreg7)
                         goto clear_dr7;
         }
 
 #ifdef CONFIG_X86_32
         if (regs->flags & X86_VM_MASK)
                 goto debug_vm86;
 #endif
 
         /* Save debug status register where ptrace can see it */
         tsk->thread.debugreg6 = condition;
 
         /*
          * Single-stepping through TF: make sure we ignore any events in
          * kernel space (but re-enable TF when returning to user mode).
          */
         if (condition & DR_STEP) {
                 if (!user_mode(regs))
                         goto clear_TF_reenable;
         }
 
         si_code = get_si_code(condition);
         /* Ok, finally something we can handle */
         send_sigtrap(tsk, regs, error_code, si_code);
 
         /*
          * Disable additional traps. They'll be re-enabled when
          * the signal is delivered.
          */
 clear_dr7:
         set_debugreg(0, 7);
         preempt_conditional_cli(regs);
         return;
 
 #ifdef CONFIG_X86_32
 debug_vm86:
         handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
         preempt_conditional_cli(regs);
         return;
 #endif
 
 clear_TF_reenable:
         set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
         regs->flags &= ~X86_EFLAGS_TF;
         preempt_conditional_cli(regs);
         return;
 }
 
 #ifdef CONFIG_X86_64
 static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr)
 {
         if (fixup_exception(regs))
                 return 1;
 
         notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE);
         /* Illegal floating point operation in the kernel */
         current->thread.trap_no = trapnr;
         die(str, regs, 0);
         return 0;
 }
 #endif
 
 /*
  * Note that we play around with the 'TS' bit in an attempt to get
  * the correct behaviour even in the presence of the asynchronous
  * IRQ13 behaviour
  */
 void math_error(void __user *ip)
 {
         struct task_struct *task;
         siginfo_t info;
         unsigned short cwd, swd;
 
         /*
          * Save the info for the exception handler and clear the error.
          */
         task = current;
         save_init_fpu(task);
         task->thread.trap_no = 16;
         task->thread.error_code = 0;
         info.si_signo = SIGFPE;
         info.si_errno = 0;
         info.si_code = __SI_FAULT;
         info.si_addr = ip;
         /*
          * (~cwd & swd) will mask out exceptions that are not set to unmasked
          * status.  0x3f is the exception bits in these regs, 0x200 is the
          * C1 reg you need in case of a stack fault, 0x040 is the stack
          * fault bit.  We should only be taking one exception at a time,
          * so if this combination doesn't produce any single exception,
          * then we have a bad program that isn't synchronizing its FPU usage
          * and it will suffer the consequences since we won't be able to
          * fully reproduce the context of the exception
          */
         cwd = get_fpu_cwd(task);
         swd = get_fpu_swd(task);
         switch (swd & ~cwd & 0x3f) {
         case 0x000: /* No unmasked exception */
 #ifdef CONFIG_X86_32
                 return;
 #endif
         default: /* Multiple exceptions */
                 break;
         case 0x001: /* Invalid Op */
                 /*
                  * swd & 0x240 == 0x040: Stack Underflow
                  * swd & 0x240 == 0x240: Stack Overflow
                  * User must clear the SF bit (0x40) if set
                  */
                 info.si_code = FPE_FLTINV;
                 break;
         case 0x002: /* Denormalize */
         case 0x010: /* Underflow */
                 info.si_code = FPE_FLTUND;
                 break;
         case 0x004: /* Zero Divide */
                 info.si_code = FPE_FLTDIV;
                 break;
         case 0x008: /* Overflow */
                 info.si_code = FPE_FLTOVF;
                 break;
         case 0x020: /* Precision */
                 info.si_code = FPE_FLTRES;
                 break;
         }
         force_sig_info(SIGFPE, &info, task);
 }
 
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 {
         conditional_sti(regs);
 
 #ifdef CONFIG_X86_32
         ignore_fpu_irq = 1;
 #else
         if (!user_mode(regs) &&
             kernel_math_error(regs, "kernel x87 math error", 16))
                 return;
 #endif
 
         math_error((void __user *)regs->ip);
 }
 
 static void simd_math_error(void __user *ip)
 {
         struct task_struct *task;
         siginfo_t info;
         unsigned short mxcsr;
 
         /*
          * Save the info for the exception handler and clear the error.
          */
         task = current;
         save_init_fpu(task);
         task->thread.trap_no = 19;
         task->thread.error_code = 0;
         info.si_signo = SIGFPE;
         info.si_errno = 0;
         info.si_code = __SI_FAULT;
         info.si_addr = ip;
         /*
          * The SIMD FPU exceptions are handled a little differently, as there
          * is only a single status/control register.  Thus, to determine which
          * unmasked exception was caught we must mask the exception mask bits
          * at 0x1f80, and then use these to mask the exception bits at 0x3f.
          */
         mxcsr = get_fpu_mxcsr(task);
         switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
         case 0x000:
         default:
                 break;
         case 0x001: /* Invalid Op */
                 info.si_code = FPE_FLTINV;
                 break;
         case 0x002: /* Denormalize */
         case 0x010: /* Underflow */
                 info.si_code = FPE_FLTUND;
                 break;
         case 0x004: /* Zero Divide */
                 info.si_code = FPE_FLTDIV;
                 break;
         case 0x008: /* Overflow */
                 info.si_code = FPE_FLTOVF;
                 break;
         case 0x020: /* Precision */
                 info.si_code = FPE_FLTRES;
                 break;
         }
         force_sig_info(SIGFPE, &info, task);
 }
 
 dotraplinkage void
 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 {
         conditional_sti(regs);
 
 #ifdef CONFIG_X86_32
         if (cpu_has_xmm) {
                 /* Handle SIMD FPU exceptions on PIII+ processors. */
                 ignore_fpu_irq = 1;
                 simd_math_error((void __user *)regs->ip);
                 return;
         }
         /*
          * Handle strange cache flush from user space exception
          * in all other cases.  This is undocumented behaviour.
          */
         if (regs->flags & X86_VM_MASK) {
                 handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code);
                 return;
         }
         current->thread.trap_no = 19;
         current->thread.error_code = error_code;
         die_if_kernel("cache flush denied", regs, error_code);
         force_sig(SIGSEGV, current);
 #else
         if (!user_mode(regs) &&
                         kernel_math_error(regs, "kernel simd math error", 19))
                 return;
         simd_math_error((void __user *)regs->ip);
 #endif
 }
 
 dotraplinkage void
 do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 {
         conditional_sti(regs);
 #if 0
         /* No need to warn about this any longer. */
         printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
 #endif
 }
 
 #ifdef CONFIG_X86_32
 unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp)
 {
         struct desc_struct *gdt = get_cpu_gdt_table(smp_processor_id());
         unsigned long base = (kesp - uesp) & -THREAD_SIZE;
         unsigned long new_kesp = kesp - base;
         unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
         __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
 
         /* Set up base for espfix segment */
         desc &= 0x00f0ff0000000000ULL;
         desc |=        ((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
                 ((((__u64)base) << 32) & 0xff00000000000000ULL) |
                 ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
                 (lim_pages & 0xffff);
         *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
 
         return new_kesp;
 }
 #else
 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 {
 }
 
 asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void)
 {
 }
 #endif
 
 /*
  * 'math_state_restore()' saves the current math information in the
  * old math state array, and gets the new ones from the current task
  *
  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
  * Don't touch unless you *really* know how it works.
  *
  * Must be called with kernel preemption disabled (in this case,
  * local interrupts are disabled at the call-site in entry.S).
  */
 asmlinkage void math_state_restore(void)
 {
         struct thread_info *thread = current_thread_info();
         struct task_struct *tsk = thread->task;
 
         if (!tsk_used_math(tsk)) {
                 local_irq_enable();
                 /*
                  * does a slab alloc which can sleep
                  */
                 if (init_fpu(tsk)) {
                         /*
                          * ran out of memory!
                          */
                         do_group_exit(SIGKILL);
                         return;
                 }
                 local_irq_disable();
         }
 
         clts();                                /* Allow maths ops (or we recurse) */
 #ifdef CONFIG_X86_32
         restore_fpu(tsk);
 #else
         /*
          * Paranoid restore. send a SIGSEGV if we fail to restore the state.
          */
         if (unlikely(restore_fpu_checking(tsk))) {
                 stts();
                 force_sig(SIGSEGV, tsk);
                 return;
         }
 #endif
         thread->status |= TS_USEDFPU;        /* So we fnsave on switch_to() */
         tsk->fpu_counter++;
 }
 EXPORT_SYMBOL_GPL(math_state_restore);
 
 #ifndef CONFIG_MATH_EMULATION
 asmlinkage void math_emulate(long arg)
 {
         printk(KERN_EMERG
                 "math-emulation not enabled and no coprocessor found.\n");
         printk(KERN_EMERG "killing %s.\n", current->comm);
         force_sig(SIGFPE, current);
         schedule();
 }
 #endif /* CONFIG_MATH_EMULATION */
 
 dotraplinkage void __kprobes
 do_device_not_available(struct pt_regs *regs, long error)
 {
 #ifdef CONFIG_X86_32
         if (read_cr0() & X86_CR0_EM) {
                 conditional_sti(regs);
                 math_emulate(0);
         } else {
                 math_state_restore(); /* interrupts still off */
                 conditional_sti(regs);
         }
 #else
         math_state_restore();
 #endif
 }
 
 #ifdef CONFIG_X86_32
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 {
         siginfo_t info;
         local_irq_enable();
 
         info.si_signo = SIGILL;
         info.si_errno = 0;
         info.si_code = ILL_BADSTK;
         info.si_addr = 0;
         if (notify_die(DIE_TRAP, "iret exception",
                         regs, error_code, 32, SIGILL) == NOTIFY_STOP)
                 return;
         do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
 }
 #endif
 
 void __init trap_init(void)
 {
 #ifdef CONFIG_X86_32
         int i;
 #endif
 
 #ifdef CONFIG_EISA
         void __iomem *p = early_ioremap(0x0FFFD9, 4);
 
         if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
                 EISA_bus = 1;
         early_iounmap(p, 4);
 #endif
 
         set_intr_gate(0, &divide_error);
         set_intr_gate_ist(1, &debug, DEBUG_STACK);
         set_intr_gate_ist(2, &nmi, NMI_STACK);
         /* int3 can be called from all */
         set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
         /* int4 can be called from all */
         set_system_intr_gate(4, &overflow);
         set_intr_gate(5, &bounds);
         set_intr_gate(6, &invalid_op);
         set_intr_gate(7, &device_not_available);
 #ifdef CONFIG_X86_32
         set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
 #else
         set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
 #endif
         set_intr_gate(9, &coprocessor_segment_overrun);
         set_intr_gate(10, &invalid_TSS);
         set_intr_gate(11, &segment_not_present);
         set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
         set_intr_gate(13, &general_protection);
         set_intr_gate(14, &page_fault);
         set_intr_gate(15, &spurious_interrupt_bug);
         set_intr_gate(16, &coprocessor_error);
         set_intr_gate(17, &alignment_check);
 #ifdef CONFIG_X86_MCE
         set_intr_gate_ist(18, &machine_check, MCE_STACK);
 #endif
         set_intr_gate(19, &simd_coprocessor_error);
 
 #ifdef CONFIG_IA32_EMULATION
         set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
 #endif
 
 #ifdef CONFIG_X86_32
         if (cpu_has_fxsr) {
                 printk(KERN_INFO "Enabling fast FPU save and restore... ");
                set_in_cr4(X86_CR4_OSFXSR);
                printk("done.\n");
        }
        if (cpu_has_xmm) {
                printk(KERN_INFO
                        "Enabling unmasked SIMD FPU exception support... ");
                set_in_cr4(X86_CR4_OSXMMEXCPT);
                printk("done.\n");
        }

        set_system_trap_gate(SYSCALL_VECTOR, &system_call);

        /* Reserve all the builtin and the syscall vector: */
        for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
                set_bit(i, used_vectors);

        set_bit(SYSCALL_VECTOR, used_vectors);
#endif
        /*
         * Should be a barrier for any external CPU state:
         */
        cpu_init();

#ifdef CONFIG_X86_32
        trap_init_hook();
#endif
}