1 files changed, 1138 insertions, 0 deletions

diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
new file mode 100644
index 000000000000..03888420775d
--- /dev/null
+++ b/arch/x86/kernel/traps_64.c
@@ -0,0 +1,1138 @@
+/*
+ *  linux/arch/x86-64/traps.c
+ *
+ *  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
+ */
+
+/*
+ * 'Traps.c' handles hardware traps and faults after we have saved some
+ * state in 'entry.S'.
+ */
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/nmi.h>
+#include <linux/kprobes.h>
+#include <linux/kexec.h>
+#include <linux/unwind.h>
+#include <linux/uaccess.h>
+#include <linux/bug.h>
+#include <linux/kdebug.h>
+
+#if defined(CONFIG_EDAC)
+#include <linux/edac.h>
+#endif
+
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/atomic.h>
+#include <asm/debugreg.h>
+#include <asm/desc.h>
+#include <asm/i387.h>
+#include <asm/processor.h>
+#include <asm/unwind.h>
+#include <asm/smp.h>
+#include <asm/pgalloc.h>
+#include <asm/pda.h>
+#include <asm/proto.h>
+#include <asm/nmi.h>
+#include <asm/stacktrace.h>
+
+asmlinkage void divide_error(void);
+asmlinkage void debug(void);
+asmlinkage void nmi(void);
+asmlinkage void int3(void);
+asmlinkage void overflow(void);
+asmlinkage void bounds(void);
+asmlinkage void invalid_op(void);
+asmlinkage void device_not_available(void);
+asmlinkage void double_fault(void);
+asmlinkage void coprocessor_segment_overrun(void);
+asmlinkage void invalid_TSS(void);
+asmlinkage void segment_not_present(void);
+asmlinkage void stack_segment(void);
+asmlinkage void general_protection(void);
+asmlinkage void page_fault(void);
+asmlinkage void coprocessor_error(void);
+asmlinkage void simd_coprocessor_error(void);
+asmlinkage void reserved(void);
+asmlinkage void alignment_check(void);
+asmlinkage void machine_check(void);
+asmlinkage void spurious_interrupt_bug(void);
+
+static inline void conditional_sti(struct pt_regs *regs)
+{
+        if (regs->eflags & X86_EFLAGS_IF)
+                local_irq_enable();
+}
+
+static inline void preempt_conditional_sti(struct pt_regs *regs)
+{
+        preempt_disable();
+        if (regs->eflags & X86_EFLAGS_IF)
+                local_irq_enable();
+}
+
+static inline void preempt_conditional_cli(struct pt_regs *regs)
+{
+        if (regs->eflags & X86_EFLAGS_IF)
+                local_irq_disable();
+        /* Make sure to not schedule here because we could be running
+           on an exception stack. */
+        preempt_enable_no_resched();
+}
+
+int kstack_depth_to_print = 12;
+
+#ifdef CONFIG_KALLSYMS
+void printk_address(unsigned long address)
+{
+        unsigned long offset = 0, symsize;
+        const char *symname;
+        char *modname;
+        char *delim = ":";
+        char namebuf[128];
+
+        symname = kallsyms_lookup(address, &symsize, &offset,
+                                        &modname, namebuf);
+        if (!symname) {
+                printk(" [<%016lx>]\n", address);
+                return;
+        }
+        if (!modname)
+                modname = delim = "";           
+        printk(" [<%016lx>] %s%s%s%s+0x%lx/0x%lx\n",
+                address, delim, modname, delim, symname, offset, symsize);
+}
+#else
+void printk_address(unsigned long address)
+{
+        printk(" [<%016lx>]\n", address);
+}
+#endif
+
+static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
+                                        unsigned *usedp, char **idp)
+{
+        static char ids[][8] = {
+                [DEBUG_STACK - 1] = "#DB",
+                [NMI_STACK - 1] = "NMI",
+                [DOUBLEFAULT_STACK - 1] = "#DF",
+                [STACKFAULT_STACK - 1] = "#SS",
+                [MCE_STACK - 1] = "#MC",
+#if DEBUG_STKSZ > EXCEPTION_STKSZ
+                [N_EXCEPTION_STACKS ... N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]"
+#endif
+        };
+        unsigned k;
+
+        /*
+         * Iterate over all exception stacks, and figure out whether
+         * 'stack' is in one of them:
+         */
+        for (k = 0; k < N_EXCEPTION_STACKS; k++) {
+                unsigned long end = per_cpu(orig_ist, cpu).ist[k];
+                /*
+                 * Is 'stack' above this exception frame's end?
+                 * If yes then skip to the next frame.
+                 */
+                if (stack >= end)
+                        continue;
+                /*
+                 * Is 'stack' above this exception frame's start address?
+                 * If yes then we found the right frame.
+                 */
+                if (stack >= end - EXCEPTION_STKSZ) {
+                        /*
+                         * Make sure we only iterate through an exception
+                         * stack once. If it comes up for the second time
+                         * then there's something wrong going on - just
+                         * break out and return NULL:
+                         */
+                        if (*usedp & (1U << k))
+                                break;
+                        *usedp |= 1U << k;
+                        *idp = ids[k];
+                        return (unsigned long *)end;
+                }
+                /*
+                 * If this is a debug stack, and if it has a larger size than
+                 * the usual exception stacks, then 'stack' might still
+                 * be within the lower portion of the debug stack:
+                 */
+#if DEBUG_STKSZ > EXCEPTION_STKSZ
+                if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
+                        unsigned j = N_EXCEPTION_STACKS - 1;
+
+                        /*
+                         * Black magic. A large debug stack is composed of
+                         * multiple exception stack entries, which we
+                         * iterate through now. Dont look:
+                         */
+                        do {
+                                ++j;
+                                end -= EXCEPTION_STKSZ;
+                                ids[j][4] = '1' + (j - N_EXCEPTION_STACKS);
+                        } while (stack < end - EXCEPTION_STKSZ);
+                        if (*usedp & (1U << j))
+                                break;
+                        *usedp |= 1U << j;
+                        *idp = ids[j];
+                        return (unsigned long *)end;
+                }
+#endif
+        }
+        return NULL;
+}
+
+#define MSG(txt) ops->warning(data, txt)
+
+/*
+ * x86-64 can have upto three kernel stacks: 
+ * process stack
+ * interrupt stack
+ * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
+ */
+
+static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
+{
+        void *t = (void *)tinfo;
+        return p > t && p < t + THREAD_SIZE - 3;
+}
+
+void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
+                unsigned long *stack,
+                struct stacktrace_ops *ops, void *data)
+{
+        const unsigned cpu = get_cpu();
+        unsigned long *irqstack_end = (unsigned long*)cpu_pda(cpu)->irqstackptr;
+        unsigned used = 0;
+        struct thread_info *tinfo;
+
+        if (!tsk)
+                tsk = current;
+
+        if (!stack) {
+                unsigned long dummy;
+                stack = &dummy;
+                if (tsk && tsk != current)
+                        stack = (unsigned long *)tsk->thread.rsp;
+        }
+
+        /*
+         * Print function call entries within a stack. 'cond' is the
+         * "end of stackframe" condition, that the 'stack++'
+         * iteration will eventually trigger.
+         */
+#define HANDLE_STACK(cond) \
+        do while (cond) { \
+                unsigned long addr = *stack++; \
+                /* Use unlocked access here because except for NMIs     \
+                   we should be already protected against module unloads */ \
+                if (__kernel_text_address(addr)) { \
+                        /* \
+                         * If the address is either in the text segment of the \
+                         * kernel, or in the region which contains vmalloc'ed \
+                         * memory, it *may* be the address of a calling \
+                         * routine; if so, print it so that someone tracing \
+                         * down the cause of the crash will be able to figure \
+                         * out the call path that was taken. \
+                         */ \
+                        ops->address(data, addr);   \
+                } \
+        } while (0)
+
+        /*
+         * Print function call entries in all stacks, starting at the
+         * current stack address. If the stacks consist of nested
+         * exceptions
+         */
+        for (;;) {
+                char *id;
+                unsigned long *estack_end;
+                estack_end = in_exception_stack(cpu, (unsigned long)stack,
+                                                &used, &id);
+
+                if (estack_end) {
+                        if (ops->stack(data, id) < 0)
+                                break;
+                        HANDLE_STACK (stack < estack_end);
+                        ops->stack(data, "<EOE>");
+                        /*
+                         * We link to the next stack via the
+                         * second-to-last pointer (index -2 to end) in the
+                         * exception stack:
+                         */
+                        stack = (unsigned long *) estack_end[-2];
+                        continue;
+                }
+                if (irqstack_end) {
+                        unsigned long *irqstack;
+                        irqstack = irqstack_end -
+                                (IRQSTACKSIZE - 64) / sizeof(*irqstack);
+
+                        if (stack >= irqstack && stack < irqstack_end) {
+                                if (ops->stack(data, "IRQ") < 0)
+                                        break;
+                                HANDLE_STACK (stack < irqstack_end);
+                                /*
+                                 * We link to the next stack (which would be
+                                 * the process stack normally) the last
+                                 * pointer (index -1 to end) in the IRQ stack:
+                                 */
+                                stack = (unsigned long *) (irqstack_end[-1]);
+                                irqstack_end = NULL;
+                                ops->stack(data, "EOI");
+                                continue;
+                        }
+                }
+                break;
+        }
+
+        /*
+         * This handles the process stack:
+         */
+        tinfo = task_thread_info(tsk);
+        HANDLE_STACK (valid_stack_ptr(tinfo, stack));
+#undef HANDLE_STACK
+        put_cpu();
+}
+EXPORT_SYMBOL(dump_trace);
+
+static void
+print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+        print_symbol(msg, symbol);
+        printk("\n");
+}
+
+static void print_trace_warning(void *data, char *msg)
+{
+        printk("%s\n", msg);
+}
+
+static int print_trace_stack(void *data, char *name)
+{
+        printk(" <%s> ", name);
+        return 0;
+}
+
+static void print_trace_address(void *data, unsigned long addr)
+{
+        touch_nmi_watchdog();
+        printk_address(addr);
+}
+
+static struct stacktrace_ops print_trace_ops = {
+        .warning = print_trace_warning,
+        .warning_symbol = print_trace_warning_symbol,
+        .stack = print_trace_stack,
+        .address = print_trace_address,
+};
+
+void
+show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long *stack)
+{
+        printk("\nCall Trace:\n");
+        dump_trace(tsk, regs, stack, &print_trace_ops, NULL);
+        printk("\n");
+}
+
+static void
+_show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long *rsp)
+{
+        unsigned long *stack;
+        int i;
+        const int cpu = smp_processor_id();
+        unsigned long *irqstack_end = (unsigned long *) (cpu_pda(cpu)->irqstackptr);
+        unsigned long *irqstack = (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE);
+
+        // debugging aid: "show_stack(NULL, NULL);" prints the
+        // back trace for this cpu.
+
+        if (rsp == NULL) {
+                if (tsk)
+                        rsp = (unsigned long *)tsk->thread.rsp;
+                else
+                        rsp = (unsigned long *)&rsp;
+        }
+
+        stack = rsp;
+        for(i=0; i < kstack_depth_to_print; i++) {
+                if (stack >= irqstack && stack <= irqstack_end) {
+                        if (stack == irqstack_end) {
+                                stack = (unsigned long *) (irqstack_end[-1]);
+                                printk(" <EOI> ");
+                        }
+                } else {
+                if (((long) stack & (THREAD_SIZE-1)) == 0)
+                        break;
+                }
+                if (i && ((i % 4) == 0))
+                        printk("\n");
+                printk(" %016lx", *stack++);
+                touch_nmi_watchdog();
+        }
+        show_trace(tsk, regs, rsp);
+}
+
+void show_stack(struct task_struct *tsk, unsigned long * rsp)
+{
+        _show_stack(tsk, NULL, rsp);
+}
+
+/*
+ * The architecture-independent dump_stack generator
+ */
+void dump_stack(void)
+{
+        unsigned long dummy;
+        show_trace(NULL, NULL, &dummy);
+}
+
+EXPORT_SYMBOL(dump_stack);
+
+void show_registers(struct pt_regs *regs)
+{
+        int i;
+        int in_kernel = !user_mode(regs);
+        unsigned long rsp;
+        const int cpu = smp_processor_id();
+        struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+
+        rsp = regs->rsp;
+        printk("CPU %d ", cpu);
+        __show_regs(regs);
+        printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
+                cur->comm, cur->pid, task_thread_info(cur), cur);
+
+        /*
+         * When in-kernel, we also print out the stack and code at the
+         * time of the fault..
+         */
+        if (in_kernel) {
+                printk("Stack: ");
+                _show_stack(NULL, regs, (unsigned long*)rsp);
+
+                printk("\nCode: ");
+                if (regs->rip < PAGE_OFFSET)
+                        goto bad;
+
+                for (i=0; i<20; i++) {
+                        unsigned char c;
+                        if (__get_user(c, &((unsigned char*)regs->rip)[i])) {
+bad:
+                                printk(" Bad RIP value.");
+                                break;
+                        }
+                        printk("%02x ", c);
+                }
+        }
+        printk("\n");
+}       
+
+int is_valid_bugaddr(unsigned long rip)
+{
+        unsigned short ud2;
+
+        if (__copy_from_user(&ud2, (const void __user *) rip, sizeof(ud2)))
+                return 0;
+
+        return ud2 == 0x0b0f;
+}
+
+#ifdef CONFIG_BUG
+void out_of_line_bug(void)
+{ 
+        BUG(); 
+} 
+EXPORT_SYMBOL(out_of_line_bug);
+#endif
+
+static DEFINE_SPINLOCK(die_lock);
+static int die_owner = -1;
+static unsigned int die_nest_count;
+
+unsigned __kprobes long oops_begin(void)
+{
+        int cpu;
+        unsigned long flags;
+
+        oops_enter();
+
+        /* racy, but better than risking deadlock. */
+        local_irq_save(flags);
+        cpu = smp_processor_id();
+        if (!spin_trylock(&die_lock)) { 
+                if (cpu == die_owner) 
+                        /* nested oops. should stop eventually */;
+                else
+                        spin_lock(&die_lock);
+        }
+        die_nest_count++;
+        die_owner = cpu;
+        console_verbose();
+        bust_spinlocks(1);
+        return flags;
+}
+
+void __kprobes oops_end(unsigned long flags)
+{ 
+        die_owner = -1;
+        bust_spinlocks(0);
+        die_nest_count--;
+        if (die_nest_count)
+                /* We still own the lock */
+                local_irq_restore(flags);
+        else
+                /* Nest count reaches zero, release the lock. */
+                spin_unlock_irqrestore(&die_lock, flags);
+        if (panic_on_oops)
+                panic("Fatal exception");
+        oops_exit();
+}
+
+void __kprobes __die(const char * str, struct pt_regs * regs, long err)
+{
+        static int die_counter;
+        printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff,++die_counter);
+#ifdef CONFIG_PREEMPT
+        printk("PREEMPT ");
+#endif
+#ifdef CONFIG_SMP
+        printk("SMP ");
+#endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+        printk("DEBUG_PAGEALLOC");
+#endif
+        printk("\n");
+        notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);
+        show_registers(regs);
+        add_taint(TAINT_DIE);
+        /* Executive summary in case the oops scrolled away */
+        printk(KERN_ALERT "RIP ");
+        printk_address(regs->rip); 
+        printk(" RSP <%016lx>\n", regs->rsp); 
+        if (kexec_should_crash(current))
+                crash_kexec(regs);
+}
+
+void die(const char * str, struct pt_regs * regs, long err)
+{
+        unsigned long flags = oops_begin();
+
+        if (!user_mode(regs))
+                report_bug(regs->rip, regs);
+
+        __die(str, regs, err);
+        oops_end(flags);
+        do_exit(SIGSEGV); 
+}
+
+void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
+{
+        unsigned long flags = oops_begin();
+
+        /*
+         * We are in trouble anyway, lets at least try
+         * to get a message out.
+         */
+        printk(str, smp_processor_id());
+        show_registers(regs);
+        if (kexec_should_crash(current))
+                crash_kexec(regs);
+        if (do_panic || panic_on_oops)
+                panic("Non maskable interrupt");
+        oops_end(flags);
+        nmi_exit();
+        local_irq_enable();
+        do_exit(SIGSEGV);
+}
+
+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;
+
+        if (user_mode(regs)) {
+                /*
+                 * 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;
+
+                if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
+                    printk_ratelimit())
+                        printk(KERN_INFO
+                               "%s[%d] trap %s rip:%lx rsp:%lx error:%lx\n",
+                               tsk->comm, tsk->pid, str,
+                               regs->rip, regs->rsp, error_code); 
+
+                if (info)
+                        force_sig_info(signr, info, tsk);
+                else
+                        force_sig(signr, tsk);
+                return;
+        }
+
+
+        /* kernel trap */ 
+        {            
+                const struct exception_table_entry *fixup;
+                fixup = search_exception_tables(regs->rip);
+                if (fixup)
+                        regs->rip = fixup->fixup;
+                else {
+                        tsk->thread.error_code = error_code;
+                        tsk->thread.trap_no = trapnr;
+                        die(str, regs, error_code);
+                }
+                return;
+        }
+}
+
+#define DO_ERROR(trapnr, signr, str, name) \
+asmlinkage 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) \
+asmlinkage 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->rip)
+DO_ERROR( 4, SIGSEGV, "overflow", overflow)
+DO_ERROR( 5, SIGSEGV, "bounds", bounds)
+DO_ERROR_INFO( 6, SIGILL,  "invalid opcode", invalid_op, ILL_ILLOPN, regs->rip)
+DO_ERROR( 7, SIGSEGV, "device not available", device_not_available)
+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)
+DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
+DO_ERROR(18, SIGSEGV, "reserved", reserved)
+
+/* Runs on IST stack */
+asmlinkage 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);
+}
+
+asmlinkage 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);
+}
+
+asmlinkage void __kprobes do_general_protection(struct pt_regs * regs,
+                                                long error_code)
+{
+        struct task_struct *tsk = current;
+
+        conditional_sti(regs);
+
+        if (user_mode(regs)) {
+                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 rip:%lx rsp:%lx error:%lx\n",
+                               tsk->comm, tsk->pid,
+                               regs->rip, regs->rsp, error_code); 
+
+                force_sig(SIGSEGV, tsk);
+                return;
+        } 
+
+        /* kernel gp */
+        {
+                const struct exception_table_entry *fixup;
+                fixup = search_exception_tables(regs->rip);
+                if (fixup) {
+                        regs->rip = fixup->fixup;
+                        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 __kprobes void
+mem_parity_error(unsigned char reason, struct pt_regs * regs)
+{
+        printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
+                reason);
+        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 __kprobes void
+io_check_error(unsigned char reason, struct pt_regs * regs)
+{
+        printk("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);
+        mdelay(2000);
+        reason &= ~8;
+        outb(reason, 0x61);
+}
+
+static __kprobes void
+unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
+{
+        printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
+                reason);
+        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");
+}
+
+/* Runs on IST stack. This code must keep interrupts off all the time.
+   Nested NMIs are prevented by the CPU. */
+asmlinkage __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;
+                /*
+                 * 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);
+
+                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);
+}
+
+/* runs on IST stack. */
+asmlinkage void __kprobes do_int3(struct pt_regs * regs, long error_code)
+{
+        if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) {
+                return;
+        }
+        preempt_conditional_sti(regs);
+        do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
+        preempt_conditional_cli(regs);
+}
+
+/* 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->rsp)
+                ;
+        /* 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->eflags & X86_EFLAGS_IF)
+                regs = (struct pt_regs *)(eregs->rsp -= sizeof(struct pt_regs));
+        if (eregs != regs)
+                *regs = *eregs;
+        return regs;
+}
+
+/* runs on IST stack. */
+asmlinkage void __kprobes do_debug(struct pt_regs * regs,
+                                   unsigned long error_code)
+{
+        unsigned long condition;
+        struct task_struct *tsk = current;
+        siginfo_t info;
+
+        get_debugreg(condition, 6);
+
+        if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
+                                                SIGTRAP) == NOTIFY_STOP)
+                return;
+
+        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;
+                }
+        }
+
+        tsk->thread.debugreg6 = condition;
+
+        /* Mask out spurious TF errors due to lazy TF clearing */
+        if (condition & DR_STEP) {
+                /*
+                 * The TF error should be masked out only if the current
+                 * process is not traced and if the TRAP flag has been set
+                 * previously by a tracing process (condition detected by
+                 * the PT_DTRACE flag); remember that the i386 TRAP flag
+                 * can be modified by the process itself in user mode,
+                 * allowing programs to debug themselves without the ptrace()
+                 * interface.
+                 */
+                if (!user_mode(regs))
+                       goto clear_TF_reenable;
+                /*
+                 * Was the TF flag set by a debugger? If so, clear it now,
+                 * so that register information is correct.
+                 */
+                if (tsk->ptrace & PT_DTRACE) {
+                        regs->eflags &= ~TF_MASK;
+                        tsk->ptrace &= ~PT_DTRACE;
+                }
+        }
+
+        /* Ok, finally something we can handle */
+        tsk->thread.trap_no = 1;
+        tsk->thread.error_code = error_code;
+        info.si_signo = SIGTRAP;
+        info.si_errno = 0;
+        info.si_code = TRAP_BRKPT;
+        info.si_addr = user_mode(regs) ? (void __user *)regs->rip : NULL;
+        force_sig_info(SIGTRAP, &info, tsk);
+
+clear_dr7:
+        set_debugreg(0UL, 7);
+        preempt_conditional_cli(regs);
+        return;
+
+clear_TF_reenable:
+        set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+        regs->eflags &= ~TF_MASK;
+        preempt_conditional_cli(regs);
+}
+
+static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr)
+{
+        const struct exception_table_entry *fixup;
+        fixup = search_exception_tables(regs->rip);
+        if (fixup) {
+                regs->rip = fixup->fixup;
+                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;
+}
+
+/*
+ * 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
+ */
+asmlinkage void do_coprocessor_error(struct pt_regs *regs)
+{
+        void __user *rip = (void __user *)(regs->rip);
+        struct task_struct * task;
+        siginfo_t info;
+        unsigned short cwd, swd;
+
+        conditional_sti(regs);
+        if (!user_mode(regs) &&
+            kernel_math_error(regs, "kernel x87 math error", 16))
+                return;
+
+        /*
+         * 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 = rip;
+        /*
+         * (~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:
+                default:
+                        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);
+}
+
+asmlinkage void bad_intr(void)
+{
+        printk("bad interrupt"); 
+}
+
+asmlinkage void do_simd_coprocessor_error(struct pt_regs *regs)
+{
+        void __user *rip = (void __user *)(regs->rip);
+        struct task_struct * task;
+        siginfo_t info;
+        unsigned short mxcsr;
+
+        conditional_sti(regs);
+        if (!user_mode(regs) &&
+                kernel_math_error(regs, "kernel simd math error", 19))
+                return;
+
+        /*
+         * 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 = rip;
+        /*
+         * 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);
+}
+
+asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs)
+{
+}
+
+asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
+{
+}
+
+asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void)
+{
+}
+
+/*
+ *  '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.
+ */
+asmlinkage void math_state_restore(void)
+{
+        struct task_struct *me = current;
+        clts();                 /* Allow maths ops (or we recurse) */
+
+        if (!used_math())
+                init_fpu(me);
+        restore_fpu_checking(&me->thread.i387.fxsave);
+        task_thread_info(me)->status |= TS_USEDFPU;
+        me->fpu_counter++;
+}
+
+void __init trap_init(void)
+{
+        set_intr_gate(0,&divide_error);
+        set_intr_gate_ist(1,&debug,DEBUG_STACK);
+        set_intr_gate_ist(2,&nmi,NMI_STACK);
+        set_system_gate_ist(3,&int3,DEBUG_STACK); /* int3 can be called from all */
+        set_system_gate(4,&overflow);   /* int4 can be called from all */
+        set_intr_gate(5,&bounds);
+        set_intr_gate(6,&invalid_op);
+        set_intr_gate(7,&device_not_available);
+        set_intr_gate_ist(8,&double_fault, DOUBLEFAULT_STACK);
+        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_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
+#endif
+       
+        /*
+         * Should be a barrier for any external CPU state.
+         */
+        cpu_init();
+}
+
+
+static int __init oops_setup(char *s)
+{ 
+        if (!s)
+                return -EINVAL;
+        if (!strcmp(s, "panic"))
+                panic_on_oops = 1;
+        return 0;
+} 
+early_param("oops", oops_setup);
+
+static int __init kstack_setup(char *s)
+{
+        if (!s)
+                return -EINVAL;
+        kstack_depth_to_print = simple_strtoul(s,NULL,0);
+        return 0;
+}
+early_param("kstack", kstack_setup);