]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/i386/trap.c
xnu-3789.60.24.tar.gz
[apple/xnu.git] / osfmk / i386 / trap.c
index a845341d89a8d8810ab0d7d64ea100d8ce2bcb6f..7924f4f7dd5f0ce543e13640e96759c0de1fe40d 100644 (file)
@@ -1,62 +1,65 @@
 /*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
- * @OSF_COPYRIGHT@
- */
+* @OSF_COPYRIGHT@
+*/
 /* 
- * Mach Operating System
- * Copyright (c) 1991,1990,1989,1988 Carnegie Mellon University
- * All Rights Reserved.
- 
- * Permission to use, copy, modify and distribute this software and its
- * documentation is hereby granted, provided that both the copyright
- * notice and this permission notice appear in all copies of the
- * software, derivative works or modified versions, and any portions
- * thereof, and that both notices appear in supporting documentation.
- 
- * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
- * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
- * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- 
- * Carnegie Mellon requests users of this software to return to
- 
- *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
- *  School of Computer Science
- *  Carnegie Mellon University
- *  Pittsburgh PA 15213-3890
- 
- * any improvements or extensions that they make and grant Carnegie Mellon
- * the rights to redistribute these changes.
- */
+* Mach Operating System
+* Copyright (c) 1991,1990,1989,1988 Carnegie Mellon University
+* All Rights Reserved.
+* 
+* Permission to use, copy, modify and distribute this software and its
+* documentation is hereby granted, provided that both the copyright
+* notice and this permission notice appear in all copies of the
+* software, derivative works or modified versions, and any portions
+* thereof, and that both notices appear in supporting documentation.
+* 
+* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+* CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+* 
+* Carnegie Mellon requests users of this software to return to
+* 
+*  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+*  School of Computer Science
+*  Carnegie Mellon University
+*  Pittsburgh PA 15213-3890
+* 
+* any improvements or extensions that they make and grant Carnegie Mellon
+* the rights to redistribute these changes.
+*/
 /*
- */
+*/
+
 /*
- * Hardware trap/fault handler.
+* Hardware trap/fault handler.
  */
 
-#include <cpus.h>
-#include <fast_idle.h>
-#include <mach_kdb.h>
-#include <mach_kgdb.h>
 #include <mach_kdp.h>
 #include <mach_ldebug.h>
 
@@ -65,6 +68,8 @@
 #include <i386/trap.h>
 #include <i386/pmap.h>
 #include <i386/fpu.h>
+#include <i386/misc_protos.h> /* panic_io_port_read() */
+#include <i386/lapic.h>
 
 #include <mach/exception.h>
 #include <mach/kern_return.h>
@@ -74,9 +79,8 @@
 #include <vm/vm_kern.h>
 #include <vm/vm_fault.h>
 
-#include <kern/etap_macros.h>
 #include <kern/kern_types.h>
-#include <kern/ast.h>
+#include <kern/processor.h>
 #include <kern/thread.h>
 #include <kern/task.h>
 #include <kern/sched.h>
 #include <kern/exception.h>
 #include <kern/spl.h>
 #include <kern/misc_protos.h>
+#include <kern/debug.h>
+#if CONFIG_TELEMETRY
+#include <kern/telemetry.h>
+#endif
+#include <sys/kdebug.h>
+#include <prng/random.h>
 
-#if    MACH_KGDB
-#include <kgdb/kgdb_defs.h>
-#endif /* MACH_KGDB */
-
-#include <i386/intel_read_fault.h>
-
-#if     MACH_KGDB
-#include <kgdb/kgdb_defs.h>
-#endif  /* MACH_KGDB */
+#include <string.h>
 
-#if    MACH_KDB
-#include <ddb/db_watch.h>
-#include <ddb/db_run.h>
-#include <ddb/db_break.h>
-#include <ddb/db_trap.h>
-#endif /* MACH_KDB */
+#include <i386/postcode.h>
+#include <i386/mp_desc.h>
+#include <i386/proc_reg.h>
+#if CONFIG_MCA
+#include <i386/machine_check.h>
+#endif
+#include <mach/i386/syscall_sw.h>
 
-#include <string.h>
+#include <libkern/OSDebug.h>
+#include <i386/cpu_threads.h>
+#include <machine/pal_routines.h>
 
-#include <i386/io_emulate.h>
+extern void throttle_lowpri_io(int);
+extern void kprint_state(x86_saved_state64_t *saved_state);
 
 /*
  * Forward declarations
  */
-extern void            user_page_fault_continue(
-                               kern_return_t           kr);
+static void user_page_fault_continue(kern_return_t kret);
+static void panic_trap(x86_saved_state64_t *saved_state, uint32_t pl, kern_return_t fault_result);
+static void set_recovery_ip(x86_saved_state64_t *saved_state, vm_offset_t ip);
 
-extern boolean_t       v86_assist(
-                               thread_t                thread,
-                               struct i386_saved_state *regs);
+volatile perfCallback perfTrapHook = NULL; /* Pointer to CHUD trap hook routine */
 
-extern boolean_t       check_io_fault(
-                               struct i386_saved_state *regs);
+#if CONFIG_DTRACE
+/* See <rdar://problem/4613924> */
+perfCallback tempDTraceTrapHook = NULL; /* Pointer to DTrace fbt trap hook routine */
 
-extern int             inst_fetch(
-                               int                     eip,
-                               int                     cs);
+extern boolean_t dtrace_tally_fault(user_addr_t);
+#endif
+
+extern boolean_t pmap_smep_enabled;
+extern boolean_t pmap_smap_enabled;
 
+__attribute__((noreturn))
 void
 thread_syscall_return(
         kern_return_t ret)
 {
-        register thread_act_t   thr_act = current_act();
-        register struct i386_saved_state *regs = USER_REGS(thr_act);
-        regs->eax = ret;
-        thread_exception_return();
+        thread_t       thr_act = current_thread();
+       boolean_t       is_mach;
+       int             code;
+
+       pal_register_cache_state(thr_act, DIRTY);
+
+        if (thread_is_64bit(thr_act)) {
+               x86_saved_state64_t     *regs;
+               
+               regs = USER_REGS64(thr_act);
+
+               code = (int) (regs->rax & SYSCALL_NUMBER_MASK);
+               is_mach = (regs->rax & SYSCALL_CLASS_MASK)
+                           == (SYSCALL_CLASS_MACH << SYSCALL_CLASS_SHIFT);
+               if (kdebug_enable && is_mach) {
+                       /* Mach trap */
+                       KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
+                             MACHDBG_CODE(DBG_MACH_EXCP_SC,code)|DBG_FUNC_END,
+                             ret, 0, 0, 0, 0);
+               }
+               regs->rax = ret;
+#if DEBUG
+               if (is_mach)
+                       DEBUG_KPRINT_SYSCALL_MACH(
+                               "thread_syscall_return: 64-bit mach ret=%u\n",
+                               ret);
+               else
+                       DEBUG_KPRINT_SYSCALL_UNIX(
+                               "thread_syscall_return: 64-bit unix ret=%u\n",
+                               ret);
+#endif
+       } else {
+               x86_saved_state32_t     *regs;
+               
+               regs = USER_REGS32(thr_act);
+
+               code = ((int) regs->eax);
+               is_mach = (code < 0);
+               if (kdebug_enable && is_mach) {
+                       /* Mach trap */
+                       KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
+                             MACHDBG_CODE(DBG_MACH_EXCP_SC,-code)|DBG_FUNC_END,
+                             ret, 0, 0, 0, 0);
+               }
+               regs->eax = ret;
+#if DEBUG
+               if (is_mach)
+                       DEBUG_KPRINT_SYSCALL_MACH(
+                               "thread_syscall_return: 32-bit mach ret=%u\n",
+                               ret);
+               else
+                       DEBUG_KPRINT_SYSCALL_UNIX(
+                               "thread_syscall_return: 32-bit unix ret=%u\n",
+                               ret);
+#endif
+       }
+       throttle_lowpri_io(1);
+
+       thread_exception_return();
         /*NOTREACHED*/
 }
 
 
-#if    MACH_KDB
-boolean_t      debug_all_traps_with_kdb = FALSE;
-extern struct db_watchpoint *db_watchpoint_list;
-extern boolean_t db_watchpoints_inserted;
-extern boolean_t db_breakpoints_inserted;
-
-void
-thread_kdb_return(void)
+static inline void
+user_page_fault_continue(
+                        kern_return_t  kr)
 {
-       register thread_act_t   thr_act = current_act();
-       register thread_t       cur_thr = current_thread();
-       register struct i386_saved_state *regs = USER_REGS(thr_act);
-
-       if (kdb_trap(regs->trapno, regs->err, regs)) {
-#if            MACH_LDEBUG
-               assert(cur_thr->mutex_count == 0); 
-#endif         /* MACH_LDEBUG */
-               check_simple_locks();
-               thread_exception_return();
-               /*NOTREACHED*/
-       }
-}
-boolean_t let_ddb_vm_fault = FALSE;
+       thread_t        thread = current_thread();
+       user_addr_t     vaddr;
 
-#if    NCPUS > 1
-extern int kdb_active[NCPUS];
-#endif /* NCPUS > 1 */
+       if (thread_is_64bit(thread)) {
+               x86_saved_state64_t     *uregs;
 
-#endif /* MACH_KDB */
+               uregs = USER_REGS64(thread);
 
-void
-user_page_fault_continue(
-       kern_return_t   kr)
-{
-       register thread_act_t   thr_act = current_act();
-       register thread_t       cur_thr = current_thread();
-       register struct i386_saved_state *regs = USER_REGS(thr_act);
-
-       if ((kr == KERN_SUCCESS) || (kr == KERN_ABORTED)) {
-#if    MACH_KDB
-               if (!db_breakpoints_inserted) {
-                       db_set_breakpoints();
-               }
-               if (db_watchpoint_list &&
-                   db_watchpoints_inserted &&
-                   (regs->err & T_PF_WRITE) &&
-                   db_find_watchpoint(thr_act->map,
-                                      (vm_offset_t)regs->cr2,
-                                      regs))
-                       kdb_trap(T_WATCHPOINT, 0, regs);
-#endif /* MACH_KDB */
-               thread_exception_return();
-               /*NOTREACHED*/
-       }
+               vaddr = (user_addr_t)uregs->cr2;
+       } else {
+               x86_saved_state32_t     *uregs;
 
-#if    MACH_KDB
-       if (debug_all_traps_with_kdb &&
-           kdb_trap(regs->trapno, regs->err, regs)) {
-#if            MACH_LDEBUG
-               assert(cur_thr->mutex_count == 0);
-#endif         /* MACH_LDEBUG */
-               check_simple_locks();
-               thread_exception_return();
-               /*NOTREACHED*/
+               uregs = USER_REGS32(thread);
+
+               vaddr = uregs->cr2;
        }
-#endif /* MACH_KDB */
 
-       i386_exception(EXC_BAD_ACCESS, kr, regs->cr2);
+
+       /* PAL debug hook */
+       pal_dbg_page_fault( thread, vaddr, kr );
+
+       i386_exception(EXC_BAD_ACCESS, kr, vaddr);
        /*NOTREACHED*/
 }
 
@@ -210,294 +232,754 @@ user_page_fault_continue(
  * Fault recovery in copyin/copyout routines.
  */
 struct recovery {
-       int     fault_addr;
-       int     recover_addr;
+       uintptr_t       fault_addr;
+       uintptr_t       recover_addr;
 };
 
 extern struct recovery recover_table[];
 extern struct recovery recover_table_end[];
 
+const char *   trap_type[] = {TRAP_NAMES};
+unsigned       TRAP_TYPES = sizeof(trap_type)/sizeof(trap_type[0]);
+
+extern void    PE_incoming_interrupt(int interrupt);
+
+#if defined(__x86_64__) && DEBUG
+void
+kprint_state(x86_saved_state64_t       *saved_state)
+{
+       kprintf("current_cpu_datap() 0x%lx\n", (uintptr_t)current_cpu_datap());
+       kprintf("Current GS base MSR 0x%llx\n", rdmsr64(MSR_IA32_GS_BASE));
+       kprintf("Kernel  GS base MSR 0x%llx\n", rdmsr64(MSR_IA32_KERNEL_GS_BASE));
+       kprintf("state at 0x%lx:\n", (uintptr_t) saved_state);
+
+       kprintf("      rdi    0x%llx\n", saved_state->rdi);        
+       kprintf("      rsi    0x%llx\n", saved_state->rsi);    
+       kprintf("      rdx    0x%llx\n", saved_state->rdx);
+       kprintf("      r10    0x%llx\n", saved_state->r10);
+       kprintf("      r8     0x%llx\n", saved_state->r8);
+       kprintf("      r9     0x%llx\n", saved_state->r9);     
+
+       kprintf("      cr2    0x%llx\n", saved_state->cr2);
+       kprintf("real  cr2    0x%lx\n", get_cr2());
+       kprintf("      r15    0x%llx\n", saved_state->r15);
+       kprintf("      r14    0x%llx\n", saved_state->r14);
+       kprintf("      r13    0x%llx\n", saved_state->r13);
+       kprintf("      r12    0x%llx\n", saved_state->r12);
+       kprintf("      r11    0x%llx\n", saved_state->r11);
+       kprintf("      rbp    0x%llx\n", saved_state->rbp);
+       kprintf("      rbx    0x%llx\n", saved_state->rbx);
+       kprintf("      rcx    0x%llx\n", saved_state->rcx);
+       kprintf("      rax    0x%llx\n", saved_state->rax);
+
+       kprintf("      gs     0x%x\n", saved_state->gs);
+       kprintf("      fs     0x%x\n", saved_state->fs);
+
+       kprintf("  isf.trapno 0x%x\n", saved_state->isf.trapno);
+       kprintf("  isf._pad   0x%x\n", saved_state->isf._pad);
+       kprintf("  isf.trapfn 0x%llx\n", saved_state->isf.trapfn);
+       kprintf("  isf.err    0x%llx\n", saved_state->isf.err);
+       kprintf("  isf.rip    0x%llx\n", saved_state->isf.rip);
+       kprintf("  isf.cs     0x%llx\n", saved_state->isf.cs);
+       kprintf("  isf.rflags 0x%llx\n", saved_state->isf.rflags);
+       kprintf("  isf.rsp    0x%llx\n", saved_state->isf.rsp);
+       kprintf("  isf.ss     0x%llx\n", saved_state->isf.ss);
+}
+#endif
+
+
 /*
- * Recovery from Successful fault in copyout does not
- * return directly - it retries the pte check, since
- * the 386 ignores write protection in kernel mode.
+ * Non-zero indicates latency assert is enabled and capped at valued
+ * absolute time units.
  */
-extern struct recovery retry_table[];
-extern struct recovery retry_table_end[];
+   
+uint64_t interrupt_latency_cap = 0;
+boolean_t ilat_assert = FALSE;
 
-char * trap_type[] = {TRAP_NAMES};
-int    TRAP_TYPES = sizeof(trap_type)/sizeof(trap_type[0]);
+void
+interrupt_latency_tracker_setup(void) {
+       uint32_t ilat_cap_us;
+       if (PE_parse_boot_argn("interrupt_latency_cap_us", &ilat_cap_us, sizeof(ilat_cap_us))) {
+               interrupt_latency_cap = ilat_cap_us * NSEC_PER_USEC;
+               nanoseconds_to_absolutetime(interrupt_latency_cap, &interrupt_latency_cap);
+       } else {
+               interrupt_latency_cap = LockTimeOut;
+       }
+       PE_parse_boot_argn("-interrupt_latency_assert_enable", &ilat_assert, sizeof(ilat_assert));
+}
+
+void interrupt_reset_latency_stats(void) {
+       uint32_t i;
+       for (i = 0; i < real_ncpus; i++) {
+               cpu_data_ptr[i]->cpu_max_observed_int_latency =
+                   cpu_data_ptr[i]->cpu_max_observed_int_latency_vector = 0;
+       }
+}
+
+void interrupt_populate_latency_stats(char *buf, unsigned bufsize) {
+       uint32_t i, tcpu = ~0;
+       uint64_t cur_max = 0;
+
+       for (i = 0; i < real_ncpus; i++) {
+               if (cur_max < cpu_data_ptr[i]->cpu_max_observed_int_latency) {
+                       cur_max = cpu_data_ptr[i]->cpu_max_observed_int_latency;
+                       tcpu = i;
+               }
+       }
+
+       if (tcpu < real_ncpus)
+               snprintf(buf, bufsize, "0x%x 0x%x 0x%llx", tcpu, cpu_data_ptr[tcpu]->cpu_max_observed_int_latency_vector, cpu_data_ptr[tcpu]->cpu_max_observed_int_latency);
+}
+
+uint32_t interrupt_timer_coalescing_enabled = 1;
+uint64_t interrupt_coalesced_timers;
 
+/*
+ * Handle interrupts:
+ *  - local APIC interrupts (IPIs, timers, etc) are handled by the kernel,
+ *  - device interrupts go to the platform expert.
+ */
+void
+interrupt(x86_saved_state_t *state)
+{
+       uint64_t        rip;
+       uint64_t        rsp;
+       int             interrupt_num;
+       boolean_t       user_mode = FALSE;
+       int             ipl;
+       int             cnum = cpu_number();
+       cpu_data_t      *cdp = cpu_data_ptr[cnum];
+       int             itype = 0;
+
+       if (is_saved_state64(state) == TRUE) {
+               x86_saved_state64_t     *state64;
+
+               state64 = saved_state64(state);
+               rip = state64->isf.rip;
+               rsp = state64->isf.rsp;
+               interrupt_num = state64->isf.trapno;
+#ifdef __x86_64__
+               if(state64->isf.cs & 0x03)
+#endif
+                       user_mode = TRUE;
+       } else {
+               x86_saved_state32_t     *state32;
+
+               state32 = saved_state32(state);
+               if (state32->cs & 0x03)
+                       user_mode = TRUE;
+               rip = state32->eip;
+               rsp = state32->uesp;
+               interrupt_num = state32->trapno;
+       }
+
+       if (cpu_data_ptr[cnum]->lcpu.package->num_idle == topoParms.nLThreadsPerPackage)
+               cpu_data_ptr[cnum]->cpu_hwIntpexits[interrupt_num]++;
+
+       if (interrupt_num == (LAPIC_DEFAULT_INTERRUPT_BASE + LAPIC_INTERPROCESSOR_INTERRUPT))
+               itype = 1;
+       else if (interrupt_num == (LAPIC_DEFAULT_INTERRUPT_BASE + LAPIC_TIMER_INTERRUPT))
+               itype = 2;
+       else
+               itype = 3;
+
+       KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
+               MACHDBG_CODE(DBG_MACH_EXCP_INTR, 0) | DBG_FUNC_START,
+               interrupt_num,
+               (user_mode ? rip : VM_KERNEL_UNSLIDE(rip)),
+               user_mode, itype, 0);
+
+       SCHED_STATS_INTERRUPT(current_processor());
+
+#if CONFIG_TELEMETRY
+       if (telemetry_needs_record) {
+               telemetry_mark_curthread(user_mode);
+       }
+#endif
+
+       ipl = get_preemption_level();
+       
+       /*
+        * Handle local APIC interrupts
+        * else call platform expert for devices.
+        */
+       if (!lapic_interrupt(interrupt_num, state)) {
+               PE_incoming_interrupt(interrupt_num);
+       }
+
+       if (__improbable(get_preemption_level() != ipl)) {
+               panic("Preemption level altered by interrupt vector 0x%x: initial 0x%x, final: 0x%x\n", interrupt_num, ipl, get_preemption_level());
+       }
+
+
+       if (__improbable(cdp->cpu_nested_istack)) {
+               cdp->cpu_nested_istack_events++;
+       }
+       else  {
+               uint64_t ctime = mach_absolute_time();
+               uint64_t int_latency = ctime - cdp->cpu_int_event_time;
+               uint64_t esdeadline, ehdeadline;
+               /* Attempt to process deferred timers in the context of
+                * this interrupt, unless interrupt time has already exceeded
+                * TCOAL_ILAT_THRESHOLD.
+                */
+#define TCOAL_ILAT_THRESHOLD (30000ULL)
+
+               if ((int_latency < TCOAL_ILAT_THRESHOLD) &&
+                   interrupt_timer_coalescing_enabled) {
+                       esdeadline = cdp->rtclock_timer.queue.earliest_soft_deadline;
+                       ehdeadline = cdp->rtclock_timer.deadline;
+                       if ((ctime >= esdeadline) && (ctime < ehdeadline)) {
+                               interrupt_coalesced_timers++;
+                               TCOAL_DEBUG(0x88880000 | DBG_FUNC_START, ctime, esdeadline, ehdeadline, interrupt_coalesced_timers, 0);
+                               rtclock_intr(state);
+                               TCOAL_DEBUG(0x88880000 | DBG_FUNC_END, ctime, esdeadline, interrupt_coalesced_timers, 0, 0);
+                       } else {
+                               TCOAL_DEBUG(0x77770000, ctime, cdp->rtclock_timer.queue.earliest_soft_deadline, cdp->rtclock_timer.deadline, interrupt_coalesced_timers, 0);
+                       }
+               }
+
+               if (__improbable(ilat_assert && (int_latency > interrupt_latency_cap) && !machine_timeout_suspended())) {
+                       panic("Interrupt vector 0x%x exceeded interrupt latency threshold, 0x%llx absolute time delta, prior signals: 0x%x, current signals: 0x%x", interrupt_num, int_latency, cdp->cpu_prior_signals, cdp->cpu_signals);
+               }
+
+               if (__improbable(int_latency > cdp->cpu_max_observed_int_latency)) {
+                       cdp->cpu_max_observed_int_latency = int_latency;
+                       cdp->cpu_max_observed_int_latency_vector = interrupt_num;
+               }
+       }
+
+       /*
+        * Having serviced the interrupt first, look at the interrupted stack depth.
+        */
+       if (!user_mode) {
+               uint64_t depth = cdp->cpu_kernel_stack
+                                + sizeof(struct x86_kernel_state)
+                                + sizeof(struct i386_exception_link *)
+                                - rsp;
+               if (__improbable(depth > kernel_stack_depth_max)) {
+                       kernel_stack_depth_max = (vm_offset_t)depth;
+                       KERNEL_DEBUG_CONSTANT(
+                               MACHDBG_CODE(DBG_MACH_SCHED, MACH_STACK_DEPTH),
+                               (long) depth, (long) VM_KERNEL_UNSLIDE(rip), 0, 0, 0);
+               }
+       }
+       
+       if (cnum == master_cpu)
+               ml_entropy_collect();
+
+       KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
+               MACHDBG_CODE(DBG_MACH_EXCP_INTR, 0) | DBG_FUNC_END,
+               interrupt_num, 0, 0, 0, 0);
+
+       assert(ml_get_interrupts_enabled() == FALSE);
+}
+
+static inline void
+reset_dr7(void)
+{
+       long dr7 = 0x400; /* magic dr7 reset value; 32 bit on i386, 64 bit on x86_64 */
+       __asm__ volatile("mov %0,%%dr7" : : "r" (dr7));
+}
+#if MACH_KDP
+unsigned kdp_has_active_watchpoints = 0;
+#define NO_WATCHPOINTS (!kdp_has_active_watchpoints)
+#else
+#define NO_WATCHPOINTS 1
+#endif
 /*
  * Trap from kernel mode.  Only page-fault errors are recoverable,
  * and then only in special circumstances.  All other errors are
  * fatal.  Return value indicates if trap was handled.
  */
-boolean_t
+
+void
 kernel_trap(
-       register struct i386_saved_state        *regs)
+       x86_saved_state_t       *state,
+       uintptr_t *lo_spp)
 {
-       int     exc;
-       int     code;
-       int     subcode;
-       int     interruptible;
-       register int    type;
-       vm_map_t        map;
-       kern_return_t   result;
-       register thread_t       thread;
-       thread_act_t            thr_act;
-       etap_data_t             probe_data;
-       pt_entry_t              *pte;
-       extern vm_offset_t      vm_last_phys;
-
-       type = regs->trapno;
-       code = regs->err;
+       x86_saved_state64_t     *saved_state;
+       int                     code;
+       user_addr_t             vaddr;
+       int                     type;
+       vm_map_t                map = 0;        /* protected by T_PAGE_FAULT */
+       kern_return_t           result = KERN_FAILURE;
+       kern_return_t           fault_result = KERN_SUCCESS;
+       thread_t                thread;
+       ast_t                   *myast;
+       boolean_t               intr;
+       vm_prot_t               prot;
+        struct recovery                *rp;
+       vm_offset_t             kern_ip;
+#if NCOPY_WINDOWS > 0
+       int                     fault_in_copy_window = -1;
+#endif
+       int                     is_user;
+       int                     trap_pl = get_preemption_level();
+
        thread = current_thread();
-       thr_act = current_act();
 
-       ETAP_DATA_LOAD(probe_data[0], regs->trapno);
-       ETAP_DATA_LOAD(probe_data[1], MACH_PORT_NULL);
-       ETAP_DATA_LOAD(probe_data[2], MACH_PORT_NULL);
-       ETAP_PROBE_DATA(ETAP_P_EXCEPTION,
-                       0,
-                       thread,
-                       &probe_data,
-                       ETAP_DATA_ENTRY*3);
+       if (__improbable(is_saved_state32(state)))
+               panic("kernel_trap(%p) with 32-bit state", state);
+       saved_state = saved_state64(state);
 
-       switch (type) {
-           case T_PREEMPT:
-               return (TRUE);
+       /* Record cpu where state was captured */
+       saved_state->isf.cpu = cpu_number();
 
-           case T_NO_FPU:
-               fpnoextflt();
-               return (TRUE);
+       vaddr = (user_addr_t)saved_state->cr2;
+       type  = saved_state->isf.trapno;
+       code  = (int)(saved_state->isf.err & 0xffff);
+       intr  = (saved_state->isf.rflags & EFL_IF) != 0;        /* state of ints at trap */
+       kern_ip = (vm_offset_t)saved_state->isf.rip;
 
-           case T_FPU_FAULT:
-               fpextovrflt();
-               return (TRUE);
+       myast = ast_pending();
 
-           case T_FLOATING_POINT_ERROR:
-               fpexterrflt();
-               return (TRUE);
+       is_user = (vaddr < VM_MAX_USER_PAGE_ADDRESS);
 
-           case T_PAGE_FAULT:
-               /*
-                * If the current map is a submap of the kernel map,
-                * and the address is within that map, fault on that
-                * map.  If the same check is done in vm_fault
-                * (vm_map_lookup), we may deadlock on the kernel map
-                * lock.
-                */
-#if    MACH_KDB
-               mp_disable_preemption();
-               if (db_active
-#if    NCPUS > 1
-                   && kdb_active[cpu_number()]
-#endif /* NCPUS > 1 */
-                   && !let_ddb_vm_fault) {
+       perfASTCallback astfn = perfASTHook;
+       if (__improbable(astfn != NULL)) {
+               if (*myast & AST_CHUD_ALL)
+                       astfn(AST_CHUD_ALL, myast);
+       } else
+               *myast &= ~AST_CHUD_ALL;
+
+
+#if CONFIG_DTRACE
+       /*
+        * Is there a DTrace hook?
+        */     
+       if (__improbable(tempDTraceTrapHook != NULL)) {
+               if (tempDTraceTrapHook(type, state, lo_spp, 0) == KERN_SUCCESS) {
                        /*
-                        * Force kdb to handle this one.
+                        * If it succeeds, we are done...
                         */
-                       mp_enable_preemption();
-                       return (FALSE);
-               }
-               mp_enable_preemption();
-#endif /* MACH_KDB */
-               subcode = regs->cr2;    /* get faulting address */
-
-               if (subcode > LINEAR_KERNEL_ADDRESS) {
-                   map = kernel_map;
-                   subcode -= LINEAR_KERNEL_ADDRESS;
-               } else if (thr_act == THR_ACT_NULL || thread == THREAD_NULL)
-                   map = kernel_map;
-               else {
-                   map = thr_act->map;
+                       return;
                }
+       }
+#endif /* CONFIG_DTRACE */
+
+       /*
+        * we come here with interrupts off as we don't want to recurse
+        * on preemption below.  but we do want to re-enable interrupts
+        * as soon we possibly can to hold latency down
+        */
+       if (__improbable(T_PREEMPT == type)) {
+               ast_taken(AST_PREEMPTION, FALSE);
+
+               KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
+                       (MACHDBG_CODE(DBG_MACH_EXCP_KTRAP_x86, type)) | DBG_FUNC_NONE,
+                       0, 0, 0, VM_KERNEL_UNSLIDE(kern_ip), 0);
+               return;
+       }
+
+       user_addr_t     kd_vaddr = is_user ? vaddr : VM_KERNEL_UNSLIDE(vaddr);
+       KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
+               (MACHDBG_CODE(DBG_MACH_EXCP_KTRAP_x86, type)) | DBG_FUNC_NONE,
+               (unsigned)(kd_vaddr >> 32), (unsigned)kd_vaddr, is_user,
+               VM_KERNEL_UNSLIDE(kern_ip), 0);
 
-#if    MACH_KDB
+
+       if (T_PAGE_FAULT == type) {
                /*
-                * Check for watchpoint on kernel static data.
-                * vm_fault would fail in this case 
+                * assume we're faulting in the kernel map
                 */
-               if (map == kernel_map && 
-                   db_watchpoint_list &&
-                   db_watchpoints_inserted &&
-                   (code & T_PF_WRITE) &&
-                   (vm_offset_t)subcode < vm_last_phys &&
-                   ((*(pte = pmap_pte(kernel_pmap, (vm_offset_t)subcode))) &
-                    INTEL_PTE_WRITE) == 0) {
-                       *pte = INTEL_PTE_VALID | INTEL_PTE_WRITE |
-                              pa_to_pte(trunc_page((vm_offset_t)subcode) -
-                                        VM_MIN_KERNEL_ADDRESS);
-                       result = KERN_SUCCESS;
-               } else
-#endif /* MACH_KDB */
-               {
-                       /*
-                        * Since the 386 ignores write protection in
-                        * kernel mode, always try for write permission
-                        * first.  If that fails and the fault was a
-                        * read fault, retry with read permission.
+               map = kernel_map;
+
+               if (__probable(thread != THREAD_NULL && thread->map != kernel_map)) {
+#if NCOPY_WINDOWS > 0
+                       vm_offset_t     copy_window_base;
+                       vm_offset_t     kvaddr;
+                       int             window_index;
+
+                       kvaddr = (vm_offset_t)vaddr;
+                       /*
+                        * must determine if fault occurred in
+                        * the copy window while pre-emption is
+                        * disabled for this processor so that
+                        * we only need to look at the window
+                        * associated with this processor
                         */
-                       if (map == kernel_map) {
-                               register struct recovery *rp;
-
-                               interruptible = THREAD_UNINT;
-                               for (rp = recover_table; rp < recover_table_end; rp++) {
-                                       if (regs->eip == rp->fault_addr) {
-                                               interruptible = THREAD_ABORTSAFE;
-                                               break;
-                                       }
+                       copy_window_base = current_cpu_datap()->cpu_copywindow_base;
+
+                       if (kvaddr >= copy_window_base && kvaddr < (copy_window_base + (NBPDE * NCOPY_WINDOWS)) ) {
+
+                               window_index = (int)((kvaddr - copy_window_base) / NBPDE);
+
+                               if (thread->machine.copy_window[window_index].user_base != (user_addr_t)-1) {
+
+                                       kvaddr -= (copy_window_base + (NBPDE * window_index));
+                                       vaddr = thread->machine.copy_window[window_index].user_base + kvaddr;
+
+                                       map = thread->map;
+                                       fault_in_copy_window = window_index;
                                }
                        }
+#else
+                       if (__probable(vaddr < VM_MAX_USER_PAGE_ADDRESS)) {
+                               /* fault occurred in userspace */
+                               map = thread->map;
+
+                               /* Intercept a potential Supervisor Mode Execute
+                                * Protection fault. These criteria identify
+                                * both NX faults and SMEP faults, but both
+                                * are fatal. We avoid checking PTEs (racy).
+                                * (The VM could just redrive a SMEP fault, hence
+                                * the intercept).
+                                */
+                               if (__improbable((code == (T_PF_PROT | T_PF_EXECUTE)) &&
+                                       (pmap_smep_enabled) && (saved_state->isf.rip == vaddr))) {
+                                       goto debugger_entry;
+                               }
 
-                       result = vm_fault(map,
-                                         trunc_page((vm_offset_t)subcode),
-                                         VM_PROT_READ|VM_PROT_WRITE,
-                                         FALSE, 
-                                         (map == kernel_map) ? interruptible : THREAD_ABORTSAFE);
-               }
-#if    MACH_KDB
-               if (result == KERN_SUCCESS) {
-                   /* Look for watchpoints */
-                   if (db_watchpoint_list &&
-                       db_watchpoints_inserted &&
-                       (code & T_PF_WRITE) &&
-                       db_find_watchpoint(map,
-                               (vm_offset_t)subcode, regs))
-                       kdb_trap(T_WATCHPOINT, 0, regs);
+                               /*
+                                * Additionally check for SMAP faults...
+                                * which are characterized by page-present and
+                                * the AC bit unset (i.e. not from copyin/out path).
+                                */
+                               if (__improbable(code & T_PF_PROT &&
+                                                pmap_smap_enabled &&
+                                                (saved_state->isf.rflags & EFL_AC) == 0)) {
+                                       goto debugger_entry;
+                               }
+
+                               /*
+                                * If we're not sharing cr3 with the user
+                                * and we faulted in copyio,
+                                * then switch cr3 here and dismiss the fault.
+                                */
+                               if (no_shared_cr3 &&
+                                   (thread->machine.specFlags&CopyIOActive) &&
+                                   map->pmap->pm_cr3 != get_cr3_base()) {
+                                       pmap_assert(current_cpu_datap()->cpu_pmap_pcid_enabled == FALSE);
+                                       set_cr3_raw(map->pmap->pm_cr3);
+                                       return;
+                               }
+                               if (__improbable(vaddr < PAGE_SIZE) &&
+                                   ((thread->machine.specFlags & CopyIOActive) == 0)) {
+                                       goto debugger_entry;
+                               }
+                       }
+#endif
                }
-               else
-#endif /* MACH_KDB */
-               if ((code & T_PF_WRITE) == 0 &&
-                   result == KERN_PROTECTION_FAILURE)
-               {
-                   /*
-                    *  Must expand vm_fault by hand,
-                    *  so that we can ask for read-only access
-                    *  but enter a (kernel)writable mapping.
-                    */
-                   result = intel_read_fault(map,
-                                         trunc_page((vm_offset_t)subcode));
+       }
+
+       (void) ml_set_interrupts_enabled(intr);
+
+       switch (type) {
+
+           case T_NO_FPU:
+               fpnoextflt();
+               return;
+
+           case T_FPU_FAULT:
+               fpextovrflt();
+               return;
+
+           case T_FLOATING_POINT_ERROR:
+               fpexterrflt();
+               return;
+
+           case T_SSE_FLOAT_ERROR:
+               fpSSEexterrflt();
+               return;
+           case T_DEBUG:
+                   if ((saved_state->isf.rflags & EFL_TF) == 0 && NO_WATCHPOINTS)
+                   {
+                           /* We've somehow encountered a debug
+                            * register match that does not belong
+                            * to the kernel debugger.
+                            * This isn't supposed to happen.
+                            */
+                           reset_dr7();
+                           return;
+                   }
+                   goto debugger_entry;
+#ifdef __x86_64__
+           case T_INT3:
+             goto debugger_entry;
+#endif
+           case T_PAGE_FAULT:
+
+#if CONFIG_DTRACE
+               if (thread != THREAD_NULL && thread->options & TH_OPT_DTRACE) { /* Executing under dtrace_probe? */
+                       if (dtrace_tally_fault(vaddr)) { /* Should a fault under dtrace be ignored? */
+                               /*
+                                * DTrace has "anticipated" the possibility of this fault, and has
+                                * established the suitable recovery state. Drop down now into the
+                                * recovery handling code in "case T_GENERAL_PROTECTION:". 
+                                */
+                               goto FALL_THROUGH;
+                       }
                }
+#endif /* CONFIG_DTRACE */
+               
+               prot = VM_PROT_READ;
+
+               if (code & T_PF_WRITE)
+                       prot |= VM_PROT_WRITE;
+               if (code & T_PF_EXECUTE)
+                       prot |= VM_PROT_EXECUTE;
+
+               fault_result = result = vm_fault(map,
+                                 vaddr,
+                                 prot,
+                                 FALSE, 
+                                 THREAD_UNINT, NULL, 0);
 
                if (result == KERN_SUCCESS) {
-                   /*
-                    * Certain faults require that we back up
-                    * the EIP.
-                    */
-                   register struct recovery *rp;
-
-                   for (rp = retry_table; rp < retry_table_end; rp++) {
-                       if (regs->eip == rp->fault_addr) {
-                           regs->eip = rp->recover_addr;
-                           break;
+#if NCOPY_WINDOWS > 0
+                       if (fault_in_copy_window != -1) {
+                               ml_set_interrupts_enabled(FALSE);
+                               copy_window_fault(thread, map,
+                                                 fault_in_copy_window);
+                               (void) ml_set_interrupts_enabled(intr);
                        }
-                   }
-                   return (TRUE);
+#endif /* NCOPY_WINDOWS > 0 */
+                       return;
                }
-
-               /* fall through */
+               /*
+                * fall through
+                */
+#if CONFIG_DTRACE
+FALL_THROUGH:
+#endif /* CONFIG_DTRACE */
 
            case T_GENERAL_PROTECTION:
-
                /*
                 * If there is a failure recovery address
                 * for this fault, go there.
                 */
-               {
-                   register struct recovery *rp;
-
-                   for (rp = recover_table;
-                        rp < recover_table_end;
-                        rp++) {
-                       if (regs->eip == rp->fault_addr) {
-                           regs->eip = rp->recover_addr;
-                           return (TRUE);
+               for (rp = recover_table; rp < recover_table_end; rp++) {
+                       if (kern_ip == rp->fault_addr) {
+                               set_recovery_ip(saved_state, rp->recover_addr);
+                               return;
                        }
-                   }
                }
 
                /*
-                * Check thread recovery address also -
-                * v86 assist uses it.
+                * Check thread recovery address also.
                 */
-               if (thread->recover) {
-                   regs->eip = thread->recover;
-                   thread->recover = 0;
-                   return (TRUE);
+               if (thread != THREAD_NULL && thread->recover) {
+                       set_recovery_ip(saved_state, thread->recover);
+                       thread->recover = 0;
+                       return;
                }
-
                /*
                 * Unanticipated page-fault errors in kernel
                 * should not happen.
+                *
+                * fall through...
                 */
-               /* fall through... */
-
            default:
                /*
-                * ...and return failure, so that locore can call into
-                * debugger.
+                * Exception 15 is reserved but some chips may generate it
+                * spuriously. Seen at startup on AMD Athlon-64.
                 */
+               if (type == 15) {
+                       kprintf("kernel_trap() ignoring spurious trap 15\n"); 
+                       return;
+               }
+debugger_entry:
+               /* Ensure that the i386_kernel_state at the base of the
+                * current thread's stack (if any) is synchronized with the
+                * context at the moment of the trap, to facilitate
+                * access through the debugger.
+                */
+               sync_iss_to_iks(state);
 #if  MACH_KDP
-               kdp_i386_trap(type, regs, result, regs->cr2);
+               if (kdp_i386_trap(type, saved_state, result, (vm_offset_t)vaddr))
+                       return;
 #endif
-               return (FALSE);
        }
-       return (TRUE);
+       pal_cli();
+       panic_trap(saved_state, trap_pl, fault_result);
+       /*
+        * NO RETURN
+        */
 }
 
-/*
- * Called if both kernel_trap() and kdb_trap() fail.
- */
-void
-panic_trap(
-       register struct i386_saved_state        *regs)
+
+static void
+set_recovery_ip(x86_saved_state64_t  *saved_state, vm_offset_t ip)
 {
-       int             code;
-       register int    type;
+        saved_state->isf.rip = ip;
+}
 
-       type = regs->trapno;
-       code = regs->err;
+static void
+panic_trap(x86_saved_state64_t *regs, uint32_t pl, kern_return_t fault_result)
+{
+       const char      *trapname = "Unknown";
+       pal_cr_t        cr0, cr2, cr3, cr4;
+       boolean_t       potential_smep_fault = FALSE, potential_kernel_NX_fault = FALSE;
+       boolean_t       potential_smap_fault = FALSE;
+
+       pal_get_control_registers( &cr0, &cr2, &cr3, &cr4 );
+       assert(ml_get_interrupts_enabled() == FALSE);
+       current_cpu_datap()->cpu_fatal_trap_state = regs;
+       /*
+        * Issue an I/O port read if one has been requested - this is an
+        * event logic analyzers can use as a trigger point.
+        */
+       panic_io_port_read();
 
-       printf("trap type %d, code = %x, pc = %x\n",
-               type, code, regs->eip);
-       panic("trap");
+       kprintf("panic trap number 0x%x, rip 0x%016llx\n",
+               regs->isf.trapno, regs->isf.rip);
+       kprintf("cr0 0x%016llx cr2 0x%016llx cr3 0x%016llx cr4 0x%016llx\n",
+               cr0, cr2, cr3, cr4);
+
+       if (regs->isf.trapno < TRAP_TYPES)
+               trapname = trap_type[regs->isf.trapno];
+
+       if ((regs->isf.trapno == T_PAGE_FAULT) && (regs->isf.err == (T_PF_PROT | T_PF_EXECUTE)) && (regs->isf.rip == regs->cr2)) {
+               if (pmap_smep_enabled && (regs->isf.rip < VM_MAX_USER_PAGE_ADDRESS)) {
+                       potential_smep_fault = TRUE;
+               } else if (regs->isf.rip >= VM_MIN_KERNEL_AND_KEXT_ADDRESS) {
+                       potential_kernel_NX_fault = TRUE;
+               }
+       } else if (pmap_smap_enabled &&
+                  regs->isf.trapno == T_PAGE_FAULT &&
+                  regs->isf.err & T_PF_PROT &&
+                  regs->cr2 < VM_MAX_USER_PAGE_ADDRESS &&
+                  regs->isf.rip >= VM_MIN_KERNEL_AND_KEXT_ADDRESS) {
+               potential_smap_fault = TRUE;
+       }
+
+#undef panic
+       panic("Kernel trap at 0x%016llx, type %d=%s, registers:\n"
+             "CR0: 0x%016llx, CR2: 0x%016llx, CR3: 0x%016llx, CR4: 0x%016llx\n"
+             "RAX: 0x%016llx, RBX: 0x%016llx, RCX: 0x%016llx, RDX: 0x%016llx\n"
+             "RSP: 0x%016llx, RBP: 0x%016llx, RSI: 0x%016llx, RDI: 0x%016llx\n"
+             "R8:  0x%016llx, R9:  0x%016llx, R10: 0x%016llx, R11: 0x%016llx\n"
+             "R12: 0x%016llx, R13: 0x%016llx, R14: 0x%016llx, R15: 0x%016llx\n"
+             "RFL: 0x%016llx, RIP: 0x%016llx, CS:  0x%016llx, SS:  0x%016llx\n"
+             "Fault CR2: 0x%016llx, Error code: 0x%016llx, Fault CPU: 0x%x%s%s%s%s, PL: %d, VF: %d\n",
+             regs->isf.rip, regs->isf.trapno, trapname,
+             cr0, cr2, cr3, cr4,
+             regs->rax, regs->rbx, regs->rcx, regs->rdx,
+             regs->isf.rsp, regs->rbp, regs->rsi, regs->rdi,
+             regs->r8,  regs->r9,  regs->r10, regs->r11,
+             regs->r12, regs->r13, regs->r14, regs->r15,
+             regs->isf.rflags, regs->isf.rip, regs->isf.cs & 0xFFFF,
+             regs->isf.ss & 0xFFFF,regs->cr2, regs->isf.err, regs->isf.cpu,
+             virtualized ? " VMM" : "",
+             potential_kernel_NX_fault ? " Kernel NX fault" : "",
+             potential_smep_fault ? " SMEP/User NX fault" : "",
+             potential_smap_fault ? " SMAP fault" : "",
+             pl,
+             fault_result);
+       /*
+        * This next statement is not executed,
+        * but it's needed to stop the compiler using tail call optimization
+        * for the panic call - which confuses the subsequent backtrace.
+        */
+       cr0 = 0;
 }
 
+#if CONFIG_DTRACE
+extern kern_return_t dtrace_user_probe(x86_saved_state_t *);
+#endif
 
 /*
  *     Trap from user mode.
  */
 void
 user_trap(
-       register struct i386_saved_state        *regs)
+       x86_saved_state_t *saved_state)
 {
-       int             exc;
-       int             code;
-       int             subcode;
-       register int    type;
-       vm_map_t        map;
-       vm_prot_t       prot;
-       kern_return_t   result;
-       register thread_act_t thr_act = current_act();
-       thread_t thread = (thr_act ? thr_act->thread : THREAD_NULL);
-       boolean_t       kernel_act = thr_act->kernel_loaded;
-       etap_data_t     probe_data;
-
-       if (regs->efl & EFL_VM) {
-           /*
-            * If hardware assist can handle exception,
-            * continue execution.
-            */
-           if (v86_assist(thread, regs))
-               return;
+       int                     exc;
+       int                     err;
+       mach_exception_code_t   code;
+       mach_exception_subcode_t subcode;
+       int                     type;
+       user_addr_t             vaddr;
+       vm_prot_t               prot;
+       thread_t                thread = current_thread();
+       ast_t                   *myast;
+       kern_return_t           kret;
+       user_addr_t             rip;
+       unsigned long           dr6 = 0; /* 32 bit for i386, 64 bit for x86_64 */
+
+       assert((is_saved_state32(saved_state) && !thread_is_64bit(thread)) ||
+              (is_saved_state64(saved_state) &&  thread_is_64bit(thread)));
+
+       if (is_saved_state64(saved_state)) {
+               x86_saved_state64_t     *regs;
+
+               regs = saved_state64(saved_state);
+
+               /* Record cpu where state was captured */
+               regs->isf.cpu = cpu_number();
+
+               type = regs->isf.trapno;
+               err  = (int)regs->isf.err & 0xffff;
+               vaddr = (user_addr_t)regs->cr2;
+               rip   = (user_addr_t)regs->isf.rip;
+       } else {
+               x86_saved_state32_t     *regs;
+
+               regs = saved_state32(saved_state);
+
+               /* Record cpu where state was captured */
+               regs->cpu = cpu_number();
+
+               type  = regs->trapno;
+               err   = regs->err & 0xffff;
+               vaddr = (user_addr_t)regs->cr2;
+               rip   = (user_addr_t)regs->eip;
+       }
+
+       if ((type == T_DEBUG) && thread->machine.ids) {
+               unsigned long clear = 0;
+               /* Stash and clear this processor's DR6 value, in the event
+                * this was a debug register match
+                */
+               __asm__ volatile ("mov %%db6, %0" : "=r" (dr6)); 
+               __asm__ volatile ("mov %0, %%db6" : : "r" (clear));
        }
 
-       type = regs->trapno;
+       pal_sti();
+
+       KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
+               (MACHDBG_CODE(DBG_MACH_EXCP_UTRAP_x86, type)) | DBG_FUNC_NONE,
+               (unsigned)(vaddr>>32), (unsigned)vaddr,
+               (unsigned)(rip>>32), (unsigned)rip, 0);
+
        code = 0;
        subcode = 0;
+       exc = 0;
 
+#if DEBUG_TRACE
+       kprintf("user_trap(0x%08x) type=%d vaddr=0x%016llx\n",
+               saved_state, type, vaddr);
+#endif
+
+       perfASTCallback astfn = perfASTHook;
+       if (__improbable(astfn != NULL)) {
+               myast = ast_pending();
+               if (*myast & AST_CHUD_ALL) {
+                       astfn(AST_CHUD_ALL, myast);
+               }
+       }
+
+       /* Is there a hook? */
+       perfCallback fn = perfTrapHook;
+       if (__improbable(fn != NULL)) {
+               if (fn(type, saved_state, 0, 0) == KERN_SUCCESS)
+                       return; /* If it succeeds, we are done... */
+       }
+
+#if CONFIG_DTRACE
+       /*
+        * DTrace does not consume all user traps, only INT_3's for now.
+        * Avoid needlessly calling tempDTraceTrapHook here, and let the
+        * INT_3 case handle them.
+        */
+#endif
+       
+       DEBUG_KPRINT_SYSCALL_MASK(1,
+               "user_trap: type=0x%x(%s) err=0x%x cr2=%p rip=%p\n",
+               type, trap_type[type], err, (void *)(long) vaddr, (void *)(long) rip);
+       
        switch (type) {
 
            case T_DIVIDE_ERROR:
@@ -506,11 +988,37 @@ user_trap(
                break;
 
            case T_DEBUG:
-               exc = EXC_BREAKPOINT;
-               code = EXC_I386_SGL;
-               break;
-
+               {
+                       pcb_t   pcb;
+                       /*
+                        * Update the PCB with this processor's DR6 value
+                        * in the event this was a debug register match.
+                        */
+                       pcb = THREAD_TO_PCB(thread);
+                       if (pcb->ids) {
+                               /*
+                                * We can get and set the status register
+                                * in 32-bit mode even on a 64-bit thread
+                                * because the high order bits are not
+                                * used on x86_64
+                                */
+                               if (thread_is_64bit(thread)) {
+                                       x86_debug_state64_t *ids = pcb->ids;
+                                       ids->dr6 = dr6;
+                               } else { /* 32 bit thread */
+                                       x86_debug_state32_t *ids = pcb->ids;
+                                       ids->dr6 = (uint32_t) dr6;
+                               }
+                       }
+                       exc = EXC_BREAKPOINT;
+                       code = EXC_I386_SGL;
+                       break;
+               }
            case T_INT3:
+#if CONFIG_DTRACE
+               if (dtrace_user_probe(saved_state) == KERN_SUCCESS)
+                       return; /* If it succeeds, we are done... */
+#endif
                exc = EXC_BREAKPOINT;
                code = EXC_I386_BPT;
                break;
@@ -531,531 +1039,109 @@ user_trap(
                break;
 
            case T_NO_FPU:
-           case 32:            /* XXX */
                fpnoextflt();
                return;
 
            case T_FPU_FAULT:
-               fpextovrflt();
+               fpextovrflt(); /* Propagates exception directly, doesn't return */
                return;
 
-           case 10:            /* invalid TSS == iret with NT flag set */
+           case T_INVALID_TSS: /* invalid TSS == iret with NT flag set */
                exc = EXC_BAD_INSTRUCTION;
                code = EXC_I386_INVTSSFLT;
-               subcode = regs->err & 0xffff;
+               subcode = err;
                break;
 
            case T_SEGMENT_NOT_PRESENT:
                exc = EXC_BAD_INSTRUCTION;
                code = EXC_I386_SEGNPFLT;
-               subcode = regs->err & 0xffff;
+               subcode = err;
                break;
 
            case T_STACK_FAULT:
                exc = EXC_BAD_INSTRUCTION;
                code = EXC_I386_STKFLT;
-               subcode = regs->err & 0xffff;
+               subcode = err;
                break;
 
            case T_GENERAL_PROTECTION:
-               if (!(regs->efl & EFL_VM)) {
-                   if (check_io_fault(regs))
-                       return;
-               }
-               exc = EXC_BAD_INSTRUCTION;
+               /*
+                * There's a wide range of circumstances which generate this
+                * class of exception. From user-space, many involve bad
+                * addresses (such as a non-canonical 64-bit address).
+                * So we map this to EXC_BAD_ACCESS (and thereby SIGSEGV).
+                * The trouble is cr2 doesn't contain the faulting address;
+                * we'd need to decode the faulting instruction to really
+                * determine this. We'll leave that to debuggers.
+                * However, attempted execution of privileged instructions
+                * (e.g. cli) also generate GP faults and so we map these to
+                * to EXC_BAD_ACCESS (and thence SIGSEGV) also - rather than
+                * EXC_BAD_INSTRUCTION which is more accurate. We just can't
+                * win!
+                */ 
+               exc = EXC_BAD_ACCESS;
                code = EXC_I386_GPFLT;
-               subcode = regs->err & 0xffff;
+               subcode = err;
                break;
 
            case T_PAGE_FAULT:
-               subcode = regs->cr2;
-               prot = VM_PROT_READ|VM_PROT_WRITE;
-               if (kernel_act == FALSE) {
-                       if (!(regs->err & T_PF_WRITE))
-                               prot = VM_PROT_READ;
-                       (void) user_page_fault_continue(vm_fault(thr_act->map,
-                               trunc_page((vm_offset_t)subcode),
-                               prot,
-                               FALSE,
-                               THREAD_ABORTSAFE));
-                       /* NOTREACHED */
-               }
-               else {
-                       if (subcode > LINEAR_KERNEL_ADDRESS) {
-                               map = kernel_map;
-                               subcode -= LINEAR_KERNEL_ADDRESS;
-                       }
-                       result = vm_fault(thr_act->map,
-                               trunc_page((vm_offset_t)subcode),
-                               prot,
-                               FALSE,
-                               (map == kernel_map) ? THREAD_UNINT : THREAD_ABORTSAFE);
-                       if ((result != KERN_SUCCESS) && (result != KERN_ABORTED)) {
-                               /*
-                                * Must expand vm_fault by hand,
-                                * so that we can ask for read-only access
-                                * but enter a (kernel) writable mapping.
-                                */
-                               result = intel_read_fault(thr_act->map,
-                                       trunc_page((vm_offset_t)subcode));
-                       }
-                       user_page_fault_continue(result);
+           {
+                   prot = VM_PROT_READ;
+
+               if (err & T_PF_WRITE)
+                       prot |= VM_PROT_WRITE;
+               if (__improbable(err & T_PF_EXECUTE))
+                       prot |= VM_PROT_EXECUTE;
+               kret = vm_fault(thread->map,
+                               vaddr,
+                               prot, FALSE,
+                               THREAD_ABORTSAFE, NULL, 0);
+
+               if (__probable((kret == KERN_SUCCESS) || (kret == KERN_ABORTED))) {
+                       thread_exception_return();
                        /*NOTREACHED*/
                }
+
+               user_page_fault_continue(kret);
+           }   /* NOTREACHED */
                break;
 
-           case T_FLOATING_POINT_ERROR:
-               fpexterrflt();
+           case T_SSE_FLOAT_ERROR:
+               fpSSEexterrflt(); /* Propagates exception directly, doesn't return */
                return;
 
-           default:
-#if     MACH_KGDB
-               Debugger("Unanticipated user trap");
-               return;
-#endif  /* MACH_KGDB */
-#if    MACH_KDB
-               if (kdb_trap(type, regs->err, regs))
-                   return;
-#endif /* MACH_KDB */
-               printf("user trap type %d, code = %x, pc = %x\n",
-                      type, regs->err, regs->eip);
-               panic("user trap");
-               return;
-       }
 
-#if    MACH_KDB
-       if (debug_all_traps_with_kdb &&
-           kdb_trap(type, regs->err, regs))
+           case T_FLOATING_POINT_ERROR:
+               fpexterrflt(); /* Propagates exception directly, doesn't return */
                return;
-#endif /* MACH_KDB */
-
-#if    ETAP_EVENT_MONITOR
-       if (thread != THREAD_NULL) {
-               ETAP_DATA_LOAD(probe_data[0], regs->trapno);
-               ETAP_DATA_LOAD(probe_data[1],
-                              thr_act->exc_actions[exc].port);
-               ETAP_DATA_LOAD(probe_data[2],
-                              thr_act->task->exc_actions[exc].port);
-               ETAP_PROBE_DATA(ETAP_P_EXCEPTION,
-                               0,
-                               thread,         
-                               &probe_data,
-                               ETAP_DATA_ENTRY*3);
-       }
-#endif /* ETAP_EVENT_MONITOR */
-
-       i386_exception(exc, code, subcode);
-       /*NOTREACHED*/
-}
-
-/*
- *     V86 mode assist for interrupt handling.
- */
-boolean_t v86_assist_on = TRUE;
-boolean_t v86_unsafe_ok = FALSE;
-boolean_t v86_do_sti_cli = TRUE;
-boolean_t v86_do_sti_immediate = FALSE;
-
-#define        V86_IRET_PENDING 0x4000
-
-int cli_count = 0;
-int sti_count = 0;
-
-boolean_t
-v86_assist(
-       thread_t                                thread,
-       register struct i386_saved_state        *regs)
-{
-       register struct v86_assist_state *v86 = &thread->top_act->mact.pcb->ims.v86s;
-
-/*
- * Build an 8086 address.  Use only when off is known to be 16 bits.
- */
-#define        Addr8086(seg,off)       ((((seg) & 0xffff) << 4) + (off))
-
-#define        EFL_V86_SAFE            (  EFL_OF | EFL_DF | EFL_TF \
-                                | EFL_SF | EFL_ZF | EFL_AF \
-                                | EFL_PF | EFL_CF )
-       struct iret_32 {
-               int             eip;
-               int             cs;
-               int             eflags;
-       };
-       struct iret_16 {
-               unsigned short  ip;
-               unsigned short  cs;
-               unsigned short  flags;
-       };
-       union iret_struct {
-               struct iret_32  iret_32;
-               struct iret_16  iret_16;
-       };
-
-       struct int_vec {
-               unsigned short  ip;
-               unsigned short  cs;
-       };
-
-       if (!v86_assist_on)
-           return FALSE;
-
-       /*
-        * If delayed STI pending, enable interrupts.
-        * Turn off tracing if on only to delay STI.
-        */
-       if (v86->flags & V86_IF_PENDING) {
-           v86->flags &= ~V86_IF_PENDING;
-           v86->flags |=  EFL_IF;
-           if ((v86->flags & EFL_TF) == 0)
-               regs->efl &= ~EFL_TF;
-       }
 
-       if (regs->trapno == T_DEBUG) {
-
-           if (v86->flags & EFL_TF) {
+           case T_DTRACE_RET:
+#if CONFIG_DTRACE
+               if (dtrace_user_probe(saved_state) == KERN_SUCCESS)
+                       return; /* If it succeeds, we are done... */
+#endif
                /*
-                * Trace flag was also set - it has priority
+                * If we get an INT 0x7f when we do not expect to,
+                * treat it as an illegal instruction
                 */
-               return FALSE;                   /* handle as single-step */
-           }
-           /*
-            * Fall through to check for interrupts.
-            */
-       }
-       else if (regs->trapno == T_GENERAL_PROTECTION) {
-           /*
-            * General protection error - must be an 8086 instruction
-            * to emulate.
-            */
-           register int        eip;
-           boolean_t   addr_32 = FALSE;
-           boolean_t   data_32 = FALSE;
-           int         io_port;
-
-           /*
-            * Set up error handler for bad instruction/data
-            * fetches.
-            */
-           __asm__("movl $(addr_error), %0" : : "m" (thread->recover));
-
-           eip = regs->eip;
-           while (TRUE) {
-               unsigned char   opcode;
-
-               if (eip > 0xFFFF) {
-                   thread->recover = 0;
-                   return FALSE;       /* GP fault: IP out of range */
-               }
-
-               opcode = *(unsigned char *)Addr8086(regs->cs,eip);
-               eip++;
-               switch (opcode) {
-                   case 0xf0:          /* lock */
-                   case 0xf2:          /* repne */
-                   case 0xf3:          /* repe */
-                   case 0x2e:          /* cs */
-                   case 0x36:          /* ss */
-                   case 0x3e:          /* ds */
-                   case 0x26:          /* es */
-                   case 0x64:          /* fs */
-                   case 0x65:          /* gs */
-                       /* ignore prefix */
-                       continue;
-
-                   case 0x66:          /* data size */
-                       data_32 = TRUE;
-                       continue;
-
-                   case 0x67:          /* address size */
-                       addr_32 = TRUE;
-                       continue;
-
-                   case 0xe4:          /* inb imm */
-                   case 0xe5:          /* inw imm */
-                   case 0xe6:          /* outb imm */
-                   case 0xe7:          /* outw imm */
-                       io_port = *(unsigned char *)Addr8086(regs->cs, eip);
-                       eip++;
-                       goto do_in_out;
-
-                   case 0xec:          /* inb dx */
-                   case 0xed:          /* inw dx */
-                   case 0xee:          /* outb dx */
-                   case 0xef:          /* outw dx */
-                   case 0x6c:          /* insb */
-                   case 0x6d:          /* insw */
-                   case 0x6e:          /* outsb */
-                   case 0x6f:          /* outsw */
-                       io_port = regs->edx & 0xffff;
-
-                   do_in_out:
-                       if (!data_32)
-                           opcode |= 0x6600;   /* word IO */
-
-                       switch (emulate_io(regs, opcode, io_port)) {
-                           case EM_IO_DONE:
-                               /* instruction executed */
-                               break;
-                           case EM_IO_RETRY:
-                               /* port mapped, retry instruction */
-                               thread->recover = 0;
-                               return TRUE;
-                           case EM_IO_ERROR:
-                               /* port not mapped */
-                               thread->recover = 0;
-                               return FALSE;
-                       }
-                       break;
-
-                   case 0xfa:          /* cli */
-                       if (!v86_do_sti_cli) {
-                           thread->recover = 0;
-                           return (FALSE);
-                       }
-
-                       v86->flags &= ~EFL_IF;
-                                       /* disable simulated interrupts */
-                       cli_count++;
-                       break;
-
-                   case 0xfb:          /* sti */
-                       if (!v86_do_sti_cli) {
-                           thread->recover = 0;
-                           return (FALSE);
-                       }
-
-                       if ((v86->flags & EFL_IF) == 0) {
-                           if (v86_do_sti_immediate) {
-                                   v86->flags |= EFL_IF;
-                           } else {
-                                   v86->flags |= V86_IF_PENDING;
-                                   regs->efl |= EFL_TF;
-                           }
-                                       /* single step to set IF next inst. */
-                       }
-                       sti_count++;
-                       break;
-
-                   case 0x9c:          /* pushf */
-                   {
-                       int     flags;
-                       vm_offset_t sp;
-                       int     size;
-
-                       flags = regs->efl;
-                       if ((v86->flags & EFL_IF) == 0)
-                           flags &= ~EFL_IF;
-
-                       if ((v86->flags & EFL_TF) == 0)
-                           flags &= ~EFL_TF;
-                       else flags |= EFL_TF;
-
-                       sp = regs->uesp;
-                       if (!addr_32)
-                           sp &= 0xffff;
-                       else if (sp > 0xffff)
-                           goto stack_error;
-                       size = (data_32) ? 4 : 2;
-                       if (sp < size)
-                           goto stack_error;
-                       sp -= size;
-                       if (copyout((char *)&flags,
-                                   (char *)Addr8086(regs->ss,sp),
-                                   size))
-                           goto addr_error;
-                       if (addr_32)
-                           regs->uesp = sp;
-                       else
-                           regs->uesp = (regs->uesp & 0xffff0000) | sp;
-                       break;
-                   }
-
-                   case 0x9d:          /* popf */
-                   {
-                       vm_offset_t sp;
-                       int     nflags;
-
-                       sp = regs->uesp;
-                       if (!addr_32)
-                           sp &= 0xffff;
-                       else if (sp > 0xffff)
-                           goto stack_error;
-
-                       if (data_32) {
-                           if (sp > 0xffff - sizeof(int))
-                               goto stack_error;
-                           nflags = *(int *)Addr8086(regs->ss,sp);
-                           sp += sizeof(int);
-                       }
-                       else {
-                           if (sp > 0xffff - sizeof(short))
-                               goto stack_error;
-                           nflags = *(unsigned short *)
-                                       Addr8086(regs->ss,sp);
-                           sp += sizeof(short);
-                       }
-                       if (addr_32)
-                           regs->uesp = sp;
-                       else
-                           regs->uesp = (regs->uesp & 0xffff0000) | sp;
-
-                       if (v86->flags & V86_IRET_PENDING) {
-                               v86->flags = nflags & (EFL_TF | EFL_IF);
-                               v86->flags |= V86_IRET_PENDING;
-                       } else {
-                               v86->flags = nflags & (EFL_TF | EFL_IF);
-                       }
-                       regs->efl = (regs->efl & ~EFL_V86_SAFE)
-                                    | (nflags & EFL_V86_SAFE);
-                       break;
-                   }
-                   case 0xcf:          /* iret */
-                   {
-                       vm_offset_t sp;
-                       int     nflags;
-                       int     size;
-                       union iret_struct iret_struct;
-
-                       v86->flags &= ~V86_IRET_PENDING;
-                       sp = regs->uesp;
-                       if (!addr_32)
-                           sp &= 0xffff;
-                       else if (sp > 0xffff)
-                           goto stack_error;
-
-                       if (data_32) {
-                           if (sp > 0xffff - sizeof(struct iret_32))
-                               goto stack_error;
-                           iret_struct.iret_32 =
-                               *(struct iret_32 *) Addr8086(regs->ss,sp);
-                           sp += sizeof(struct iret_32);
-                       }
-                       else {
-                           if (sp > 0xffff - sizeof(struct iret_16))
-                               goto stack_error;
-                           iret_struct.iret_16 =
-                               *(struct iret_16 *) Addr8086(regs->ss,sp);
-                           sp += sizeof(struct iret_16);
-                       }
-                       if (addr_32)
-                           regs->uesp = sp;
-                       else
-                           regs->uesp = (regs->uesp & 0xffff0000) | sp;
-
-                       if (data_32) {
-                           eip       = iret_struct.iret_32.eip;
-                           regs->cs  = iret_struct.iret_32.cs & 0xffff;
-                           nflags    = iret_struct.iret_32.eflags;
-                       }
-                       else {
-                           eip       = iret_struct.iret_16.ip;
-                           regs->cs  = iret_struct.iret_16.cs;
-                           nflags    = iret_struct.iret_16.flags;
-                       }
-
-                       v86->flags = nflags & (EFL_TF | EFL_IF);
-                       regs->efl = (regs->efl & ~EFL_V86_SAFE)
-                                    | (nflags & EFL_V86_SAFE);
-                       break;
-                   }
-                   default:
-                       /*
-                        * Instruction not emulated here.
-                        */
-                       thread->recover = 0;
-                       return FALSE;
-               }
-               break;  /* exit from 'while TRUE' */
-           }
-           regs->eip = (regs->eip & 0xffff0000 | eip);
-       }
-       else {
-           /*
-            * Not a trap we handle.
-            */
-           thread->recover = 0;
-           return FALSE;
-       }
-
-       if ((v86->flags & EFL_IF) && ((v86->flags & V86_IRET_PENDING)==0)) {
-
-           struct v86_interrupt_table *int_table;
-           int int_count;
-           int vec;
-           int i;
-
-           int_table = (struct v86_interrupt_table *) v86->int_table;
-           int_count = v86->int_count;
+               exc = EXC_BAD_INSTRUCTION;
+               code = EXC_I386_INVOP;
+               break;
 
-           vec = 0;
-           for (i = 0; i < int_count; int_table++, i++) {
-               if (!int_table->mask && int_table->count > 0) {
-                   int_table->count--;
-                   vec = int_table->vec;
-                   break;
-               }
-           }
-           if (vec != 0) {
-               /*
-                * Take this interrupt
-                */
-               vm_offset_t     sp;
-               struct iret_16 iret_16;
-               struct int_vec int_vec;
-
-               sp = regs->uesp & 0xffff;
-               if (sp < sizeof(struct iret_16))
-                   goto stack_error;
-               sp -= sizeof(struct iret_16);
-               iret_16.ip = regs->eip;
-               iret_16.cs = regs->cs;
-               iret_16.flags = regs->efl & 0xFFFF;
-               if ((v86->flags & EFL_TF) == 0)
-                   iret_16.flags &= ~EFL_TF;
-               else iret_16.flags |= EFL_TF;
-
-               (void) memcpy((char *) &int_vec, 
-                             (char *) (sizeof(struct int_vec) * vec),
-                             sizeof (struct int_vec));
-               if (copyout((char *)&iret_16,
-                           (char *)Addr8086(regs->ss,sp),
-                           sizeof(struct iret_16)))
-                   goto addr_error;
-               regs->uesp = (regs->uesp & 0xFFFF0000) | (sp & 0xffff);
-               regs->eip = int_vec.ip;
-               regs->cs  = int_vec.cs;
-               regs->efl  &= ~EFL_TF;
-               v86->flags &= ~(EFL_IF | EFL_TF);
-               v86->flags |= V86_IRET_PENDING;
-           }
+           default:
+               panic("Unexpected user trap, type %d", type);
+               return;
        }
-
-       thread->recover = 0;
-       return TRUE;
-
-       /*
-        *      On address error, report a page fault.
-        *      XXX report GP fault - we don`t save
-        *      the faulting address.
+       /* Note: Codepaths that directly return from user_trap() have pending
+        * ASTs processed in locore
         */
-    addr_error:
-       __asm__("addr_error:;");
-       thread->recover = 0;
-       return FALSE;
-
-       /*
-        *      On stack address error, return stack fault (12).
-        */
-    stack_error:
-       thread->recover = 0;
-       regs->trapno = T_STACK_FAULT;
-       return FALSE;
+       i386_exception(exc, code, subcode);
+       /* NOTREACHED */
 }
 
+
 /*
  * Handle AST traps for i386.
- * Check for delayed floating-point exception from
- * AT-bus machines.
  */
 
 extern void     log_thread_action (thread_t, char *);
@@ -1063,75 +1149,17 @@ extern void     log_thread_action (thread_t, char *);
 void
 i386_astintr(int preemption)
 {
-       int             mycpu;
        ast_t           mask = AST_ALL;
        spl_t           s;
-       thread_t        self = current_thread();
-
-       s = splsched();         /* block interrupts to check reasons */
-       mp_disable_preemption();
-       mycpu = cpu_number();
-       if (need_ast[mycpu] & AST_I386_FP) {
-           /*
-            * AST was for delayed floating-point exception -
-            * FP interrupt occured while in kernel.
-            * Turn off this AST reason and handle the FPU error.
-            */
-
-           ast_off(AST_I386_FP);
-           mp_enable_preemption();
-           splx(s);
-
-           fpexterrflt();
-       }
-       else {
-           /*
-            * Not an FPU trap.  Handle the AST.
-            * Interrupts are still blocked.
-            */
-
-#ifdef XXX
-           if (preemption) {
-
-           /*
-            * We don't want to process any AST if we were in
-            * kernel-mode and the current thread is in any
-            * funny state (waiting and/or suspended).
-            */
-
-               thread_lock (self);
-
-               if (thread_not_preemptable(self) || self->preempt) {
-                       ast_off(AST_URGENT);
-                       thread_unlock (self);
-                       mp_enable_preemption();
-                       splx(s);
-                       return;
-               }
-               else mask = AST_PREEMPT;
-               mp_enable_preemption();
 
-/*
-               self->preempt = TH_NOT_PREEMPTABLE;
-*/
+       if (preemption)
+               mask = AST_PREEMPTION;
 
-               thread_unlock (self);
-           } else {
-               mp_enable_preemption();
-           }
-#else
-       mp_enable_preemption();
-#endif
+       s = splsched();
 
-           ast_taken(mask, s
-#if    FAST_IDLE
-                     ,NO_IDLE_THREAD
-#endif /* FAST_IDLE */
-                     );
-/*
-           self->preempt = TH_PREEMPTABLE;
-*/
-       }
+       ast_taken(mask, s);
+
+       splx(s);
 }
 
 /*
@@ -1147,150 +1175,122 @@ i386_astintr(int preemption)
 void
 i386_exception(
        int     exc,
-       int     code,
-       int     subcode)
+       mach_exception_code_t code,
+       mach_exception_subcode_t subcode)
 {
-       spl_t                   s;
-       exception_data_type_t   codes[EXCEPTION_CODE_MAX];
-
-       /*
-        * Turn off delayed FPU error handling.
-        */
-       s = splsched();
-       mp_disable_preemption();
-       ast_off(AST_I386_FP);
-       mp_enable_preemption();
-       splx(s);
+       mach_exception_data_type_t   codes[EXCEPTION_CODE_MAX];
 
+       DEBUG_KPRINT_SYSCALL_MACH("i386_exception: exc=%d code=0x%llx subcode=0x%llx\n",
+                                                         exc, code, subcode);
        codes[0] = code;                /* new exception interface */
        codes[1] = subcode;
-       exception(exc, codes, 2);
+       exception_triage(exc, codes, 2);
        /*NOTREACHED*/
 }
 
-boolean_t
-check_io_fault(
-       struct i386_saved_state         *regs)
+
+/* Synchronize a thread's x86_kernel_state (if any) with the given
+ * x86_saved_state_t obtained from the trap/IPI handler; called in
+ * kernel_trap() prior to entering the debugger, and when receiving
+ * an "MP_KDP" IPI. Called with null saved_state if an incoming IPI
+ * was detected from the kernel while spinning with interrupts masked.
+ */
+  
+void
+sync_iss_to_iks(x86_saved_state_t *saved_state)
 {
-       int             eip, opcode, io_port;
-       boolean_t       data_16 = FALSE;
+       struct x86_kernel_state *iks;
+       vm_offset_t kstack;
+       boolean_t record_active_regs = FALSE;
 
-       /*
-        * Get the instruction.
-        */
-       eip = regs->eip;
-
-       for (;;) {
-           opcode = inst_fetch(eip, regs->cs);
-           eip++;
-           switch (opcode) {
-               case 0x66:      /* data-size prefix */
-                   data_16 = TRUE;
-                   continue;
-
-               case 0xf3:      /* rep prefix */
-               case 0x26:      /* es */
-               case 0x2e:      /* cs */
-               case 0x36:      /* ss */
-               case 0x3e:      /* ds */
-               case 0x64:      /* fs */
-               case 0x65:      /* gs */
-                   continue;
-
-               case 0xE4:      /* inb imm */
-               case 0xE5:      /* inl imm */
-               case 0xE6:      /* outb imm */
-               case 0xE7:      /* outl imm */
-                   /* port is immediate byte */
-                   io_port = inst_fetch(eip, regs->cs);
-                   eip++;
-                   break;
-
-               case 0xEC:      /* inb dx */
-               case 0xED:      /* inl dx */
-               case 0xEE:      /* outb dx */
-               case 0xEF:      /* outl dx */
-               case 0x6C:      /* insb */
-               case 0x6D:      /* insl */
-               case 0x6E:      /* outsb */
-               case 0x6F:      /* outsl */
-                   /* port is in DX register */
-                   io_port = regs->edx & 0xFFFF;
-                   break;
-
-               default:
-                   return FALSE;
-           }
-           break;
-       }
+       /* The PAL may have a special way to sync registers */
+       if (saved_state && saved_state->flavor == THREAD_STATE_NONE)
+               pal_get_kern_regs( saved_state );
 
-       if (data_16)
-           opcode |= 0x6600;           /* word IO */
+       if ((kstack = current_thread()->kernel_stack) != 0) {
+               x86_saved_state64_t     *regs = saved_state64(saved_state);
 
-       switch (emulate_io(regs, opcode, io_port)) {
-           case EM_IO_DONE:
-               /* instruction executed */
-               regs->eip = eip;
-               return TRUE;
+               iks = STACK_IKS(kstack);
 
-           case EM_IO_RETRY:
-               /* port mapped, retry instruction */
-               return TRUE;
+               /* Did we take the trap/interrupt in kernel mode? */
+               if (saved_state == NULL || /* NULL => polling in kernel */
+                   regs == USER_REGS64(current_thread()))
+                       record_active_regs = TRUE;
+               else {
+                       iks->k_rbx = regs->rbx;
+                       iks->k_rsp = regs->isf.rsp;
+                       iks->k_rbp = regs->rbp;
+                       iks->k_r12 = regs->r12;
+                       iks->k_r13 = regs->r13;
+                       iks->k_r14 = regs->r14;
+                       iks->k_r15 = regs->r15;
+                       iks->k_rip = regs->isf.rip;
+               }
+       }
 
-           case EM_IO_ERROR:
-               /* port not mapped */
-               return FALSE;
+       if (record_active_regs == TRUE) {
+               /* Show the trap handler path */
+               __asm__ volatile("movq %%rbx, %0" : "=m" (iks->k_rbx));
+               __asm__ volatile("movq %%rsp, %0" : "=m" (iks->k_rsp));
+               __asm__ volatile("movq %%rbp, %0" : "=m" (iks->k_rbp));
+               __asm__ volatile("movq %%r12, %0" : "=m" (iks->k_r12));
+               __asm__ volatile("movq %%r13, %0" : "=m" (iks->k_r13));
+               __asm__ volatile("movq %%r14, %0" : "=m" (iks->k_r14));
+               __asm__ volatile("movq %%r15, %0" : "=m" (iks->k_r15));
+               /* "Current" instruction pointer */
+               __asm__ volatile("leaq 1f(%%rip), %%rax; mov %%rax, %0\n1:"
+                                : "=m" (iks->k_rip)
+                                :
+                                : "rax");
        }
-       return FALSE;
 }
 
+/*
+ * This is used by the NMI interrupt handler (from mp.c) to
+ * uncondtionally sync the trap handler context to the IKS
+ * irrespective of whether the NMI was fielded in kernel
+ * or user space.
+ */
 void
-kernel_preempt_check (void)
-{
-       mp_disable_preemption();
-        if ((need_ast[cpu_number()] & AST_URGENT) &&
-#if    NCPUS > 1
-           get_interrupt_level() == 1
-#else  /* NCPUS > 1 */
-           get_interrupt_level() == 0
-#endif /* NCPUS > 1 */
-           ) {
-               mp_enable_preemption_no_check();
-                __asm__ volatile ("     int     $0xff");
-        } else {
-               mp_enable_preemption_no_check();
+sync_iss_to_iks_unconditionally(__unused x86_saved_state_t *saved_state) {
+       struct x86_kernel_state *iks;
+       vm_offset_t kstack;
+
+       if ((kstack = current_thread()->kernel_stack) != 0) {
+               iks = STACK_IKS(kstack);
+               /* Display the trap handler path */
+               __asm__ volatile("movq %%rbx, %0" : "=m" (iks->k_rbx));
+               __asm__ volatile("movq %%rsp, %0" : "=m" (iks->k_rsp));
+               __asm__ volatile("movq %%rbp, %0" : "=m" (iks->k_rbp));
+               __asm__ volatile("movq %%r12, %0" : "=m" (iks->k_r12));
+               __asm__ volatile("movq %%r13, %0" : "=m" (iks->k_r13));
+               __asm__ volatile("movq %%r14, %0" : "=m" (iks->k_r14));
+               __asm__ volatile("movq %%r15, %0" : "=m" (iks->k_r15));
+               /* "Current" instruction pointer */
+               __asm__ volatile("leaq 1f(%%rip), %%rax; mov %%rax, %0\n1:" : "=m" (iks->k_rip)::"rax");
        }
 }
 
-#if    MACH_KDB
+#if DEBUG
+extern void    thread_exception_return_internal(void) __dead2;
 
-extern void    db_i386_state(struct i386_saved_state *regs);
+void thread_exception_return(void) {
+       thread_t thread = current_thread();
+       ml_set_interrupts_enabled(FALSE);
+       if (thread_is_64bit(thread) != task_has_64BitAddr(thread->task)) {
+               panic("Task/thread bitness mismatch %p %p, task: %d, thread: %d", thread, thread->task, thread_is_64bit(thread),  task_has_64BitAddr(thread->task));
+       }
 
-#include <ddb/db_output.h>
+       if (thread_is_64bit(thread)) {
+               if ((gdt_desc_p(USER64_CS)->access & ACC_PL_U) == 0) {
+                       panic("64-GDT mismatch %p, descriptor: %p", thread, gdt_desc_p(USER64_CS));
+               }
+       } else {
+                       if ((gdt_desc_p(USER_CS)->access & ACC_PL_U) == 0) {
+                               panic("32-GDT mismatch %p, descriptor: %p", thread, gdt_desc_p(USER_CS));
 
-void 
-db_i386_state(
-       struct i386_saved_state *regs)
-{
-       db_printf("eip  %8x\n", regs->eip);
-       db_printf("trap %8x\n", regs->trapno);
-       db_printf("err  %8x\n", regs->err);
-       db_printf("efl  %8x\n", regs->efl);
-       db_printf("ebp  %8x\n", regs->ebp);
-       db_printf("esp  %8x\n", regs->esp);
-       db_printf("uesp %8x\n", regs->uesp);
-       db_printf("cs   %8x\n", regs->cs & 0xff);
-       db_printf("ds   %8x\n", regs->ds & 0xff);
-       db_printf("es   %8x\n", regs->es & 0xff);
-       db_printf("fs   %8x\n", regs->fs & 0xff);
-       db_printf("gs   %8x\n", regs->gs & 0xff);
-       db_printf("ss   %8x\n", regs->ss & 0xff);
-       db_printf("eax  %8x\n", regs->eax);
-       db_printf("ebx  %8x\n", regs->ebx);
-       db_printf("ecx  %8x\n", regs->ecx);
-       db_printf("edx  %8x\n", regs->edx);
-       db_printf("esi  %8x\n", regs->esi);
-       db_printf("edi  %8x\n", regs->edi);
+               }
+       }
+       thread_exception_return_internal();
 }
-
-#endif /* MACH_KDB */
+#endif