xnu-7195.101.1.tar.gz

[apple/xnu.git] / osfmk / i386 / commpage / commpage.c

/*
 * Copyright (c) 2003-2020 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * 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.
 *
 * 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 *      Here's what to do if you want to add a new routine to the comm page:
 *
 *              1. Add a definition for it's address in osfmk/i386/cpu_capabilities.h,
 *                 being careful to reserve room for future expansion.
 *
 *              2. Write one or more versions of the routine, each with it's own
 *                 commpage_descriptor.  The tricky part is getting the "special",
 *                 "musthave", and "canthave" fields right, so that exactly one
 *                 version of the routine is selected for every machine.
 *                 The source files should be in osfmk/i386/commpage/.
 *
 *              3. Add a ptr to your new commpage_descriptor(s) in the "routines"
 *                 array in osfmk/i386/commpage/commpage_asm.s.  There are two
 *                 arrays, one for the 32-bit and one for the 64-bit commpage.
 *
 *              4. Write the code in Libc to use the new routine.
 */

#include <mach/mach_types.h>
#include <mach/machine.h>
#include <mach/vm_map.h>
#include <mach/mach_vm.h>
#include <mach/machine.h>
#include <i386/cpuid.h>
#include <i386/tsc.h>
#include <i386/rtclock_protos.h>
#include <i386/cpu_data.h>
#include <i386/machine_routines.h>
#include <i386/misc_protos.h>
#include <i386/cpuid.h>
#include <machine/cpu_capabilities.h>
#include <machine/commpage.h>
#include <machine/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <stdatomic.h>

#include <ipc/ipc_port.h>

#include <kern/page_decrypt.h>
#include <kern/processor.h>

#include <sys/kdebug.h>

#if CONFIG_ATM
#include <atm/atm_internal.h>
#endif

/* the lists of commpage routines are in commpage_asm.s  */
extern  commpage_descriptor*    commpage_32_routines[];
extern  commpage_descriptor*    commpage_64_routines[];

extern vm_map_t commpage32_map; // the shared submap, set up in vm init
extern vm_map_t commpage64_map; // the shared submap, set up in vm init
extern vm_map_t commpage_text32_map;    // the shared submap, set up in vm init
extern vm_map_t commpage_text64_map;    // the shared submap, set up in vm init


char    *commPagePtr32 = NULL;          // virtual addr in kernel map of 32-bit commpage
char    *commPagePtr64 = NULL;          // ...and of 64-bit commpage
char    *commPageTextPtr32 = NULL;      // virtual addr in kernel map of 32-bit commpage
char    *commPageTextPtr64 = NULL;      // ...and of 64-bit commpage

uint64_t     _cpu_capabilities = 0;     // define the capability vector

typedef uint32_t commpage_address_t;

static commpage_address_t       next;   // next available address in comm page

static char    *commPagePtr;            // virtual addr in kernel map of commpage we are working on
static commpage_address_t       commPageBaseOffset; // subtract from 32-bit runtime address to get offset in virtual commpage in kernel map

static  commpage_time_data      *time_data32 = NULL;
static  commpage_time_data      *time_data64 = NULL;
static  new_commpage_timeofday_data_t *gtod_time_data32 = NULL;
static  new_commpage_timeofday_data_t *gtod_time_data64 = NULL;


decl_simple_lock_data(static, commpage_active_cpus_lock);

/* Allocate the commpage and add to the shared submap created by vm:
 *      1. allocate a page in the kernel map (RW)
 *      2. wire it down
 *      3. make a memory entry out of it
 *      4. map that entry into the shared comm region map (R-only)
 */

static  void*
commpage_allocate(
        vm_map_t        submap,                 // commpage32_map or commpage_map64
        size_t          area_used,              // _COMM_PAGE32_AREA_USED or _COMM_PAGE64_AREA_USED
        vm_prot_t       uperm)
{
        vm_offset_t     kernel_addr = 0;        // address of commpage in kernel map
        vm_offset_t     zero = 0;
        vm_size_t       size = area_used;       // size actually populated
        vm_map_entry_t  entry;
        ipc_port_t      handle;
        kern_return_t   kr;
        vm_map_kernel_flags_t vmk_flags;

        if (submap == NULL) {
                panic("commpage submap is null");
        }

        kr = vm_map_kernel(kernel_map,
            &kernel_addr,
            area_used,
            0,
            VM_FLAGS_ANYWHERE,
            VM_MAP_KERNEL_FLAGS_NONE,
            VM_KERN_MEMORY_OSFMK,
            NULL,
            0,
            FALSE,
            VM_PROT_ALL,
            VM_PROT_ALL,
            VM_INHERIT_NONE);
        if (kr != KERN_SUCCESS) {
                panic("cannot allocate commpage %d", kr);
        }

        if ((kr = vm_map_wire_kernel(kernel_map,
            kernel_addr,
            kernel_addr + area_used,
            VM_PROT_DEFAULT, VM_KERN_MEMORY_OSFMK,
            FALSE))) {
                panic("cannot wire commpage: %d", kr);
        }

        /*
         * Now that the object is created and wired into the kernel map, mark it so that no delay
         * copy-on-write will ever be performed on it as a result of mapping it into user-space.
         * If such a delayed copy ever occurred, we could remove the kernel's wired mapping - and
         * that would be a real disaster.
         *
         * JMM - What we really need is a way to create it like this in the first place.
         */
        if (!(kr = vm_map_lookup_entry( kernel_map, vm_map_trunc_page(kernel_addr, VM_MAP_PAGE_MASK(kernel_map)), &entry) || entry->is_sub_map)) {
                panic("cannot find commpage entry %d", kr);
        }
        VME_OBJECT(entry)->copy_strategy = MEMORY_OBJECT_COPY_NONE;

        if ((kr = mach_make_memory_entry( kernel_map,           // target map
            &size,                                      // size
            kernel_addr,                                // offset (address in kernel map)
            uperm,                              // protections as specified
            &handle,                                    // this is the object handle we get
            NULL ))) {                                  // parent_entry (what is this?)
                panic("cannot make entry for commpage %d", kr);
        }

        vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
        if (uperm == (VM_PROT_READ | VM_PROT_EXECUTE)) {
                /*
                 * Mark this unsigned executable mapping as "jit" to avoid
                 * code-signing violations when attempting to execute unsigned
                 * code.
                 */
                vmk_flags.vmkf_map_jit = TRUE;
        }

        kr = vm_map_64_kernel(
                submap,                 // target map (shared submap)
                &zero,                  // address (map into 1st page in submap)
                area_used,              // size
                0,                      // mask
                VM_FLAGS_FIXED,         // flags (it must be 1st page in submap)
                vmk_flags,
                VM_KERN_MEMORY_NONE,
                handle,                 // port is the memory entry we just made
                0,                      // offset (map 1st page in memory entry)
                FALSE,                  // copy
                uperm,                  // cur_protection (R-only in user map)
                uperm,                  // max_protection
                VM_INHERIT_SHARE);      // inheritance
        if (kr != KERN_SUCCESS) {
                panic("cannot map commpage %d", kr);
        }

        ipc_port_release(handle);
        /* Make the kernel mapping non-executable. This cannot be done
         * at the time of map entry creation as mach_make_memory_entry
         * cannot handle disjoint permissions at this time.
         */
        kr = vm_protect(kernel_map, kernel_addr, area_used, FALSE, VM_PROT_READ | VM_PROT_WRITE);
        assert(kr == KERN_SUCCESS);

        return (void*)(intptr_t)kernel_addr;                     // return address in kernel map
}

/* Get address (in kernel map) of a commpage field. */

static void*
commpage_addr_of(
        commpage_address_t     addr_at_runtime )
{
        return (void*) ((uintptr_t)commPagePtr + (addr_at_runtime - commPageBaseOffset));
}

/*
 * Calculate address of data within 32- and 64-bit commpages (not to be used with commpage
 * text).
 */
static void*
commpage_specific_addr_of(char *commPageBase, commpage_address_t addr_at_runtime)
{
        /*
         * Note that the base address (_COMM_PAGE32_BASE_ADDRESS) is the same for
         * 32- and 64-bit commpages
         */
        return (void*) ((uintptr_t)commPageBase + (addr_at_runtime - _COMM_PAGE32_BASE_ADDRESS));
}

/* Determine number of CPUs on this system.  We cannot rely on
 * machine_info.max_cpus this early in the boot.
 */
static int
commpage_cpus( void )
{
        unsigned int cpus;

        cpus = ml_wait_max_cpus();                   // NB: this call can block

        if (cpus == 0) {
                panic("commpage cpus==0");
        }
        if (cpus > 0xFF) {
                cpus = 0xFF;
        }

        return cpus;
}

/* Initialize kernel version of _cpu_capabilities vector (used by KEXTs.) */

static void
commpage_init_cpu_capabilities( void )
{
        uint64_t bits;
        int cpus;
        ml_cpu_info_t cpu_info;

        bits = 0;
        ml_cpu_get_info(&cpu_info);

        switch (cpu_info.vector_unit) {
        case 9:
                bits |= kHasAVX1_0;
                OS_FALLTHROUGH;
        case 8:
                bits |= kHasSSE4_2;
                OS_FALLTHROUGH;
        case 7:
                bits |= kHasSSE4_1;
                OS_FALLTHROUGH;
        case 6:
                bits |= kHasSupplementalSSE3;
                OS_FALLTHROUGH;
        case 5:
                bits |= kHasSSE3;
                OS_FALLTHROUGH;
        case 4:
                bits |= kHasSSE2;
                OS_FALLTHROUGH;
        case 3:
                bits |= kHasSSE;
                OS_FALLTHROUGH;
        case 2:
                bits |= kHasMMX;
                OS_FALLTHROUGH;
        default:
                break;
        }
        switch (cpu_info.cache_line_size) {
        case 128:
                bits |= kCache128;
                break;
        case 64:
                bits |= kCache64;
                break;
        case 32:
                bits |= kCache32;
                break;
        default:
                break;
        }
        cpus = commpage_cpus();                 // how many CPUs do we have

        bits |= (cpus << kNumCPUsShift);

        bits |= kFastThreadLocalStorage;        // we use %gs for TLS

#define setif(_bits, _bit, _condition) \
        if (_condition) _bits |= _bit

        setif(bits, kUP, cpus == 1);
        setif(bits, k64Bit, cpu_mode_is64bit());
        setif(bits, kSlow, tscFreq <= SLOW_TSC_THRESHOLD);

        setif(bits, kHasAES, cpuid_features() &
            CPUID_FEATURE_AES);
        setif(bits, kHasF16C, cpuid_features() &
            CPUID_FEATURE_F16C);
        setif(bits, kHasRDRAND, cpuid_features() &
            CPUID_FEATURE_RDRAND);
        setif(bits, kHasFMA, cpuid_features() &
            CPUID_FEATURE_FMA);

        setif(bits, kHasBMI1, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_BMI1);
        setif(bits, kHasBMI2, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_BMI2);
        /* Do not advertise RTM and HLE if the TSX FORCE ABORT WA is required */
        if (cpuid_wa_required(CPU_INTEL_TSXFA) & CWA_OFF) {
                setif(bits, kHasRTM, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_RTM);
                setif(bits, kHasHLE, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_HLE);
        }
        setif(bits, kHasAVX2_0, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_AVX2);
        setif(bits, kHasRDSEED, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_RDSEED);
        setif(bits, kHasADX, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_ADX);

#if 0   /* The kernel doesn't support MPX or SGX */
        setif(bits, kHasMPX, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_MPX);
        setif(bits, kHasSGX, cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_SGX);
#endif

        if (ml_fpu_avx512_enabled()) {
                setif(bits, kHasAVX512F, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512F);
                setif(bits, kHasAVX512CD, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512CD);
                setif(bits, kHasAVX512DQ, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512DQ);
                setif(bits, kHasAVX512BW, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512BW);
                setif(bits, kHasAVX512VL, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512VL);
                setif(bits, kHasAVX512IFMA, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512IFMA);
                setif(bits, kHasAVX512VBMI, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512VBMI);
                setif(bits, kHasVAES, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_VAES);
                setif(bits, kHasVPCLMULQDQ, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_VPCLMULQDQ);
                setif(bits, kHasAVX512VNNI, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512VNNI);
                setif(bits, kHasAVX512BITALG, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512BITALG);
                setif(bits, kHasAVX512VPOPCNTDQ, cpuid_leaf7_features() &
                    CPUID_LEAF7_FEATURE_AVX512VPCDQ);
        }

        uint64_t misc_enable = rdmsr64(MSR_IA32_MISC_ENABLE);
        setif(bits, kHasENFSTRG, (misc_enable & 1ULL) &&
            (cpuid_leaf7_features() &
            CPUID_LEAF7_FEATURE_ERMS));

        _cpu_capabilities = bits;               // set kernel version for use by drivers etc
}

/* initialize the approx_time_supported flag and set the approx time to 0.
 * Called during initial commpage population.
 */
static void
commpage_mach_approximate_time_init(void)
{
        char *cp = commPagePtr32;
        uint8_t supported;

#ifdef CONFIG_MACH_APPROXIMATE_TIME
        supported = 1;
#else
        supported = 0;
#endif
        if (cp) {
                cp += (_COMM_PAGE_APPROX_TIME_SUPPORTED - _COMM_PAGE32_BASE_ADDRESS);
                *(boolean_t *)cp = supported;
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_APPROX_TIME_SUPPORTED - _COMM_PAGE32_START_ADDRESS);
                *(boolean_t *)cp = supported;
        }
        commpage_update_mach_approximate_time(0);
}

static void
commpage_mach_continuous_time_init(void)
{
        commpage_update_mach_continuous_time(0);
}

static void
commpage_boottime_init(void)
{
        clock_sec_t secs;
        clock_usec_t microsecs;
        clock_get_boottime_microtime(&secs, &microsecs);
        commpage_update_boottime(secs * USEC_PER_SEC + microsecs);
}

uint64_t
_get_cpu_capabilities(void)
{
        return _cpu_capabilities;
}

/* Copy data into commpage. */

static void
commpage_stuff(
        commpage_address_t  address,
        const void  *source,
        int         length  )
{
        void        *dest = commpage_addr_of(address);

        if (address < next) {
                panic("commpage overlap at address 0x%p, 0x%x < 0x%x", dest, address, next);
        }

        bcopy(source, dest, length);

        next = address + length;
}

/*
 * Updates both the 32-bit and 64-bit commpages with the new data.
 */
static void
commpage_update(commpage_address_t address, const void *source, int length)
{
        void *dest = commpage_specific_addr_of(commPagePtr32, address);
        bcopy(source, dest, length);

        dest = commpage_specific_addr_of(commPagePtr64, address);
        bcopy(source, dest, length);
}

void
commpage_post_ucode_update(void)
{
        commpage_init_cpu_capabilities();
        commpage_update(_COMM_PAGE_CPU_CAPABILITIES64, &_cpu_capabilities, sizeof(_cpu_capabilities));
        commpage_update(_COMM_PAGE_CPU_CAPABILITIES, &_cpu_capabilities, sizeof(uint32_t));
}

/* Copy a routine into comm page if it matches running machine.
 */
static void
commpage_stuff_routine(
        commpage_descriptor *rd     )
{
        commpage_stuff(rd->commpage_address, rd->code_address, rd->code_length);
}


/* Fill in the 32- or 64-bit commpage.  Called once for each.
 */

static void
commpage_populate_one(
        vm_map_t        submap,         // commpage32_map or compage64_map
        char **         kernAddressPtr, // &commPagePtr32 or &commPagePtr64
        size_t          area_used,      // _COMM_PAGE32_AREA_USED or _COMM_PAGE64_AREA_USED
        commpage_address_t base_offset, // will become commPageBaseOffset
        commpage_time_data** time_data, // &time_data32 or &time_data64
        new_commpage_timeofday_data_t** gtod_time_data, // &gtod_time_data32 or &gtod_time_data64
        const char*     signature,      // "commpage 32-bit" or "commpage 64-bit"
        vm_prot_t       uperm)
{
        uint8_t         c1;
        uint16_t        c2;
        uint64_t        c8;
        uint32_t        cfamily;
        short   version = _COMM_PAGE_THIS_VERSION;

        next = 0;
        commPagePtr = (char *)commpage_allocate( submap, (vm_size_t) area_used, uperm );
        *kernAddressPtr = commPagePtr;                          // save address either in commPagePtr32 or 64
        commPageBaseOffset = base_offset;

        *time_data = commpage_addr_of( _COMM_PAGE_TIME_DATA_START );
        *gtod_time_data = commpage_addr_of( _COMM_PAGE_NEWTIMEOFDAY_DATA );

        /* Stuff in the constants.  We move things into the comm page in strictly
         * ascending order, so we can check for overlap and panic if so.
         * Note: the 32-bit cpu_capabilities vector is retained in addition to
         * the expanded 64-bit vector.
         */
        commpage_stuff(_COMM_PAGE_SIGNATURE, signature, (int)MIN(_COMM_PAGE_SIGNATURELEN, strlen(signature)));
        commpage_stuff(_COMM_PAGE_CPU_CAPABILITIES64, &_cpu_capabilities, sizeof(_cpu_capabilities));
        commpage_stuff(_COMM_PAGE_VERSION, &version, sizeof(short));
        commpage_stuff(_COMM_PAGE_CPU_CAPABILITIES, &_cpu_capabilities, sizeof(uint32_t));

        c2 = 32;  // default
        if (_cpu_capabilities & kCache64) {
                c2 = 64;
        } else if (_cpu_capabilities & kCache128) {
                c2 = 128;
        }
        commpage_stuff(_COMM_PAGE_CACHE_LINESIZE, &c2, 2);

        /* machine_info valid after ml_wait_max_cpus() */
        c1 = machine_info.physical_cpu_max;
        commpage_stuff(_COMM_PAGE_PHYSICAL_CPUS, &c1, 1);
        c1 = machine_info.logical_cpu_max;
        commpage_stuff(_COMM_PAGE_LOGICAL_CPUS, &c1, 1);

        c8 = ml_cpu_cache_size(0);
        commpage_stuff(_COMM_PAGE_MEMORY_SIZE, &c8, 8);

        cfamily = cpuid_info()->cpuid_cpufamily;
        commpage_stuff(_COMM_PAGE_CPUFAMILY, &cfamily, 4);
        c1 = PAGE_SHIFT;
        commpage_stuff(_COMM_PAGE_KERNEL_PAGE_SHIFT, &c1, 1);
        commpage_stuff(_COMM_PAGE_USER_PAGE_SHIFT_64, &c1, 1);

        if (next > _COMM_PAGE_END) {
                panic("commpage overflow: next = 0x%08x, commPagePtr = 0x%p", next, commPagePtr);
        }
}


/* Fill in commpages: called once, during kernel initialization, from the
 * startup thread before user-mode code is running.
 *
 * See the top of this file for a list of what you have to do to add
 * a new routine to the commpage.
 */

void
commpage_populate( void )
{
        commpage_init_cpu_capabilities();

        commpage_populate_one(  commpage32_map,
            &commPagePtr32,
            _COMM_PAGE32_AREA_USED,
            _COMM_PAGE32_BASE_ADDRESS,
            &time_data32,
            &gtod_time_data32,
            _COMM_PAGE32_SIGNATURE_STRING,
            VM_PROT_READ);
#ifndef __LP64__
        pmap_commpage32_init((vm_offset_t) commPagePtr32, _COMM_PAGE32_BASE_ADDRESS,
            _COMM_PAGE32_AREA_USED / INTEL_PGBYTES);
#endif
        time_data64 = time_data32;                      /* if no 64-bit commpage, point to 32-bit */
        gtod_time_data64 = gtod_time_data32;

        if (_cpu_capabilities & k64Bit) {
                commpage_populate_one(  commpage64_map,
                    &commPagePtr64,
                    _COMM_PAGE64_AREA_USED,
                    _COMM_PAGE32_START_ADDRESS,                     /* commpage address are relative to 32-bit commpage placement */
                    &time_data64,
                    &gtod_time_data64,
                    _COMM_PAGE64_SIGNATURE_STRING,
                    VM_PROT_READ);
#ifndef __LP64__
                pmap_commpage64_init((vm_offset_t) commPagePtr64, _COMM_PAGE64_BASE_ADDRESS,
                    _COMM_PAGE64_AREA_USED / INTEL_PGBYTES);
#endif
        }

        simple_lock_init(&commpage_active_cpus_lock, 0);

        commpage_update_active_cpus();
        commpage_mach_approximate_time_init();
        commpage_mach_continuous_time_init();
        commpage_boottime_init();
        rtc_nanotime_init_commpage();
        commpage_update_kdebug_state();
#if CONFIG_ATM
        commpage_update_atm_diagnostic_config(atm_get_diagnostic_config());
#endif
}

/* Fill in the common routines during kernel initialization.
 * This is called before user-mode code is running.
 */
void
commpage_text_populate( void )
{
        commpage_descriptor **rd;

        next = 0;
        commPagePtr = (char *) commpage_allocate(commpage_text32_map, (vm_size_t) _COMM_PAGE_TEXT_AREA_USED, VM_PROT_READ | VM_PROT_EXECUTE);
        commPageTextPtr32 = commPagePtr;

        char *cptr = commPagePtr;
        int i = 0;
        for (; i < _COMM_PAGE_TEXT_AREA_USED; i++) {
                cptr[i] = 0xCC;
        }

        commPageBaseOffset = _COMM_PAGE_TEXT_START;
        for (rd = commpage_32_routines; *rd != NULL; rd++) {
                commpage_stuff_routine(*rd);
        }

#ifndef __LP64__
        pmap_commpage32_init((vm_offset_t) commPageTextPtr32, _COMM_PAGE_TEXT_START,
            _COMM_PAGE_TEXT_AREA_USED / INTEL_PGBYTES);
#endif

        if (_cpu_capabilities & k64Bit) {
                next = 0;
                commPagePtr = (char *) commpage_allocate(commpage_text64_map, (vm_size_t) _COMM_PAGE_TEXT_AREA_USED, VM_PROT_READ | VM_PROT_EXECUTE);
                commPageTextPtr64 = commPagePtr;

                cptr = commPagePtr;
                for (i = 0; i < _COMM_PAGE_TEXT_AREA_USED; i++) {
                        cptr[i] = 0xCC;
                }

                for (rd = commpage_64_routines; *rd != NULL; rd++) {
                        commpage_stuff_routine(*rd);
                }

#ifndef __LP64__
                pmap_commpage64_init((vm_offset_t) commPageTextPtr64, _COMM_PAGE_TEXT_START,
                    _COMM_PAGE_TEXT_AREA_USED / INTEL_PGBYTES);
#endif
        }

        if (next > _COMM_PAGE_TEXT_END) {
                panic("commpage text overflow: next=0x%08x, commPagePtr=%p", next, commPagePtr);
        }
}

/* Update commpage nanotime information.
 *
 * This routine must be serialized by some external means, ie a lock.
 */

void
commpage_set_nanotime(
        uint64_t        tsc_base,
        uint64_t        ns_base,
        uint32_t        scale,
        uint32_t        shift )
{
        commpage_time_data      *p32 = time_data32;
        commpage_time_data      *p64 = time_data64;
        static uint32_t generation = 0;
        uint32_t        next_gen;

        if (p32 == NULL) {              /* have commpages been allocated yet? */
                return;
        }

        if (generation != p32->nt_generation) {
                panic("nanotime trouble 1");    /* possibly not serialized */
        }
        if (ns_base < p32->nt_ns_base) {
                panic("nanotime trouble 2");
        }
        if ((shift != 0) && ((_cpu_capabilities & kSlow) == 0)) {
                panic("nanotime trouble 3");
        }

        next_gen = ++generation;
        if (next_gen == 0) {
                next_gen = ++generation;
        }

        p32->nt_generation = 0;         /* mark invalid, so commpage won't try to use it */
        p64->nt_generation = 0;

        p32->nt_tsc_base = tsc_base;
        p64->nt_tsc_base = tsc_base;

        p32->nt_ns_base = ns_base;
        p64->nt_ns_base = ns_base;

        p32->nt_scale = scale;
        p64->nt_scale = scale;

        p32->nt_shift = shift;
        p64->nt_shift = shift;

        p32->nt_generation = next_gen;  /* mark data as valid */
        p64->nt_generation = next_gen;
}

/* Update commpage gettimeofday() information.  As with nanotime(), we interleave
 * updates to the 32- and 64-bit commpage, in order to keep time more nearly in sync
 * between the two environments.
 *
 * This routine must be serializeed by some external means, ie a lock.
 */

void
commpage_set_timestamp(
        uint64_t        abstime,
        uint64_t        sec,
        uint64_t        frac,
        uint64_t        scale,
        uint64_t        tick_per_sec)
{
        new_commpage_timeofday_data_t   *p32 = gtod_time_data32;
        new_commpage_timeofday_data_t   *p64 = gtod_time_data64;

        p32->TimeStamp_tick = 0x0ULL;
        p64->TimeStamp_tick = 0x0ULL;

        p32->TimeStamp_sec = sec;
        p64->TimeStamp_sec = sec;

        p32->TimeStamp_frac = frac;
        p64->TimeStamp_frac = frac;

        p32->Ticks_scale = scale;
        p64->Ticks_scale = scale;

        p32->Ticks_per_sec = tick_per_sec;
        p64->Ticks_per_sec = tick_per_sec;

        p32->TimeStamp_tick = abstime;
        p64->TimeStamp_tick = abstime;
}

/* Update _COMM_PAGE_MEMORY_PRESSURE.  Called periodically from vm's compute_memory_pressure()  */

void
commpage_set_memory_pressure(
        unsigned int    pressure )
{
        char        *cp;
        uint32_t    *ip;

        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_MEMORY_PRESSURE - _COMM_PAGE32_BASE_ADDRESS);
                ip = (uint32_t*) (void *) cp;
                *ip = (uint32_t) pressure;
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_MEMORY_PRESSURE - _COMM_PAGE32_START_ADDRESS);
                ip = (uint32_t*) (void *) cp;
                *ip = (uint32_t) pressure;
        }
}

/* Updated every time a logical CPU goes offline/online */
void
commpage_update_active_cpus(void)
{
        char        *cp;
        volatile uint8_t    *ip;

        /* At least 32-bit commpage must be initialized */
        if (!commPagePtr32) {
                return;
        }

        simple_lock(&commpage_active_cpus_lock, LCK_GRP_NULL);

        cp = commPagePtr32;
        cp += (_COMM_PAGE_ACTIVE_CPUS - _COMM_PAGE32_BASE_ADDRESS);
        ip = (volatile uint8_t*) cp;
        *ip = (uint8_t) processor_avail_count_user;

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_ACTIVE_CPUS - _COMM_PAGE32_START_ADDRESS);
                ip = (volatile uint8_t*) cp;
                *ip = (uint8_t) processor_avail_count_user;
        }

        simple_unlock(&commpage_active_cpus_lock);
}

/*
 * Update the commpage with current kdebug state. This currently has bits for
 * global trace state, and typefilter enablement. It is likely additional state
 * will be tracked in the future.
 *
 * INVARIANT: This value will always be 0 if global tracing is disabled. This
 * allows simple guard tests of "if (*_COMM_PAGE_KDEBUG_ENABLE) { ... }"
 */
void
commpage_update_kdebug_state(void)
{
        volatile uint32_t *saved_data_ptr;
        char *cp;

        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_KDEBUG_ENABLE - _COMM_PAGE32_BASE_ADDRESS);
                saved_data_ptr = (volatile uint32_t *)cp;
                *saved_data_ptr = kdebug_commpage_state();
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_KDEBUG_ENABLE - _COMM_PAGE32_START_ADDRESS);
                saved_data_ptr = (volatile uint32_t *)cp;
                *saved_data_ptr = kdebug_commpage_state();
        }
}

/* Ditto for atm_diagnostic_config */
void
commpage_update_atm_diagnostic_config(uint32_t diagnostic_config)
{
        volatile uint32_t *saved_data_ptr;
        char *cp;

        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_ATM_DIAGNOSTIC_CONFIG - _COMM_PAGE32_BASE_ADDRESS);
                saved_data_ptr = (volatile uint32_t *)cp;
                *saved_data_ptr = diagnostic_config;
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_ATM_DIAGNOSTIC_CONFIG - _COMM_PAGE32_START_ADDRESS);
                saved_data_ptr = (volatile uint32_t *)cp;
                *saved_data_ptr = diagnostic_config;
        }
}

/*
 * update the commpage with if dtrace user land probes are enabled
 */
void
commpage_update_dof(boolean_t enabled)
{
#if CONFIG_DTRACE
        char *cp;

        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_DTRACE_DOF_ENABLED - _COMM_PAGE32_BASE_ADDRESS);
                *cp = (enabled ? 1 : 0);
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_DTRACE_DOF_ENABLED - _COMM_PAGE32_START_ADDRESS);
                *cp = (enabled ? 1 : 0);
        }
#else
        (void)enabled;
#endif
}


/*
 * update the dyld global config flags
 */
void
commpage_update_dyld_flags(uint64_t value)
{
        char *cp;

        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_DYLD_FLAGS - _COMM_PAGE32_BASE_ADDRESS);
                *(uint64_t *)cp = value;
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_DYLD_FLAGS - _COMM_PAGE32_BASE_ADDRESS);
                *(uint64_t *)cp = value;
        }
}


/*
 * update the commpage data for last known value of mach_absolute_time()
 */

void
commpage_update_mach_approximate_time(uint64_t abstime)
{
#ifdef CONFIG_MACH_APPROXIMATE_TIME
        uint64_t saved_data;
        char *cp;

        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_APPROX_TIME - _COMM_PAGE32_BASE_ADDRESS);
                saved_data = atomic_load_explicit((_Atomic uint64_t *)(uintptr_t)cp, memory_order_relaxed);
                if (saved_data < abstime) {
                        /* ignoring the success/fail return value assuming that
                         * if the value has been updated since we last read it,
                         * "someone" has a newer timestamp than us and ours is
                         * now invalid. */
                        atomic_compare_exchange_strong_explicit((_Atomic uint64_t *)(uintptr_t)cp,
                            &saved_data, abstime, memory_order_relaxed, memory_order_relaxed);
                }
        }
        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_APPROX_TIME - _COMM_PAGE32_START_ADDRESS);
                saved_data = atomic_load_explicit((_Atomic uint64_t *)(uintptr_t)cp, memory_order_relaxed);
                if (saved_data < abstime) {
                        /* ignoring the success/fail return value assuming that
                         * if the value has been updated since we last read it,
                         * "someone" has a newer timestamp than us and ours is
                         * now invalid. */
                        atomic_compare_exchange_strong_explicit((_Atomic uint64_t *)(uintptr_t)cp,
                            &saved_data, abstime, memory_order_relaxed, memory_order_relaxed);
                }
        }
#else
#pragma unused (abstime)
#endif
}

void
commpage_update_mach_continuous_time(uint64_t sleeptime)
{
        char *cp;
        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_CONT_TIMEBASE - _COMM_PAGE32_START_ADDRESS);
                *(uint64_t *)cp = sleeptime;
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_CONT_TIMEBASE - _COMM_PAGE32_START_ADDRESS);
                *(uint64_t *)cp = sleeptime;
        }
}

void
commpage_update_boottime(uint64_t boottime)
{
        char *cp;
        cp = commPagePtr32;
        if (cp) {
                cp += (_COMM_PAGE_BOOTTIME_USEC - _COMM_PAGE32_START_ADDRESS);
                *(uint64_t *)cp = boottime;
        }

        cp = commPagePtr64;
        if (cp) {
                cp += (_COMM_PAGE_BOOTTIME_USEC - _COMM_PAGE32_START_ADDRESS);
                *(uint64_t *)cp = boottime;
        }
}


extern user32_addr_t commpage_text32_location;
extern user64_addr_t commpage_text64_location;

/* Check to see if a given address is in the Preemption Free Zone (PFZ) */

uint32_t
commpage_is_in_pfz32(uint32_t addr32)
{
        if ((addr32 >= (commpage_text32_location + _COMM_TEXT_PFZ_START_OFFSET))
            && (addr32 < (commpage_text32_location + _COMM_TEXT_PFZ_END_OFFSET))) {
                return 1;
        } else {
                return 0;
        }
}

uint32_t
commpage_is_in_pfz64(addr64_t addr64)
{
        if ((addr64 >= (commpage_text64_location + _COMM_TEXT_PFZ_START_OFFSET))
            && (addr64 < (commpage_text64_location + _COMM_TEXT_PFZ_END_OFFSET))) {
                return 1;
        } else {
                return 0;
        }
}