xnu-7195.101.1.tar.gz

[apple/xnu.git] / osfmk / i386 / i386_init.c

/*
 * Copyright (c) 2003-2019 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@
 */
/*
 * @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.
 */


#include <mach/i386/vm_param.h>

#include <string.h>
#include <stdint.h>
#include <mach/vm_param.h>
#include <mach/vm_prot.h>
#include <mach/machine.h>
#include <mach/time_value.h>
#include <kern/spl.h>
#include <kern/assert.h>
#include <kern/debug.h>
#include <kern/misc_protos.h>
#include <kern/startup.h>
#include <kern/clock.h>
#include <kern/pms.h>
#include <kern/cpu_data.h>
#include <kern/processor.h>
#include <sys/kdebug.h>
#include <console/serial_protos.h>
#include <vm/vm_page.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <machine/pal_routines.h>
#include <i386/fpu.h>
#include <i386/pmap.h>
#include <i386/misc_protos.h>
#include <i386/cpu_threads.h>
#include <i386/cpuid.h>
#include <i386/lapic.h>
#include <i386/mp.h>
#include <i386/mp_desc.h>
#if CONFIG_MTRR
#include <i386/mtrr.h>
#endif
#include <i386/machine_routines.h>
#if CONFIG_MCA
#include <i386/machine_check.h>
#endif
#include <i386/ucode.h>
#include <i386/postcode.h>
#include <i386/Diagnostics.h>
#include <i386/pmCPU.h>
#include <i386/tsc.h>
#include <i386/locks.h> /* LcksOpts */
#include <i386/acpi.h>
#if DEBUG
#include <machine/pal_routines.h>
#endif
extern void xcpm_bootstrap(void);
#if DEVELOPMENT || DEBUG
#include <i386/trap.h>
#endif

#if MONOTONIC
#include <kern/monotonic.h>
#endif /* MONOTONIC */

#include <san/kasan.h>

#if DEBUG || DEVELOPMENT
#define DBG(x, ...)          kprintf(x, ##__VA_ARGS__)
#define dyldLogFunc(x, ...) kprintf(x, ##__VA_ARGS__)
#else
#define DBG(x ...)
#endif

#include <libkern/kernel_mach_header.h>
#include <mach/dyld_kernel_fixups.h>


int                     debug_task;

int                     early_boot = 1;

bool                    serial_console_enabled = false;

static boot_args        *kernelBootArgs;

extern int              disableConsoleOutput;
extern const char       version[];
extern const char       version_variant[];
extern int              nx_enabled;

/*
 * Set initial values so that ml_phys_* routines can use the booter's ID mapping
 * to touch physical space before the kernel's physical aperture exists.
 */
uint64_t                physmap_base = 0;
uint64_t                physmap_max = 4 * GB;

pd_entry_t              *KPTphys;
pd_entry_t              *IdlePTD;
pdpt_entry_t            *IdlePDPT;
pml4_entry_t            *IdlePML4;

int                     kernPhysPML4Index;
int                     kernPhysPML4EntryCount;

/*
 * These are 4K mapping page table pages from KPTphys[] that we wound
 * up not using. They get ml_static_mfree()'d once the VM is initialized.
 */
ppnum_t                 released_PT_ppn = 0;
uint32_t                released_PT_cnt = 0;

#if DEVELOPMENT || DEBUG
int panic_on_cacheline_mismatch = -1;
char panic_on_trap_procname[64];
uint32_t panic_on_trap_mask;
#endif
bool last_branch_support_enabled;
int insn_copyin_count;
#if DEVELOPMENT || DEBUG
#define DEFAULT_INSN_COPYIN_COUNT x86_INSTRUCTION_STATE_MAX_INSN_BYTES
#else
#define DEFAULT_INSN_COPYIN_COUNT 192
#endif

char *physfree;
void idt64_remap(void);

/*
 * Note: ALLOCPAGES() can only be used safely within Idle_PTs_init()
 * due to the mutation of physfree.
 */
static void *
ALLOCPAGES(int npages)
{
        uintptr_t tmp = (uintptr_t)physfree;
        bzero(physfree, npages * PAGE_SIZE);
        physfree += npages * PAGE_SIZE;
        tmp += VM_MIN_KERNEL_ADDRESS & ~LOW_4GB_MASK;
        return (void *)tmp;
}

static void
fillkpt(pt_entry_t *base, int prot, uintptr_t src, int index, int count)
{
        int i;
        for (i = 0; i < count; i++) {
                base[index] = src | prot | INTEL_PTE_VALID;
                src += PAGE_SIZE;
                index++;
        }
}

extern pmap_paddr_t first_avail;

int break_kprintf = 0;

uint64_t
x86_64_pre_sleep(void)
{
        IdlePML4[0] = IdlePML4[KERNEL_PML4_INDEX];
        uint64_t oldcr3 = get_cr3_raw();
        set_cr3_raw((uint32_t) (uintptr_t)ID_MAP_VTOP(IdlePML4));
        return oldcr3;
}

void
x86_64_post_sleep(uint64_t new_cr3)
{
        IdlePML4[0] = 0;
        set_cr3_raw((uint32_t) new_cr3);
}




// Set up the physical mapping - NPHYSMAP GB of memory mapped at a high address
// NPHYSMAP is determined by the maximum supported RAM size plus 4GB to account
// the PCI hole (which is less 4GB but not more).

static int
physmap_init_L2(uint64_t *physStart, pt_entry_t **l2ptep)
{
        unsigned i;
        pt_entry_t *physmapL2 = ALLOCPAGES(1);

        if (physmapL2 == NULL) {
                DBG("physmap_init_L2 page alloc failed when initting L2 for physAddr 0x%llx.\n", *physStart);
                *l2ptep = NULL;
                return -1;
        }

        for (i = 0; i < NPDPG; i++) {
                physmapL2[i] = *physStart
                    | INTEL_PTE_PS
                    | INTEL_PTE_VALID
                    | INTEL_PTE_NX
                    | INTEL_PTE_WRITE;

                *physStart += NBPD;
        }
        *l2ptep = physmapL2;
        return 0;
}

static int
physmap_init_L3(int startIndex, uint64_t highest_phys, uint64_t *physStart, pt_entry_t **l3ptep)
{
        unsigned i;
        int ret;
        pt_entry_t *l2pte;
        pt_entry_t *physmapL3 = ALLOCPAGES(1);  /* ALLOCPAGES bzeroes the memory */

        if (physmapL3 == NULL) {
                DBG("physmap_init_L3 page alloc failed when initting L3 for  physAddr 0x%llx.\n", *physStart);
                *l3ptep = NULL;
                return -1;
        }

        for (i = startIndex; i < NPDPTPG && *physStart < highest_phys; i++) {
                if ((ret = physmap_init_L2(physStart, &l2pte)) < 0) {
                        return ret;
                }

                physmapL3[i] =  ((uintptr_t)ID_MAP_VTOP(l2pte))
                    | INTEL_PTE_VALID
                    | INTEL_PTE_NX
                    | INTEL_PTE_WRITE;
        }

        *l3ptep = physmapL3;

        return 0;
}

static void
physmap_init(uint8_t phys_random_L3, uint64_t *new_physmap_base, uint64_t *new_physmap_max)
{
        pt_entry_t *l3pte;
        int pml4_index, i;
        int L3_start_index;
        uint64_t physAddr = 0;
        uint64_t highest_physaddr;
        unsigned pdpte_count;

#if DEVELOPMENT || DEBUG
        if (kernelBootArgs->PhysicalMemorySize > K64_MAXMEM) {
                panic("Installed physical memory exceeds configured maximum.");
        }
#endif

        /*
         * Add 4GB to the loader-provided physical memory size to account for MMIO space
         * XXX in a perfect world, we'd scan PCI buses and count the max memory requested in BARs by
         * XXX all enumerated device, then add more for hot-pluggable devices.
         */
        highest_physaddr = kernelBootArgs->PhysicalMemorySize + 4 * GB;

        /*
         * Calculate the number of PML4 entries we'll need.  The total number of entries is
         * pdpte_count = (((highest_physaddr) >> PDPT_SHIFT) + entropy_value +
         *               ((highest_physaddr & PDPT_MASK) == 0 ? 0 : 1))
         * pml4e_count = pdpte_count >> (PML4_SHIFT - PDPT_SHIFT)
         */
        assert(highest_physaddr < (UINT64_MAX - PDPTMASK));
        pdpte_count = (unsigned) (((highest_physaddr + PDPTMASK) >> PDPTSHIFT) + phys_random_L3);
        kernPhysPML4EntryCount = (pdpte_count + ((1U << (PML4SHIFT - PDPTSHIFT)) - 1)) >> (PML4SHIFT - PDPTSHIFT);
        if (kernPhysPML4EntryCount == 0) {
                kernPhysPML4EntryCount = 1;
        }
        if (kernPhysPML4EntryCount > KERNEL_PHYSMAP_PML4_COUNT_MAX) {
#if DEVELOPMENT || DEBUG
                panic("physmap too large");
#else
                kprintf("[pmap] Limiting physmap to %d PML4s (was %d)\n", KERNEL_PHYSMAP_PML4_COUNT_MAX,
                    kernPhysPML4EntryCount);
                kernPhysPML4EntryCount = KERNEL_PHYSMAP_PML4_COUNT_MAX;
#endif
        }

        kernPhysPML4Index = KERNEL_KEXTS_INDEX - kernPhysPML4EntryCount;        /* utb: KERNEL_PHYSMAP_PML4_INDEX */

        /*
         * XXX: Make sure that the addresses returned for physmapL3 and physmapL2 plus their extents
         * are in the system-available memory range
         */


        /* We assume NX support. Mark all levels of the PHYSMAP NX
         * to avoid granting executability via a single bit flip.
         */
#if DEVELOPMENT || DEBUG
        uint32_t reg[4];
        do_cpuid(0x80000000, reg);
        if (reg[eax] >= 0x80000001) {
                do_cpuid(0x80000001, reg);
                assert(reg[edx] & CPUID_EXTFEATURE_XD);
        }
#endif /* DEVELOPMENT || DEBUG */

        L3_start_index = phys_random_L3;

        for (pml4_index = kernPhysPML4Index;
            pml4_index < (kernPhysPML4Index + kernPhysPML4EntryCount) && physAddr < highest_physaddr;
            pml4_index++) {
                if (physmap_init_L3(L3_start_index, highest_physaddr, &physAddr, &l3pte) < 0) {
                        panic("Physmap page table initialization failed");
                        /* NOTREACHED */
                }

                L3_start_index = 0;

                IdlePML4[pml4_index] = ((uintptr_t)ID_MAP_VTOP(l3pte))
                    | INTEL_PTE_VALID
                    | INTEL_PTE_NX
                    | INTEL_PTE_WRITE;
        }

        *new_physmap_base = KVADDR(kernPhysPML4Index, phys_random_L3, 0, 0);
        /*
         * physAddr contains the last-mapped physical address, so that's what we
         * add to physmap_base to derive the ending VA for the physmap.
         */
        *new_physmap_max = *new_physmap_base + physAddr;

        DBG("Physical address map base: 0x%qx\n", *new_physmap_base);
        for (i = kernPhysPML4Index; i < (kernPhysPML4Index + kernPhysPML4EntryCount); i++) {
                DBG("Physical map idlepml4[%d]: 0x%llx\n", i, IdlePML4[i]);
        }
}

void doublemap_init(uint8_t);

static void
Idle_PTs_init(void)
{
        uint64_t        rand64;
        uint64_t        new_physmap_base, new_physmap_max;

        /* Allocate the "idle" kernel page tables: */
        KPTphys  = ALLOCPAGES(NKPT);            /* level 1 */
        IdlePTD  = ALLOCPAGES(NPGPTD);          /* level 2 */
        IdlePDPT = ALLOCPAGES(1);               /* level 3 */
        IdlePML4 = ALLOCPAGES(1);               /* level 4 */

        // Fill the lowest level with everything up to physfree
        fillkpt(KPTphys,
            INTEL_PTE_WRITE, 0, 0, (int)(((uintptr_t)physfree) >> PAGE_SHIFT));

        /* IdlePTD */
        fillkpt(IdlePTD,
            INTEL_PTE_WRITE, (uintptr_t)ID_MAP_VTOP(KPTphys), 0, NKPT);

        // IdlePDPT entries
        fillkpt(IdlePDPT,
            INTEL_PTE_WRITE, (uintptr_t)ID_MAP_VTOP(IdlePTD), 0, NPGPTD);

        // IdlePML4 single entry for kernel space.
        fillkpt(IdlePML4 + KERNEL_PML4_INDEX,
            INTEL_PTE_WRITE, (uintptr_t)ID_MAP_VTOP(IdlePDPT), 0, 1);

        postcode(VSTART_PHYSMAP_INIT);

        /*
         * early_random() cannot be called more than one time before the cpu's
         * gsbase is initialized, so use the full 64-bit value to extract the
         * two 8-bit entropy values needed for address randomization.
         */
        rand64 = early_random();
        physmap_init(rand64 & 0xFF, &new_physmap_base, &new_physmap_max);
        doublemap_init((rand64 >> 8) & 0xFF);
        idt64_remap();

        postcode(VSTART_SET_CR3);

        /*
         * Switch to the page tables. We set physmap_base and physmap_max just
         * before switching to the new page tables to avoid someone calling
         * kprintf() or otherwise using physical memory in between.
         * This is needed because kprintf() writes to physical memory using
         * ml_phys_read_data and PHYSMAP_PTOV, which requires physmap_base to be
         * set correctly.
         */
        physmap_base = new_physmap_base;
        physmap_max = new_physmap_max;
        set_cr3_raw((uintptr_t)ID_MAP_VTOP(IdlePML4));
}

/*
 * Release any still unused, preallocated boot kernel page tables.
 * start..end is the VA range currently unused.
 */
void
Idle_PTs_release(vm_offset_t start, vm_offset_t end)
{
        uint32_t i;
        uint32_t index_start;
        uint32_t index_limit;
        ppnum_t pn_first;
        ppnum_t pn;
        uint32_t cnt;

        /*
         * Align start to the next large page boundary
         */
        start = ((start + I386_LPGMASK) & ~I386_LPGMASK);

        /*
         * convert start into an index in KPTphys[]
         */
        index_start = (uint32_t)((start - KERNEL_BASE) >> PAGE_SHIFT);

        /*
         * Find the ending index in KPTphys[]
         */
        index_limit = (uint32_t)((end - KERNEL_BASE) >> PAGE_SHIFT);

        if (index_limit > NKPT * PTE_PER_PAGE) {
                index_limit = NKPT * PTE_PER_PAGE;
        }

        /*
         * Make sure all the 4K page tables are empty.
         * If not, panic a development/debug kernel.
         * On a production kernel, since this would stop us from booting,
         * just abort the operation.
         */
        for (i = index_start; i < index_limit; ++i) {
                assert(KPTphys[i] == 0);
                if (KPTphys[i] != 0) {
                        return;
                }
        }

        /*
         * Now figure out the indices into the 2nd level page tables, IdlePTD[].
         */
        index_start >>= PTPGSHIFT;
        index_limit >>= PTPGSHIFT;
        if (index_limit > NPGPTD * PTE_PER_PAGE) {
                index_limit = NPGPTD * PTE_PER_PAGE;
        }

        if (index_limit <= index_start) {
                return;
        }


        /*
         * Now check the pages referenced from Level 2 tables.
         * They should be contiguous, assert fail if not on development/debug.
         * In production, just fail the removal to allow the system to boot.
         */
        pn_first = 0;
        cnt = 0;
        for (i = index_start; i < index_limit; ++i) {
                assert(IdlePTD[i] != 0);
                if (IdlePTD[i] == 0) {
                        return;
                }

                pn = (ppnum_t)((PG_FRAME & IdlePTD[i]) >> PTSHIFT);
                if (cnt == 0) {
                        pn_first = pn;
                } else {
                        assert(pn == pn_first + cnt);
                        if (pn != pn_first + cnt) {
                                return;
                        }
                }
                ++cnt;
        }

        /*
         * Good to go, clear the level 2 entries and invalidate the TLB
         */
        for (i = index_start; i < index_limit; ++i) {
                IdlePTD[i] = 0;
        }
        set_cr3_raw(get_cr3_raw());

        /*
         * Remember these PFNs to be released later in pmap_lowmem_finalize()
         */
        released_PT_ppn = pn_first;
        released_PT_cnt = cnt;
#if DEVELOPMENT || DEBUG
        printf("Idle_PTs_release %d pages from PFN 0x%x\n", released_PT_cnt, released_PT_ppn);
#endif
}

extern void vstart_trap_handler;

#define BOOT_TRAP_VECTOR(t)                             \
        [t] = {                                         \
                (uintptr_t) &vstart_trap_handler,       \
                KERNEL64_CS,                            \
                0,                                      \
                ACC_P|ACC_PL_K|ACC_INTR_GATE,           \
                0                                       \
        },

/* Recursive macro to iterate 0..31 */
#define L0(x, n)  x(n)
#define L1(x, n)  L0(x,n-1)     L0(x,n)
#define L2(x, n)  L1(x,n-2)     L1(x,n)
#define L3(x, n)  L2(x,n-4)     L2(x,n)
#define L4(x, n)  L3(x,n-8)     L3(x,n)
#define L5(x, n)  L4(x,n-16)    L4(x,n)
#define FOR_0_TO_31(x) L5(x,31)

/*
 * Bootstrap IDT. Active only during early startup.
 * Only the trap vectors are defined since interrupts are masked.
 * All traps point to a common handler.
 */
struct fake_descriptor64 master_boot_idt64[IDTSZ]
__attribute__((section("__HIB,__desc")))
__attribute__((aligned(PAGE_SIZE))) = {
        FOR_0_TO_31(BOOT_TRAP_VECTOR)
};

static void
vstart_idt_init(boolean_t master)
{
        x86_64_desc_register_t  vstart_idt = {
                sizeof(master_boot_idt64),
                master_boot_idt64
        };

        if (master) {
                fix_desc64(master_boot_idt64, 32);
        }
        lidt((void *)&vstart_idt);
}

extern void *collection_base_pointers[KCNumKinds];

kern_return_t
i386_slide_individual_kext(kernel_mach_header_t *mh, uintptr_t slide)
{
        int ret = kernel_collection_slide(mh, (const void **) (void *)collection_base_pointers);
        if (ret != 0) {
                printf("Sliding pageable kc was stopped\n");
                return KERN_FAILURE;
        }

        kernel_collection_adjust_fileset_entry_addrs(mh, slide);
        return KERN_SUCCESS;
}

kern_return_t
i386_slide_kext_collection_mh_addrs(kernel_mach_header_t *mh, uintptr_t slide, bool adjust_mach_headers)
{
        int ret = kernel_collection_slide(mh, (const void **) (void *)collection_base_pointers);
        if (ret != KERN_SUCCESS) {
                printf("Kernel Collection slide was stopped with value %d\n", ret);
                return KERN_FAILURE;
        }

        kernel_collection_adjust_mh_addrs(mh, slide, adjust_mach_headers,
            NULL, NULL, NULL, NULL, NULL, NULL, NULL);

        return KERN_SUCCESS;
}

static void
i386_slide_and_rebase_image(uintptr_t kstart_addr)
{
        extern uintptr_t kc_highest_nonlinkedit_vmaddr;
        kernel_mach_header_t *k_mh, *kc_mh = NULL;
        kernel_segment_command_t *seg;
        uintptr_t slide;

        k_mh = &_mh_execute_header;
        /*
         * If we're not booting, an MH_FILESET, we don't need to slide
         * anything because EFI has done that for us. When booting an
         * MH_FILESET, EFI will slide the kernel proper, but not the kexts.
         * Below, we infer the slide by comparing the slid address of the
         * kernel's mach-o header and the unslid vmaddr of the first segment
         * of the mach-o (which is assumed to always point to the mach-o
         * header).
         */
        if (!kernel_mach_header_is_in_fileset(k_mh)) {
                DBG("[MH] kcgen-style KC\n");
                return;
        }

        /*
         * The kernel is part of a MH_FILESET kernel collection: determine slide
         * based on first segment's mach-o vmaddr.
         */
        seg = (kernel_segment_command_t *)((uintptr_t)k_mh + sizeof(*k_mh));
        assert(seg->cmd == LC_SEGMENT_KERNEL);
        slide = (uintptr_t)k_mh - seg->vmaddr;
        DBG("[MH] Sliding new-style KC: %llu\n", (unsigned long long)slide);

        /*
         * The kernel collection mach-o header should be the start address
         * passed to us by EFI.
         */
        kc_mh  = (kernel_mach_header_t *)(kstart_addr);
        assert(kc_mh->filetype == MH_FILESET);

        PE_set_kc_header(KCKindPrimary, kc_mh, slide);

        /*
         * rebase/slide all the kexts in the collection
         * (EFI should have already rebased the kernel)
         */
        kernel_collection_slide(kc_mh, (const void **) (void *)collection_base_pointers);


        /*
         * Now adjust the vmaddr fields of all mach-o headers
         * and symbols in this MH_FILESET
         */
        kernel_collection_adjust_mh_addrs(kc_mh, slide, false,
            NULL, NULL, NULL, NULL, NULL, NULL, &kc_highest_nonlinkedit_vmaddr);
}

/*
 * vstart() is called in the natural mode (64bit for K64, 32 for K32)
 * on a set of bootstrap pagetables which use large, 2MB pages to map
 * all of physical memory in both. See idle_pt.c for details.
 *
 * In K64 this identity mapping is mirrored the top and bottom 512GB
 * slots of PML4.
 *
 * The bootstrap processor called with argument boot_args_start pointing to
 * the boot-args block. The kernel's (4K page) page tables are allocated and
 * initialized before switching to these.
 *
 * Non-bootstrap processors are called with argument boot_args_start NULL.
 * These processors switch immediately to the existing kernel page tables.
 */
__attribute__((noreturn))
void
vstart(vm_offset_t boot_args_start)
{
        boolean_t       is_boot_cpu = !(boot_args_start == 0);
        int             cpu = 0;
        uint32_t        lphysfree;
#if DEBUG
        uint64_t        gsbase;
#endif


        postcode(VSTART_ENTRY);

        /*
         * Set-up temporary trap handlers during page-table set-up.
         */

        if (is_boot_cpu) {
                vstart_idt_init(TRUE);
                postcode(VSTART_IDT_INIT);

                /*
                 * Ensure that any %gs-relative access results in an immediate fault
                 * until gsbase is properly initialized below
                 */
                wrmsr64(MSR_IA32_GS_BASE, EARLY_GSBASE_MAGIC);

                /*
                 * Get startup parameters.
                 */
                kernelBootArgs = (boot_args *)boot_args_start;
                lphysfree = kernelBootArgs->kaddr + kernelBootArgs->ksize;
                physfree = (void *)(uintptr_t)((lphysfree + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1));

                pal_serial_init();

                DBG("revision      0x%x\n", kernelBootArgs->Revision);
                DBG("version       0x%x\n", kernelBootArgs->Version);
                DBG("command line  %s\n", kernelBootArgs->CommandLine);
                DBG("memory map    0x%x\n", kernelBootArgs->MemoryMap);
                DBG("memory map sz 0x%x\n", kernelBootArgs->MemoryMapSize);
                DBG("kaddr         0x%x\n", kernelBootArgs->kaddr);
                DBG("ksize         0x%x\n", kernelBootArgs->ksize);
                DBG("physfree      %p\n", physfree);
                DBG("bootargs: %p, &ksize: %p &kaddr: %p\n",
                    kernelBootArgs,
                    &kernelBootArgs->ksize,
                    &kernelBootArgs->kaddr);
                DBG("SMBIOS mem sz 0x%llx\n", kernelBootArgs->PhysicalMemorySize);
                DBG("KC_hdrs_vaddr %p\n", (void *)kernelBootArgs->KC_hdrs_vaddr);

                if (kernelBootArgs->Version >= 2 && kernelBootArgs->Revision >= 1 &&
                    kernelBootArgs->KC_hdrs_vaddr != 0) {
                        /*
                         * slide the header addresses in all mach-o segments and sections, and
                         * perform any new-style chained-fixup sliding for kexts, as necessary.
                         * Note that efiboot has already loaded the kernel and all LC_SEGMENT_64s
                         * that correspond to the kexts present in the primary KC, into slid addresses.
                         */
                        i386_slide_and_rebase_image((uintptr_t)ml_static_ptovirt(kernelBootArgs->KC_hdrs_vaddr));
                }

                /*
                 * Setup boot args given the physical start address.
                 * Note: PE_init_platform needs to be called before Idle_PTs_init
                 * because access to the DeviceTree is required to read the
                 * random seed before generating a random physical map slide.
                 */
                kernelBootArgs = (boot_args *)
                    ml_static_ptovirt(boot_args_start);
                DBG("i386_init(0x%lx) kernelBootArgs=%p\n",
                    (unsigned long)boot_args_start, kernelBootArgs);

#if KASAN
                kasan_reserve_memory(kernelBootArgs);
#endif

                PE_init_platform(FALSE, kernelBootArgs);
                postcode(PE_INIT_PLATFORM_D);

                Idle_PTs_init();
                postcode(VSTART_IDLE_PTS_INIT);

#if KASAN
                /* Init kasan and map whatever was stolen from physfree */
                kasan_init();
                kasan_notify_stolen((uintptr_t)ml_static_ptovirt((vm_offset_t)physfree));
#endif

#if MONOTONIC
                mt_early_init();
#endif /* MONOTONIC */

                first_avail = (vm_offset_t)ID_MAP_VTOP(physfree);

                cpu_data_alloc(TRUE);

                cpu_desc_init(cpu_datap(0));
                postcode(VSTART_CPU_DESC_INIT);
                cpu_desc_load(cpu_datap(0));

                postcode(VSTART_CPU_MODE_INIT);
                cpu_syscall_init(cpu_datap(0)); /* cpu_syscall_init() will be
                                                 * invoked on the APs
                                                 * via i386_init_slave()
                                                 */
        } else {
                /* Slave CPUs should use the basic IDT until i386_init_slave() */
                vstart_idt_init(FALSE);

                /* Switch to kernel's page tables (from the Boot PTs) */
                set_cr3_raw((uintptr_t)ID_MAP_VTOP(IdlePML4));

                /* Find our logical cpu number */
                cpu = lapic_to_cpu[lapic_safe_apicid()];
#if DEBUG
                gsbase = rdmsr64(MSR_IA32_GS_BASE);
#endif
                cpu_desc_load(cpu_datap(cpu));
#if DEBUG
                DBG("CPU: %d, GSBASE initial value: 0x%llx\n", cpu, (unsigned long long)gsbase);
#endif

                /*
                 * Before we can discover our local APIC ID, we need to potentially
                 * initialize X2APIC, if it's enabled and firmware started us with
                 * the APIC in legacy mode.
                 */
                lapic_init_slave();
        }

        early_boot = 0;
        postcode(VSTART_EXIT);
        x86_init_wrapper(is_boot_cpu ? (uintptr_t) i386_init
            : (uintptr_t) i386_init_slave,
            cpu_datap(cpu)->cpu_int_stack_top);
}

void
pstate_trace(void)
{
}

/*
 *      Cpu initialization.  Running virtual, but without MACH VM
 *      set up.
 */
void
i386_init(void)
{
        unsigned int    maxmem;
        uint64_t        maxmemtouse;
        unsigned int    cpus = 0;
        boolean_t       fidn;
        boolean_t       IA32e = TRUE;

        postcode(I386_INIT_ENTRY);

        pal_i386_init();
        tsc_init();
        rtclock_early_init();   /* mach_absolute_time() now functional */

        kernel_debug_string_early("i386_init");
        pstate_trace();

#if CONFIG_MCA
        /* Initialize machine-check handling */
        mca_cpu_init();
#endif

        master_cpu = 0;

        kernel_debug_string_early("kernel_startup_bootstrap");
        kernel_startup_bootstrap();

        /*
         * Initialize the timer callout world
         */
        timer_call_init();

        cpu_init();

        postcode(CPU_INIT_D);

        /* setup debugging output if one has been chosen */
        kernel_startup_initialize_upto(STARTUP_SUB_KPRINTF);
        kprintf("kprintf initialized\n");

        if (!PE_parse_boot_argn("diag", &dgWork.dgFlags, sizeof(dgWork.dgFlags))) {
                dgWork.dgFlags = 0;
        }

        if (PE_parse_boot_argn("insn_capcnt", &insn_copyin_count, sizeof(insn_copyin_count))) {
                /*
                 * Enforce max and min values (allowing 0 to disable copying completely)
                 * for the instruction copyin count
                 */
                if (insn_copyin_count > x86_INSTRUCTION_STATE_MAX_INSN_BYTES ||
                    (insn_copyin_count != 0 && insn_copyin_count < 64)) {
                        insn_copyin_count = DEFAULT_INSN_COPYIN_COUNT;
                }
        } else {
                insn_copyin_count = DEFAULT_INSN_COPYIN_COUNT;
        }

#if DEVELOPMENT || DEBUG
        if (!PE_parse_boot_argn("panic_clmismatch", &panic_on_cacheline_mismatch,
            sizeof(panic_on_cacheline_mismatch))) {
                panic_on_cacheline_mismatch = 0;
        }

        if (!PE_parse_boot_argn("panic_on_trap_procname", &panic_on_trap_procname[0],
            sizeof(panic_on_trap_procname))) {
                panic_on_trap_procname[0] = 0;
        }

        if (!PE_parse_boot_argn("panic_on_trap_mask", &panic_on_trap_mask,
            sizeof(panic_on_trap_mask))) {
                if (panic_on_trap_procname[0] != 0) {
                        panic_on_trap_mask = DEFAULT_PANIC_ON_TRAP_MASK;
                } else {
                        panic_on_trap_mask = 0;
                }
        }
#endif
        /* But allow that to be overridden via boot-arg: */
        if (!PE_parse_boot_argn("lbr_support", &last_branch_support_enabled,
            sizeof(last_branch_support_enabled))) {
                /* Disable LBR support by default due to its high context switch overhead */
                last_branch_support_enabled = false;
        }

        serialmode = 0;
        if (PE_parse_boot_argn("serial", &serialmode, sizeof(serialmode))) {
                /* We want a serial keyboard and/or console */
                kprintf("Serial mode specified: %08X\n", serialmode);
                int force_sync = serialmode & SERIALMODE_SYNCDRAIN;
                if (force_sync || PE_parse_boot_argn("drain_uart_sync", &force_sync, sizeof(force_sync))) {
                        if (force_sync) {
                                serialmode |= SERIALMODE_SYNCDRAIN;
                                kprintf(
                                        "WARNING: Forcing uart driver to output synchronously."
                                        "printf()s/IOLogs will impact kernel performance.\n"
                                        "You are advised to avoid using 'drain_uart_sync' boot-arg.\n");
                        }
                }
        }
        if (serialmode & SERIALMODE_OUTPUT) {
                serial_console_enabled = true;
                (void)switch_to_serial_console();
                disableConsoleOutput = FALSE; /* Allow printfs to happen */
        }

        /* setup console output */
        kernel_debug_string_early("PE_init_printf");
        PE_init_printf(FALSE);

        kprintf("version_variant = %s\n", version_variant);
        kprintf("version         = %s\n", version);

        if (!PE_parse_boot_argn("maxmem", &maxmem, sizeof(maxmem))) {
                maxmemtouse = 0;
        } else {
                maxmemtouse = ((uint64_t)maxmem) * MB;
        }

        max_cpus_from_firmware = acpi_count_enabled_logical_processors();

        if (PE_parse_boot_argn("cpus", &cpus, sizeof(cpus))) {
                if ((0 < cpus) && (cpus < max_ncpus)) {
                        max_ncpus = cpus;
                }
        }

        /*
         * debug support for > 4G systems
         */
        PE_parse_boot_argn("himemory_mode", &vm_himemory_mode, sizeof(vm_himemory_mode));
        if (!vm_himemory_mode) {
                kprintf("himemory_mode disabled\n");
        }

        if (!PE_parse_boot_argn("immediate_NMI", &fidn, sizeof(fidn))) {
                force_immediate_debugger_NMI = FALSE;
        } else {
                force_immediate_debugger_NMI = fidn;
        }

#if DEBUG
        nanoseconds_to_absolutetime(URGENCY_NOTIFICATION_ASSERT_NS, &urgency_notification_assert_abstime_threshold);
#endif
        PE_parse_boot_argn("urgency_notification_abstime",
            &urgency_notification_assert_abstime_threshold,
            sizeof(urgency_notification_assert_abstime_threshold));

        if (!(cpuid_extfeatures() & CPUID_EXTFEATURE_XD)) {
                nx_enabled = 0;
        }

        /*
         * VM initialization, after this we're using page tables...
         * Thn maximum number of cpus must be set beforehand.
         */
        kernel_debug_string_early("i386_vm_init");
        i386_vm_init(maxmemtouse, IA32e, kernelBootArgs);

        /* create the console for verbose or pretty mode */
        /* Note: doing this prior to tsc_init() allows for graceful panic! */
        PE_init_platform(TRUE, kernelBootArgs);
        PE_create_console();

        kernel_debug_string_early("power_management_init");
        power_management_init();
        xcpm_bootstrap();

#if MONOTONIC
        mt_cpu_up(cpu_datap(0));
#endif /* MONOTONIC */

        processor_bootstrap();
        thread_t thread = thread_bootstrap();
        machine_set_current_thread(thread);

        pstate_trace();
        kernel_debug_string_early("machine_startup");
        machine_startup();
        pstate_trace();
}

static void __dead2
do_init_slave(boolean_t fast_restart)
{
        void    *init_param     = FULL_SLAVE_INIT;

        postcode(I386_INIT_SLAVE);

        if (!fast_restart) {
                /* Ensure that caching and write-through are enabled */
                set_cr0(get_cr0() & ~(CR0_NW | CR0_CD));

                DBG("i386_init_slave() CPU%d: phys (%d) active.\n",
                    get_cpu_number(), get_cpu_phys_number());

                assert(!ml_get_interrupts_enabled());

                cpu_syscall_init(current_cpu_datap());
                pmap_cpu_init();

#if CONFIG_MCA
                mca_cpu_init();
#endif

                LAPIC_INIT();
                /*
                 * Note that the true argument here does not necessarily mean we're
                 * here from a resume (this code path is also executed on boot).
                 * The implementation of lapic_configure checks to see if the
                 * state variable has been initialized, as it would be before
                 * sleep.  If it has not been, it's construed as an indicator of
                 * first boot.
                 */
                lapic_configure(true);
                LAPIC_DUMP();
                LAPIC_CPU_MAP_DUMP();

                init_fpu();

#if CONFIG_MTRR
                mtrr_update_cpu();
#endif
                /* update CPU microcode and apply CPU workarounds */
                ucode_update_wake_and_apply_cpu_was();

                /* Enable LBRs on non-boot CPUs */
                i386_lbr_init(cpuid_info(), false);
        } else {
                init_param = FAST_SLAVE_INIT;
        }

#if CONFIG_VMX
        /* resume VT operation */
        vmx_resume(FALSE);
#endif

#if CONFIG_MTRR
        if (!fast_restart) {
                pat_init();
        }
#endif

        cpu_thread_init();      /* not strictly necessary */

        cpu_init();     /* Sets cpu_running which starter cpu waits for */


#if MONOTONIC
        mt_cpu_up(current_cpu_datap());
#endif /* MONOTONIC */

        slave_main(init_param);

        panic("do_init_slave() returned from slave_main()");
}

/*
 * i386_init_slave() is called from pstart.
 * We're in the cpu's interrupt stack with interrupts disabled.
 * At this point we are in legacy mode. We need to switch on IA32e
 * if the mode is set to 64-bits.
 */
void
i386_init_slave(void)
{
        do_init_slave(FALSE);
}

/*
 * i386_init_slave_fast() is called from pmCPUHalt.
 * We're running on the idle thread and need to fix up
 * some accounting and get it so that the scheduler sees this
 * CPU again.
 */
void
i386_init_slave_fast(void)
{
        do_init_slave(TRUE);
}


/* TODO: Evaluate global PTEs for the double-mapped translations */

uint64_t dblmap_base, dblmap_max;
kernel_segment_command_t *hdescseg;

pt_entry_t *dblmapL3;
unsigned int dblallocs;
uint64_t dblmap_dist;
extern uint64_t idt64_hndl_table0[];


void
doublemap_init(uint8_t randL3)
{
        dblmapL3 = ALLOCPAGES(1); // for 512 1GiB entries
        dblallocs++;

        struct {
                pt_entry_t entries[PTE_PER_PAGE];
        } * dblmapL2 = ALLOCPAGES(1); // for 512 2MiB entries
        dblallocs++;

        dblmapL3[randL3] = ((uintptr_t)ID_MAP_VTOP(&dblmapL2[0]))
            | INTEL_PTE_VALID
            | INTEL_PTE_WRITE;

        hdescseg = getsegbynamefromheader(&_mh_execute_header, "__HIB");

        vm_offset_t hdescb = hdescseg->vmaddr;
        unsigned long hdescsz = hdescseg->vmsize;
        unsigned long hdescszr = round_page_64(hdescsz);
        vm_offset_t hdescc = hdescb, hdesce = hdescb + hdescszr;

        kernel_section_t *thdescsect = getsectbynamefromheader(&_mh_execute_header, "__HIB", "__text");
        vm_offset_t thdescb = thdescsect->addr;
        unsigned long thdescsz = thdescsect->size;
        unsigned long thdescszr = round_page_64(thdescsz);
        vm_offset_t thdesce = thdescb + thdescszr;

        assert((hdescb & 0xFFF) == 0);
        /* Mirror HIB translations into the double-mapped pagetable subtree*/
        for (int i = 0; hdescc < hdesce; i++) {
                struct {
                        pt_entry_t entries[PTE_PER_PAGE];
                } * dblmapL1 = ALLOCPAGES(1);
                dblallocs++;
                dblmapL2[0].entries[i] = ((uintptr_t)ID_MAP_VTOP(&dblmapL1[0])) | INTEL_PTE_VALID | INTEL_PTE_WRITE | INTEL_PTE_REF;
                int hdescn = (int) ((hdesce - hdescc) / PAGE_SIZE);
                for (int j = 0; j < MIN(PTE_PER_PAGE, hdescn); j++) {
                        uint64_t template = INTEL_PTE_VALID;
                        if ((hdescc >= thdescb) && (hdescc < thdesce)) {
                                /* executable */
                        } else {
                                template |= INTEL_PTE_WRITE | INTEL_PTE_NX;  /* Writeable, NX */
                        }
                        dblmapL1[0].entries[j] = ((uintptr_t)ID_MAP_VTOP(hdescc)) | template;
                        hdescc += PAGE_SIZE;
                }
        }

        IdlePML4[KERNEL_DBLMAP_PML4_INDEX] = ((uintptr_t)ID_MAP_VTOP(dblmapL3)) | INTEL_PTE_VALID | INTEL_PTE_WRITE | INTEL_PTE_REF;

        dblmap_base = KVADDR(KERNEL_DBLMAP_PML4_INDEX, randL3, 0, 0);
        dblmap_max = dblmap_base + hdescszr;
        /* Calculate the double-map distance, which accounts for the current
         * KASLR slide
         */

        dblmap_dist = dblmap_base - hdescb;
        idt64_hndl_table0[1] = DBLMAP(idt64_hndl_table0[1]);    /* 64-bit exit trampoline */
        idt64_hndl_table0[3] = DBLMAP(idt64_hndl_table0[3]);    /* 32-bit exit trampoline */
        idt64_hndl_table0[6] = (uint64_t)(uintptr_t)&kernel_stack_mask;

        extern cpu_data_t cpshadows[], scdatas[];
        uintptr_t cd1 = (uintptr_t) &cpshadows[0];
        uintptr_t cd2 = (uintptr_t) &scdatas[0];
/* Record the displacement from the kernel's per-CPU data pointer, eventually
 * programmed into GSBASE, to the "shadows" in the doublemapped
 * region. These are not aliases, but separate physical allocations
 * containing data required in the doublemapped trampolines.
 */
        idt64_hndl_table0[2] = dblmap_dist + cd1 - cd2;

        DBG("Double map base: 0x%qx\n", dblmap_base);
        DBG("double map idlepml4[%d]: 0x%llx\n", KERNEL_DBLMAP_PML4_INDEX, IdlePML4[KERNEL_DBLMAP_PML4_INDEX]);
        assert(LDTSZ > LDTSZ_MIN);
}

vm_offset_t dyn_dblmap(vm_offset_t, vm_offset_t);

#include <i386/pmap_internal.h>

/* Use of this routine is expected to be synchronized by callers
 * Creates non-executable aliases.
 */
vm_offset_t
dyn_dblmap(vm_offset_t cva, vm_offset_t sz)
{
        vm_offset_t ava = dblmap_max;

        assert((sz & PAGE_MASK) == 0);
        assert(cva != 0);

        pmap_alias(ava, cva, cva + sz, VM_PROT_READ | VM_PROT_WRITE, PMAP_EXPAND_OPTIONS_ALIASMAP);
        dblmap_max += sz;
        return ava - cva;
}
/* Adjust offsets interior to the bootstrap interrupt descriptor table to redirect
 * control to the double-mapped interrupt vectors. The IDTR proper will be
 * programmed via cpu_desc_load()
 */
void
idt64_remap(void)
{
        for (int i = 0; i < IDTSZ; i++) {
                master_idt64[i].offset64 = DBLMAP(master_idt64[i].offset64);
        }
}