8322 nl: misleading-indentation

[unleashed/tickless.git] / usr / src / uts / i86pc / os / fastboot.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * This file contains the functions for performing Fast Reboot -- a
 * reboot which bypasses the firmware and bootloader, considerably
 * reducing downtime.
 *
 * fastboot_load_kernel(): This function is invoked by mdpreboot() in the
 * reboot path.  It loads the new kernel and boot archive into memory, builds
 * the data structure containing sufficient information about the new
 * kernel and boot archive to be passed to the fast reboot switcher
 * (see fb_swtch_src.s for details).  When invoked the switcher relocates
 * the new kernel and boot archive to physically contiguous low memory,
 * similar to where the boot loader would have loaded them, and jumps to
 * the new kernel.
 *
 * If fastreboot_onpanic is enabled, fastboot_load_kernel() is called
 * by fastreboot_post_startup() to load the back up kernel in case of
 * panic.
 *
 * The physical addresses of the memory allocated for the new kernel, boot
 * archive and their page tables must be above where the boot archive ends
 * after it has been relocated by the switcher, otherwise the new files
 * and their page tables could be overridden during relocation.
 *
 * fast_reboot(): This function is invoked by mdboot() once it's determined
 * that the system is capable of fast reboot.  It jumps to the fast reboot
 * switcher with the data structure built by fastboot_load_kernel() as the
 * argument.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/segments.h>
#include <sys/sysmacros.h>
#include <sys/vm.h>

#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/kmem.h>

#include <sys/reboot.h>
#include <sys/uadmin.h>

#include <sys/cred.h>
#include <sys/vnode.h>
#include <sys/file.h>

#include <sys/cmn_err.h>
#include <sys/dumphdr.h>
#include <sys/bootconf.h>
#include <sys/ddidmareq.h>
#include <sys/varargs.h>
#include <sys/promif.h>
#include <sys/modctl.h>

#include <vm/hat.h>
#include <vm/as.h>
#include <vm/page.h>
#include <vm/seg.h>
#include <vm/hat_i86.h>
#include <sys/vm_machparam.h>
#include <sys/archsystm.h>
#include <sys/machsystm.h>
#include <sys/mman.h>
#include <sys/x86_archext.h>
#include <sys/smp_impldefs.h>
#include <sys/spl.h>

#include <sys/fastboot_impl.h>
#include <sys/machelf.h>
#include <sys/kobj.h>
#include <sys/multiboot.h>
#include <sys/kobj_lex.h>

/*
 * Macro to determine how many pages are needed for PTEs to map a particular
 * file.  Allocate one extra page table entry for terminating the list.
 */
#define FASTBOOT_PTE_LIST_SIZE(fsize)   \
        P2ROUNDUP((((fsize) >> PAGESHIFT) + 1) * sizeof (x86pte_t), PAGESIZE)

/*
 * Data structure containing necessary information for the fast reboot
 * switcher to jump to the new kernel.
 */
fastboot_info_t newkernel = { 0 };
char            fastboot_args[OBP_MAXPATHLEN];

static char fastboot_filename[2][OBP_MAXPATHLEN] = { { 0 }, { 0 }};
static x86pte_t ptp_bits = PT_VALID | PT_REF | PT_USER | PT_WRITABLE;
static x86pte_t pte_bits =
    PT_VALID | PT_REF | PT_MOD | PT_NOCONSIST | PT_WRITABLE;
static uint_t fastboot_shift_amt_pae[] = {12, 21, 30, 39};

/* Index into Fast Reboot not supported message array */
static uint32_t fastreboot_nosup_id = FBNS_DEFAULT;

/* Fast Reboot not supported message array */
static const char * const fastreboot_nosup_desc[FBNS_END] = {
#define fastboot_nosup_msg(id, str)     str,
#include <sys/fastboot_msg.h>
};

int fastboot_debug = 0;
int fastboot_contig = 0;

/*
 * Fake starting va for new kernel and boot archive.
 */
static uintptr_t fake_va = FASTBOOT_FAKE_VA;

/*
 * Reserve memory below PA 1G in preparation of fast reboot.
 *
 * This variable is only checked when fastreboot_capable is set, but
 * fastreboot_onpanic is not set.  The amount of memory reserved
 * is negligible, but just in case we are really short of low memory,
 * this variable will give us a backdoor to not consume memory at all.
 */
int reserve_mem_enabled = 1;

/*
 * Mutex to protect fastreboot_onpanic.
 */
kmutex_t fastreboot_config_mutex;

/*
 * Amount of memory below PA 1G to reserve for constructing the multiboot
 * data structure and the page tables as we tend to run out of those
 * when more drivers are loaded.
 */
static size_t fastboot_mbi_size = 0x2000;       /* 8K */
static size_t fastboot_pagetable_size = 0x5000; /* 20K */

/*
 * Minimum system uptime in clock_t before Fast Reboot should be used
 * on panic.  Will be initialized in fastboot_post_startup().
 */
clock_t fastreboot_onpanic_uptime = LONG_MAX;

/*
 * lbolt value when the system booted.  This value will be used if the system
 * panics to calculate how long the system has been up.  If the uptime is less
 * than fastreboot_onpanic_uptime, a reboot through BIOS will be performed to
 * avoid a potential panic/reboot loop.
 */
clock_t lbolt_at_boot = LONG_MAX;

/*
 * Use below 1G for page tables as
 *      1. we are only doing 1:1 mapping of the bottom 1G of physical memory.
 *      2. we are using 2G as the fake virtual address for the new kernel and
 *      boot archive.
 */
static ddi_dma_attr_t fastboot_below_1G_dma_attr = {
        DMA_ATTR_V0,
        0x0000000008000000ULL,  /* dma_attr_addr_lo: 128MB */
        0x000000003FFFFFFFULL,  /* dma_attr_addr_hi: 1G */
        0x00000000FFFFFFFFULL,  /* dma_attr_count_max */
        0x0000000000001000ULL,  /* dma_attr_align: 4KB */
        1,                      /* dma_attr_burstsize */
        1,                      /* dma_attr_minxfer */
        0x00000000FFFFFFFFULL,  /* dma_attr_maxxfer */
        0x00000000FFFFFFFFULL,  /* dma_attr_seg */
        1,                      /* dma_attr_sgllen */
        0x1000ULL,              /* dma_attr_granular */
        0,                      /* dma_attr_flags */
};

static ddi_dma_attr_t fastboot_dma_attr = {
        DMA_ATTR_V0,
        0x0000000008000000ULL,  /* dma_attr_addr_lo: 128MB */
#ifdef  __amd64
        0xFFFFFFFFFFFFFFFFULL,  /* dma_attr_addr_hi: 2^64B */
#else
        0x0000000FFFFFFFFFULL,  /* dma_attr_addr_hi: 64GB */
#endif  /* __amd64 */
        0x00000000FFFFFFFFULL,  /* dma_attr_count_max */
        0x0000000000001000ULL,  /* dma_attr_align: 4KB */
        1,                      /* dma_attr_burstsize */
        1,                      /* dma_attr_minxfer */
        0x00000000FFFFFFFFULL,  /* dma_attr_maxxfer */
        0x00000000FFFFFFFFULL,  /* dma_attr_seg */
        1,                      /* dma_attr_sgllen */
        0x1000ULL,              /* dma_attr_granular */
        0,                      /* dma_attr_flags */
};

/*
 * Various information saved from the previous boot to reconstruct
 * multiboot_info.
 */
extern multiboot_info_t saved_mbi;
extern mb_memory_map_t saved_mmap[FASTBOOT_SAVED_MMAP_COUNT];
extern uint8_t saved_drives[FASTBOOT_SAVED_DRIVES_SIZE];
extern char saved_cmdline[FASTBOOT_SAVED_CMDLINE_LEN];
extern int saved_cmdline_len;
extern size_t saved_file_size[];

extern void* contig_alloc(size_t size, ddi_dma_attr_t *attr,
    uintptr_t align, int cansleep);
extern void contig_free(void *addr, size_t size);


/* PRINTLIKE */
extern void vprintf(const char *, va_list);


/*
 * Need to be able to get boot_archives from other places
 */
#define BOOTARCHIVE64   "/platform/i86pc/amd64/boot_archive"
#define BOOTARCHIVE32   "/platform/i86pc/boot_archive"
#define BOOTARCHIVE32_FAILSAFE  "/boot/x86.miniroot-safe"
#define BOOTARCHIVE64_FAILSAFE  "/boot/amd64/x86.miniroot-safe"
#define FAILSAFE_BOOTFILE32     "/boot/platform/i86pc/kernel/unix"
#define FAILSAFE_BOOTFILE64     "/boot/platform/i86pc/kernel/amd64/unix"

static uint_t fastboot_vatoindex(fastboot_info_t *, uintptr_t, int);
static void fastboot_map_with_size(fastboot_info_t *, uintptr_t,
    paddr_t, size_t, int);
static void fastboot_build_pagetables(fastboot_info_t *);
static int fastboot_build_mbi(char *, fastboot_info_t *);
static void fastboot_free_file(fastboot_file_t *);

static const char fastboot_enomem_msg[] = "!Fastboot: Couldn't allocate 0x%"
        PRIx64" bytes below %s to do fast reboot";

static void
dprintf(char *fmt, ...)
{
        va_list adx;

        if (!fastboot_debug)
                return;

        va_start(adx, fmt);
        vprintf(fmt, adx);
        va_end(adx);
}


/*
 * Return the index corresponding to a virt address at a given page table level.
 */
static uint_t
fastboot_vatoindex(fastboot_info_t *nk, uintptr_t va, int level)
{
        return ((va >> nk->fi_shift_amt[level]) & (nk->fi_ptes_per_table - 1));
}


/*
 * Add mapping from vstart to pstart for the specified size.
 * vstart, pstart and size should all have been aligned at 2M boundaries.
 */
static void
fastboot_map_with_size(fastboot_info_t *nk, uintptr_t vstart, paddr_t pstart,
    size_t size, int level)
{
        x86pte_t        pteval, *table;
        uintptr_t       vaddr;
        paddr_t         paddr;
        int             index, l;

        table = (x86pte_t *)(nk->fi_pagetable_va);

        for (l = nk->fi_top_level; l >= level; l--) {

                index = fastboot_vatoindex(nk, vstart, l);

                if (l == level) {
                        /*
                         * Last level.  Program the page table entries.
                         */
                        for (vaddr = vstart, paddr = pstart;
                            vaddr < vstart + size;
                            vaddr += (1ULL << nk->fi_shift_amt[l]),
                            paddr += (1ULL << nk->fi_shift_amt[l])) {

                                uint_t index = fastboot_vatoindex(nk, vaddr, l);

                                if (l > 0)
                                        pteval = paddr | pte_bits | PT_PAGESIZE;
                                else
                                        pteval = paddr | pte_bits;

                                table[index] = pteval;
                        }
                } else if (table[index] & PT_VALID) {

                        table = (x86pte_t *)
                            ((uintptr_t)(((paddr_t)table[index] & MMU_PAGEMASK)
                            - nk->fi_pagetable_pa) + nk->fi_pagetable_va);
                } else {
                        /*
                         * Intermediate levels.
                         * Program with either valid bit or PTP bits.
                         */
                        if (l == nk->fi_top_level) {
#ifdef  __amd64
                                ASSERT(nk->fi_top_level == 3);
                                table[index] = nk->fi_next_table_pa | ptp_bits;
#else
                                table[index] = nk->fi_next_table_pa | PT_VALID;
#endif  /* __amd64 */
                        } else {
                                table[index] = nk->fi_next_table_pa | ptp_bits;
                        }
                        table = (x86pte_t *)(nk->fi_next_table_va);
                        nk->fi_next_table_va += MMU_PAGESIZE;
                        nk->fi_next_table_pa += MMU_PAGESIZE;
                }
        }
}

/*
 * Build page tables for the lower 1G of physical memory using 2M
 * pages, and prepare page tables for mapping new kernel and boot
 * archive pages using 4K pages.
 */
static void
fastboot_build_pagetables(fastboot_info_t *nk)
{
        /*
         * Map lower 1G physical memory.  Use large pages.
         */
        fastboot_map_with_size(nk, 0, 0, ONE_GIG, 1);

        /*
         * Map one 4K page to get the middle page tables set up.
         */
        fake_va = P2ALIGN_TYPED(fake_va, nk->fi_lpagesize, uintptr_t);
        fastboot_map_with_size(nk, fake_va,
            nk->fi_files[0].fb_pte_list_va[0] & MMU_PAGEMASK, PAGESIZE, 0);
}


/*
 * Sanity check.  Look for dboot offset.
 */
static int
fastboot_elf64_find_dboot_load_offset(void *img, off_t imgsz, uint32_t *offp)
{
        Elf64_Ehdr      *ehdr = (Elf64_Ehdr *)img;
        Elf64_Phdr      *phdr;
        uint8_t         *phdrbase;
        int             i;

        if ((ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize) >= imgsz)
                return (-1);

        phdrbase = (uint8_t *)img + ehdr->e_phoff;

        for (i = 0; i < ehdr->e_phnum; i++) {
                phdr = (Elf64_Phdr *)(phdrbase + ehdr->e_phentsize * i);

                if (phdr->p_type == PT_LOAD) {
                        if (phdr->p_vaddr == phdr->p_paddr &&
                            phdr->p_vaddr == DBOOT_ENTRY_ADDRESS) {
                                ASSERT(phdr->p_offset <= UINT32_MAX);
                                *offp = (uint32_t)phdr->p_offset;
                                return (0);
                        }
                }
        }

        return (-1);
}


/*
 * Initialize text and data section information for 32-bit kernel.
 * sectcntp - is both input/output parameter.
 * On entry, *sectcntp contains maximum allowable number of sections;
 * on return, it contains the actual number of sections filled.
 */
static int
fastboot_elf32_find_loadables(void *img, off_t imgsz, fastboot_section_t *sectp,
    int *sectcntp, uint32_t *offp)
{
        Elf32_Ehdr      *ehdr = (Elf32_Ehdr *)img;
        Elf32_Phdr      *phdr;
        uint8_t         *phdrbase;
        int             i;
        int             used_sections = 0;
        const int       max_sectcnt = *sectcntp;

        if ((ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize) >= imgsz)
                return (-1);

        phdrbase = (uint8_t *)img + ehdr->e_phoff;

        for (i = 0; i < ehdr->e_phnum; i++) {
                phdr = (Elf32_Phdr *)(phdrbase + ehdr->e_phentsize * i);

                if (phdr->p_type == PT_INTERP)
                        return (-1);

                if (phdr->p_type != PT_LOAD)
                        continue;

                if (phdr->p_vaddr == phdr->p_paddr &&
                    phdr->p_paddr == DBOOT_ENTRY_ADDRESS) {
                        *offp = (uint32_t)phdr->p_offset;
                } else {
                        if (max_sectcnt <= used_sections)
                                return (-1);

                        sectp[used_sections].fb_sec_offset = phdr->p_offset;
                        sectp[used_sections].fb_sec_paddr = phdr->p_paddr;
                        sectp[used_sections].fb_sec_size = phdr->p_filesz;
                        sectp[used_sections].fb_sec_bss_size =
                            (phdr->p_filesz < phdr->p_memsz) ?
                            (phdr->p_memsz - phdr->p_filesz) : 0;

                        /* Extra sanity check for the input object file */
                        if (sectp[used_sections].fb_sec_paddr +
                            sectp[used_sections].fb_sec_size +
                            sectp[used_sections].fb_sec_bss_size >=
                            DBOOT_ENTRY_ADDRESS)
                                return (-1);

                        used_sections++;
                }
        }

        *sectcntp = used_sections;
        return (0);
}

/*
 * Create multiboot info structure (mbi) base on the saved mbi.
 * Recalculate values of the pointer type fields in the data
 * structure based on the new starting physical address of the
 * data structure.
 */
static int
fastboot_build_mbi(char *mdep, fastboot_info_t *nk)
{
        mb_module_t     *mbp;
        multiboot_info_t        *mbi;   /* pointer to multiboot structure */
        uintptr_t       start_addr_va;  /* starting VA of mbi */
        uintptr_t       start_addr_pa;  /* starting PA of mbi */
        size_t          offs = 0;       /* offset from the starting address */
        size_t          arglen;         /* length of the command line arg */
        size_t          size;   /* size of the memory reserved for mbi */
        size_t          mdnsz;  /* length of the boot archive name */

        /*
         * If mdep is not NULL or empty, use the length of mdep + 1
         * (for NULL terminating) as the length of the new command
         * line; else use the saved command line length as the
         * length for the new command line.
         */
        if (mdep != NULL && strlen(mdep) != 0) {
                arglen = strlen(mdep) + 1;
        } else {
                arglen = saved_cmdline_len;
        }

        /*
         * Allocate memory for the new multiboot info structure (mbi).
         * If we have reserved memory for mbi but it's not enough,
         * free it and reallocate.
         */
        size = PAGESIZE + P2ROUNDUP(arglen, PAGESIZE);
        if (nk->fi_mbi_size && nk->fi_mbi_size < size) {
                contig_free((void *)nk->fi_new_mbi_va, nk->fi_mbi_size);
                nk->fi_mbi_size = 0;
        }

        if (nk->fi_mbi_size == 0) {
                if ((nk->fi_new_mbi_va =
                    (uintptr_t)contig_alloc(size, &fastboot_below_1G_dma_attr,
                    PAGESIZE, 0)) == NULL) {
                        cmn_err(CE_NOTE, fastboot_enomem_msg,
                            (uint64_t)size, "1G");
                        return (-1);
                }
                /*
                 * fi_mbi_size must be set after the allocation succeeds
                 * as it's used to determine how much memory to free.
                 */
                nk->fi_mbi_size = size;
        }

        /*
         * Initalize memory
         */
        bzero((void *)nk->fi_new_mbi_va, nk->fi_mbi_size);

        /*
         * Get PA for the new mbi
         */
        start_addr_va = nk->fi_new_mbi_va;
        start_addr_pa = mmu_ptob((uint64_t)hat_getpfnum(kas.a_hat,
            (caddr_t)start_addr_va));
        nk->fi_new_mbi_pa = (paddr_t)start_addr_pa;

        /*
         * Populate the rest of the fields in the data structure
         */

        /*
         * Copy from the saved mbi to preserve all non-pointer type fields.
         */
        mbi = (multiboot_info_t *)start_addr_va;
        bcopy(&saved_mbi, mbi, sizeof (*mbi));

        /*
         * Recalculate mods_addr.  Set mod_start and mod_end based on
         * the physical address of the new boot archive.  Set mod_name
         * to the name of the new boto archive.
         */
        offs += sizeof (multiboot_info_t);
        mbi->mods_addr = start_addr_pa + offs;
        mbp = (mb_module_t *)(start_addr_va + offs);
        mbp->mod_start = nk->fi_files[FASTBOOT_BOOTARCHIVE].fb_dest_pa;
        mbp->mod_end = nk->fi_files[FASTBOOT_BOOTARCHIVE].fb_next_pa;

        offs += sizeof (mb_module_t);
        mdnsz = strlen(fastboot_filename[FASTBOOT_NAME_BOOTARCHIVE]) + 1;
        bcopy(fastboot_filename[FASTBOOT_NAME_BOOTARCHIVE],
            (void *)(start_addr_va + offs), mdnsz);
        mbp->mod_name = start_addr_pa + offs;
        mbp->reserved = 0;

        /*
         * Make sure the offset is 16-byte aligned to avoid unaligned access.
         */
        offs += mdnsz;
        offs = P2ROUNDUP_TYPED(offs, 16, size_t);

        /*
         * Recalculate mmap_addr
         */
        mbi->mmap_addr = start_addr_pa + offs;
        bcopy((void *)(uintptr_t)saved_mmap, (void *)(start_addr_va + offs),
            saved_mbi.mmap_length);
        offs += saved_mbi.mmap_length;

        /*
         * Recalculate drives_addr
         */
        mbi->drives_addr = start_addr_pa + offs;
        bcopy((void *)(uintptr_t)saved_drives, (void *)(start_addr_va + offs),
            saved_mbi.drives_length);
        offs += saved_mbi.drives_length;

        /*
         * Recalculate the address of cmdline.  Set cmdline to contain the
         * new boot argument.
         */
        mbi->cmdline = start_addr_pa + offs;

        if (mdep != NULL && strlen(mdep) != 0) {
                bcopy(mdep, (void *)(start_addr_va + offs), arglen);
        } else {
                bcopy((void *)saved_cmdline, (void *)(start_addr_va + offs),
                    arglen);
        }

        /* clear fields and flags that are not copied */
        bzero(&mbi->config_table,
            sizeof (*mbi) - offsetof(multiboot_info_t, config_table));
        mbi->flags &= ~(MB_INFO_CONFIG_TABLE | MB_INFO_BOOT_LOADER_NAME |
            MB_INFO_APM_TABLE | MB_INFO_VIDEO_INFO);

        return (0);
}

/*
 * Initialize HAT related fields
 */
static void
fastboot_init_fields(fastboot_info_t *nk)
{
        if (is_x86_feature(x86_featureset, X86FSET_PAE)) {
                nk->fi_has_pae = 1;
                nk->fi_shift_amt = fastboot_shift_amt_pae;
                nk->fi_ptes_per_table = 512;
                nk->fi_lpagesize = (2 << 20);   /* 2M */
#ifdef  __amd64
                nk->fi_top_level = 3;
#else
                nk->fi_top_level = 2;
#endif  /* __amd64 */
        }
}

/*
 * Process boot argument
 */
static void
fastboot_parse_mdep(char *mdep, char *kern_bootpath, int *bootpath_len,
    char *bootargs)
{
        int     i;

        /*
         * If mdep is not NULL, it comes in the format of
         *      mountpoint unix args
         */
        if (mdep != NULL && strlen(mdep) != 0) {
                if (mdep[0] != '-') {
                        /* First get the root argument */
                        i = 0;
                        while (mdep[i] != '\0' && mdep[i] != ' ') {
                                i++;
                        }

                        if (i < 4 || strncmp(&mdep[i-4], "unix", 4) != 0) {
                                /* mount point */
                                bcopy(mdep, kern_bootpath, i);
                                kern_bootpath[i] = '\0';
                                *bootpath_len = i;

                                /*
                                 * Get the next argument. It should be unix as
                                 * we have validated in in halt.c.
                                 */
                                if (strlen(mdep) > i) {
                                        mdep += (i + 1);
                                        i = 0;
                                        while (mdep[i] != '\0' &&
                                            mdep[i] != ' ') {
                                                i++;
                                        }
                                }

                        }
                        bcopy(mdep, kern_bootfile, i);
                        kern_bootfile[i] = '\0';
                        bcopy(mdep, bootargs, strlen(mdep));
                } else {
                        int off = strlen(kern_bootfile);
                        bcopy(kern_bootfile, bootargs, off);
                        bcopy(" ", &bootargs[off++], 1);
                        bcopy(mdep, &bootargs[off], strlen(mdep));
                        off += strlen(mdep);
                        bootargs[off] = '\0';
                }
        }
}

/*
 * Reserve memory under PA 1G for mapping the new kernel and boot archive.
 * This function is only called if fastreboot_onpanic is *not* set.
 */
static void
fastboot_reserve_mem(fastboot_info_t *nk)
{
        int i;

        /*
         * A valid kernel is in place.  No need to reserve any memory.
         */
        if (nk->fi_valid)
                return;

        /*
         * Reserve memory under PA 1G for PTE lists.
         */
        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                fastboot_file_t *fb = &nk->fi_files[i];
                size_t fsize_roundup, size;

                fsize_roundup = P2ROUNDUP_TYPED(saved_file_size[i],
                    PAGESIZE, size_t);
                size = FASTBOOT_PTE_LIST_SIZE(fsize_roundup);
                if ((fb->fb_pte_list_va = contig_alloc(size,
                    &fastboot_below_1G_dma_attr, PAGESIZE, 0)) == NULL) {
                        return;
                }
                fb->fb_pte_list_size = size;
        }

        /*
         * Reserve memory under PA 1G for page tables.
         */
        if ((nk->fi_pagetable_va =
            (uintptr_t)contig_alloc(fastboot_pagetable_size,
            &fastboot_below_1G_dma_attr, PAGESIZE, 0)) == NULL) {
                return;
        }
        nk->fi_pagetable_size = fastboot_pagetable_size;

        /*
         * Reserve memory under PA 1G for multiboot structure.
         */
        if ((nk->fi_new_mbi_va = (uintptr_t)contig_alloc(fastboot_mbi_size,
            &fastboot_below_1G_dma_attr, PAGESIZE, 0)) == NULL) {
                return;
        }
        nk->fi_mbi_size = fastboot_mbi_size;
}

/*
 * Calculate MD5 digest for the given fastboot_file.
 * Assumes that the file is allready loaded properly.
 */
static void
fastboot_cksum_file(fastboot_file_t *fb, uchar_t *md5_hash)
{
        MD5_CTX md5_ctx;

        MD5Init(&md5_ctx);
        MD5Update(&md5_ctx, (void *)fb->fb_va, fb->fb_size);
        MD5Final(md5_hash, &md5_ctx);
}

/*
 * Free up the memory we have allocated for a file
 */
static void
fastboot_free_file(fastboot_file_t *fb)
{
        size_t  fsize_roundup;

        fsize_roundup = P2ROUNDUP_TYPED(fb->fb_size, PAGESIZE, size_t);
        if (fsize_roundup) {
                contig_free((void *)fb->fb_va, fsize_roundup);
                fb->fb_va = NULL;
                fb->fb_size = 0;
        }
}

/*
 * Free up memory used by the PTEs for a file.
 */
static void
fastboot_free_file_pte(fastboot_file_t *fb, uint64_t endaddr)
{
        if (fb->fb_pte_list_size && fb->fb_pte_list_pa < endaddr) {
                contig_free((void *)fb->fb_pte_list_va, fb->fb_pte_list_size);
                fb->fb_pte_list_va = 0;
                fb->fb_pte_list_pa = 0;
                fb->fb_pte_list_size = 0;
        }
}

/*
 * Free up all the memory used for representing a kernel with
 * fastboot_info_t.
 */
static void
fastboot_free_mem(fastboot_info_t *nk, uint64_t endaddr)
{
        int i;

        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                fastboot_free_file(nk->fi_files + i);
                fastboot_free_file_pte(nk->fi_files + i, endaddr);
        }

        if (nk->fi_pagetable_size && nk->fi_pagetable_pa < endaddr) {
                contig_free((void *)nk->fi_pagetable_va, nk->fi_pagetable_size);
                nk->fi_pagetable_va = 0;
                nk->fi_pagetable_pa = 0;
                nk->fi_pagetable_size = 0;
        }

        if (nk->fi_mbi_size && nk->fi_new_mbi_pa < endaddr) {
                contig_free((void *)nk->fi_new_mbi_va, nk->fi_mbi_size);
                nk->fi_new_mbi_va = 0;
                nk->fi_new_mbi_pa = 0;
                nk->fi_mbi_size = 0;
        }
}

/*
 * Only free up the memory allocated for the kernel and boot archive,
 * but not for the page tables.
 */
void
fastboot_free_newkernel(fastboot_info_t *nk)
{
        int i;

        nk->fi_valid = 0;
        /*
         * Free the memory we have allocated
         */
        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                fastboot_free_file(&(nk->fi_files[i]));
        }
}

static void
fastboot_cksum_cdata(fastboot_info_t *nk, uchar_t *md5_hash)
{
        int i;
        MD5_CTX md5_ctx;

        MD5Init(&md5_ctx);
        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                MD5Update(&md5_ctx, nk->fi_files[i].fb_pte_list_va,
                    nk->fi_files[i].fb_pte_list_size);
        }
        MD5Update(&md5_ctx, (void *)nk->fi_pagetable_va, nk->fi_pagetable_size);
        MD5Update(&md5_ctx, (void *)nk->fi_new_mbi_va, nk->fi_mbi_size);

        MD5Final(md5_hash, &md5_ctx);
}

/*
 * Generate MD5 checksum of the given kernel.
 */
static void
fastboot_cksum_generate(fastboot_info_t *nk)
{
        int i;

        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                fastboot_cksum_file(nk->fi_files + i, nk->fi_md5_hash[i]);
        }
        fastboot_cksum_cdata(nk, nk->fi_md5_hash[i]);
}

/*
 * Calculate MD5 checksum of the given kernel and verify that
 * it matches with what was calculated before.
 */
int
fastboot_cksum_verify(fastboot_info_t *nk)
{
        int i;
        uchar_t md5_hash[MD5_DIGEST_LENGTH];

        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                fastboot_cksum_file(nk->fi_files + i, md5_hash);
                if (bcmp(nk->fi_md5_hash[i], md5_hash,
                    sizeof (nk->fi_md5_hash[i])) != 0)
                        return (i + 1);
        }

        fastboot_cksum_cdata(nk, md5_hash);
        if (bcmp(nk->fi_md5_hash[i], md5_hash,
            sizeof (nk->fi_md5_hash[i])) != 0)
                return (i + 1);

        return (0);
}

/*
 * This function performs the following tasks:
 * - Read the sizes of the new kernel and boot archive.
 * - Allocate memory for the new kernel and boot archive.
 * - Allocate memory for page tables necessary for mapping the memory
 *   allocated for the files.
 * - Read the new kernel and boot archive into memory.
 * - Map in the fast reboot switcher.
 * - Load the fast reboot switcher to FASTBOOT_SWTCH_PA.
 * - Build the new multiboot_info structure
 * - Build page tables for the low 1G of physical memory.
 * - Mark the data structure as valid if all steps have succeeded.
 */
void
fastboot_load_kernel(char *mdep)
{
        void            *buf = NULL;
        int             i;
        fastboot_file_t *fb;
        uint32_t        dboot_start_offset;
        char            kern_bootpath[OBP_MAXPATHLEN];
        extern uintptr_t postbootkernelbase;
        uintptr_t       saved_kernelbase;
        int             bootpath_len = 0;
        int             is_failsafe = 0;
        int             is_retry = 0;
        uint64_t        end_addr;

        if (!fastreboot_capable)
                return;

        if (newkernel.fi_valid)
                fastboot_free_newkernel(&newkernel);

        saved_kernelbase = postbootkernelbase;

        postbootkernelbase = 0;

        /*
         * Initialize various HAT related fields in the data structure
         */
        fastboot_init_fields(&newkernel);

        bzero(kern_bootpath, OBP_MAXPATHLEN);

        /*
         * Process the boot argument
         */
        bzero(fastboot_args, OBP_MAXPATHLEN);
        fastboot_parse_mdep(mdep, kern_bootpath, &bootpath_len, fastboot_args);

        /*
         * Make sure we get the null character
         */
        bcopy(kern_bootpath, fastboot_filename[FASTBOOT_NAME_UNIX],
            bootpath_len);
        bcopy(kern_bootfile,
            &fastboot_filename[FASTBOOT_NAME_UNIX][bootpath_len],
            strlen(kern_bootfile) + 1);

        bcopy(kern_bootpath, fastboot_filename[FASTBOOT_NAME_BOOTARCHIVE],
            bootpath_len);

        if (bcmp(kern_bootfile, FAILSAFE_BOOTFILE32,
            (sizeof (FAILSAFE_BOOTFILE32) - 1)) == 0 ||
            bcmp(kern_bootfile, FAILSAFE_BOOTFILE64,
            (sizeof (FAILSAFE_BOOTFILE64) - 1)) == 0) {
                is_failsafe = 1;
        }

load_kernel_retry:
        /*
         * Read in unix and boot_archive
         */
        end_addr = DBOOT_ENTRY_ADDRESS;
        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                struct _buf     *file;
                uintptr_t       va;
                uint64_t        fsize;
                size_t          fsize_roundup, pt_size;
                int             page_index;
                uintptr_t       offset;
                ddi_dma_attr_t dma_attr = fastboot_dma_attr;


                dprintf("fastboot_filename[%d] = %s\n",
                    i, fastboot_filename[i]);

                if ((file = kobj_open_file(fastboot_filename[i])) ==
                    (struct _buf *)-1) {
                        cmn_err(CE_NOTE, "!Fastboot: Couldn't open %s",
                            fastboot_filename[i]);
                        goto err_out;
                }

                if (kobj_get_filesize(file, &fsize) != 0) {
                        cmn_err(CE_NOTE,
                            "!Fastboot: Couldn't get filesize for %s",
                            fastboot_filename[i]);
                        goto err_out;
                }

                fsize_roundup = P2ROUNDUP_TYPED(fsize, PAGESIZE, size_t);

                /*
                 * Where the files end in physical memory after being
                 * relocated by the fast boot switcher.
                 */
                end_addr += fsize_roundup;
                if (end_addr > fastboot_below_1G_dma_attr.dma_attr_addr_hi) {
                        cmn_err(CE_NOTE, "!Fastboot: boot archive is too big");
                        goto err_out;
                }

                /*
                 * Adjust dma_attr_addr_lo so that the new kernel and boot
                 * archive will not be overridden during relocation.
                 */
                if (end_addr > fastboot_dma_attr.dma_attr_addr_lo ||
                    end_addr > fastboot_below_1G_dma_attr.dma_attr_addr_lo) {

                        if (is_retry) {
                                /*
                                 * If we have already tried and didn't succeed,
                                 * just give up.
                                 */
                                cmn_err(CE_NOTE,
                                    "!Fastboot: boot archive is too big");
                                goto err_out;
                        } else {
                                /* Set the flag so we don't keep retrying */
                                is_retry++;

                                /* Adjust dma_attr_addr_lo */
                                fastboot_dma_attr.dma_attr_addr_lo = end_addr;
                                fastboot_below_1G_dma_attr.dma_attr_addr_lo =
                                    end_addr;

                                /*
                                 * Free the memory we have already allocated
                                 * whose physical addresses might not fit
                                 * the new lo and hi constraints.
                                 */
                                fastboot_free_mem(&newkernel, end_addr);
                                goto load_kernel_retry;
                        }
                }


                if (!fastboot_contig)
                        dma_attr.dma_attr_sgllen = (fsize / PAGESIZE) +
                            (((fsize % PAGESIZE) == 0) ? 0 : 1);

                if ((buf = contig_alloc(fsize, &dma_attr, PAGESIZE, 0))
                    == NULL) {
                        cmn_err(CE_NOTE, fastboot_enomem_msg, fsize, "64G");
                        goto err_out;
                }

                va = P2ROUNDUP_TYPED((uintptr_t)buf, PAGESIZE, uintptr_t);

                if (kobj_read_file(file, (char *)va, fsize, 0) < 0) {
                        cmn_err(CE_NOTE, "!Fastboot: Couldn't read %s",
                            fastboot_filename[i]);
                        goto err_out;
                }

                fb = &newkernel.fi_files[i];
                fb->fb_va = va;
                fb->fb_size = fsize;
                fb->fb_sectcnt = 0;

                pt_size = FASTBOOT_PTE_LIST_SIZE(fsize_roundup);

                /*
                 * If we have reserved memory but it not enough, free it.
                 */
                if (fb->fb_pte_list_size && fb->fb_pte_list_size < pt_size) {
                        contig_free((void *)fb->fb_pte_list_va,
                            fb->fb_pte_list_size);
                        fb->fb_pte_list_size = 0;
                }

                if (fb->fb_pte_list_size == 0) {
                        if ((fb->fb_pte_list_va =
                            (x86pte_t *)contig_alloc(pt_size,
                            &fastboot_below_1G_dma_attr, PAGESIZE, 0))
                            == NULL) {
                                cmn_err(CE_NOTE, fastboot_enomem_msg,
                                    (uint64_t)pt_size, "1G");
                                goto err_out;
                        }
                        /*
                         * fb_pte_list_size must be set after the allocation
                         * succeeds as it's used to determine how much memory to
                         * free.
                         */
                        fb->fb_pte_list_size = pt_size;
                }

                bzero((void *)(fb->fb_pte_list_va), fb->fb_pte_list_size);

                fb->fb_pte_list_pa = mmu_ptob((uint64_t)hat_getpfnum(kas.a_hat,
                    (caddr_t)fb->fb_pte_list_va));

                for (page_index = 0, offset = 0; offset < fb->fb_size;
                    offset += PAGESIZE) {
                        uint64_t paddr;

                        paddr = mmu_ptob((uint64_t)hat_getpfnum(kas.a_hat,
                            (caddr_t)fb->fb_va + offset));

                        ASSERT(paddr >= fastboot_dma_attr.dma_attr_addr_lo);

                        /*
                         * Include the pte_bits so we don't have to make
                         * it in assembly.
                         */
                        fb->fb_pte_list_va[page_index++] = (x86pte_t)
                            (paddr | pte_bits);
                }

                fb->fb_pte_list_va[page_index] = FASTBOOT_TERMINATE;

                if (i == FASTBOOT_UNIX) {
                        Ehdr    *ehdr = (Ehdr *)va;
                        int     j;

                        /*
                         * Sanity checks:
                         */
                        for (j = 0; j < SELFMAG; j++) {
                                if (ehdr->e_ident[j] != ELFMAG[j]) {
                                        cmn_err(CE_NOTE, "!Fastboot: Bad ELF "
                                            "signature");
                                        goto err_out;
                                }
                        }

                        if (ehdr->e_ident[EI_CLASS] == ELFCLASS32 &&
                            ehdr->e_ident[EI_DATA] == ELFDATA2LSB &&
                            ehdr->e_machine == EM_386) {

                                fb->fb_sectcnt = sizeof (fb->fb_sections) /
                                    sizeof (fb->fb_sections[0]);

                                if (fastboot_elf32_find_loadables((void *)va,
                                    fsize, &fb->fb_sections[0],
                                    &fb->fb_sectcnt, &dboot_start_offset) < 0) {
                                        cmn_err(CE_NOTE, "!Fastboot: ELF32 "
                                            "program section failure");
                                        goto err_out;
                                }

                                if (fb->fb_sectcnt == 0) {
                                        cmn_err(CE_NOTE, "!Fastboot: No ELF32 "
                                            "program sections found");
                                        goto err_out;
                                }

                                if (is_failsafe) {
                                        /* Failsafe boot_archive */
                                        bcopy(BOOTARCHIVE32_FAILSAFE,
                                            &fastboot_filename
                                            [FASTBOOT_NAME_BOOTARCHIVE]
                                            [bootpath_len],
                                            sizeof (BOOTARCHIVE32_FAILSAFE));
                                } else {
                                        bcopy(BOOTARCHIVE32,
                                            &fastboot_filename
                                            [FASTBOOT_NAME_BOOTARCHIVE]
                                            [bootpath_len],
                                            sizeof (BOOTARCHIVE32));
                                }

                        } else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64 &&
                            ehdr->e_ident[EI_DATA] == ELFDATA2LSB &&
                            ehdr->e_machine == EM_AMD64) {

                                if (fastboot_elf64_find_dboot_load_offset(
                                    (void *)va, fsize, &dboot_start_offset)
                                    != 0) {
                                        cmn_err(CE_NOTE, "!Fastboot: Couldn't "
                                            "find ELF64 dboot entry offset");
                                        goto err_out;
                                }

                                if (!is_x86_feature(x86_featureset,
                                    X86FSET_64) ||
                                    !is_x86_feature(x86_featureset,
                                    X86FSET_PAE)) {
                                        cmn_err(CE_NOTE, "Fastboot: Cannot "
                                            "reboot to %s: "
                                            "not a 64-bit capable system",
                                            kern_bootfile);
                                        goto err_out;
                                }

                                if (is_failsafe) {
                                        /* Failsafe boot_archive */
                                        bcopy(BOOTARCHIVE64_FAILSAFE,
                                            &fastboot_filename
                                            [FASTBOOT_NAME_BOOTARCHIVE]
                                            [bootpath_len],
                                            sizeof (BOOTARCHIVE64_FAILSAFE));
                                } else {
                                        bcopy(BOOTARCHIVE64,
                                            &fastboot_filename
                                            [FASTBOOT_NAME_BOOTARCHIVE]
                                            [bootpath_len],
                                            sizeof (BOOTARCHIVE64));
                                }
                        } else {
                                cmn_err(CE_NOTE, "!Fastboot: Unknown ELF type");
                                goto err_out;
                        }

                        fb->fb_dest_pa = DBOOT_ENTRY_ADDRESS -
                            dboot_start_offset;

                        fb->fb_next_pa = DBOOT_ENTRY_ADDRESS + fsize_roundup;
                } else {
                        fb->fb_dest_pa = newkernel.fi_files[i - 1].fb_next_pa;
                        fb->fb_next_pa = fb->fb_dest_pa + fsize_roundup;
                }

                kobj_close_file(file);

        }

        /*
         * Add the function that will switch us to 32-bit protected mode
         */
        fb = &newkernel.fi_files[FASTBOOT_SWTCH];
        fb->fb_va = fb->fb_dest_pa = FASTBOOT_SWTCH_PA;
        fb->fb_size = MMU_PAGESIZE;

        hat_devload(kas.a_hat, (caddr_t)fb->fb_va,
            MMU_PAGESIZE, mmu_btop(fb->fb_dest_pa),
            PROT_READ | PROT_WRITE | PROT_EXEC,
            HAT_LOAD_NOCONSIST | HAT_LOAD_LOCK);

        /*
         * Build the new multiboot_info structure
         */
        if (fastboot_build_mbi(fastboot_args, &newkernel) != 0) {
                goto err_out;
        }

        /*
         * Build page table for low 1G physical memory. Use big pages.
         * Allocate 4 (5 for amd64) pages for the page tables.
         *    1 page for PML4 (amd64)
         *    1 page for Page-Directory-Pointer Table
         *    2 pages for Page Directory
         *    1 page for Page Table.
         * The page table entry will be rewritten to map the physical
         * address as we do the copying.
         */
        if (newkernel.fi_has_pae) {
#ifdef  __amd64
                size_t size = MMU_PAGESIZE * 5;
#else
                size_t size = MMU_PAGESIZE * 4;
#endif  /* __amd64 */

                if (newkernel.fi_pagetable_size && newkernel.fi_pagetable_size
                    < size) {
                        contig_free((void *)newkernel.fi_pagetable_va,
                            newkernel.fi_pagetable_size);
                        newkernel.fi_pagetable_size = 0;
                }

                if (newkernel.fi_pagetable_size == 0) {
                        if ((newkernel.fi_pagetable_va = (uintptr_t)
                            contig_alloc(size, &fastboot_below_1G_dma_attr,
                            MMU_PAGESIZE, 0)) == NULL) {
                                cmn_err(CE_NOTE, fastboot_enomem_msg,
                                    (uint64_t)size, "1G");
                                goto err_out;
                        }
                        /*
                         * fi_pagetable_size must be set after the allocation
                         * succeeds as it's used to determine how much memory to
                         * free.
                         */
                        newkernel.fi_pagetable_size = size;
                }

                bzero((void *)(newkernel.fi_pagetable_va), size);

                newkernel.fi_pagetable_pa =
                    mmu_ptob((uint64_t)hat_getpfnum(kas.a_hat,
                    (caddr_t)newkernel.fi_pagetable_va));

                newkernel.fi_last_table_pa = newkernel.fi_pagetable_pa +
                    size - MMU_PAGESIZE;

                newkernel.fi_next_table_va = newkernel.fi_pagetable_va +
                    MMU_PAGESIZE;
                newkernel.fi_next_table_pa = newkernel.fi_pagetable_pa +
                    MMU_PAGESIZE;

                fastboot_build_pagetables(&newkernel);
        }


        /* Generate MD5 checksums */
        fastboot_cksum_generate(&newkernel);

        /* Mark it as valid */
        newkernel.fi_valid = 1;
        newkernel.fi_magic = FASTBOOT_MAGIC;

        postbootkernelbase = saved_kernelbase;
        return;

err_out:
        postbootkernelbase = saved_kernelbase;
        newkernel.fi_valid = 0;
        fastboot_free_newkernel(&newkernel);
}


/* ARGSUSED */
static int
fastboot_xc_func(fastboot_info_t *nk, xc_arg_t unused2, xc_arg_t unused3)
{
        void (*fastboot_func)(fastboot_info_t *);
        fastboot_file_t *fb = &nk->fi_files[FASTBOOT_SWTCH];
        fastboot_func = (void (*)())(fb->fb_va);
        kthread_t *t_intr = curthread->t_intr;

        if (&kas != curproc->p_as) {
                hat_devload(curproc->p_as->a_hat, (caddr_t)fb->fb_va,
                    MMU_PAGESIZE, mmu_btop(fb->fb_dest_pa),
                    PROT_READ | PROT_WRITE | PROT_EXEC,
                    HAT_LOAD_NOCONSIST | HAT_LOAD_LOCK);
        }

        /*
         * If we have pinned a thread, make sure the address is mapped
         * in the address space of the pinned thread.
         */
        if (t_intr && t_intr->t_procp->p_as->a_hat != curproc->p_as->a_hat &&
            t_intr->t_procp->p_as != &kas)
                hat_devload(t_intr->t_procp->p_as->a_hat, (caddr_t)fb->fb_va,
                    MMU_PAGESIZE, mmu_btop(fb->fb_dest_pa),
                    PROT_READ | PROT_WRITE | PROT_EXEC,
                    HAT_LOAD_NOCONSIST | HAT_LOAD_LOCK);

        (*psm_shutdownf)(A_SHUTDOWN, AD_FASTREBOOT);
        (*fastboot_func)(nk);

        /*NOTREACHED*/
        return (0);
}

/*
 * Jump to the fast reboot switcher.  This function never returns.
 */
void
fast_reboot()
{
        processorid_t bootcpuid = 0;
        extern uintptr_t postbootkernelbase;
        extern char     fb_swtch_image[];
        fastboot_file_t *fb;
        int i;

        postbootkernelbase = 0;

        fb = &newkernel.fi_files[FASTBOOT_SWTCH];

        /*
         * Map the address into both the current proc's address
         * space and the kernel's address space in case the panic
         * is forced by kmdb.
         */
        if (&kas != curproc->p_as) {
                hat_devload(curproc->p_as->a_hat, (caddr_t)fb->fb_va,
                    MMU_PAGESIZE, mmu_btop(fb->fb_dest_pa),
                    PROT_READ | PROT_WRITE | PROT_EXEC,
                    HAT_LOAD_NOCONSIST | HAT_LOAD_LOCK);
        }

        bcopy((void *)fb_swtch_image, (void *)fb->fb_va, fb->fb_size);


        /*
         * Set fb_va to fake_va
         */
        for (i = 0; i < FASTBOOT_MAX_FILES_MAP; i++) {
                newkernel.fi_files[i].fb_va = fake_va;

        }

        if (panicstr && CPU->cpu_id != bootcpuid &&
            CPU_ACTIVE(cpu_get(bootcpuid))) {
                extern void panic_idle(void);
                cpuset_t cpuset;

                CPUSET_ZERO(cpuset);
                CPUSET_ADD(cpuset, bootcpuid);
                xc_priority((xc_arg_t)&newkernel, 0, 0, CPUSET2BV(cpuset),
                    (xc_func_t)fastboot_xc_func);

                panic_idle();
        } else
                (void) fastboot_xc_func(&newkernel, 0, 0);
}


/*
 * Get boot property value for fastreboot_onpanic.
 *
 * NOTE: If fastreboot_onpanic is set to non-zero in /etc/system,
 * new setting passed in via "-B fastreboot_onpanic" is ignored.
 * This order of precedence is to enable developers debugging panics
 * that occur early in boot to utilize Fast Reboot on panic.
 */
static void
fastboot_get_bootprop(void)
{
        int             val = 0xaa, len, ret;
        dev_info_t      *devi;
        char            *propstr = NULL;

        devi = ddi_root_node();

        ret = ddi_prop_lookup_string(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
            FASTREBOOT_ONPANIC, &propstr);

        if (ret == DDI_PROP_SUCCESS) {
                if (FASTREBOOT_ONPANIC_NOTSET(propstr))
                        val = 0;
                else if (FASTREBOOT_ONPANIC_ISSET(propstr))
                        val = UA_FASTREBOOT_ONPANIC;

                /*
                 * Only set fastreboot_onpanic to the value passed in
                 * if it's not already set to non-zero, and the value
                 * has indeed been passed in via command line.
                 */
                if (!fastreboot_onpanic && val != 0xaa)
                        fastreboot_onpanic = val;
                ddi_prop_free(propstr);
        } else if (ret != DDI_PROP_NOT_FOUND && ret != DDI_PROP_UNDEFINED) {
                cmn_err(CE_NOTE, "!%s value is invalid, will be ignored",
                    FASTREBOOT_ONPANIC);
        }

        len = sizeof (fastreboot_onpanic_cmdline);
        ret = ddi_getlongprop_buf(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
            FASTREBOOT_ONPANIC_CMDLINE, fastreboot_onpanic_cmdline, &len);

        if (ret == DDI_PROP_BUF_TOO_SMALL)
                cmn_err(CE_NOTE, "!%s value is too long, will be ignored",
                    FASTREBOOT_ONPANIC_CMDLINE);
}

/*
 * This function is called by main() to either load the backup kernel for panic
 * fast reboot, or to reserve low physical memory for fast reboot.
 */
void
fastboot_post_startup()
{
        lbolt_at_boot = ddi_get_lbolt();

        /* Default to 10 minutes */
        if (fastreboot_onpanic_uptime == LONG_MAX)
                fastreboot_onpanic_uptime = SEC_TO_TICK(10 * 60);

        if (!fastreboot_capable)
                return;

        mutex_enter(&fastreboot_config_mutex);

        fastboot_get_bootprop();

        if (fastreboot_onpanic)
                fastboot_load_kernel(fastreboot_onpanic_cmdline);
        else if (reserve_mem_enabled)
                fastboot_reserve_mem(&newkernel);

        mutex_exit(&fastreboot_config_mutex);
}

/*
 * Update boot configuration settings.
 * If the new fastreboot_onpanic setting is false, and a kernel has
 * been preloaded, free the memory;
 * if the new fastreboot_onpanic setting is true and newkernel is
 * not valid, load the new kernel.
 */
void
fastboot_update_config(const char *mdep)
{
        uint8_t boot_config = (uint8_t)*mdep;
        int cur_fastreboot_onpanic;

        if (!fastreboot_capable)
                return;

        mutex_enter(&fastreboot_config_mutex);

        cur_fastreboot_onpanic = fastreboot_onpanic;
        fastreboot_onpanic = boot_config & UA_FASTREBOOT_ONPANIC;

        if (fastreboot_onpanic && (!cur_fastreboot_onpanic ||
            !newkernel.fi_valid))
                fastboot_load_kernel(fastreboot_onpanic_cmdline);
        if (cur_fastreboot_onpanic && !fastreboot_onpanic)
                fastboot_free_newkernel(&newkernel);

        mutex_exit(&fastreboot_config_mutex);
}

/*
 * This is an internal interface to disable Fast Reboot on Panic.
 * It frees up memory allocated for the backup kernel and sets
 * fastreboot_onpanic to zero.
 */
static void
fastreboot_onpanic_disable(void)
{
        uint8_t boot_config = (uint8_t)(~UA_FASTREBOOT_ONPANIC);
        fastboot_update_config((const char *)&boot_config);
}

/*
 * This is the interface to be called by fm_panic() in case FMA has diagnosed
 * a terminal machine check exception.  It does not free up memory allocated
 * for the backup kernel.  General disabling fastreboot_onpanic in a
 * non-panicking situation must go through fastboot_onpanic_disable().
 */
void
fastreboot_disable_highpil(void)
{
        fastreboot_onpanic = 0;
}

/*
 * This is an internal interface to disable Fast Reboot by Default.
 * It does not free up memory allocated for the backup kernel.
 */
static void
fastreboot_capable_disable(uint32_t msgid)
{
        if (fastreboot_capable != 0) {
                fastreboot_capable = 0;
                if (msgid < sizeof (fastreboot_nosup_desc) /
                    sizeof (fastreboot_nosup_desc[0]))
                        fastreboot_nosup_id = msgid;
                else
                        fastreboot_nosup_id = FBNS_DEFAULT;
        }
}

/*
 * This is the kernel interface for disabling
 * Fast Reboot by Default and Fast Reboot on Panic.
 * Frees up memory allocated for the backup kernel.
 * General disabling of the Fast Reboot by Default feature should be done
 * via the userland interface scf_fastreboot_default_set_transient().
 */
void
fastreboot_disable(uint32_t msgid)
{
        fastreboot_capable_disable(msgid);
        fastreboot_onpanic_disable();
}

/*
 * Returns Fast Reboot not support message for fastreboot_nosup_id.
 * If fastreboot_nosup_id contains invalid index, default
 * Fast Reboot not support message is returned.
 */
const char *
fastreboot_nosup_message(void)
{
        uint32_t msgid;

        msgid = fastreboot_nosup_id;
        if (msgid >= sizeof (fastreboot_nosup_desc) /
            sizeof (fastreboot_nosup_desc[0]))
                msgid = FBNS_DEFAULT;

        return (fastreboot_nosup_desc[msgid]);
}

/*
 * A simplified interface for uadmin to call to update the configuration
 * setting and load a new kernel if necessary.
 */
void
fastboot_update_and_load(int fcn, char *mdep)
{
        if (fcn != AD_FASTREBOOT) {
                /*
                 * If user has explicitly requested reboot to prom,
                 * or uadmin(1M) was invoked with other functions,
                 * don't try to fast reboot after dumping.
                 */
                fastreboot_onpanic_disable();
        }

        mutex_enter(&fastreboot_config_mutex);

        if (fastreboot_onpanic)
                fastboot_load_kernel(mdep);

        mutex_exit(&fastreboot_config_mutex);
}