6198 Let's EOL cachefs

[illumos-gate.git] / usr / src / uts / common / os / swapgeneric.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) 1982, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
 */

/*
 * Configure root, swap and dump devices.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/signal.h>
#include <sys/cred.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/conf.h>
#include <sys/buf.h>
#include <sys/systm.h>
#include <sys/vm.h>
#include <sys/reboot.h>
#include <sys/file.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/errno.h>
#include <sys/kmem.h>
#include <sys/uio.h>
#include <sys/open.h>
#include <sys/mount.h>
#include <sys/kobj.h>
#include <sys/bootconf.h>
#include <sys/sysconf.h>
#include <sys/modctl.h>
#include <sys/autoconf.h>
#include <sys/debug.h>
#include <sys/fs/snode.h>
#include <fs/fs_subr.h>
#include <sys/socket.h>
#include <net/if.h>

#include <sys/mkdev.h>
#include <sys/cmn_err.h>
#include <sys/console.h>

#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/hwconf.h>
#include <sys/dc_ki.h>
#include <sys/promif.h>
#include <sys/bootprops.h>

/*
 * Local routines
 */
static int preload_module(struct sysparam *, void *);
static struct vfssw *getfstype(char *, char *, size_t);
static int getphysdev(char *, char *, size_t);
static int load_bootpath_drivers(char *bootpath);
static int load_boot_driver(char *drv);
static int load_boot_platform_modules(char *drv);
static dev_info_t *path_to_devinfo(char *path);
static boolean_t netboot_over_ib(char *bootpath);
static boolean_t netboot_over_iscsi(void);

/*
 * Module linkage information for the kernel.
 */
static struct modlmisc modlmisc = {
        &mod_miscops, "root and swap configuration"
};

static struct modlinkage modlinkage = {
        MODREV_1, (void *)&modlmisc, NULL
};

int
_init(void)
{
        return (mod_install(&modlinkage));
}

int
_fini(void)
{
        return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
        return (mod_info(&modlinkage, modinfop));
}

extern ib_boot_prop_t *iscsiboot_prop;
/*
 * Configure root file system.
 */
int
rootconf(void)
{
        int             error;
        struct vfssw    *vsw;
        extern void pm_init(void);
        int ret = -1;
        BMDPRINTF(("rootconf: fstype %s\n", rootfs.bo_fstype));
        BMDPRINTF(("rootconf: name %s\n", rootfs.bo_name));
        BMDPRINTF(("rootconf: flags 0x%x\n", rootfs.bo_flags));
        BMDPRINTF(("rootconf: obp_bootpath %s\n", obp_bootpath));

        /*
         * Install cluster modules that were only loaded during
         * loadrootmodules().
         */
        if (error = clboot_rootconf())
                return (error);

        if (root_is_svm) {
                (void) strncpy(rootfs.bo_name, obp_bootpath, BO_MAXOBJNAME);

                BMDPRINTF(("rootconf: svm: rootfs name %s\n", rootfs.bo_name));
                BMDPRINTF(("rootconf: svm: svm name %s\n", svm_bootpath));
        }

        /*
         * Run _init on the root filesystem (we already loaded it
         * but we've been waiting until now to _init it) which will
         * have the side-effect of running vsw_init() on this vfs.
         * Because all the nfs filesystems are lumped into one
         * module we need to special case it.
         */
        if (strncmp(rootfs.bo_fstype, "nfs", 3) == 0) {
                if (modload("fs", "nfs") == -1) {
                        cmn_err(CE_CONT, "Cannot initialize %s filesystem\n",
                            rootfs.bo_fstype);
                        return (ENXIO);
                }
        } else {
                if (modload("fs", rootfs.bo_fstype) == -1) {
                        cmn_err(CE_CONT, "Cannot initialize %s filesystem\n",
                            rootfs.bo_fstype);
                        return (ENXIO);
                }
        }
        RLOCK_VFSSW();
        vsw = vfs_getvfsswbyname(rootfs.bo_fstype);
        RUNLOCK_VFSSW();
        if (vsw == NULL) {
                cmn_err(CE_CONT, "Cannot find %s filesystem\n",
                    rootfs.bo_fstype);
                return (ENXIO);
        }
        VFS_INIT(rootvfs, &vsw->vsw_vfsops, (caddr_t)0);
        VFS_HOLD(rootvfs);

        if (root_is_svm) {
                rootvfs->vfs_flag |= VFS_RDONLY;
        }

        /*
         * This pm-releated call has to occur before root is mounted since we
         * need to power up all devices.  It is placed after VFS_INIT() such
         * that opening a device via ddi_lyr_ interface just before root has
         * been mounted would work.
         */
        pm_init();

        if (netboot && iscsiboot_prop) {
                cmn_err(CE_WARN, "NFS boot and iSCSI boot"
                    " shouldn't happen in the same time");
                return (EINVAL);
        }

        if (netboot || iscsiboot_prop) {
                ret = strplumb();
                if (ret != 0) {
                        cmn_err(CE_WARN, "Cannot plumb network device %d", ret);
                        return (EFAULT);
                }
        }

        if ((ret == 0) && iscsiboot_prop) {
                ret = modload("drv", "iscsi");
                /* -1 indicates fail */
                if (ret == -1) {
                        cmn_err(CE_WARN, "Failed to load iscsi module");
                        iscsi_boot_prop_free();
                        return (EINVAL);
                } else {
                        if (!i_ddi_attach_pseudo_node("iscsi")) {
                                cmn_err(CE_WARN,
                                    "Failed to attach iscsi driver");
                                iscsi_boot_prop_free();
                                return (ENODEV);
                        }
                }
        }

        /*
         * ufs_mountroot() ends up calling getrootdev()
         * (below) which actually triggers the _init, identify,
         * probe and attach of the drivers that make up root device
         * bush; these are also quietly waiting in memory.
         */
        BMDPRINTF(("rootconf: calling VFS_MOUNTROOT %s\n", rootfs.bo_fstype));

        error = VFS_MOUNTROOT(rootvfs, ROOT_INIT);
        vfs_unrefvfssw(vsw);
        rootdev = rootvfs->vfs_dev;

        if (error)
                cmn_err(CE_CONT, "Cannot mount root on %s fstype %s\n",
                    rootfs.bo_name, rootfs.bo_fstype);
        else
                cmn_err(CE_CONT, "?root on %s fstype %s\n",
                    rootfs.bo_name, rootfs.bo_fstype);
        return (error);
}

/*
 * Remount root on an SVM mirror root device
 * Only supported on UFS filesystems at present
 */
int
svm_rootconf(void)
{
        int     error;
        extern int ufs_remountroot(struct vfs *vfsp);

        ASSERT(root_is_svm == 1);

        if (strcmp(rootfs.bo_fstype, "ufs") != 0) {
                cmn_err(CE_CONT, "Mounting root on %s with filesystem "
                    "type %s is not supported\n",
                    rootfs.bo_name, rootfs.bo_fstype);
                return (EINVAL);
        }

        (void) strncpy(rootfs.bo_name, svm_bootpath, BO_MAXOBJNAME);

        BMDPRINTF(("svm_rootconf: rootfs %s\n", rootfs.bo_name));

        error = ufs_remountroot(rootvfs);

        if (error) {
                cmn_err(CE_CONT, "Cannot remount root on %s fstype %s\n",
                    rootfs.bo_name, rootfs.bo_fstype);
        } else {
                cmn_err(CE_CONT, "?root remounted on %s fstype %s\n",
                    rootfs.bo_name, rootfs.bo_fstype);
        }
        return (error);
}

/*
 * Under the assumption that our root file system is on a
 * disk partition, get the dev_t of the partition in question.
 *
 * By now, boot has faithfully loaded all our modules into memory, and
 * we've taken over resource management.  Before we go any further, we
 * have to fire up the device drivers and stuff we need to mount the
 * root filesystem.  That's what we do here.  Fingers crossed.
 */
dev_t
getrootdev(void)
{
        dev_t   d;

        d = ddi_pathname_to_dev_t(rootfs.bo_name);
        if ((d == NODEV) && (iscsiboot_prop != NULL)) {
                /* Give it another try with the 'disk' path */
                get_iscsi_bootpath_phy(rootfs.bo_name);
                d = ddi_pathname_to_dev_t(rootfs.bo_name);
        }
        if (d == NODEV)
                cmn_err(CE_CONT, "Cannot assemble drivers for root %s\n",
                    rootfs.bo_name);
        return (d);
}

/*
 * If booted with ASKNAME, prompt on the console for a filesystem
 * name and return it.
 */
void
getfsname(char *askfor, char *name, size_t namelen)
{
        if (boothowto & RB_ASKNAME) {
                printf("%s name: ", askfor);
                console_gets(name, namelen);
        }
}

/*ARGSUSED1*/
static int
preload_module(struct sysparam *sysp, void *p)
{
        static char *wmesg = "forceload of %s failed";
        char *name;

        name = sysp->sys_ptr;
        BMDPRINTF(("preload_module: %s\n", name));
        if (modloadonly(NULL, name) < 0)
                cmn_err(CE_WARN, wmesg, name);
        return (0);
}

/*
 * We want to load all the modules needed to mount the root filesystem,
 * so that when we start the ball rolling in 'getrootdev', every module
 * should already be in memory, just waiting to be init-ed.
 */

int
loadrootmodules(void)
{
        struct vfssw    *vsw;
        char            *this;
        char            *name;
        int             err;
        int             i, proplen;
        extern char     *impl_module_list[];
        extern char     *platform_module_list[];

        /* Make sure that the PROM's devinfo tree has been created */
        ASSERT(ddi_root_node());

        BMDPRINTF(("loadrootmodules: fstype %s\n", rootfs.bo_fstype));
        BMDPRINTF(("loadrootmodules: name %s\n", rootfs.bo_name));
        BMDPRINTF(("loadrootmodules: flags 0x%x\n", rootfs.bo_flags));

        /*
         * zzz We need to honor what's in rootfs if it's not null.
         * non-null means use what's there.  This way we can
         * change rootfs with /etc/system AND with tunetool.
         */
        if (root_is_svm) {
                /* user replaced rootdev, record obp_bootpath */
                obp_bootpath[0] = '\0';
                (void) getphysdev("root", obp_bootpath, BO_MAXOBJNAME);
                BMDPRINTF(("loadrootmodules: obp_bootpath %s\n", obp_bootpath));
        } else {
                /*
                 * Get the root fstype and root device path from boot.
                 */
                rootfs.bo_fstype[0] = '\0';
                rootfs.bo_name[0] = '\0';
        }

        /*
         * This lookup will result in modloadonly-ing the root
         * filesystem module - it gets _init-ed in rootconf()
         */
        if ((vsw = getfstype("root", rootfs.bo_fstype, BO_MAXFSNAME)) == NULL)
                return (ENXIO); /* in case we have no file system types */

        (void) strcpy(rootfs.bo_fstype, vsw->vsw_name);

        vfs_unrefvfssw(vsw);

        /*
         * Load the favored drivers of the implementation.
         * e.g. 'sbus' and possibly 'zs' (even).
         *
         * Called whilst boot is still loaded (because boot does
         * the i/o for us), and DDI services are unavailable.
         */
        BMDPRINTF(("loadrootmodules: impl_module_list\n"));
        for (i = 0; (this = impl_module_list[i]) != NULL; i++) {
                if ((err = load_boot_driver(this)) != 0) {
                        cmn_err(CE_WARN, "Cannot load drv/%s", this);
                        return (err);
                }
        }
        /*
         * Now load the platform modules (if any)
         */
        BMDPRINTF(("loadrootmodules: platform_module_list\n"));
        for (i = 0; (this = platform_module_list[i]) != NULL; i++) {
                if ((err = load_boot_platform_modules(this)) != 0) {
                        cmn_err(CE_WARN, "Cannot load drv/%s", this);
                        return (err);
                }
        }

loop:
        (void) getphysdev("root", rootfs.bo_name, BO_MAXOBJNAME);
        /*
         * Given a physical pathname, load the correct set of driver
         * modules into memory, including all possible parents.
         *
         * NB: The code sets the variable 'name' for error reporting.
         */
        err = 0;
        BMDPRINTF(("loadrootmodules: rootfs %s\n", rootfs.bo_name));
        if (root_is_svm == 0) {
                BMDPRINTF(("loadrootmodules: rootfs %s\n", rootfs.bo_name));
                name = rootfs.bo_name;
                err = load_bootpath_drivers(rootfs.bo_name);
        }

        /*
         * Load driver modules in obp_bootpath, this is always
         * required for mountroot to succeed. obp_bootpath is
         * is set if rootdev is set via /etc/system, which is
         * the case if booting of a SVM/VxVM mirror.
         */
        if ((err == 0) && obp_bootpath[0] != '\0') {
                BMDPRINTF(("loadrootmodules: obp_bootpath %s\n", obp_bootpath));
                name = obp_bootpath;
                err = load_bootpath_drivers(obp_bootpath);
        }

        if (err != 0) {
                cmn_err(CE_CONT, "Cannot load drivers for %s\n", name);
                goto out;
        }

        /*
         * Check to see if the booter performed DHCP configuration
         * ("bootp-response" boot property exists). If so, then before
         * bootops disappears we need to save the value of this property
         * such that the userland dhcpagent can adopt the DHCP management
         * of our primary network interface.
         */
        proplen = BOP_GETPROPLEN(bootops, "bootp-response");
        if (proplen > 0) {
                dhcack = kmem_zalloc(proplen, KM_SLEEP);
                if (BOP_GETPROP(bootops, "bootp-response", dhcack) == -1) {
                        cmn_err(CE_WARN, "BOP_GETPROP of  "
                            "\"bootp-response\" failed\n");
                        kmem_free(dhcack, dhcacklen);
                        dhcack = NULL;
                        goto out;
                }
                dhcacklen = proplen;

                /*
                 * Fetch the "netdev-path" boot property (if it exists), and
                 * stash it for later use by sysinfo(SI_DHCP_CACHE, ...).
                 */
                proplen = BOP_GETPROPLEN(bootops, "netdev-path");
                if (proplen > 0) {
                        netdev_path = kmem_zalloc(proplen, KM_SLEEP);
                        if (BOP_GETPROP(bootops, "netdev-path",
                            (uchar_t *)netdev_path) == -1) {
                                cmn_err(CE_WARN, "BOP_GETPROP of  "
                                    "\"netdev-path\" failed\n");
                                kmem_free(netdev_path, proplen);
                                goto out;
                        }
                }
        }

        /*
         * Preload (load-only, no init) all modules which
         * were added to the /etc/system file with the
         * FORCELOAD keyword.
         */
        BMDPRINTF(("loadrootmodules: preload_module\n"));
        (void) mod_sysctl_type(MOD_FORCELOAD, preload_module, NULL);

        /*
         * If we booted otw then load in the plumbing
         * routine now while we still can. If we didn't
         * boot otw then we will load strplumb in main().
         *
         * NFS is actually a set of modules, the core routines,
         * a diskless helper module, rpcmod, and the tli interface.  Load
         * them now while we still can.
         *
         * Because we glomb all versions of nfs into a single module
         * we check based on the initial string "nfs".
         *
         * XXX: A better test for this is to see if device_type
         * XXX: from the PROM is "network".
         */

        if (strncmp(rootfs.bo_fstype, "nfs", 3) == 0) {
                ++netboot;

                /*
                 * Preload (load-only, no init) the dacf module. We cannot
                 * init the module because one of its requisite modules is
                 * dld whose _init function will call taskq_create(), which
                 * will panic the system at this point.
                 */
                if ((err = modloadonly("dacf", "net_dacf")) < 0)  {
                        cmn_err(CE_CONT, "Cannot load dacf/net_dacf\n");
                        goto out;
                }
                if ((err = modload("misc", "tlimod")) < 0)  {
                        cmn_err(CE_CONT, "Cannot load misc/tlimod\n");
                        goto out;
                }
                if ((err = modload("strmod", "rpcmod")) < 0)  {
                        cmn_err(CE_CONT, "Cannot load strmod/rpcmod\n");
                        goto out;
                }
                if ((err = modload("misc", "nfs_dlboot")) < 0)  {
                        cmn_err(CE_CONT, "Cannot load misc/nfs_dlboot\n");
                        goto out;
                }
                if ((err = modload("mac", "mac_ether")) < 0)  {
                        cmn_err(CE_CONT, "Cannot load mac/mac_ether\n");
                        goto out;
                }
                if ((err = modload("misc", "strplumb")) < 0)  {
                        cmn_err(CE_CONT, "Cannot load misc/strplumb\n");
                        goto out;
                }
                if ((err = strplumb_load()) < 0) {
                        goto out;
                }
        }
        if (netboot_over_iscsi() == B_TRUE) {
                /* iscsi boot */
                if ((err = modloadonly("dacf", "net_dacf")) < 0) {
                        cmn_err(CE_CONT, "Cannot load dacf/net_dacf\n");
                        goto out;
                }
                if ((err = modload("misc", "tlimod")) < 0) {
                        cmn_err(CE_CONT, "Cannot load misc/tlimod\n");
                        goto out;
                }
                if ((err = modload("mac", "mac_ether")) < 0) {
                        cmn_err(CE_CONT, "Cannot load mac/mac_ether\n");
                        goto out;
                }
                if ((err = modloadonly("drv", "iscsi")) < 0) {
                        cmn_err(CE_CONT, "Cannot load drv/iscsi\n");
                        goto out;
                }
                if ((err = modloadonly("drv", "ssd")) < 0) {
                        cmn_err(CE_CONT, "Cannot load drv/ssd\n");
                        goto out;
                }
                if ((err = modloadonly("drv", "sd")) < 0) {
                        cmn_err(CE_CONT, "Cannot load drv/sd\n");
                        goto out;
                }
                if ((err = modload("misc", "strplumb")) < 0) {
                        cmn_err(CE_CONT, "Cannot load misc/strplumb\n");
                        goto out;
                }
                if ((err = strplumb_load()) < 0) {
                        goto out;
                }
        }
        /*
         * Preload modules needed for booting as a cluster.
         */
        err = clboot_loadrootmodules();

out:
        if (err != 0 && (boothowto & RB_ASKNAME))
                goto loop;

        return (err);
}

static int
get_bootpath_prop(char *bootpath)
{
        if (root_is_ramdisk) {
                if (BOP_GETPROP(bootops, "bootarchive", bootpath) == -1)
                        return (-1);
                (void) strlcat(bootpath, ":a", BO_MAXOBJNAME);
        } else {
                /*
                 * Look for the 1275 compliant name 'bootpath' first,
                 * but make certain it has a non-NULL value as well.
                 */
                if ((BOP_GETPROP(bootops, "bootpath", bootpath) == -1) ||
                    strlen(bootpath) == 0) {
                        if (BOP_GETPROP(bootops,
                            "boot-path", bootpath) == -1)
                                return (-1);
                }
                if (memcmp(bootpath, BP_ISCSI_DISK,
                    strlen(BP_ISCSI_DISK)) == 0) {
                        /* iscsi boot */
                        get_iscsi_bootpath_vhci(bootpath);
                }
        }
        return (0);
}

static int
get_fstype_prop(char *fstype)
{
        char *prop = (root_is_ramdisk) ? "archive-fstype" : "fstype";

        return (BOP_GETPROP(bootops, prop, fstype));
}

/*
 * Get the name of the root or swap filesystem type, and return
 * the corresponding entry in the vfs switch.
 *
 * If we're not asking the user, and we're trying to find the
 * root filesystem type, we ask boot for the filesystem
 * type that it came from and use that.  Similarly, if we're
 * trying to find the swap filesystem, we try and derive it from
 * the root filesystem type.
 *
 * If we are booting via NFS we currently have these options:
 *      nfs -   dynamically choose NFS V2. V3, or V4 (default)
 *      nfs2 -  force NFS V2
 *      nfs3 -  force NFS V3
 *      nfs4 -  force NFS V4
 * Because we need to maintain backward compatibility with the naming
 * convention that the NFS V2 filesystem name is "nfs" (see vfs_conf.c)
 * we need to map "nfs" => "nfsdyn" and "nfs2" => "nfs".  The dynamic
 * nfs module will map the type back to either "nfs", "nfs3", or "nfs4".
 * This is only for root filesystems, all other uses will expect
 * that "nfs" == NFS V2.
 *
 * If the filesystem isn't already loaded, vfs_getvfssw() will load
 * it for us, but if (at the time we call it) modrootloaded is
 * still not set, it won't run the filesystems _init routine (and
 * implicitly it won't run the filesystems vsw_init() entry either).
 * We do that explicitly in rootconf().
 */
static struct vfssw *
getfstype(char *askfor, char *fsname, size_t fsnamelen)
{
        struct vfssw *vsw;
        static char defaultfs[BO_MAXFSNAME];
        int root = 0;

        if (strcmp(askfor, "root") == 0) {
                (void) get_fstype_prop(defaultfs);
                root++;
        } else {
                (void) strcpy(defaultfs, "swapfs");
        }

        if (boothowto & RB_ASKNAME) {
                for (*fsname = '\0'; *fsname == '\0'; *fsname = '\0') {
                        printf("%s filesystem type [%s]: ", askfor, defaultfs);
                        console_gets(fsname, fsnamelen);
                        if (*fsname == '\0')
                                (void) strcpy(fsname, defaultfs);
                        if (root) {
                                if (strcmp(fsname, "nfs2") == 0)
                                        (void) strcpy(fsname, "nfs");
                                else if (strcmp(fsname, "nfs") == 0)
                                        (void) strcpy(fsname, "nfsdyn");
                        }
                        if ((vsw = vfs_getvfssw(fsname)) != NULL)
                                return (vsw);
                        printf("Unknown filesystem type '%s'\n", fsname);
                }
        } else if (*fsname == '\0') {
                fsname = defaultfs;
        }
        if (*fsname == '\0') {
                return (NULL);
        }

        if (root) {
                if (strcmp(fsname, "nfs2") == 0)
                        (void) strcpy(fsname, "nfs");
                else if (strcmp(fsname, "nfs") == 0)
                        (void) strcpy(fsname, "nfsdyn");
        }

        return (vfs_getvfssw(fsname));
}


/*
 * Get a physical device name, and maybe load and attach
 * the driver.
 *
 * XXX  Need better checking of whether or not a device
 *      actually exists if the user typed in a pathname.
 *
 * XXX  Are we sure we want to expose users to this sort
 *      of physical namespace gobbledygook (now there's
 *      a word to conjure with..)
 *
 * XXX  Note that on an OBP machine, we can easily ask the
 *      prom and pretty-print some plausible set of bootable
 *      devices.  We can also user the prom to verify any
 *      such device.  Later tim.. later.
 */
static int
getphysdev(char *askfor, char *name, size_t namelen)
{
        static char fmt[] = "Enter physical name of %s device\n[%s]: ";
        dev_t dev;
        static char defaultpath[BO_MAXOBJNAME];

        /*
         * Establish 'default' values - we get the root device from
         * boot, and we infer the swap device is the same but with
         * a 'b' on the end instead of an 'a'.  A first stab at
         * ease-of-use ..
         */
        if (strcmp(askfor, "root") == 0) {
                if (get_bootpath_prop(defaultpath) == -1)
                        boothowto |= RB_ASKNAME | RB_VERBOSE;
        } else {
                (void) strcpy(defaultpath, rootfs.bo_name);
                defaultpath[strlen(defaultpath) - 1] = 'b';
        }

retry:
        if (boothowto & RB_ASKNAME) {
                printf(fmt, askfor, defaultpath);
                console_gets(name, namelen);
        }
        if (*name == '\0')
                (void) strcpy(name, defaultpath);

        if (strcmp(askfor, "swap") == 0)   {

                /*
                 * Try to load and install the swap device driver.
                 */
                dev = ddi_pathname_to_dev_t(name);

                if (dev == (dev_t)-1)  {
                        printf("Not a supported device for swap.\n");
                        boothowto |= RB_ASKNAME | RB_VERBOSE;
                        goto retry;
                }

                /*
                 * Ensure that we're not trying to swap on the floppy.
                 */
                if (strncmp(ddi_major_to_name(getmajor(dev)), "fd", 2) == 0) {
                        printf("Too dangerous to swap on the floppy\n");
                        if (boothowto & RB_ASKNAME)
                                goto retry;
                        return (-1);
                }
        }

        return (0);
}


/*
 * Load a driver needed to boot.
 */
static int
load_boot_driver(char *drv)
{
        char            *drvname;
        major_t         major;
#ifdef  sparc
        struct devnames *dnp;
        ddi_prop_t      *propp;
        char            *module;
        char            *dir, *mf;
        int             plen;
        int             mlen;
#endif  /* sparc */

        if ((major = ddi_name_to_major(drv)) == DDI_MAJOR_T_NONE) {
                cmn_err(CE_CONT, "%s: no major number\n", drv);
                return (-1);
        }
        /*
         * resolve aliases
         */
        drvname = ddi_major_to_name(major);

#ifdef  DEBUG
        if (strcmp(drv, drvname) == 0) {
                BMDPRINTF(("load_boot_driver: %s\n", drv));
        } else {
                BMDPRINTF(("load_boot_driver: %s -> %s\n", drv, drvname));
        }
#endif  /* DEBUG */

        if (modloadonly("drv", drvname) == -1) {
                cmn_err(CE_CONT, "%s: cannot load driver\n", drvname);
                return (-1);
        }

#ifdef  sparc
        /*
         * NOTE: this can be removed when newboot-sparc is delivered.
         *
         * Check to see if the driver had a 'ddi-forceload' global driver.conf
         * property to identify additional modules that need to be loaded.
         * The driver still needs to use ddi_modopen() to open these modules,
         * but the 'ddi-forceload' property allows the modules to be loaded
         * into memory prior to lights-out, so that driver ddi_modopen()
         * calls during lights-out (when mounting root) will work correctly.
         * Use of 'ddi-forceload' is only required for drivers involved in
         * getting root mounted.
         */
        dnp = &devnamesp[major];
        if (dnp->dn_global_prop_ptr && dnp->dn_global_prop_ptr->prop_list &&
            ((propp = i_ddi_prop_search(DDI_DEV_T_ANY,
            "ddi-forceload", DDI_PROP_TYPE_STRING,
            &dnp->dn_global_prop_ptr->prop_list)) != NULL)) {

                module = (char *)propp->prop_val;
                plen = propp->prop_len;
                while (plen > 0) {
                        mlen = strlen(module);
                        mf = strrchr(module, '/');
                        if (mf) {
                                dir = module;
                                *mf++ = '\0';           /* '/' -> '\0' */
                        } else {
                                dir = "misc";
                                mf = module;
                        }
                        if (modloadonly(dir, mf) == -1)
                                cmn_err(CE_CONT,
                                    "misc/%s: can't load module\n", mf);
                        if (mf != module)
                                *(mf - 1) = '/';        /* '\0' -> '/' */

                        module += mlen + 1;
                        plen -= mlen + 1;
                }
        }
#endif  /* sparc */

        return (0);
}


/*
 * For a given instance, load that driver and its parents
 */
static int
load_parent_drivers(dev_info_t *dip, char *path)
{
        int     rval = 0;
        major_t major = DDI_MAJOR_T_NONE;
        char    *drv;
        char    *p;

        while (dip) {
                /* check for path-oriented alias */
                if (path)
                        major = ddi_name_to_major(path);
                else
                        major = DDI_MAJOR_T_NONE;

                if (major != DDI_MAJOR_T_NONE)
                        drv = ddi_major_to_name(major);
                else
                        drv = ddi_binding_name(dip);

                if (load_boot_driver(drv) != 0)
                        rval = -1;

                dip = ddi_get_parent(dip);
                if (path) {
                        p = strrchr(path, '/');
                        if (p)
                                *p = 0;
                }
        }

        return (rval);
}


/*
 * For a given path to a boot device,
 * load that driver and all its parents.
 */
static int
load_bootpath_drivers(char *bootpath)
{
        dev_info_t      *dip;
        char            *pathcopy;
        int             pathcopy_len;
        int             rval;
        char            *p;
        int             proplen;
        char            iscsi_network_path[BO_MAXOBJNAME];

        if (bootpath == NULL || *bootpath == 0)
                return (-1);

        BMDPRINTF(("load_bootpath_drivers: %s\n", bootpath));
#ifdef _OBP
        if (netboot_over_iscsi()) {
                /* iscsi boot */
                if (root_is_ramdisk) {
                        if (modloadonly("drv", "ramdisk") < 0)
                                return (-1);
                }
                proplen = BOP_GETPROPLEN(bootops, BP_ISCSI_NETWORK_BOOTPATH);
                if (proplen > 0) {
                        if (BOP_GETPROP(bootops, BP_ISCSI_NETWORK_BOOTPATH,
                            iscsi_network_path) > 0) {
                                p = strchr(iscsi_network_path, ':');
                                if (p != NULL) {
                                        *p = '\0';
                                }
                                pathcopy = i_ddi_strdup(iscsi_network_path,
                                    KM_SLEEP);
                                pathcopy_len = strlen(pathcopy) + 1;
                        } else {
                                return (-1);
                        }
                } else {
                        return (-1);
                }
        } else {
#endif
                pathcopy = i_ddi_strdup(bootpath, KM_SLEEP);
                pathcopy_len = strlen(pathcopy) + 1;
#ifdef _OBP
        }
#endif
        dip = path_to_devinfo(pathcopy);

#if defined(__i386) || defined(__amd64)
        /*
         * i386 does not provide stub nodes for all boot devices,
         * but we should be able to find the node for the parent,
         * and the leaf of the boot path should be the driver name,
         * which we go ahead and load here.
         */
        if (dip == NULL) {
                char    *leaf;

                /*
                 * Find last slash to build the full path to the
                 * parent of the leaf boot device
                 */
                p = strrchr(pathcopy, '/');
                *p++ = 0;

                /*
                 * Now isolate the driver name of the leaf device
                 */
                leaf = p;
                p = strchr(leaf, '@');
                *p = 0;

                BMDPRINTF(("load_bootpath_drivers: parent=%s leaf=%s\n",
                    bootpath, leaf));

                dip = path_to_devinfo(pathcopy);
                if (leaf) {
                        rval = load_boot_driver(leaf, NULL);
                        if (rval == -1) {
                                kmem_free(pathcopy, pathcopy_len);
                                return (NULL);
                        }
                }
        }
#endif

        if (dip == NULL) {
                cmn_err(CE_WARN, "can't bind driver for boot path <%s>",
                    bootpath);
                kmem_free(pathcopy, pathcopy_len);
                return (NULL);
        }

        /*
         * Load IP over IB driver when netbooting over IB.
         * As per IB 1275 binding, IP over IB is represented as
         * service on the top of the HCA node. So, there is no
         * PROM node and generic framework cannot pre-load
         * IP over IB driver based on the bootpath. The following
         * code preloads IP over IB driver when doing netboot over
         * InfiniBand.
         */
        if (netboot_over_ib(bootpath) &&
            modloadonly("drv", "ibp") == -1) {
                cmn_err(CE_CONT, "ibp: cannot load platform driver\n");
                kmem_free(pathcopy, pathcopy_len);
                return (NULL);
        }

        /*
         * The PROM node for hubs have incomplete compatible
         * properties and therefore do not bind to the hubd driver.
         * As a result load_bootpath_drivers() loads the usb_mid driver
         * for hub nodes rather than the hubd driver. This causes
         * mountroot failures when booting off USB storage. To prevent
         * this, if we are booting via USB hubs, we preload the hubd driver.
         */
        if (strstr(bootpath, "/hub@") && modloadonly("drv", "hubd") == -1) {
                cmn_err(CE_WARN, "bootpath contains a USB hub, "
                    "but cannot load hubd driver");
        }

        /* get rid of minor node at end of copy (if not already done above) */
        p = strrchr(pathcopy, '/');
        if (p) {
                p = strchr(p, ':');
                if (p)
                        *p = 0;
        }

        rval = load_parent_drivers(dip, pathcopy);
        kmem_free(pathcopy, pathcopy_len);
        return (rval);
}




/*
 * Load drivers required for a platform
 * Since all hardware nodes should be available in the device
 * tree, walk the per-driver list and load the parents of
 * each node found. If not a hardware node, try to load it.
 * Pseudo nexus is already loaded.
 */
static int
load_boot_platform_modules(char *drv)
{
        major_t major;
        dev_info_t *dip;
        char    *drvname;
        int     rval = 0;

        if ((major = ddi_name_to_major(drv)) == DDI_MAJOR_T_NONE) {
                cmn_err(CE_CONT, "%s: no major number\n", drv);
                return (-1);
        }

        /*
         * resolve aliases
         */
        drvname = ddi_major_to_name(major);
        if ((major = ddi_name_to_major(drvname)) == DDI_MAJOR_T_NONE)
                return (-1);

#ifdef  DEBUG
        if (strcmp(drv, drvname) == 0) {
                BMDPRINTF(("load_boot_platform_modules: %s\n", drv));
        } else {
                BMDPRINTF(("load_boot_platform_modules: %s -> %s\n",
                    drv, drvname));
        }
#endif  /* DEBUG */

        dip = devnamesp[major].dn_head;
        if (dip == NULL) {
                /* pseudo node, not-enumerated, needs to be loaded */
                if (modloadonly("drv", drvname) == -1) {
                        cmn_err(CE_CONT, "%s: cannot load platform driver\n",
                            drvname);
                        rval = -1;
                }
        } else {
                while (dip) {
                        if (load_parent_drivers(dip, NULL) != 0)
                                rval = -1;
                        dip = ddi_get_next(dip);
                }
        }

        return (rval);
}


/*
 * i_find_node: Internal routine used by path_to_devinfo
 * to locate a given nodeid in the device tree.
 */
struct i_path_findnode {
        pnode_t nodeid;
        dev_info_t *dip;
};

static int
i_path_find_node(dev_info_t *dev, void *arg)
{
        struct i_path_findnode *f = (struct i_path_findnode *)arg;


        if (ddi_get_nodeid(dev) == (int)f->nodeid) {
                f->dip = dev;
                return (DDI_WALK_TERMINATE);
        }
        return (DDI_WALK_CONTINUE);
}

/*
 * Return the devinfo node to a boot device
 */
static dev_info_t *
path_to_devinfo(char *path)
{
        struct i_path_findnode fn;
        extern dev_info_t *top_devinfo;

        /*
         * Get the nodeid of the given pathname, if such a mapping exists.
         */
        fn.dip = NULL;
        fn.nodeid = prom_finddevice(path);
        if (fn.nodeid != OBP_BADNODE) {
                /*
                 * Find the nodeid in our copy of the device tree and return
                 * whatever name we used to bind this node to a driver.
                 */
                ddi_walk_devs(top_devinfo, i_path_find_node, (void *)(&fn));
        }

#ifdef  DEBUG
        /*
         * If we're bound to something other than the nodename,
         * note that in the message buffer and system log.
         */
        if (fn.dip) {
                char *p, *q;

                p = ddi_binding_name(fn.dip);
                q = ddi_node_name(fn.dip);
                if (p && q && (strcmp(p, q) != 0)) {
                        BMDPRINTF(("path_to_devinfo: %s bound to %s\n",
                            path, p));
                }
        }
#endif  /* DEBUG */

        return (fn.dip);
}

/*
 * This routine returns B_TRUE if the bootpath corresponds to
 * IP over IB driver.
 *
 * The format of the bootpath for the IP over IB looks like
 * /pci@1f,700000/pci@1/ib@0:port=1,pkey=8001,protocol=ip
 *
 * The minor node portion "port=1,pkey=8001,protocol=ip" represents
 * IP over IB driver.
 */
static boolean_t
netboot_over_ib(char *bootpath)
{

        char            *temp;
        boolean_t       ret = B_FALSE;
        pnode_t         node = prom_finddevice(bootpath);
        int             len;
        char            devicetype[OBP_MAXDRVNAME];

        /* Is this IB node ? */
        if (node == OBP_BADNODE || node == OBP_NONODE) {
                return (B_FALSE);
        }
        len = prom_getproplen(node, OBP_DEVICETYPE);
        if (len <= 1 || len >= OBP_MAXDRVNAME)
                return (B_FALSE);

        (void) prom_getprop(node, OBP_DEVICETYPE, (caddr_t)devicetype);

        if (strncmp("ib", devicetype, 2) == 0) {
                /* Check for proper IP over IB string */
                if ((temp = strstr(bootpath, ":port=")) != NULL) {
                        if ((temp = strstr(temp, ",pkey=")) != NULL)
                                if ((temp = strstr(temp,
                                    ",protocol=ip")) != NULL) {
                                        ret = B_TRUE;
                                }
                }
        }
        return (ret);
}

static boolean_t
netboot_over_iscsi(void)
{
        int proplen;
        boolean_t       ret = B_FALSE;
        char    bootpath[OBP_MAXPATHLEN];

        proplen = BOP_GETPROPLEN(bootops, BP_BOOTPATH);
        if (proplen > 0) {
                if (BOP_GETPROP(bootops, BP_BOOTPATH, bootpath) > 0) {
                        if (memcmp(bootpath, BP_ISCSI_DISK,
                            strlen(BP_ISCSI_DISK)) == 0) {
                                ret = B_TRUE;
                        }
                }
        }
        return (ret);
}